1 Mobile Computing DataBase and Content Providers Copyright 2014 by Janson Industries EC AssgAssg

1

Mobile ComputingDataBase and Content Providers

Copyright 2014 by Janson Industries

EC AssgAssg

Copyright 2014 by Janson Industries2

Objectives▀ Explain

SQLite

Data Encapsulation

Content providers

Permissions


▀ DataBase Management System that comes with Android

▀ A database consists of many tables

▀ Tables hold data

In rows/columns (records/fields)

SQLite


▀ To create and manipulate databases and tables, use:

Standard SQL commands

Specialized Android object’s►SQLiteDatabase►SQLiteOpenHelper►Cursor►ContentValues

SQLite


SQLite▀ Will create a To Do List

application

▀ Will allow To Do List items to be entered, displayed, and edited

▀ Will use the Contacts content provider that comes with Android to provide responsible names

More on this a little later


To Do List▀ Will display an initial screen that allows

user to select the function to be performed Insert a to do list item Display a to do list item End to do list app

▀ If insert, user specifies Priority (1,2,3) To do item text Due date Responsible person




To Do List▀ If display

Will display all items text

If user clicks on a item’s text, an edit screen with all the item info will be displayed

▀ Will also display a toast with a success message after inserts and updates



Displays all the item info and allow changes


To Do List

▀ Create a new Android 2.2 project called DBProj

App called ToDoList

Package is my.tdl.com

Activity is Main, layout is main


To Do List Change Main.java to be an Activity not ActionBarActivity

In manifest, change the application theme

: : : : : : : android:theme="@android:style/Theme.Black"

: : : : : : :

//import android.support.v7.app.ActionBarActivity;import android.app.Activity;

: : : : :public class Main extends Activity {


<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" ><TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="Choose the function to perform" android:textSize="35sp" /> <CheckBox android:id="@+id/insertCB" android:text="Insert"

android:onClick="clickHandler" android:layout_width="wrap_content"android:layout_height="wrap_content" android:textSize="25sp"/>

<CheckBox android:id="@+id/displayCB" android:text="Display"android:onClick="clickHandler" android:layout_width="wrap_content"android:layout_height="wrap_content" android:textSize="25sp"/>

<CheckBox android:id="@+id/finishedCB" android:text="End App"android:onClick="clickHandler" android:layout_width="wrap_content"android:layout_height="wrap_content" android:textSize="25sp"/>

</LinearLayout>

14

main.xml


Test by running in emulator


To Do List▀ When insert clicked, the

Specify To Do List Task screen will be displayed to collect the info

▀ When Insert button clicked A row with the info will be inserted

into a table named task

The Insert/Display/End App screen redisplayed



<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" >

<TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_horizontal" android:gravity="center_vertical" android:text="Specify a To Do List Task" android:textSize="20sp" />

<LinearLayout android:layout_width="wrap_content" android:layout_height="wrap_content" android:orientation="horizontal" >

<TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_vertical" android:gravity="center_vertical" android:text="Enter the task " android:textSize="15sp" />

<EditText android:id="@+id/task" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_gravity="center" android:text="" android:width="300px"/></LinearLayout>


<TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_vertical" android:text="Enter a priority of 1, 2, or 3 " android:textSize="15sp"/>

<EditText android:id="@+id/priority" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center" android:text=" " /></LinearLayout>


<TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_vertical" android:gravity="center_vertical" android:text="Enter a due date as YYYY/MM/DD " android:textSize="15sp"/>

<EditText android:id="@+id/DueDate" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_gravity="center" android:text="" android:width="150px" /></LinearLayout>

<Button android:id="@+id/insert" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Insert" android:onClick="onClick" android:layout_gravity="center_horizontal"/></LinearLayout>

18

insert.xml


Insert and Display Stubspackage my.tdl.com;import android.app.Activity;import android.os.Bundle; public class Insert extends Activity { public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.insert); }}

package my.tdl.com;import android.app.Activity;import android.os.Bundle;

public class Display extends Activity {public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);}

}


Mainpackage my.tdl.com;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.view.View;import android.widget.CheckBox;import android.widget.TextView;

public class Main extends Activity {Intent intent;String actionName;@Override

public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); } protected void onResume() { super.onResume();

CheckBox icb = (CheckBox) findViewById(R.id.insertCB);CheckBox dcb = (CheckBox) findViewById(R.id.displayCB);

/** Erases any checks in the check boxes. */icb.setChecked(false);dcb.setChecked(false);

}


Main public void clickHandler(View target) { switch(target.getId()) { case R.id.insertCB:

actionName = "my.tdl.com.Insert";intent = new Intent(actionName);

startActivity(intent); break; case R.id.displayCB:

actionName = "my.tdl.com.Display";intent = new Intent(actionName);

startActivity(intent); break; case R.id.finishedCB: finish(); break; } } }


Manifest<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="my.tdl.com" android:versionCode="1" android:versionName="1.0" >

<uses-sdk android:minSdkVersion="8" android:targetSdkVersion="21" />

<application android:allowBackup="true" android:icon="@drawable/ic_launcher" android:label="@string/app_name" android:theme="@android:style/Theme.Black" > <activity android:name=".Main" android:label="@string/app_name"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity>


Manifest

<activity android:name="Insert" android:label="Insert To Do List Task"android:theme="@android:style/Theme.Black"><intent-filter> <action android:name="my.tdl.com.Insert" />

<category android:name="android.intent.category.DEFAULT" /></intent-filter>

</activity>

<activity android:name="Display" android:label="Display To Do List Tasks"android:theme="@android:style/Theme.Black"><intent-filter>

<action android:name="my.tdl.com.Display" /><category android:name="android.intent.category.DEFAULT" />

</intent-filter></activity></application></manifest>

Activity definitions for Insert and Display


To Do List

▀ Run the program

▀ Click Insert check box

▀ Make sure the Insert screen is displayed



SQLite▀ Need to create the ToDoList data

base and the tasks table

▀ The structure of the tasks table is: _id INTEGER PRIMARY KEY

Task TEXT

Priority TEXT

CreatedDate TEXT

DueDate TEXT

Responsible TEXT


SQLite▀ Need a java program to create

the DB

A folder called databases will be created in data/data/my.tdl.com on the device/emulator

The DB will be stored in the databases folder

▀ After created, can see the DB in the DDMS perspective


SQLite▀ To create DB, create Java class

(ToDoListDBHelper) as a subclass of SQLiteOpenHelper

It’s constructor will call SQLiteOpenHelper’s constructor

If the DB doesn’t exist, SQLiteOpenHelper’s constructor will call it’s own onCreate method

►onCreate will create the DB


SQLite▀ SQLiteOpenHelper does all the

"heavy lifting"

No only creates the DB, will provide a "writable" version of the DB for our app to use

▀ ToDoListDBHelper must code an onUpgrade method


ToDoListDBHelperpackage my.tdl.com;

import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteOpenHelper;

public class ToDoListDBHelper extends SQLiteOpenHelper {

// Variables to hold metadata about the DB and task table protected static final String DATABASE_NAME = "ToDoList";protected static final int DATABASE_VERSION = 1;protected final static String TASK_FN = "Task";protected final static String PRI_FN = "Priority";protected final static String CREATE_FN = "CreatedDate";protected final static String DUE_FN = "DueDate";protected final static String RESP_FN = "Responsible";protected final static String COMP_FN = "CompletionDate";


ToDoListDBHelper

// This SQL statement that will create the table private static final String TABLE_CREATE =

"create table TasksTable (" +"_id integer primary key autoincrement, " +

TASK_FN + " text, " + PRI_FN + " text, " + CREATE_FN + " text, " + DUE_FN + " text, " + RESP_FN + " text, " + COMP_FN + " text);";


ToDoListDBHelperpublic ToDoListDBHelper(Context context) {

// Creates the databasesuper(context, DATABASE_NAME, null, DATABASE_VERSION);

}

public void onCreate(SQLiteDatabase db) {

// Creates the tasks tabledb.execSQL(TABLE_CREATE);

}

public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

}

}

Copyright 2014 by Janson Industries 35

Encapsulation Many terms used to describe:

Transparency

Information hiding

Implementation ignorance

Programmers have an “interface” to an object with no idea of how it works


Encapsulation For example, driving a car

Someone knows how to drive: Turn the key Step on gas pedal Steer Step on brake pedal

The driver doesn’t have to know how the car works or any of its internal components


Encapsulation Many methods and data are

hidden from the user/ application

Changes to the class (variables and methods) do not affect users of the class

Data accessible only through publicly defined methods


Data Encapsulation

DATA

Getters

SettersRules

Constructors


Encapsulation If programmers can’t directly

access the data, their applications are less likely to screw it up!!

PUBLIC methods comprise the interface

PRIVATE methods for internal functions and non-user fields


How to Encapsulate a File Define a class for the file (ex.

TasksTable)

In the class, define private variables for each field in the file

For each private variable: Define a getter method Define a setter with validation

functions

Define CRUD functions


How to Encapsulate a File Define unique functions to return

data

All tasks for a particular person

All tasks for a certain priority

Define business functions

Number of tasks closed by day

Number of tasks opened by day


Define a private variable for each field

42

TasksTable

private int ID;private String Task;private String Priority;private String CreatedDate;private String DueDate;private String Responsible;private String CompletionDate;


TasksTable

public int getID() { return ID; }public void setID(int iD) { ID = iD; } // Need for updatespublic String getTask() { return Task; }public void setTask(String task) { Task = task; }public String getPriority() { return Priority; }public void setPriority(String priority) { Priority = priority;}public String getCreatedDate() { return CreatedDate; }public void setCreatedDate(String createdDate) {

CreatedDate = createdDate;}public String getDueDate() { return DueDate; }public void setDueDate(String dueDate) { DueDate = dueDate;}public String getResponsible() { return Responsible; }public void setResponsible(String responsible) {

Responsible = responsible;}public String getCompletionDate() {return CompletionDate; }public void setCompletionDate(String completionDate) {

CompletionDate = completionDate; }

Define getters and setters


Create pretty easy, plus it creates the helper class that…

…supplies the ToDoList DB (a SQLite DB) that we will read and write to

44

CRUD Functions

public TasksTable(Context ctx) {this.context = ctx;DBHelper = new ToDoListDBHelper(context);this.open();

}

public TasksTable open() throws SQLException { db = DBHelper.getWritableDatabase(); return this;}


CRUD Functions

public long insert() { values.put(TASK_FN, getTask()); values.put(PRI_FN, getPriority()); values.put(CREATE_FN, getCreatedDate()); values.put(DUE_FN, getDueDate()); values.put(RESP_FN, getResponsible()); values.put(COMP_FN, getCompletionDate()); return db.insert(DATABASE_TABLE, null, values);}

Insert and Update require a ContentValues object It holds the data to be inserted

Each data paired with the field name that will hold the data


Need some import statements

Also need some other variables

Let’s test

46

CRUD Functions

private SQLiteDatabase db;private Context context; private ToDoListDBHelper DBHelper;private ContentValues values = new ContentValues();private final String DATABASE_TABLE = "TasksTable";protected final String ID_FN = "ID";protected final String TASK_FN = "Task";protected final String PRI_FN = "Priority";protected final String CREATE_FN = "CreatedDate";protected final String DUE_FN = "DueDate";protected final String RESP_FN = "Responsible";protected final String COMP_FN = "CompletionDate";

package my.tdl.com;import android.content.ContentValues;import android.content.Context;import android.database.SQLException;import android.database.sqlite.SQLiteDatabase;


Time to test

Prove the insert works: Switch to the DDMS perspective

Click on emulator

Expand data/data

Scroll down and expand my.tdl.com No databases folder

47

To Do List


No databases folder, just lib


Need to display Insert screen

When Insert button pressed need a java activity (insert) to: Read screen data

Create TasksTable object

Set the TasksTable object’s task, priority, and due date properties

Insert the data into the table

Display a success msg49

Insert


package my.tdl.com;

import android.app.Activity;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.EditText;import android.widget.Toast;

public class Insert extends Activity implements OnClickListener {TasksTable tt;EditText taskET, priorityET, dueDateET;long insertResult;

public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.insert); taskET = (EditText) findViewById(R.id.task); // get priorityET = (EditText) findViewById(R.id.priority); // GUI dueDateET = (EditText) findViewById(R.id.DueDate); // fields Button insertBtn = (Button) findViewById(R.id.insert); insertBtn.setOnClickListener(this); // add listener to button tt = new TasksTable(this); // create TasksTable object }

50

Insert


Insertpublic void onClick(View target) {

// Set TasksTable properties tt.setTask(taskET.getText().toString()); tt.setPriority(priorityET.getText().toString()); tt.setDueDate(dueDateET.getText().toString());

// Insert the data insertResult = tt.insert();

// Build msg and display it in a toastString text = "The task '" + tt.getTask() +

" was added successfully! Return code was " + insertResult;int duration = Toast.LENGTH_LONG;Toast toast = Toast.makeText(this, text, duration);toast.show();

}}



Proof that it worked


Need to return to the main menu after insert

After the toast is shown add finish();

For the example, I added a couple of other tasks

To Do List


Allows you to download the DB

Select the DB and click the Pull a file from the device button

DDMS Perspecitive



Then specify where to store it


SQLite browser lets you access and manipulate the DB


http://web.fscj.edu/Janson/CIS2930

Download SQLite browser, unzip, run the exe file


File, Open Database, specify ToDoListThen click Browse Data, select TasksTable


Need a display function

Will display all tasks text

When a task is clicked, will allow user to update all the task info

To Do List


Display all the tasks


Display all task info and allow changes


Going to need:

Read and update functions in TasksTable

Two new screen definitions display.xml edit.xml

Change Display.java to React to a click on a task Retrieve that tasks info from DB Invoke TaskEdit and pass DB info via

the bundle

To Do List


Create TaskEdit.java to

Display the task info

Update the task

Display a confirmation of the update

Return back to the main menu

Add TaskEdit activity to manifest

To Do List


Update works similarly to insert

Uses a ContentValues object to hold data

Uses the writable ToDoList db object (provided by ToDoListDBHelper)

New requirement: must identify the row to be updated

TasksTable Update


Going to execute an SQL Select statement

Will use the writable db object’s rawQuery method to perform the Select statement

Returns the results in a Cursor object Essentially a table with rows and

columns

TasksTable Read


TasksTableimport android.database.Cursor; : : : : :

public long update() { values.put(TASK_FN, getTask()); values.put(PRI_FN, getPriority()); values.put(CREATE_FN, getCreatedDate()); values.put(DUE_FN, getDueDate()); values.put(RESP_FN, getResponsible()); values.put(COMP_FN, getCompletionDate()); return db.update(DATABASE_TABLE, values, "_id = " + getID(), null ); }

public Cursor read() { return db.rawQuery("SELECT * FROM TasksTable ", null); }


display.xml Create a ListView object called

list (holds list of scrollable items)

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:orientation="vertical" android:layout_width="fill_parent"android:layout_height="fill_parent"><ListView android:id="@+id/android:list"

android:layout_width="wrap_content"android:layout_height="wrap_content" />

<TextView android:id="@+id/taskTV" android:layout_width="wrap_content"

android:layout_height="wrap_content"android:textSize="30sp" />

</LinearLayout>


edit.xml Initial LinearLayout and Textview

Followed by a series of horizontal LinearLayouts with components

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:orientation="vertical" android:layout_width="fill_parent"android:layout_height="fill_parent"><TextView android:layout_width="wrap_content"

android:layout_height="wrap_content" android:textSize="18sp"

android:text="" android:gravity="center_vertical"android:layout_gravity="center_horizontal" />


<LinearLayout android:layout_width="wrap_content" android:layout_height="wrap_content"android:orientation="horizontal"><TextView android:layout_width="wrap_content"

android:layout_height="wrap_content" android:text="Change the task "

android:gravity="center_vertical" android:layout_gravity="center_vertical"

android:textSize="15sp" /><EditText android:id="@+id/taskET" android:text=""

android:layout_height="wrap_content" android:layout_width="fill_parent"android:layout_gravity="center" android:width="300px">

</EditText></LinearLayout>

For each db field will have text and an entry field


<LinearLayout android:orientation="horizontal" android:layout_width="wrap_content"android:layout_height="wrap_content"><TextView android:layout_width="wrap_content"

android:layout_height="wrap_content"android:textSize="15sp"

android:text="Change the priority (1, 2, or 3) "android:layout_gravity="center_vertical" />

<EditText android:id="@+id/priorityET" android:layout_width="wrap_content"

android:layout_gravity="center" android:text=" "android:layout_height="wrap_content"></EditText>

</LinearLayout><LinearLayout android:layout_width="wrap_content"

android:layout_height="wrap_content"android:orientation="horizontal"><TextView android:layout_width="wrap_content"

android:layout_height="wrap_content" android:text="Change created date (YYYY/MM/DD) "android:gravity="center_vertical"

android:layout_gravity="center_vertical"android:textSize="15sp" />

<EditText android:id="@+id/createdDateET" android:text=""android:layout_height="wrap_content"

android:layout_width="fill_parent"android:layout_gravity="center"

android:width="150px"></EditText></LinearLayout>



android:layout_height="wrap_content" android:text="Change due date (YYYY/MM/DD) "android:gravity="center_vertical" android:layout_gravity="center_vertical"android:textSize="15sp" />

<EditText android:id="@+id/dueDateET" android:text=""android:layout_height="wrap_content" android:layout_width="fill_parent"android:layout_gravity="center" android:width="150px"></EditText>

</LinearLayout><LinearLayout android:layout_width="wrap_content"

android:layout_height="wrap_content"android:orientation="horizontal"><TextView android:layout_width="wrap_content"

android:layout_height="wrap_content" android:text="Change/enter person assigned "android:gravity="center_vertical" android:layout_gravity="center_vertical"android:textSize="15sp" />

<EditText android:id="@+id/respET" android:text=""android:layout_height="wrap_content" android:layout_width="fill_parent"android:layout_gravity="center" android:width="150px"></EditText>

</LinearLayout>

edit.xml



android:layout_height="wrap_content" android:text="Change/enter finished date (YYYY/MM/DD) "android:gravity="center_vertical" android:layout_gravity="center_vertical" android:textSize="15sp"/>

<EditText android:id="@+id/compDateET" android:text=""android:layout_height="wrap_content" android:layout_width="fill_parent"android:layout_gravity="center" android:width="150px"></EditText>

</LinearLayout>

<Button android:id="@+id/update" android:layout_width="wrap_content"android:layout_height="wrap_content" android:text="Update"android:onClick="onClick" android:layout_gravity="center_horizontal" />

</LinearLayout>

edit.xml


Has to invoke TransTable’s read method

Read returns a Cursor object

Should make sure cursor is managed, startManagingCursor

i.e. Cursor automatically deleted when activity is finished

Display.java


To move between records/rows and retrieve field data, use Cursor methods

To retrieve a field must know the column/field number

Will use a SimpleCursorAdapter to populate the list view

Adapters are classes that make managing list views way easier

Display.java


Requires

The layout be identified

The Cursor object with the data

In a String array (we’ll call it from), the field(s) in the cursor object that are to be retrieved

In an int array (we’ll call it to), the project ids of the GUI component(s) that will display the retrieved data

SimpleCursorAdapter


package my.tdl.com;

import android.app.Activity;import android.app.ListActivity;import android.widget.SimpleCursorAdapter;import android.content.Intent;import android.database.Cursor;import android.os.Bundle;import android.view.View;import android.widget.EditText;import android.widget.ListView;import android.widget.TextView;

public class Display extends ListActivity {// Various variables needed to display the list of tasksTextView taskTV;TasksTable tt;Cursor c;SimpleCursorAdapter taskAdapter;String[] from;int[] to;

Change Display.java


onCreate will show the current tasks

79

public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.display); // Display the list view from = new String[]{"Task"}; // Identify the task field as the source of data to = new int[]{R.id.taskTV}; // Identify taskTV as the target of the data tt = new TasksTable(this); // Create TasksTable object c = tt.read(); // Invoke the read method and store in c startManagingCursor(c); // Let system manage the c

// Create the SimpleCursorAdapter object taskAdapter = new SimpleCursorAdapter(this, R.layout.display, c, from, to); setListAdapter(taskAdapter); // Binds adapter to the listview in display layout }

Display.java


onListItemClick is passed both

The location in the list that was clicked

The associated DB record/row id for the clicked item

To read data must first position to the correct row with cursor’s moveToPosition method

c.moveToPosition(rowid);80

Display


Then for each field in the row, retrieve the column # with the cursor’s getColumnIndexOrThrow method

int colNum = c. getColumnIndexOrThrow(“fld_name”)

Lastly retrieve the field data with the getString method passing the column number

c.getString(colNum)

81

Display


Will create a TaskEdit intent and pass the DB data via the intent’s bundle

Mentioned a while ago that bundles used to pass info between activities

Today’s the day we do it

82

Display


Like the ContentValues object, bundle holds paired data

In this case, the name of the DB field and the value of the field

To write to the bundle use the intents putExtra method

83

Display


protected void onListItemClick(ListView l, View v, int position, long id) { super.onListItemClick(l, v, position, id);

c.moveToPosition(position); //Position to correct row in cursor Intent i = new Intent(this, TaskEdit.class); //Create the edit intent i.putExtra("_id", id); //Populate the bundle with the task info

//Pass the field name to get the column number, which is used in getString to retrieve //the data from the cursor then the field name and data are written to the bundle i.putExtra(ToDoListDBHelper.TASK_FN, c.getString( c.getColumnIndexOrThrow(ToDoListDBHelper.TASK_FN))); i.putExtra(ToDoListDBHelper.PRI_FN, c.getString( c.getColumnIndexOrThrow(ToDoListDBHelper.PRI_FN))); i.putExtra(ToDoListDBHelper.CREATE_FN, c.getString( c.getColumnIndexOrThrow(ToDoListDBHelper.CREATE_FN))); i.putExtra(ToDoListDBHelper.DUE_FN, c.getString( c.getColumnIndexOrThrow(ToDoListDBHelper.DUE_FN))); i.putExtra(ToDoListDBHelper.RESP_FN, c.getString( c.getColumnIndexOrThrow(ToDoListDBHelper.RESP_FN))); i.putExtra(ToDoListDBHelper.COMP_FN, c.getString( c.getColumnIndexOrThrow(ToDoListDBHelper.COMP_FN))); startActivity(i); //Start the edit task finish(); //End the display task }}

Display.java


package my.tdl.com;

import android.app.Activity;import android.os.Bundle;import android.view.View;import android.widget.Button;import android.widget.EditText;import android.widget.Toast;

public class TaskEdit extends Activity {EditText taskET, priorityET, createdDateET, dueDateET, respET, compDateET;Button updateBtn;long _id;String task, priority, createdDate, dueDate, responsible, completionDate;Bundle extras;TasksTable tt;

TaskEdit Create various variables needed

to display and edit task info


protected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.edit);

// Retrieve visual components used to display info

taskET = (EditText) findViewById(R.id.taskET);priorityET = (EditText) findViewById(R.id.priorityET);createdDateET = (EditText) findViewById(R.id.createdDateET);dueDateET = (EditText) findViewById(R.id.dueDateET);respET = (EditText) findViewById(R.id.respET);compDateET = (EditText) findViewById(R.id.compDateET);

// Retrieve the button and the bundle

updateBtn = (Button) findViewById(R.id.update);extras = getIntent().getExtras();

TaskEdit


// Get data from bundle and assign to string variables

_id = extras.getLong("_id");task = extras.getString(ToDoListDBHelper.TASK_FN);priority = extras.getString(ToDoListDBHelper.PRI_FN);createdDate = extras.getString(ToDoListDBHelper.CREATE_FN);dueDate = extras.getString(ToDoListDBHelper.DUE_FN);responsible = extras.getString(ToDoListDBHelper.RESP_FN);completionDate = extras.getString(ToDoListDBHelper.COMP_FN);

// Put task data into edit text components

taskET.setText(task);priorityET.setText(priority);createdDateET.setText(createdDate);dueDateET.setText(dueDate);respET.setText(responsible);compDateET.setText(completionDate);

}

TaskEdit


public void onClick(View view) {// Create new TasksTable objecttt = new TasksTable(this);

// Set TasksTable object’s properties to values entered by usertt.setID((int) _id);tt.setTask(taskET.getText().toString());tt.setPriority(priorityET.getText().toString());tt.setCreatedDate(createdDateET.getText().toString());tt.setDueDate(dueDateET.getText().toString());tt.setResponsible(respET.getText().toString());tt.setCompletionDate(compDateET.getText().toString());

// Invoke update and display a success msglong updateResult = tt.update();String text = "The task '" + tt.getTask()

+ "' was editted successfully! Return code was "+ updateResult;

int duration = Toast.LENGTH_LONG;Toast toast = Toast.makeText(this, text, duration);toast.show();finish(); //End task edit activity

}}

TaskEdit


Manifest Need to add a TaskEdit activity inside the application tags

Time to test

Run DBProj, click Display

<activity android:name="Display" android:label="Display To Do List Tasks" android:theme="@android:style/Theme.Black"> <intent-filter>

<action android:name="my.tdl.com.Display" /><category android:name="android.intent.category.DEFAULT" />

</intent-filter></activity><activity android:name="TaskEdit" android:label="Edit Task"

android:theme="@android:style/Theme.Black"></activity>


Click Test payroll program


Initial displayChange the text and add a created date


Click Update then display the task


Notice Test text changed and if you click on it…


… created date was saved and retrieved


Created DBProj such that items can be added and edited in the table

Assg


Basically, a formalized interface to an encapsulated database table

Allows multiple apps access to the stored data

Many already provide a user interface to insert, read, and update

Content Providers


Content Providers Lots of different ones:

Browser CallLog Contacts

People Phones Photos Groups

MediaStore Audio

Albums Artists Genres Playlists


On the Home screen, click the Phone icon


Click Menu button then New contact


Initial entry screen


Enter some info and click DoneA toast will be displayed saying info was saved


Click < button to go to contacts


For this example, will add a couple more contacts


Content Providers Have an API (application program

interface)

An API provides applications access to the content providers data

Lots of rules and objects to work with a content provider


Content Providers Identified by a URI called an authority

name content://com.compname.provider/

NotePads URI is: content://com.google.provider.NotePad/

Some native Android providers don’t have a fully qualified name For example, content://contacts


Content Providers To identify the underlying DB:

content://com.google.provider.NotePad/Notes

To identify a particular note : content://com.google.provider.NotePad/

Notes/14 Each added element is called a path

segment and is identified by a number (1, 2, 3, etc) So, the provider URI acts like a Web

domain name


Content Providers The Android SDK provides predefined

authority name URI variables

For example, instead of creating a URI and specifying this character string:

content://contacts/people/

You can use

Contacts.People.CONTENT_URI


Content Providers To insert, need ContentValues

and ContentResolver objects

ContentValues holds the data to be inserted (just like with SQLite)

Use the put method to identify the field and specify the value

ContentResolver does the insert

Returns the URI of the new row


Content Providers

To read:

Define/identify the URI

Run a managed query an inherited Activity method

Retrieve the data from the returned Cursor


Content Providers To read and display a contact:

import android.provider.Contacts;import android.net.Uri;import android.database.Cursor;import android.provider.Contacts.People; : : : : ://This identifies the second contactUri respPersonUri = Uri.withAppendedPath(Contacts.People.CONTENT_URI, "2");Cursor c = managedQuery(respPersonUri, null, null, null, null);c.moveToFirst();int nameColumnIndex = c.getColumnIndex(People.NAME);

//This is how to read the field and put the result in a String//String name = c.getString(nameColumnIndex);

// This is how to put the name into the responsible ET on the TaskEdit screenrespET.setText(c.getString(nameColumnIndex));


Security Android protects a mobile

device’s resources and features Camera, Contact info, Internet

access, Phone, etc.

Complete list at: http://developer.android.com/

reference/android/Manifest.permission.html

An app must have a permission request defined in the manifest file to access these items


Security Permissions are placed either

before or after the application tags like this:

When an app is installed permission is granted/denied

: :</application><uses-permission android:name="android.permission.CAMERA" /><uses-permission android:name="android.permission.READ_CONTACTS"/></manifest>


Content Providers

Must add permission for contacts

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android" package="my.tdl.com" android:versionCode="1" android:versionName="1.0"> <uses-sdk android:minSdkVersion="8" android:targetSdkVersion="21" /> <uses-permission android:name="android.permission.READ_CONTACTS"/> <application

android:icon="@drawable/ic_launcher" : : : : :



Content Providers Really what we should do is:

Add a “person responsible” spinner to the insert screen

Populate the spinner with all the contact people so user can just select one

Also, should set a created date when inserted


Content Providers New spinner with text for insert.xml

Don't forget the permission!

<LinearLayout android:layout_width="wrap_content" android:layout_height="wrap_content" android:orientation="horizontal"> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Assign the task to " android:gravity="center_vertical"

android:layout_gravity="center_vertical"android:textSize="15sp"/>

<Spinnerandroid:id="@+id/respSpinner"android:layout_width= "wrap_content"android:layout_height="wrap_content">

</Spinner></LinearLayout>


Content Providers In Insert.java

import android.widget.Spinner;import android.provider.Contacts.People;import android.widget.SimpleCursorAdapter;import android.database.Cursor;

: : : Spinner respSpinner; //Spinner variable for spinner to display contactsString[] from; //Array for field names to be retrieved from Cursorint[] to; //Array to hold GUI component(s) to display contactsCursor c; //Holds the retrieved contact info : : : respSpinner = (Spinner) findViewById(R.id.respSpinner); Cursor c = managedQuery(People.CONTENT_URI, null, null, null, People.NAME); //Query contactsfrom = new String[] {People.NAME}; //Specify the field to be retrievedto = new int[] {android.R.id.text1}; //Specify the text portion of the

//spinner as the target for nameSimpleCursorAdapter adapter = new SimpleCursorAdapter(this,

android.R.layout.simple_spinner_item, c, from, to); //create the adapter respSpinner.setAdapter(adapter); //assign the adapter to the spinner


Run and the spinner will be displayed


Click the drop down button and list is displayed


Date and Time Formatters A little complicated

First of all, you can get the current date by

Importing java.util.Date

Creating a date objectimport java.util.Date; : : : Date d = new Date();System.out.println(d);

Results in: Tue May 31 13:11:59 EDT 2011


DateFormat DateFormat class has predefined formats

To use a DateFormat:

Import DateFormat class

Get a DateFormat instance (getDateInstance) and specify the format to use

Create a date object

Passing the date object as a parameter, use date format object’s format method


Results in: Tue Mar 13 14:38:59 EDT 20143/13/14Mar 13, 2014March 13, 2014Tuesday, March 13, 2014 123

DateFormat import java.text.DateFormat; : : : :

Date d = new Date();DateFormat dfShort= DateFormat.getDateInstance(DateFormat.SHORT);DateFormat dfMed = DateFormat.getDateInstance(DateFormat.MEDIUM);DateFormat dfLong = DateFormat.getDateInstance(DateFormat.LONG);DateFormat dfFull = DateFormat.getDateInstance(DateFormat.FULL);System.out.println(d);System.out.println(dfShort.format(d));System.out.println(dfMed.format(d));System.out.println(dfLong.format(d));System.out.println(dfFull.format(d));


SimpleDateFormat Allows you to define a unique format

To use a SimpleDateFormat: Import SimpleDateFormat class Create a SimpleDateFormat object and

specify the format using date format symbols

y – year, s – seconds, a – (AM or PM) M – month, m – minute H – hour (0-23), h – hour (1-12) d – day of month (1-31), D – day of year z – time zone


Results: 05/31/201101:19 PM1 O'clock PM, Eastern Daylight Time151 125

SimpleDateFormatimport java.text.SimpleDateFormat; : : : :SimpleDateFormat sdf = new SimpleDateFormat("MM/dd/yyyy"); SimpleDateFormat stf = new SimpleDateFormat("hh:mm a");SimpleDateFormat st2f = new SimpleDateFormat("h 'O''clock' a, zzzz"); SimpleDateFormat sd2f = new SimpleDateFormat("D"); System.out.println(sdf.format(d));System.out.println(stf.format(d));System.out.println(st2f.format(d));System.out.println(sd2f.format(d));


Extra Credit Assg Finish Insert such that

The selected name in the spinner is read and inserted into the TasksTable

Add a created date text view and edit view

Put the current date in the edit view in YYYY/MM/DD format

Read the entered created date and insert it into TasksTable


When Insert selected, screen should look like this with current date


Adding this info and clicking Insert…


…means the update screen would look like this


Error You Will Get In a Year Error generating final archive:

Debug certificate expired on XXXX

Android requires that apps be signed

It uses a keystore file called debug.keystore to hold the keys

By default the keystore file is valid for 365 days


Error You Will Get In a Year Solution:

Navigate to the .android folder in your home directory

C:\Users\youruserid\.android

Delete the debug.keystore file

Go to eclipse and clean all your projects

This creates a new debug.keystore file which will be valid for 365 more days

Documents

1 Mobile Computing DataBase and Content Providers Copyright 2014 by Janson Industries EC AssgAssg