android development introduction chương 22 vandroid services
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22
Android Services
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Android Services
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onCreate
onStart
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Service Life Cycle
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1. void onCreate ()
2. void onStart (Intent intent)
3. void onDestroy ()
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Service Life Cycle
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Broadcast Receiver Lifecycle
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The system delivers a broadcast Intent to all interested broadcast receivers, which handle the Intent sequenally.
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Registering a Broadcast Receiver
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Broadcast Receiver Lifecycle
void onReceive (Context context, Intent broadcastMsg)
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Services, BroadcastReceivers and the AdroidManifest
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Services, BroadcastReceivers and the AdroidManifest
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android=" /> package="cis493.demos" android:versionCode="1" android:versionName="1.0.0">
<uses-sdk android:minSdkVersion="4"></uses-sdk>
<application android:icon="@drawable/icon" android:label="@string/app_name">
<activity android:name=".MyServiceDriver2">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<service android:name="MyService2" />
<receiver android:name="MyBroadcastReceiver">
<intent-filter>
<action android:name = "matos.action.GOSERVICE2" />
</intent-filter>
</receiver>
</application>
</manifest>
======
==
Types of Broadcasts
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1. Normal broadcasts(!Context.sendBroadcast+$""
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2. Ordered broadcasts(!Context.sendOrderedBroadcast+
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Useful Methods – The Driver
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Intent intentMyService = new Intent(this, MyService3.class);
Service myService = startService(intentMyService);
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IntentFilter mainFilter = new IntentFilter("matos.action.GOSERVICE3");
BroadcastReceiver receiver = new MyMainLocalReceiver();
registerReceiver(receiver, mainFilter);
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public void onReceive(Context localContext, Intent callerIntent)
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Useful Methods – The Service
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Intent myFilteredResponse = new Intent("matos.action.GOSERVICE3");
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Object msg = some user data goes here;
myFilteredResponse.putExtra("myServiceData", msg);
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sendBroadcast(myFilteredResponse);
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Useful Methods – The Driver (again)
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stopService(new Intent(intentMyService) );
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unregisterReceiver(receiver);
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Example 1. A very Simple Service
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package cis493.demos;
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public class ServiceDriver1 extends Ac7vity {
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Example 1. cont.
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
txtMsg = (TextView) findViewById(R.id.txtMsg);
intentMyService = new Intent(this, MyService1.class);
service = startService(intentMyService);
btnStopService = (Button) findViewById(R.id.btnStopService);
btnStopService.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
try {
stopService((intentMyService) );
txtMsg.setText("After stoping Service: \n" + service.getClassName());
} catch (Exception e) {
Toast.makeText(getApplicationContext(), e.getMessage(), 1).show();
}
}//onClick
});
}//onCreate
}
=:=:=:
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Example 1. cont.
//non CPU intensive service running the main task in its main thread
package cis493.demos;
import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.util.Log;
public class MyService1 extends Service {
@Override
public IBinder onBind(Intent arg0) {
return null;
}
@Override
public void onCreate() {
super.onCreate();
Log.i ("<<MyService1-onStart>>", "I am alive-1!");
}
@Override
public void onStart(Intent intent, int startId) {
super.onStart(intent, startId);
Log.i ("<<MyService1-onStart>>", "I did something very quickly");
}
@Override
public void onDestroy() {
super.onDestroy();
Log.i ("<<MyService1-onDestroy>>", "I am dead-1");
}
}//MyService1
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Example 1. cont.
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Example 1. cont. Manifest
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android=" /> package="cis493.demos"
android:versionCode="1"
android:versionName="1.0">
<application android:icon="@drawable/icon"
android:label="@string/app_name">
<activity android:name=".ServiceDriver1"
android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<service android:name=".MyService1"> </service>
</application>
<uses-sdk android:minSdkVersion="4" />
</manifest>
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Example 1. cont. Layout
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Example 2. A More Realis7c Ac7vity-Service Interac7on
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Example 2. Layout
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Example 2. Manifest
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// Application logic and its BroadcastReceiver in the same class
package cis493.demos;
import java.util.Date;
import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.os.SystemClock;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.*;
public class MyServiceDriver3 extends Activity {
TextView txtMsg;
Button btnStopService;
ComponentName service;
Intent intentMyService;
BroadcastReceiver receiver;
Example 2. Main Ac7vity
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
txtMsg = (TextView) findViewById(R.id.txtMsg);
intentMyService = new Intent(this, MyService3.class);
service = startService(intentMyService);
txtMsg.setText("MyService3 started - (see DDMS Log)");
btnStopService = (Button) findViewById(R.id.btnStopService);
btnStopService.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
try {
stopService(new Intent(intentMyService) );
txtMsg.setText("After stoping Service: \n" +
service.getClassName());
} catch (Exception e) {
e.printStackTrace();
}
}
});
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Example 2. Main Ac7vity
