IntentService的優點

IntentService會創建單獨的線程處理所有的Intent請求，

會處理onHandleIntent方法實現的代碼，

隱藏開發者無須處理多線程問題，

當所有請求處理完成后，IntentService會自動停止

Action的使用

Action其實就是一個字符串，可以起到一個標識的作用

BroadcastReceiver的使用

BroadcastReceiver本質是一個監聽器，有自己的進程

重寫onReceive方法即可，但是在該方法里面不要執行耗時的操作，否則會ANR

發送

創建Intent

設置Action

putExtra

send發送

接收

實現onReceive方法

在AndroidManifest內增加配置

BroadcastReceiver

其他

開機自動運行的Service

第一步

動態注冊廣播

broadcastReceiver = new MyReceiver();

IntentFilter intentFilter = new IntentFilter();

intentFilter.addAction("com.example.space.text2.action.MSGTEXT");

//這個Action的作用是當發送為該Action的廣播時，

該MyReceiver類的onReceive方法將會接收到并處理

registerReceiver(broadcastReceiver,intentFilter);

第二步

在Activity中添加一個UI組件，比如按鈕

為按鈕添加監聽器

在該監聽器內啟動IntentService

Intent intent = new Intent(FinsihActivity.this,TextIntentService.class);

intent.setAction("com.example.space.text2.action.MSGFINSIH");

//設置該Action以便IntentService接收到Intent，

判斷是哪個Action,如果是這個Action話，就進行相應處理

intent.putExtra("finish","這是finishactivity發送的消息");

FinsihActivity.this.startService(intent);

第三步

添加一個IntentService.java類，可以使用Android Studio的自動生成

注釋掉沒有用的代碼

但是一定要保留protected void onHandleIntent(Intent intent) 和

public TextIntentService() {

super("TextIntentService");

}

方法

在protected void onHandleIntent(Intent intent) 方法中進行后臺任務的處理即可

protected void onHandleIntent(Intent intent) {

if (intent != null) {

final String action = intent.getAction();

if (ACTION_MSGFINSIH.equals(action)) {

String param1 = intent.getStringExtra("finish");

Intent intent1 = new Intent(ACTION_MSGTEXT);

//此處ACTION_MSGTEXT等于"com.example.space.text2.action.MSGTEXT"，

生成包含該Action的Intent后，就可以使用sendBroadcast發送廣播了，

之后自己定義的MyReceiver類的onReceive方法將會接收到并處理

intent1.putExtra("msg",param1+",IntentService收到并且廣播了出去");

sendBroadcast(intent1);

}

}

}

第四步

在自己定義的MyReceiver類的onReceive方法將會接收到并處理收到的intent

這個自己定義的MyReceiver類最好以內部類的形式寫在使用該廣播的Activity中，

這樣就可以使用該Activity的UI組件了，

即可實現把后臺服務進程中的數據更新在UI線程中的UI組件中

//內部類

public class MyReceiver extends BroadcastReceiver {

@Override

public void onReceive(Context context, Intent intent) {

// TODO: This method is called when the BroadcastReceiver is receiving

// an Intent broadcast.

Toast.makeText(getApplicationContext(), intent.getStringExtra("msg"),

Toast.LENGTH_SHORT).show();

//throw new UnsupportedOperationException("Not yet implemented");

//注意，該句是自動生成的，

一定要注釋掉，否則程序會崩潰重啟，

無法顯示出后臺服務通過廣播改變前臺UI的效果

}

}

完整代碼

第一個是Activity

public class FinsihActivity extends AppCompatActivity {

BroadcastReceiver broadcastReceiver;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_finsih);

//第一步：注冊廣播，綁定廣播和action

try

{

broadcastReceiver = new MyReceiver();

IntentFilter intentFilter = new IntentFilter();

intentFilter.addAction("com.example.space.text2.action.MSGTEXT");

registerReceiver(broadcastReceiver,intentFilter);

Log.i("mss","registerReceiver(broadcastReceiver,intentFilter);");

}

catch (ParcelFormatException e)

{

Log.i("mss","catch");

}

Button button = (Button)super.findViewById(R.id.button2);

button.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View view) {

//第二步：開始IntentService

try

{

Intent intent = new Intent(FinsihActivity.this,TextIntentService.class);

Log.i("mss","Intent intent = new Intent(FinsihActivity.this,TextIntentService.class)");

intent.setAction("com.example.space.text2.action.MSGFINSIH");

intent.putExtra("finish","這是finishactivity發送的消息");

FinsihActivity.this.startService(intent);

Log.i("mss","FinsihActivity.this.startService(intent);");

Toast.makeText(getApplicationContext(), "startService(intent)", Toast.LENGTH_SHORT).show();

}

catch(ParcelFormatException e)

{

Log.i("mss","catch");

}

}

});

}

//內部類

public class MyReceiver extends BroadcastReceiver {

@Override

public void onReceive(Context context, Intent intent) {

// TODO: This method is called when the BroadcastReceiver is receiving

// an Intent broadcast.

//

Toast.makeText(getApplicationContext(), intent.getStringExtra("msg"), Toast.LENGTH_SHORT).show();

// TextView textView = (TextView)FinsihActivity.super.findViewById(R.id.textView13);

// textView.setText(""+intent.getStringExtra("msg"));

//throw new UnsupportedOperationException("Not yet implemented");

}

}

}

第二個是IntentService

public class TextIntentService extends IntentService {

// TODO: Rename actions, choose action names that describe tasks that this

// IntentService can perform, e.g. ACTION_FETCH_NEW_ITEMS

private static final String ACTION_MSGTEXT = "com.example.space.text2.action.MSGTEXT";

private static final String ACTION_MSGFINSIH = "com.example.space.text2.action.MSGFINSIH";

private static final String ACTION_BAZ = "com.example.space.text2.action.BAZ";

// TODO: Rename parameters

public TextIntentService() {

super("TextIntentService");

}

// /**

// * Starts this service to perform action Foo with the given parameters. If

// * the service is already performing a task this action will be queued.

// *

// * @see IntentService

// */

// // TODO: Customize helper method

// public static void startActionFoo(Context context, String param1, String param2) {

// Intent intent = new Intent(context, TextIntentService.class);

// intent.setAction(ACTION_MSGTEXT);

// intent.putExtra(EXTRA_PARAM1, param1);

// intent.putExtra(EXTRA_PARAM2, param2);

// context.startService(intent);

// }

//

// /**

// * Starts this service to perform action Baz with the given parameters. If

// * the service is already performing a task this action will be queued.

// *

// * @see IntentService

// */

// // TODO: Customize helper method

// public static void startActionBaz(Context context, String param1, String param2) {

// Intent intent = new Intent(context, TextIntentService.class);

// intent.setAction(ACTION_BAZ);

// intent.putExtra(EXTRA_PARAM1, param1);

// intent.putExtra(EXTRA_PARAM2, param2);

// context.startService(intent);

// }

@Override

protected void onHandleIntent(Intent intent) {

Log.i("mss","onHandleIntent");

if (intent != null) {

final String action = intent.getAction();

if (ACTION_MSGFINSIH.equals(action)) {

Log.i("mss","ACTION_MSGFINSIH.equals(action)");

String param1 = intent.getStringExtra("finish");

Log.i("mss","intent.getStringExtra(\"finish\") = "+param1);

Intent intent1 = new Intent(ACTION_MSGTEXT);

Log.i("mss","Intent intent1 = new Intent(ACTION_MSGTEXT);");

Log.i("mss",ACTION_MSGTEXT);

intent1.putExtra("msg",param1+",IntentService收到并且廣播了出去");

Log.i("mss","intent1.putExtra(\"msg\",param1+\",IntentService收到并且廣播了出去\");");

sendBroadcast(intent1);

Log.i("mss","super.sendBroadcast(intent1);");

}

}

}

// /**

// * Handle action Foo in the provided background thread with the provided

// * parameters.

// */

// private void handleActionFoo(String param1, String param2) {

// // TODO: Handle action Foo

// throw new UnsupportedOperationException("Not yet implemented");

// }

// private void handleActionFinish(String param1, String param2) {

// // TODO: Handle action Foo

// throw new UnsupportedOperationException("Not yet implemented");

// }

// /**

// * Handle action Baz in the provided background thread with the provided

// * parameters.

// */

// private void handleActionBaz(String param1, String param2) {

// // TODO: Handle action Baz

// throw new UnsupportedOperationException("Not yet implemented");

// }

}

第三個是AndroidManifest

android:name=".TextIntentService"

android:exported="false">

其中exported="false"的意思是防止其他應用訪問該Service

總結

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