大家都知道，關於Android廣播事件的註冊有兩種方式。1：在程式碼中動態註冊；2：在Manifest中的靜態註冊。

本文主要討論怎麼取消  靜態註冊的廣播

經過查詢資料發現，可以利用PackageManager中的setComponentEnableSetting()這個函式來解決這個問題，對於setComponetEnableSetting()這個函式的描述在官方文件中如是說：

1. /**
    * Set the enabled setting for a package component (activity, receiver, service, provider).
    * This setting will override any enabled state which may have been set by the component in its
    
    * manifest.
    *
    * @param componentName The component to enable
    * @param newState The new enabled state for the component.  The legal values for this state
    *                 are:
    *                   {@link #COMPONENT_ENABLED_STATE_ENABLED},
    *                   {@link #COMPONENT_ENABLED_STATE_DISABLED}
    
    *                   and
    *                   {@link #COMPONENT_ENABLED_STATE_DEFAULT}
    *                 The last one removes the setting, thereby restoring the component's state to
    *                 whatever was set in it's manifest (or enabled, by default).
    * @param flags Optional behavior flags: {
    
   @link #DONT_KILL_APP} or 0.

第一個引數是一個ComponentName()物件，指定你要設定的元件的名字和所在的報名；
第二個引數newState這個引數來決定如何轉換；

第三個引數flags表示行為，有兩種不同的行為，如果設定為DONT_KILL_APP那麼在呼叫PackageManager.setComponentEnableSetting()設定Manifest.xml的時候就不至於殺死APP，反之就是0,這個時候你在設定就會出現閃退，因為這個時候已經把APP殺死了。

下面用一個例子來說明：

MainActivity.Java:

1. package com.example.testbroadcastreceiver;
   
   import android.app.AlarmManager;
   import android.app.PendingIntent;
   import android.content.ComponentName;
   import android.content.Intent;
   import android.content.pm.PackageManager;
   import android.os.Message;
   import android.support.v7.app.AppCompatActivity;
   import android.os.Bundle;
   import android.view.View;
   import android.widget.Button;
   
   import java.util.Timer;
   import java.util.TimerTask;
   
   public class MainActivity extends AppCompatActivity {
   
       private Button sendButton;
       private Button cancelButton;
       private Button resumeButton;
   
       @Override
   protected void onCreate(Bundle savedInstanceState) {
           super.onCreate(savedInstanceState);
           setContentView(R.layout.activity_main);
   
           sendButton = (Button) findViewById(R.id.sendButton);
           cancelButton = (Button) findViewById(R.id.cancelButton);
           resumeButton = (Button) findViewById(R.id.resumeButton);
       }
   
       TimerTask task = new TimerTask() {
           @Override
   public void run() {
               //建立Intent物件，action為ELITOR_CLOCK，”
   Intent intent = new Intent("ELITOR_CLOCK");
               intent.putExtra("msg", "time over!");
               sendBroadcast(intent);
           }
       };
   
       public void myOnclick(View view){
           switch (view.getId()){
               case R.id.sendButton:
                   Timer timer = new Timer();
                   timer.schedule( task , 1000, 9000);
                   break;
               case R.id.cancelButton:  //取消靜態註冊的廣播
   getPackageManager().setComponentEnabledSetting( new ComponentName("com.example.testbroadcastreceiver", MyBroadcastReceiver.class.getName()),
                           PackageManager.COMPONENT_ENABLED_STATE_DISABLED,
                           PackageManager.DONT_KILL_APP);
                   break;
               case R.id.resumeButton:
                   //這個地方因為當你點選 cancelButton 按鈕使靜態註冊的廣播disabled之後，下次進來的時候廣播就不能用了，相當於修改了Manifest中 靜態廣播註冊中的 android:enabled="false"，
                   //這個地方還原成default，也就是在Manifest中設定的預設值（android:enable="true"）
   getPackageManager().setComponentEnabledSetting( new ComponentName("com.example.testbroadcastreceiver" , MyBroadcastReceiver.class.getName()),
                   PackageManager.COMPONENT_ENABLED_STATE_DEFAULT,
                   PackageManager.DONT_KILL_APP);
                   break;
           }
       }
       @Override
   protected void onDestroy() {
           super.onDestroy();
           if( null != task){
               task.cancel();
               task = null;
           }
       }
   }
   

MyReceiver.java:

1. package com.example.testbroadcastreceiver;
   
   import android.content.BroadcastReceiver;
   import android.content.Context;
   import android.content.Intent;
   import android.util.Log;
   import android.widget.Toast;
   
   public class MyReceiver extends BroadcastReceiver {
       public MyReceiver(){
       }
       @Override
   public void onReceive(Context context, Intent intent) {
           // TODO Auto-generated method stub
   String action = intent.getAction();
           Log.e("TAG","action=  " + action);
           if( action == "ELITOR_CLOCK"){
               String msg = intent.getStringExtra("msg");
               Toast.makeText(context, msg, Toast.LENGTH_SHORT).show();
           }
       }
   
   }

1. package com.example.broadcasttest;  
2. import android.content.BroadcastReceiver;  
3. import android.content.Context;  
4. import android.content.Intent;  
5. publicclass mStaBroadcastReceiver extends BroadcastReceiver {  
6.     @Override
7.     publicvoid onReceive(Context context, Intent intent) {  
8.         MainActivity.tv.append("\n" + "mStaBroadcastReceiver=>"
9.                 + intent.getAction().toString());  
10.     }  
11. }  

activity_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
android:orientation="vertical"
tools:context="com.example.testbroadcastreceiver.MainActivity">

    <Button
android:id="@+id/sendButton"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:onClick="myOnclick"
android:text="Send BroadcastReceiver"/>

    <Button
android:id="@+id/cancelButton"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="20dp"
android:onClick="myOnclick"
android:text="Cancel BroadcastReceiver"/>

    <Button
android:id="@+id/resumeButton"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="20dp"
android:onClick="myOnclick"
android:text="恢復 BroadcastReceiver"/>

</LinearLayout>

在AndroidManifest.xml中註冊一下要靜態註冊的廣播

1. <?xml version="1.0" encoding="utf-8"?>
   <manifest xmlns:android="http://schemas.android.com/apk/res/android"
   package="com.example.testbroadcastreceiver" >
   
       <application
   android:allowBackup="true"
   android:icon="@mipmap/ic_launcher"
   android:label="@string/app_name"
   android:supportsRtl="true"
   android:theme="@style/AppTheme" >
   
           <activity android:name=".MainActivity" >
               <intent-filter>
                   <action android:name="android.intent.action.MAIN" />
   
                   <category android:name="android.intent.category.LAUNCHER" />
               </intent-filter>
           </activity>
   
           <!-- 靜態註冊 -->
   <receiver android:name="com.example.testbroadcastreceiver.MyBroadcastReceiver"
   android:enabled="true">
               <intent-filter >
                   <action android:name="ELITOR_CLOCK" />
               </intent-filter>
           </receiver>
   
       </application>
   
   </manifest>