VA对Broadcast的处理讨论及分析 #9

Activity

1. prife commented on Aug 24, 2016

   

   prife

   on Aug 24, 2016

   Last edited by prife

   OwnerAuthor

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   设计了如下demo，应用A按下按钮发送广播（携带一段字符串），应用B静态注册广播，在onReceive函数中启动一个Activity并把广播中的字符串显示在TextView控件上。

   应用A代码

   一个helleworld应用，有个button，按下button时，即发送。

       protected void onCreate(Bundle savedInstanceState) {
           super.onCreate(savedInstanceState);
           setContentView(R.layout.activity_main);
   
           Button btn = (Button) findViewById(R.id.send_broadcast);
           btn.setOnClickListener(new View.OnClickListener() {
               @Override
               public void onClick(View view) {
                   //String name = "study.broadcast.test";
                   String name = "prife.test";
                   String value = "hello world";
                   Intent intent = new Intent(name);
                   intent.putExtra("prife_value", value);
                   Log.d(TAG, String.format("send action[%s], value[%s]", name, value));
                   sendBroadcast(intent);
               }
           });
       }

   应用B代码

   广播接收应用B，当收到广播（action为prife.test），则启动一个Activity（ReceiveBroadCast.java），并讲Intent中携带的字符串显示出来，主要代码如下。

   AndroidManifest.xml

           <receiver android:name=".Receiver" >
               <intent-filter>
                   <!--<action android:name="study.broadcast.test" />-->
                   <action android:name="prife.test" />
               </intent-filter>
           </receiver>
           <activity android:name=".ReceiveBroadCast">
               <intent-filter>
                   <action android:name="android.intent.action.MAIN"/>
                   <category android:name="android.intent.category.LAUNCHER"/>
               </intent-filter>
           </activity>

   Receiver.java

   public class Receiver extends BroadcastReceiver {
   
       static final String TAG = "Receiver";
   
       @Override
       public void onReceive(Context context, Intent intent) {
           String action = intent.getAction();
           String values = intent.getStringExtra("prife_value");
           Log.d(TAG, String.format("action[%s], value[%s]", action, values));
   
           Intent intent1 = new Intent(context, ReceiveBroadCast.class);
           intent1.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
           intent1.putExtra("value", values);
           context.startActivity(intent1);
     }
   }

   ReceiveBroadCast.java

   public class ReceiveBroadCast extends AppCompatActivity {
   
       @Override
       protected void onCreate(Bundle savedInstanceState) {
           super.onCreate(savedInstanceState);
           setContentView(R.layout.activity_receivebroad);
   
           Intent intent = getIntent();
           String value = intent.getStringExtra("value");
           TextView view = (TextView)findViewById(R.id.receive_broadcast);
           view.setText(value);
       }
   }
2. cddjr commented on Nov 10, 2016

   

   cddjr

   on Nov 10, 2016

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   其实只要在广播前先判断接收器是否已经在VA中注册，如果没有注册那么广播不做任何修改直接传给系统，这样就实现了场景1。