android之IntentFilter的用法_Intent.ACTION_TIME_TICK在manifest.xml不起作用
在模仿一个天气预报的widget时候,用到了IntentFilter,感觉在manifest.xml注册的receiver跟用代码写registerReceiver（）的效果应该是相同的,于是想证明一下,就写了如下一段程序:
MainActivity:
public class MainActivity extends Activity {
public static final int UPDATE = 000;
TextView xml;
TextView java;
int count = 0;
Handler handler = new Handler(){
@Override
public void handleMessage(Message msg) {
// TODO Auto-generated method stub
switch (msg.what) {
case UPDATE:
count ++;
xml.setText(count);
break;
default:
break;
}
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
IntentFilter javaFilter = new IntentFilter();
javaFilter.addAction("android.intent.action.TIME_TICK");
registerReceiver(receiver, javaFilter);
xml = (TextView) findViewById(R.id.xml);
java = (TextView) findViewById(R.id.java);
}
BroadcastReceiver receiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
// TODO Auto-generated method stub
Date date = new Date();
SimpleDateFormat dateFormat = new SimpleDateFormat("HHmm");
java.setText(dateFormat.format(date));
}
};
protected void onDestroy() {
unregisterReceiver(receiver);
};
class Accept extends BroadcastReceiver {
@Override
public void onReceive(Context arg0, Intent arg1) {
// TODO Auto-generated method stub
Message message = handler.obtainMessage();
message.what = UPDATE;
handler.sendMessage(message);
}
}
}
在manifest文件中注册如下:
<receiver android:name="jason.recevertext.Accept">
<intent-filter >
<action android:name="android.intent.action.TIME_TICK"/>
</intent-filter>
</receiver>
布局文件如下:
<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:orientation="vertical">
<TextView
android:id="@+id/xml"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/hello_world" />
<TextView
android:id="@+id/java"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/hello_world" />
</LinearLayout>
总体说来很简单,就是通过两种方式注册了IntentFilter,然后接收到更新的intent之后更新主界面上的两个textview
结果java代码注册的IntentFilter很正常,xml注册的IntentFilter没有任何作用.
事实证明我的想法是错的,经过查询资料,发现:
在众多的Intent的action动作中，Intent.ACTION_TIME_TICK是比较特殊的一个，根据SDK描述:
Broadcast Action: The current time has changed. Sent every minute. You can not receive this through components declared in manifests, only by exlicitly registering for it withContext.registerReceiver()
意思是说这个广播动作是以每分钟一次的形式发送。但你不能通过在manifest.xml里注册的方式接收到这个广播，只能在代码里通过registerReceiver()方法注册。
作者：jason0539
微博：http://weibo.com/2553717707
博客：http://blog.csdn.net/jason0539/article/details/10815787（转载请说明出处）