zz内部broadcastreceiver初始化异常

http://blog.csdn.net/zhangjm123/article/details/7978909

     当想实现广播接收功能时，因java  是单继承，所以一般一个类都会extends Activity，所以会想到内部类来extends BroadcastReceiver,这中间可能会出现两种异常

 

1:java.lang.RuntimeException: Unable to instantiate
     receiver com.example.progressbar.ProgressBarActivity$mBroadcastReceiver:
     java.lang.InstantiationException: com.example.progressbar.ProgressBarActivity$mBroadcastReceiver

 

 

      这是因为内部类需要写成静态的，即static 

 

static class mBroadcastReceiver extends BroadcastReceiver {
//必须为静态公开的(public static)


@Override
public void onReceive(Context context, Intent intent) {
// TODO Auto-generated method stub
}
}

 

 

2: java.lang.RuntimeException: Unable to instantiate
    receiver com.example.progressbar.ProgressBarActivity$mBroadcastReceiver:
    java.lang.IllegalAccessException: access to class not allowed

 

public static  class mBroadcastReceiver extends BroadcastReceiver {
 //必须为静态公开的(public static)
@Override
public void onReceive(Context context, Intent intent) {
// TODO Auto-generated method stub
}
}

用静态类的问题是不能访问外部类实例，无法操作外部类

 

    这是因为需要将此类写成public ，若没写默认为protected的，则会出现access to class not allowed

正确的为：

 

内部类需要加上$

 

<receiver android:name="com.example.progressbar.ProgressBarActivity$mBroadcastReceiver" >
            <intent-filter>
                <action android:name="com.example.progressbar.ProgressBarActivity.mBroadcastReceiver" />
            </intent-filter>
        </receiver>

 ---------------------------------------------------------------------------------------------------------------------------------------

用下面这个动态注册的方法比较好，不用在androidmanifest.xml中声明receiver

      当然还有另一种方法即实现其一个实例

 

private BroadcastReceiver mBroadcastReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {


        }
};

 

然后就是注册和注销

在onCreate（） 或onResume（）中调用registerBoradcastReceiver()

 

public void registerBoradcastReceiver() {
IntentFilter myIntentFilter = new IntentFilter();
myIntentFilter.addAction(ACTION_NAME);
// 注册广播
registerReceiver(mBroadcastReceiver, myIntentFilter);
}


@Override
public void onDestroy() {
super.onDestroy();
unregisterReceiver(mBroadcastReceiver);
}