(广播是android四大组件之一)
广播必须要注册才能接收,注册广播接收器BroadcastReceiver的方式有两种:
1.静态注册:在AndroidManifest.xml文件中注册。
<!-- 注册广播 -->
<receiver android:name="broadcast.CommonBroadCast">
<intent-filter>
<!-- 为广播设置一个频率 -->
<action android:name="com.ybj.NORMAL_BROADCAST"/>
</intent-filter>
</receiver>
2.动态注册:在代码中指定广播地址并注册,通常是在Activity或Service注册广播。注意:如果有带有优先级的静态注册,则注明优先级的广播接收为最先;如果是没有优先级的静态注册,则代码注册的广播接收为最先。
//动态注册广播
IntentFilter filter = new IntentFilter();
filter.addAction("com.ybj.NORMAL_BROADCAST");
CommonBroadCast receiver = new CommonBroadCast();
registerReceiver(receiver, filter);
如果你想注销广播的话,方法如下:
//注销广播
unregisterReceiver(receiver);
**下面介绍几种类型广播的发送
1.普通广播
接收者之间互不影响,均能无等待接收,接收者无法影响广播发送。
BroadCastActivity.java中:
//发送普通广播
Intent intent = new Intent();
intent.setAction("com.ybj.NORMAL_BROADCAST");
intent.putExtra("info", "content");
sendBroadcast(intent);
CommonBroadCast.java
/** * 接收普通广播 * @author Administrator * */
public class CommonBroadCast extends BroadcastReceiver {
/** * 广播处理业务的方法 * 处理简单业务 */
@Override
public void onReceive(Context context, Intent intent) {
// TODO Auto-generated method stub
String info = intent.getStringExtra("info");
Log.e("广播接收到", info);
}
}
运行结果:
2.有序广播
广播先发送到优先级高的接收者,高优先级接收者可以终止广播,并能向优先级低的接收者传递信息。
(1)
BroadCastActivity.java中:
//发送有序广播
Intent intent = new Intent();
intent.setAction("com.ybj.ORDER_BROADCAST");
intent.putExtra("info", "content");
//null表示不要求接收者声明指定权限
sendOrderedBroadcast(intent, null);
在AndroidManifest.xml注册广播接收者:
<!-- android:priority : 配置广播接收器的优先级(-1000,1000) -->
<receiver android:name="broadcast.OrderBroadcast1" >
<intent-filter android:priority="100">
<!-- 为广播设置一个频率 -->
<action android:name="com.ybj.ORDER_BROADCAST" />
</intent-filter>
</receiver>
<receiver android:name="broadcast.OrderBroadcast2" >
<intent-filter android:priority="200">
<!-- 为广播设置一个频率 -->
<action android:name="com.ybj.ORDER_BROADCAST" />
</intent-filter>
</receiver>
OrderBroadcast1.java
public class OrderBroadcast1 extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
// TODO Auto-generated method stub
String info = intent.getStringExtra("info");
Log.e("接收者1接收到有序广播", info);
}
}
OrderBroadcast2.java
public class OrderBroadcast2 extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
// TODO Auto-generated method stub
String info = intent.getStringExtra("info");
Log.e("接收者2接收到有序广播", info);
}
}
运行结果:
(2)
(与(1)对照)在这里如果OrderBroadcast2.java是这样写的:
public class OrderBroadcast2 extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
// TODO Auto-generated method stub
String info = intent.getStringExtra("info");
Log.e("接收者2接收到有序广播", info);
//优先级别高的接收者结束这个广播
this.abortBroadcast();
Log.e("接收者2结束有序广播", info);
}
}
则运行结果为:
(3)
(与(1)对照)如果OrderBroadcast1.java是这样写的:
public class OrderBroadcast1 extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
// TODO Auto-generated method stub
String info = intent.getStringExtra("info");
Log.e("接收者1接收到有序广播", info);
//接收优先级别高的接收者发送的内容
Bundle bundle = getResultExtras(false);
String msg = bundle.getString("result");
Log.e("接收者1接收到优先级别高的接收者发送的内容", msg);
}
}
如果OrderBroadcast2.java是这样写的:
public class OrderBroadcast2 extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
// TODO Auto-generated method stub
String info = intent.getStringExtra("info");
Log.e("接收者2接收到有序广播", info);
//优先级别高的接收者发送内容给优先级别低的接收者
Bundle extras = new Bundle();
extras.putString("result", "接收者2发送的content");
setResultExtras(extras);
}
}
则运行结果为:
(4)
(与(1)对照)如果BroadCastActivity.java中是这样写的:
//发送有序广播
Intent intent = new Intent();
intent.setAction("com.ybj.ORDER_BROADCAST");
intent.putExtra("info", "content");
//在这里指定权限不为空,接收者接收需要声明指定权限
sendOrderedBroadcast(intent, "com.ybj.permission");
break;
清单文件AndroidManifest.xml中需要配置权限接收者才能收到,如果不配置则接收不到:
<!-- 定义一个权限 -->
<permission android:name="com.ybj.permission"></permission>
<!-- 使用这个权限 -->
<uses-permission android:name="com.ybj.permission"/>
运行结果与(1)相同。
3.粘性广播
intent会保持到广播事件结束,没有所谓的10秒限制,10秒限制是指普通的广播如果执行onReceive()时间超过10秒,系统会将这个广播置为可以干掉的candicate,一旦资源不够时就会干掉这个广播不让它执行。
粘性广播需要在AndroidManifest.xml中设置权限:
<!-- 粘性广播权限 -->
<uses-permission android:name="android.permission.BROADCAST_STICKY"/>
BroadCastActivity.java中:
//发送粘性广播
Intent intent = new Intent();
intent.setAction("com.ybj.STICKY_BROADCAST");
intent.putExtra("info", "content");
sendStickyBroadcast(intent);
StickyBroadcast.java:
public class StickyBroadcast extends BroadcastReceiver {
private boolean flag = true;
private int i = 0;
@Override
public void onReceive(Context context, Intent intent) {
// TODO Auto-generated method stub
String info = intent.getStringExtra("info");
Log.e("接收到粘性广播内容", info);
Log.e("粘性广播接收", "开始。。50秒后结束");
new Thread(new Runnable(){
@Override
public void run() {
// TODO Auto-generated method stub
while(flag){
Log.e("i=", "" + i++);
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
if(i == 50){
flag = false;
Log.e("粘性广播接收", "广播终止了");
}
}
}
}).start();
}
}
在AndroidManifest.xml中注册接收者:
<receiver android:name="broadcast.StickyBroadcast" >
<intent-filter>
<!-- 为广播设置一个频率 -->
<action android:name="com.ybj.STICKY_BROADCAST" />
</intent-filter>
</receiver>
运行结果为:
……
这里说一下,广播接收者中不要创建线程或者做一些耗时操作,否则广播结束时会造成异常。