Android系统组件BroadcastReceiver
2016-03-20 21:44
627 查看
Android系统的4个组件终于还剩一种组件了BroadcastReceiver,这个组件是全局监听器,可以监听系统全局的广播消息,可以方便的实现系统中不同组件之间的通信
BroadcastReceiver有自己的进程,系统级监听器,只要存在与之匹配的Intent被广播出来,BroadcastReceiver就会被激发
要创建自己的BroadcastReceiver对象,我们需要继承android.content.BroadcastReceiver,并实现其onReceive方法
MyReceiver.java
[java] view
plain copy
![](https://code.csdn.net/assets/CODE_ico.png)
![](https://code.csdn.net/assets/ico_fork.svg)
public class MyReceiver extends BroadcastReceiver
{
@Override
public void onReceive(Context context, Intent intent)
{
Toast.makeText(context,
"接收到的Intent的Action为:" + intent.getAction()
+ "\n消息内容是:" + intent.getStringExtra("msg")
, Toast.LENGTH_LONG).show();
}
}
Manifest.xml清单文件配置的receiver
[html] view
plain copy
![](https://code.csdn.net/assets/CODE_ico.png)
![](https://code.csdn.net/assets/ico_fork.svg)
<receiver android:name=".MyReceiver">
<intent-filter>
<action android:name="org.crazyit.action.CRAZY_BROADCAST" />
</intent-filter>
</receiver>
就是说无论哪个组件中,intent的Action是"org.crazyit.action.CRAZY_BROADCAST" 并使用使用sendBroadcast(intent)发出广播,那么MyReceiver就会被启动
[java] view
plain copy
![](https://code.csdn.net/assets/CODE_ico.png)
![](https://code.csdn.net/assets/ico_fork.svg)
public class BroadcastMain extends Activity
{
Button send;
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// 获取程序界面中的按钮
send = (Button) findViewById(R.id.send);
send.setOnClickListener(new OnClickListener()
{
@Override
public void onClick(View v)
{
// 创建Intent对象
Intent intent = new Intent();
// 设置Intent的Action属性
intent.setAction("org.crazyit.action.CRAZY_BROADCAST");
intent.putExtra("msg", "简单的消息");
// 发送广播
sendBroadcast(intent);
}
});
}
}
注册Receiver有两种方法:
静态注册
静态注册是在AndroidManifest.xml文件中配置的,我们就来为MyReceiver注册一个广播地址:
[html] view
plain copy
![](https://code.csdn.net/assets/CODE_ico.png)
![](https://code.csdn.net/assets/ico_fork.svg)
<receiver android:name=".MyReceiver">
<intent-filter>
<action android:name="android.intent.action.MY_BROADCAST"/>
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</receiver>
配置了以上信息之后,只要是android.intent.action.MY_BROADCAST这个地址的广播,MyReceiver都能够接收的到。注意,这种方式的注册是常驻型的,也就是说当应用关闭后,如果有广播信息传来,MyReceiver也会被系统调用而自动运行。
动态注册
动态注册需要在代码中动态的指定广播地址并注册,通常我们是在Activity或Service注册一个广播,下面我们就来看一下注册的代码:
[java] view
plain copy
![](https://code.csdn.net/assets/CODE_ico.png)
![](https://code.csdn.net/assets/ico_fork.svg)
MyReceiver receiver = new MyReceiver();
IntentFilter filter = new IntentFilter();
filter.addAction("android.intent.action.MY_BROADCAST");
registerReceiver(receiver, filter); //注册<pre name="code" class="java">receiver 和filter
普通广播
普通广播对于多个接收者来说是完全异步的,通常每个接收者都无需等待即可以接收到广播,接收者相互之间不会有影响。对于这种广播,接收者无法终止广播,即无法阻止其他接收者的接收动作。上面的例子就是发送的普通广播
有序广播
有序广播比较特殊,它每次只发送到优先级较高的接收者那里,然后由优先级高的接受者再传播到优先级低的接收者那里,优先级高的接收者有能力终止这个广播。
例如:优先级A>B>C,Broadcast先传给A,再传给B,在传给C。优先级别声明<Intent-filter>元素的android:priority中,数越大级别越高,取值范围在-1000~1000
优先收到Broadcast的接受者可以通过setResultExtras(Bundle)方法将处理结果存入Broadcast中,然后传给下一个接受者,通过Bundle bunde=getResultExtras(true)柯获得上一个接受者存入的数据
[java] view
plain copy
![](https://code.csdn.net/assets/CODE_ico.png)
![](https://code.csdn.net/assets/ico_fork.svg)
public class SortedBroadcast extends Activity
{
Button send;
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// 获取程序中的send按钮
send = (Button) findViewById(R.id.send);
send.setOnClickListener(new OnClickListener()
{
@Override
public void onClick(View v)
{
// 创建Intent对象
Intent intent = new Intent();
intent.setAction("org.crazyit.action.CRAZY_BROADCAST");
intent.putExtra("msg", "简单的消息");
// 发送有序广播
sendOrderedBroadcast(intent, null);
}
});
}
}
MyReceiver.java
[java] view
plain copy
![](https://code.csdn.net/assets/CODE_ico.png)
![](https://code.csdn.net/assets/ico_fork.svg)
public class MyReceiver extends BroadcastReceiver
{
@Override
public void onReceive(Context context, Intent intent)
{
Toast.makeText(context, "接收到的Intent的Action为:"
+ intent.getAction() + "\n消息内容是:"
+ intent.getStringExtra("msg")
, Toast.LENGTH_LONG).show();
// 创建一个Bundle对象,并存入数据
Bundle bundle = new Bundle();
bundle.putString("first", "第一个BroadcastReceiver存入的消息");
// 将bundle放入结果中
setResultExtras(bundle);
// 取消Broadcast的继续传播
// abortBroadcast(); //①
}
}
MyReceiver2.java
[java] view
plain copy
![](https://code.csdn.net/assets/CODE_ico.png)
![](https://code.csdn.net/assets/ico_fork.svg)
public class MyReceiver2 extends BroadcastReceiver
{
@Override
public void onReceive(Context context, Intent intent)
{
Bundle bundle = getResultExtras(true);
// 解析前一个BroadcastReceiver所存入的key为first的消息
String first = bundle.getString("first");
Toast.makeText(context, "第一个Broadcast存入的消息为:"
+ first, Toast.LENGTH_LONG).show();
}
}
清单文件
[html] view
plain copy
![](https://code.csdn.net/assets/CODE_ico.png)
![](https://code.csdn.net/assets/ico_fork.svg)
<receiver android:name=".MyReceiver">
<intent-filter android:priority="20">
<action android:name="org.crazyit.action.CRAZY_BROADCAST" />
</intent-filter>
</receiver>
<receiver android:name=".MyReceiver2">
<intent-filter android:priority="0">
<action android:name="org.crazyit.action.CRAZY_BROADCAST" />
</intent-filter>
</receiver>
BroadcastReceiver有自己的进程,系统级监听器,只要存在与之匹配的Intent被广播出来,BroadcastReceiver就会被激发
要创建自己的BroadcastReceiver对象,我们需要继承android.content.BroadcastReceiver,并实现其onReceive方法
MyReceiver.java
[java] view
plain copy
![](https://code.csdn.net/assets/CODE_ico.png)
public class MyReceiver extends BroadcastReceiver
{
@Override
public void onReceive(Context context, Intent intent)
{
Toast.makeText(context,
"接收到的Intent的Action为:" + intent.getAction()
+ "\n消息内容是:" + intent.getStringExtra("msg")
, Toast.LENGTH_LONG).show();
}
}
Manifest.xml清单文件配置的receiver
[html] view
plain copy
![](https://code.csdn.net/assets/CODE_ico.png)
<receiver android:name=".MyReceiver">
<intent-filter>
<action android:name="org.crazyit.action.CRAZY_BROADCAST" />
</intent-filter>
</receiver>
就是说无论哪个组件中,intent的Action是"org.crazyit.action.CRAZY_BROADCAST" 并使用使用sendBroadcast(intent)发出广播,那么MyReceiver就会被启动
[java] view
plain copy
![](https://code.csdn.net/assets/CODE_ico.png)
public class BroadcastMain extends Activity
{
Button send;
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// 获取程序界面中的按钮
send = (Button) findViewById(R.id.send);
send.setOnClickListener(new OnClickListener()
{
@Override
public void onClick(View v)
{
// 创建Intent对象
Intent intent = new Intent();
// 设置Intent的Action属性
intent.setAction("org.crazyit.action.CRAZY_BROADCAST");
intent.putExtra("msg", "简单的消息");
// 发送广播
sendBroadcast(intent);
}
});
}
}
注册Receiver有两种方法:
静态注册
静态注册是在AndroidManifest.xml文件中配置的,我们就来为MyReceiver注册一个广播地址:
[html] view
plain copy
![](https://code.csdn.net/assets/CODE_ico.png)
<receiver android:name=".MyReceiver">
<intent-filter>
<action android:name="android.intent.action.MY_BROADCAST"/>
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</receiver>
配置了以上信息之后,只要是android.intent.action.MY_BROADCAST这个地址的广播,MyReceiver都能够接收的到。注意,这种方式的注册是常驻型的,也就是说当应用关闭后,如果有广播信息传来,MyReceiver也会被系统调用而自动运行。
动态注册
动态注册需要在代码中动态的指定广播地址并注册,通常我们是在Activity或Service注册一个广播,下面我们就来看一下注册的代码:
[java] view
plain copy
![](https://code.csdn.net/assets/CODE_ico.png)
MyReceiver receiver = new MyReceiver();
IntentFilter filter = new IntentFilter();
filter.addAction("android.intent.action.MY_BROADCAST");
registerReceiver(receiver, filter); //注册<pre name="code" class="java">receiver 和filter
普通广播
普通广播对于多个接收者来说是完全异步的,通常每个接收者都无需等待即可以接收到广播,接收者相互之间不会有影响。对于这种广播,接收者无法终止广播,即无法阻止其他接收者的接收动作。上面的例子就是发送的普通广播
有序广播
有序广播比较特殊,它每次只发送到优先级较高的接收者那里,然后由优先级高的接受者再传播到优先级低的接收者那里,优先级高的接收者有能力终止这个广播。
例如:优先级A>B>C,Broadcast先传给A,再传给B,在传给C。优先级别声明<Intent-filter>元素的android:priority中,数越大级别越高,取值范围在-1000~1000
优先收到Broadcast的接受者可以通过setResultExtras(Bundle)方法将处理结果存入Broadcast中,然后传给下一个接受者,通过Bundle bunde=getResultExtras(true)柯获得上一个接受者存入的数据
[java] view
plain copy
![](https://code.csdn.net/assets/CODE_ico.png)
public class SortedBroadcast extends Activity
{
Button send;
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// 获取程序中的send按钮
send = (Button) findViewById(R.id.send);
send.setOnClickListener(new OnClickListener()
{
@Override
public void onClick(View v)
{
// 创建Intent对象
Intent intent = new Intent();
intent.setAction("org.crazyit.action.CRAZY_BROADCAST");
intent.putExtra("msg", "简单的消息");
// 发送有序广播
sendOrderedBroadcast(intent, null);
}
});
}
}
MyReceiver.java
[java] view
plain copy
![](https://code.csdn.net/assets/CODE_ico.png)
public class MyReceiver extends BroadcastReceiver
{
@Override
public void onReceive(Context context, Intent intent)
{
Toast.makeText(context, "接收到的Intent的Action为:"
+ intent.getAction() + "\n消息内容是:"
+ intent.getStringExtra("msg")
, Toast.LENGTH_LONG).show();
// 创建一个Bundle对象,并存入数据
Bundle bundle = new Bundle();
bundle.putString("first", "第一个BroadcastReceiver存入的消息");
// 将bundle放入结果中
setResultExtras(bundle);
// 取消Broadcast的继续传播
// abortBroadcast(); //①
}
}
MyReceiver2.java
[java] view
plain copy
![](https://code.csdn.net/assets/CODE_ico.png)
public class MyReceiver2 extends BroadcastReceiver
{
@Override
public void onReceive(Context context, Intent intent)
{
Bundle bundle = getResultExtras(true);
// 解析前一个BroadcastReceiver所存入的key为first的消息
String first = bundle.getString("first");
Toast.makeText(context, "第一个Broadcast存入的消息为:"
+ first, Toast.LENGTH_LONG).show();
}
}
清单文件
[html] view
plain copy
![](https://code.csdn.net/assets/CODE_ico.png)
<receiver android:name=".MyReceiver">
<intent-filter android:priority="20">
<action android:name="org.crazyit.action.CRAZY_BROADCAST" />
</intent-filter>
</receiver>
<receiver android:name=".MyReceiver2">
<intent-filter android:priority="0">
<action android:name="org.crazyit.action.CRAZY_BROADCAST" />
</intent-filter>
</receiver>
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