发送有序广播

   一、1.有序广播        有序广播是一种同步执行的广播，在广播发出之后，同一时刻只会有一个广播接收器能够接收到这条消息，当这个广播接收器中的逻辑执行完毕后，广播才会继续传递。所以此时的广播接收器是有先后顺序的，并且可以被拦截。2.创建应用程序对应的布局文件 activity_main.xml  代码如下:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/stitch_one"
tools:context="cn.edu.bzu.myapplication.MainActivity">

<Button
android:id="@+id/btn1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="发送有序广播"
android:layout_centerHorizontal="true"
android:layout_marginTop="100dp"
android:textSize="20sp"
android:background="#FBFBFF"
android:onClick="send"/>

</RelativeLayout>

3.在布局文件中为按钮Button注册了一个事件send，当点击按钮时，会发送一条有序广播。MainActivity的代码如下：

package cn.edu.bzu.myapplication;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void send(View view){
Intent intent=new Intent();
intent.setAction("intercept_stitch");
sendBroadcast(intent,null);
}
}

4.添加三个广播接收者MyReceiverOne、MyReceiverTwo、MyReceiverThree。不同的广播接收者打印不同的提示信息。（1）MyReceiverOne的代码如下：

package cn.edu.bzu.myapplication;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log;

public class MyReceiverOne extends BroadcastReceiver {
public MyReceiverOne() {
}

@Override
public void onReceive(Context context, Intent intent) {
Log.i("MyReceiverOne","自定义的广播接收者one,接收到了广播事件");

}
}

（2）MyReceiverTwo的代码如下：

package cn.edu.bzu.myapplication;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log;

public class MyReceiverTwo extends BroadcastReceiver {
public MyReceiverTwo() {
}

@Override
public void onReceive(Context context, Intent intent) {
Log.i("MyReceiverTwo","自定义广播接收者Two，已接受到了广播事件");

}
}

（3）MyReceiverThree的代码如下：

package cn.edu.bzu.myapplication;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log;

public class MyReceiverThree extends BroadcastReceiver {
public MyReceiverThree() {
}

@Override
public void onReceive(Context context, Intent intent) {
Log.i("MyreceiverThree","自定义广播接收者Three,已接收到了广播事件");
}
}

5.在清单文件中注册并为它们指定不同的优先级，代码如下：

<receiver android:name="cn.edu.bzu.myapplication.MyReceiverOne" >
<intent-filter android:priority="1000">
<action android:name="intercept_stitch"></action>
</intent-filter>
</receiver>
<receiver android:name="cn.edu.bzu.myapplication.MyReceiverTwo"
>
<intent-filter android:priority="200">
<action android:name="intercept_stitch" ></action>
</intent-filter>

</receiver>
<receiver android:name="cn.edu.bzu.myapplication.MyReceiverThree"
>
<intent-filter android:priority="600">
<action android:name="intercept_stitch" ></action>
</intent-filter>
</receiver>