广播接收者--有序广播

界面图：

1.创建一个OrderBroadcastReceiver的项目，编写布局activity_main.xml文件，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="bzu.edu.cn.orderbroadcastreceiver.MainActivity">    <Button        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_centerHorizontal="true"        android:text="发送有序广播"        android:background="#ffffff"        android:layout_marginTop="80dp"        android:onClick="send"/></RelativeLayout>

2.点击Button按钮时就会发送一条有序广播，MainAcivity代码如下：

package bzu.edu.cn.orderbroadcastreceiver;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();        //定义广播的事件类型        intent.setAction("Intercept_Stitch");        //发送广播        sendOrderedBroadcast(intent,null);    }}

上述代码中，sendOrderedBroadcast(intent,null)用于发送一个有序广播，在该方法中接收两个参数，第一个参数是指定的意图，设置要发送的广播事件。第二个参数制定接受者的权限，如果不想让所有的接受者都看到，可以显示的指定接受者的权限，目前不关心权限可以将其指定为null。

3.点中app文件夹击右键->new->Other->BroadcastReceiver创建广播
MyReceiverOne代码如下：

package bzu.edu.cn.orderbroadcastreceiver;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) {        // TODO: This method is called when the BroadcastReceiver is receiving        // an Intent broadcast.        Log.i("MyReceiverOne","自定义的广播接受者One，接受到了广播事件");    }}

MyReceiverTwo代码如下：

package bzu.edu.cn.orderbroadcastreceiver;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) {        // TODO: This method is called when the BroadcastReceiver is receiving        // an Intent broadcast.        Log.i("MyReceiverTwo","自定义的广播接受者Two，接受到了广播事件");    }}

MyReceiverThree代码如下：

package bzu.edu.cn.orderbroadcastreceiver;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) {        // TODO: This method is called when the BroadcastReceiver is receiving        // an Intent broadcast.        Log.i("MyReceiverThree","自定义的广播接受者Three，接受到了广播事件");    }}

4.在配置文件里配置广播，AndroidManifest.xml代码如下：

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="bzu.edu.cn.orderbroadcastreceiver">    <application        android:allowBackup="true"        android:icon="@mipmap/ic_launcher"        android:label="@string/app_name"        android:supportsRtl="true"        android:theme="@style/AppTheme">        <activity android:name=".MainActivity">            <intent-filter>                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />            </intent-filter>        </activity>        <receiver            android:name=".MyReceiverOne"            android:enabled="true"            android:exported="true">            <intent-filter android:priority="1000">                <action android:name="Intercept_Stitch"/>            </intent-filter>        </receiver>        <receiver            android:name=".MyReceiverTwo"            android:enabled="true"            android:exported="true">            <intent-filter android:priority="200">                <action android:name="Intercept_Stitch"/>            </intent-filter>        </receiver>        <receiver            android:name=".MyReceiverThree"            android:enabled="true"            android:exported="true">            <intent-filter android:priority="600">                <action android:name="Intercept_Stitch"/>            </intent-filter>        </receiver>    </application></manifest>

5.点击“发送有序广播”按钮运行程序后，LogCat窗口下的提示信息如下：

出现这样的输出结果是因为给广播设置了优先级，android:priority=”1000”值越大优先级越高,优先级决定了广播接收的先后顺序。

6.若将广播接收者MyBroadcastReceiverTwo优先级同样设置为1000，并将MyBroadcastReceiverTwo注册在MyBroadcastReceiverOne前面，LogCat窗口下的提示信息如下：

注意观察，这时Two移到了One的上面，这说明优先级相同时，先注册的广播接收者会先接收到广播事件。

7.修改MyBroadcastReceiverTwo如下：

public void onReceive(Context context, Intent intent) {        // TODO: This method is called when the BroadcastReceiver is receiving        // an Intent broadcast.        Log.i("MyReceiverTwo","自定义的广播接受者Two，接受到了广播事件");        abortBroadcast();//拦截有序广播        Log.i("MyReceiverTwo","我是广播接受者Two，广播被我终结了");    }

8.修改后运行得到的LogCat窗口下的提示信息如下：

我们可以看到广播被终结了，这说明高优先级的广播是可以被终结的，abortBroadcast()语句用于终止有序广播，当程序执行完这句代码后，广播事件将会被终结，不会向下传递。