一、实验目的
掌握有序广播的使用
二、实验仪器
Andriod Studio
三、实验任务
运行程序，解决以下三个问题：
问题1：程序启动后，单击“发送有序广播”按钮，发出一条广播事件，此时观察LogCat窗口下的提示信息，输出什么？为什么？
运行程序，输出结果如下图，因为广播接收者MyBroadcastReceiverOne的优先级为1000，广播接收者MyBroadcastReceiverTwo的优先级为200，
广播接收者MyBroadcastReceiverThree的优先级为600，优先级高的先接收到。
问题2：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，再来运行程序，观察结果，你能得出什么结论？
运行程序结果如下图,优先级相同的时候在清单文件中先注册的广播接收者先接收到广播。
问题3：修改MyBroadcastReceiverTwo如下，观察结果，你又可以得出什么结论？
运行结果如下图，在广播接收者Two接收到广播之后调用了abortBroadcast()方法之后。广播被拦截了，所以广播不会往下继续传递，
广播接收者one和广播接收者Three则不会接收到广播。
四、实验运行结果图及实现代码
1.布局activity_main：
<?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:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" android:background="@drawable/stitch_one" tools:context="bzu.edu.cn.orderedbroadcast.MainActivity"> <Button android:id="@+id/btnFS" android:text="发送有序广播" android:onClick="send" android:textSize="16sp" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginTop="50dp" android:layout_alignParentTop="true" android:layout_centerHorizontal="true" /> </RelativeLayout>
2.创建的第一个广播接收者MyBroadcastReceiverOne：
package bzu.edu.cn.orderedbroadcast;
import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.util.Log;
public class MyBroadcastReceiverOne extends BroadcastReceiver { public MyBroadcastReceiverOne() { }
@Override public void onReceive(Context context, Intent intent) { Log.i("MyBroadcastReceiverOne","自定义的广播接收者one,接收到了广播事件"); } }
3.创建第二个广播接收者MyBroadcastReceiverTwo:
package bzu.edu.cn.orderedbroadcast; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.util.Log; public class MyBroadcastReceiverTwo extends BroadcastReceiver { public MyBroadcastReceiverTwo() { } @Override public void onReceive(Context context, Intent intent) { Log.i("MyBroadcastReceiverTwo","自定义的广播接收者Two,接收到了广播事件"); abortBroadcast();//拦截有序广播 Log.i("MyBroadcastReceiverTwo","我是广播接收者Two，广播被我拦截了"); } } 4.创建第三个广播接收者MyBroadcastReceiverThree: package bzu.edu.cn.orderedbroadcast; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.util.Log; public class MyBroadcastReceiverThree extends BroadcastReceiver { public MyBroadcastReceiverThree() { } @Override public void onReceive(Context context, Intent intent) { Log.i("MyBroadcastReceiverThree","自定义的广播接收者Three,接收到了广播事件"); } } 5.MainActivity: 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); } } 6.配置文件AndroidManifest.xml： <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="bzu.edu.cn.orderedbroadcast"> <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=".MyBroadcastReceiverTwo" android:enabled="true" android:exported="true" > <intent-filter android:priority="200"> <action android:name="Intercept_Stitch"></action> </intent-filter> </receiver> <receiver android:name=".MyBroadcastReceiverOne" android:enabled="true" android:exported="true"> <intent-filter android:priority="1000"> <action android:name="Intercept_Stitch"></action> </intent-filter> </receiver> <receiver android:name=".MyBroadcastReceiverThree" android:enabled="true" android:exported="true"> <intent-filter android:priority="600"> <action android:name="Intercept_Stitch"></action> </intent-filter> </receiver> </application> </manifest>
