Android开发从0开始(广播)

应用广播

发送标准广播的三步骤

发送标准广播:

//发送标准广播

Intent intent =new Intent("com.dongnaoedu.chapter09.standard");

sendBroadcast(intent);

定义广播接受者:

public class StanderdReceiver extends BroadcastReceiver {

public  static final String  STANDARD_ACTION="com.dongnaoedu.chapter09.standard";

//一旦收到广播就会触发onReceive的方法

 @Override

public void onReceive(Context context, Intent intent) {

if(intent!=null &&intent.getAction().equals(STANDARD_ACTION)){

Log.d("ning","收到一个标准广播");    }   }   }

开关广播接受者:

protected void onStart()

    {

        super.onStart();

        standerdReceiver = new StanderdReceiver();

        //创建一个意图过滤器,只处理STANDARD_ACTION广播

        IntentFilter filter = new IntentFilter(StanderdReceiver.STANDARD_ACTION);

        registerReceiver(standerdReceiver,filter);

    }

protected void onStop()

    {

        super.onStop();

        //注销接收器

        unregisterReceiver(standerdReceiver);

}

发送有序广播:(可截断广播abortBroadcast())

发送标准广播:

 Intent intent=new Intent(ORDER_ACTION);

 sendOrderedBroadcast(intent,null);

定义广播接受者:

    public void onReceive(Context context, Intent intent) {

        if(intent!=null&&intent.getAction().equals(BoradOraderActivity.ORDER_ACTION)){

            Log.d("ning","接收器B收到一个有序广播");

        }

}

public void onReceive(Context context, Intent intent) {

if(intent!=null&&intent.getAction().equals(BoradOraderActivity.ORDER_ACTION)){

             Log.d("ning","接收器A收到一个有序广播");

        }

    }

开关广播接受者:

  protected void OnStart()

    {

        super.onStart();

        //注册广播A

        orderAReceiver = new OrderAReceiver();

        IntentFilter filterA=new IntentFilter(ORDER_ACTION);

        filterA.setPriority(3);

        registerReceiver(orderAReceiver,filterA);

        //注册广播B

        orderBReceiver = new OrderBReceiver();

        IntentFilter filterB=new IntentFilter(ORDER_ACTION);

        filterB.setPriority(6);

        registerReceiver(orderAReceiver,filterB);

    }

    protected void OnStop()

    {

        super.onStop();

        unregisterReceiver(orderAReceiver);

        unregisterReceiver(orderBReceiver);

    }

静态注册广播:(不推荐

  在AndroidManifest.xml中注册,为静态注册

   权限

注册部分

            

          

广播定义:   public void onReceive(Context context, Intent intent) {

        if(intent!=null&&intent.getAction().equals(SHOCK_ACTION))

        {

            Log.d("ning","震动");

     Vibrator vb= (Vibrator) context.getSystemService(Context.VIBRATOR_SERVICE);

            vb.vibrate(500);

        }

    }

广播发送

public void onClick(View view) {

        String fullName="com.dongnaoedu.chapter09.shock";

        Intent intent =new Intent("com.dongnaooedu.chapter09.shock");

        //指定接收路径

        ComponentName componentName=new ComponentName(this,fullName);

        //设置组件意图

        intent.setComponent(componentName);

        sendBroadcast(intent);}

系统广播

  由系统发送的广播,故注册一个广播接受者即可。

系统分钟到达广播

      protected void onStart(){

        super.onStart();

        //注册一个分钟变更的广播接收器

        timeReceiver = new TimeReceiver();

        IntentFilter filter= new IntentFilter(Intent.ACTION_TIME_TICK);

        registerReceiver(timeReceiver,filter);

    }

    protected void onStop(){

        super.onStop();

        //取消注册广播

        unregisterReceiver(timeReceiver);

}

系统网络变更广播

      protected void onStart(){

        super.onStart();

        //注册网络变更的广播接收器

        networkReceiver = new NetWorkReceiver();

        IntentFilter filter= new IntentFilter("android.net.conn.CONNECTIVITY_CHANGE");

        registerReceiver(networkReceiver,filter);

    }

    protected void onStop(){

        super.onStop();

        //取消注册广播

        unregisterReceiver(networkReceiver);}

 屏幕变更事件

 定时管理器:AlarmManager

①定义定时管理器AlarmReceiver

public class AlarmReceiver extends BroadcastReceiver {

public static final String ALARM_ACTION="com.dongnaoedu.chapter09.alarm";

private final Context mContext;

public AlarmReceiver(Context context){

        super();

        this.mContext=context; }

@Override

    public void onReceive(Context context, Intent intent) {

        if(intent!=null && intent.getAction().equals(ALARM_ACTION) )

        {  Log.d("ning","收到闹钟广播");  }   }

  //发送闹钟广播的方法

    public  void  sendAlarm()

    {   //设置意图给延时意图使用

        Intent intent= new Intent(ALARM_ACTION);

        //设置用于广播的延迟意图

        PendingIntent pendingIntent = PendingIntent.getBroadcast(mContext,0,intent,PendingIntent.FLAG_IMMUTABLE);

        //从系统中拿到闹钟管理器

        AlarmManager alarmManager=(AlarmManager) mContext.getSystemService(Context.ALARM_SERVICE);

        //判断版本,Android6.0

        if(Build.VERSION.SDK_INT>=Build.VERSION_CODES.M){

            alarmManager.setAndAllowWhileIdle(AlarmManager.RTC_WAKEUP,1000,pendingIntent);

        }else

        {

            //设置闹钟管理器(android6.0,后该方法,在灭屏不保证发送广播)

            alarmManager.set(AlarmManager.RTC_WAKEUP,1000,pendingIntent);

        }

    }

}

注册定时管理器

  public class AlarmActivity extends AppCompatActivity implements View.OnClickListener {

    private AlarmReceiver alarmReceiver;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_alarm);

        findViewById(R.id.btn_alarm).setOnClickListener(this);

    }

    @Override

public void onClick(View view) {alarmReceiver.sendAlarm(); }

    protected void onStart(){

        super.onStart();

        alarmReceiver = new AlarmReceiver(getApplicationContext());

        IntentFilter filter=new IntentFilter(AlarmReceiver.ALARM_ACTION);

        registerReceiver(alarmReceiver,filter);

    }

    protected void onStop(){

        super.onStop();

        unregisterReceiver(alarmReceiver);

    }

}

竖屏与横屏切换

  切换时会将之前的生命周期结束,重新创建一个新的生命周期。若想不重启,则

①在AndroidManifest.xml中,给activity节点增加Android:configChanges。

②修改活动页面java代码,重写活动的onConfigurationChanged方法。

Android开发从0开始(广播)_第1张图片

在AndroidManifest.xml中配置Android:screenOrientation=”portrait”可以指定横屏或竖屏

回到桌面与切换任务列表:

  通过Intent.ACTION_CLOSE_SYSTEM_DIALOGS可判断是否回到桌面,任务列表是否打开。

  收到意图中reason字段,值为homekey时表示为回桌面,recentapps时为打开任务列表。

  在AndroidManifest.xml中加入android:supportsPictureInPicture="true"支持画中画权限

public class ReturnDesktopActivity extends AppCompatActivity {

    private DesktopRecevier desktopRecevier;

    @Override//在创建函数中注册画中画

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_return_desktop);

        desktopRecevier = new DesktopRecevier();

        IntentFilter filter=new IntentFilter(Intent.ACTION_CLOSE_SYSTEM_DIALOGS);

        registerReceiver(desktopRecevier,filter);

    }

//注销画中画

    @Override

    protected void onDestroy() {

        super.onDestroy();

        unregisterReceiver(desktopRecevier);

    }

    //进入画中画模式或退出画中画时触发

    @Override

    public void onPictureInPictureModeChanged(boolean isInPictureInPictureMode, Configuration newConfig) {

        super.onPictureInPictureModeChanged(isInPictureInPictureMode, newConfig);

        if(isInPictureInPictureMode){

            Log.d("ning","进入画中画模式");

        }else {

            Log.d("ning","退出画中画模式");

        }

    }

    //定义一个返回桌面的广播接收器

private class DesktopRecevier extends BoradOraderActivity{

public void onReceive(Context context, Intent intent){

if(intent!=null&&intent.getAction().equals(Intent.ACTION_CLOSE_SYSTEM_DIALOGS)){

String reason=intent.getStringExtra("reason");

              if(!TextUtils.isEmpty(reason)&&(reason.equals("homekey")||reason.equals("recentapps"))){

                  //android 8.0后才有画中画判断一下

 if(Build.VERSION.SDK_INT>=Build.VERSION_CODES.O&&!isInPictureInPictureMode())

  {            //创建画中画模式的参数构建器

   PictureInPictureParams.Builder builder = new PictureInPictureParams.Builder();

    Rational ratio = new Rational(10,5); //指定屏幕宽高比例

    builder.setAspectRatio(ratio);                      enterPictureInPictureMode(builder.build());   //进入画中画       }       }    }   } } }

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