Android课堂学习笔记————BroadcastReceiver广播

最新推荐文章于 2024-04-13 15:17:50 发布

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本文详细介绍了Android中的广播机制，包括广播的发送与接收方式、静态与动态注册的区别、有序与无序广播的特点及应用场景，并提供了具体的代码示例。

什么是广播

广播是Android四大组件之一，全称BroadcastReceiver。
广播分为发送和接收方，就算没有接收方，发送方也会发送数据。
广播可以实现跨多个页面的数据通信。
广播可以实现跨进程间的数据通讯。

广播使用

静态注册无序广播

public class MainActivity extends AppCompatActivity {

    private Button zfBt;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        zfBt = findViewById(R.id.zf_btn);
        zfBt.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent("zhifubao");
                sendBroadcast(intent);
            }
        });

    }
}

新建一个类继承BroadcastReceiver

public class MyReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        Toast.makeText(context,"哎",Toast.LENGTH_SHORT).show();
    }
}

静态无序广播在androigmanifest文件中注册

<receiver android:name=".MyReceiver">
            <intent-filter>
                <action android:name="zhifubao"/>
            </intent-filter>
        </receiver>

动态注册无序广播

public class MainActivity extends AppCompatActivity {

    private MyReceiver1 receiver;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        IntentFilter intentFilter = new IntentFilter();
        intentFilter.addAction("zhifubao");
        receiver = new MyReceiver1();
        registerReceiver(receiver,intentFilter);

    }
    class MyReceiver1 extends BroadcastReceiver{

        @Override
        public void onReceive(Context context, Intent intent) {
            Toast.makeText(context, "哎", Toast.LENGTH_SHORT).show();
        }
    }
}

静态注册有序广播

public class BroadcastActivity extends AppCompatActivity {
    //定义一个按钮点击发送广播
    private Button broadBtn;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_broadcast);
        //绑定id与设置监听事件
        broadBtn=findViewById(R.id.broad_btn);
        broadBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent=new Intent("com.send");
                //有序广播需要用sendOrderedBroadcast()方法发送
                sendOrderedBroadcast(intent,null);
            }
        });
    }
}

public class GostBroadcast extends BroadcastReceiver {
    private String TAG="GostBroadcast";
    @Override
    public void onReceive(Context context, Intent intent) {
        Toast.makeText(context, "收到请回答GostBroadcast", Toast.LENGTH_SHORT).show();
        Log.d(TAG, "广播++++++++++++++++++++++++++++++++++++");
        //终止此广播，不在传递下去
        abortBroadcast();
    }

}

<receiver android:name=".GostBroadcast">
       <intent-filter android:priority="100" >
            <action android:name="com.send"/>
       </intent-filter>
</receiver>
<receiver android:name=".SecondBroadcast">
      <intent-filter android:priority="1000" >
           <action android:name="com.send"/>
      </intent-filter>
</receiver>

动态注册有序广播

 protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_broad_b);
  // 1. 实例化BroadcastReceiver子类 &  IntentFilter
        GostBroadcast mBroadcastReceiver = new GostBroadcast();
        SecondBroadcast secondBroadcast=new SecondBroadcast();
        IntentFilter intentFilter1 = new IntentFilter();
        IntentFilter intentFilter2 = new IntentFilter();
        // 2. 设置接收广播的类型
        intentFilter1.addAction("com.send");
        //运用setPriority（）方法设置优先级关系
        intentFilter1.setPriority(1000);
        intentFilter2.addAction("com.send");
        intentFilter2.setPriority(1000);
        // 3. 动态注册：调用Context的registerReceiver（）方法
        registerReceiver(mBroadcastReceiver, intentFilter1);
        registerReceiver(secondBroadcast, intentFilter2);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        //移除广播接收器
        unregisterReceiver(mBroadcastReceiver);
        unregisterReceiver(secondBroadcast);
    }
}

public class BroadcastActivity extends AppCompatActivity {
    private Button broadBtn;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_broadcast);
        broadBtn=findViewById(R.id.broad_btn);
        broadBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent=new Intent("com.send");
                //有序广播需要用sendOrderedBroadcast()方法发送
                sendOrderedBroadcast(intent,null);
            }
        });
    }
}