Android四大组件之BroadcastReceiver

Posted 2020-06-14

(1)BroadcastReceiver的两种注册方式

     当我们创建了一个继承于BroadcastReceiver的广播接收者类以后，要在程序中去注册，注册的第一种方式是xml方式，在Mainfest注册文件中去注册，注册的xml代码如下

<application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <receiver android:name="MyReceiver">
            <intent-filter>
                <action android:name="dengchaoqun.Reciever"/>
            </intent-filter>
        </receiver>
    </application>

　　然后再程序中发送广播

Intent intent=new Intent("dengchaoqun.Reciever");
sendBroadcast(intent);

（2）通过java代码动态注册

private Button btnStart;
    private Button btnStop;
    private BroadcastReceiver receiver;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        //动态方式注册BordCastrecever
        receiver=new MyReceiver();
        IntentFilter filter=new IntentFilter("Myreceiver");
        registerReceiver(receiver, filter);
        
        btnStart=(Button) findViewById(R.id.button1);
        btnStop=(Button)findViewById(R.id.button2);
        
        btnStart.setOnClickListener(new View.OnClickListener() {
            
            @Override
            public void onClick(View v) {
                //静态方式
                /*Intent intent=new Intent("dengchaoqun.Reciever");
                sendBroadcast(intent);*/
                Intent intent=new Intent("Myreceiver");
                sendBroadcast(intent);
            }
        });
        
        btnStop.setOnClickListener(new View.OnClickListener() {
            
            @Override
            public void onClick(View v) {
                unregisterReceiver(receiver);
            }
        });
    }

（3）接收者对象的销毁  unregisterReciever（receiver）；

（4）在接收者对象中的

@Override
public void onReceive(Context context, Intent intent) {
Toast.makeText(context, "测试", 2000).show();
}

onReceiver中不能进行耗时操作，如果有耗时操作，必须开线程，或者通过intent启动services来完成