Android 广播 - 静态注册与动态注册对广播接收器实例创建的影响

一、静态注册对广播接收器实例创建的影响

1、基本介绍

• 静态注册的广播接收器，每次发送广播，都会新建一个广播接收器实例

2、演示

（1）Receiver

• TestReceiver.java

public class TestReceiver extends BroadcastReceiver {

    public static final String TAG = TestReceiver.class.getSimpleName();

    @Override
    public void onReceive(Context context, Intent intent) {
        Log.i(TAG, "收到内容 - " + this);
    }
}

• AndroidManifest.xml

<receiver
    android:name=".mybroadcast.TestReceiver"
    android:exported="false" />

（2）Activity

• activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/btn_send"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="发送广播"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

• MainActivity.java

public class MainActivity extends AppCompatActivity {

    public static final String TAG = MainActivity.class.getSimpleName();

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

        Button btnSend = findViewById(R.id.btn_send);

        btnSend.setOnClickListener(v -> {
            Intent intent = new Intent();
            ComponentName component = new ComponentName(this, TestReceiver.class);
            intent.setComponent(component);
            sendBroadcast(intent);
        });
    }
}

（3）Test

1. 第 1 次点击按钮，发送广播，输出结果如下

   收到内容 - com.my.broadcast.mybroadcast.TestReceiver@1a66a22

2. 第 2 次点击按钮，发送广播，输出结果如下

   收到内容 - com.my.broadcast.mybroadcast.TestReceiver@58d710f

---

二、动态注册对广播接收器实例创建的影响

1、基本介绍

• 动态注册的广播接收器，每次发送广播，只有一个广播接收器实例

2、演示

（1）Receiver

public class TestReceiver extends BroadcastReceiver {

    public static final String TAG = TestReceiver.class.getSimpleName();

    public static final String ACTION = TAG;

    @Override
    public void onReceive(Context context, Intent intent) {
        Log.i(TAG, "收到内容 - " + this);
    }
}

（2）Activity

• activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/btn_send"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="发送广播"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

• MainActivity.java

public class MainActivity extends AppCompatActivity {

    public static final String TAG = MainActivity.class.getSimpleName();

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

        TestReceiver receiver = new TestReceiver();
        IntentFilter intentFilter = new IntentFilter(TestReceiver.ACTION);
        registerReceiver(receiver, intentFilter);

        Button btnSend = findViewById(R.id.btn_send);

        btnSend.setOnClickListener(v -> {
            Intent intent = new Intent();
            intent.setAction(TestReceiver.ACTION);
            sendBroadcast(intent);
        });
    }
}

（3）Test

1. 第 1 次点击按钮，发送广播，输出结果如下

   收到内容 - com.my.broadcast.mybroadcast.TestReceiver@6458b62

2. 第 2 次点击按钮，发送广播，输出结果如下

   收到内容 - com.my.broadcast.mybroadcast.TestReceiver@6458b62

---

三、在 Application 中动态注册

1、基本介绍

• 在 Application 的 onCreate 方法中采用动态注册来注册广播接收器，只会创建一个广播接收器实例

2、演示

（1）Receiver

public class TestReceiver extends BroadcastReceiver {

    public static final String TAG = TestReceiver.class.getSimpleName();

    public static final String ACTION = TAG;

    @Override
    public void onReceive(Context context, Intent intent) {
        Log.i(TAG, "收到内容 - " + this);
    }
}

（2）Application

• MyApplication.java

public class MyApplication extends Application {

    private TestReceiver testReceiver;

    @Override
    public void onCreate() {
        super.onCreate();

        testReceiver = new TestReceiver();
        IntentFilter filter = new IntentFilter(TestReceiver.ACTION);
        registerReceiver(testReceiver, filter);
    }
}

（3）Activity

• activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/btn_send"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="发送广播"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

• MainActivity.java

public class MainActivity extends AppCompatActivity {

    public static final String TAG = MainActivity.class.getSimpleName();

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

        Button btnSend = findViewById(R.id.btn_send);

        btnSend.setOnClickListener(v -> {
            Intent intent = new Intent();
            intent.setAction(TestReceiver.ACTION);
            sendBroadcast(intent);
        });
    }
}

（4）Test

1. 第 1 次点击按钮，发送广播，输出结果如下

   收到内容 - com.my.broadcast.mybroadcast.TestReceiver@332c7bc

2. 第 2 次点击按钮，发送广播，输出结果如下

   收到内容 - com.my.broadcast.mybroadcast.TestReceiver@332c7bc

---

四、在 Activity 中动态注册

1、基本介绍

1. 如果在 Activity 中采用动态注册来注册广播接收器，需要在合适的时机注销广播接收器，否则会创建多个广播接收器实例

2. 如果存在多个广播接收器实例，它们会同时接收广播

2、多个广播接收器实例

（1）Receiver

public class TestReceiver extends BroadcastReceiver {

    public static final String TAG = TestReceiver.class.getSimpleName();

    public static final String ACTION = TAG;

    @Override
    public void onReceive(Context context, Intent intent) {
        Log.i(TAG, "收到内容 - " + this);
    }
}

（2）Activity

• activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/btn_send"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="发送广播"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

• MainActivity.java

public class MainActivity extends AppCompatActivity {

    public static final String TAG = MainActivity.class.getSimpleName();

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

        registerReceiver(new TestReceiver(), new IntentFilter(TestReceiver.ACTION));
        registerReceiver(new TestReceiver(), new IntentFilter(TestReceiver.ACTION));

        Button btnSend = findViewById(R.id.btn_send);

        btnSend.setOnClickListener(v -> {
            Intent intent = new Intent();
            intent.setAction(TestReceiver.ACTION);
            sendBroadcast(intent);
        });
    }
}

（3）Test

1. 第 1 次点击按钮，发送广播，输出结果如下

   收到内容 - com.my.broadcast.mybroadcast.TestReceiver@6458b62
   收到内容 - com.my.broadcast.mybroadcast.TestReceiver@be064f3

2. 第 2 次点击按钮，发送广播，输出结果如下

   收到内容 - com.my.broadcast.mybroadcast.TestReceiver@6458b62
   收到内容 - com.my.broadcast.mybroadcast.TestReceiver@be064f3