想在Android中访问Power Button事件

Question

   i=0;
   public boolean onKeyDown(int keyCode, KeyEvent event) {
    System.out.println("In Key Down Method." + event.getKeyCode());
    if (event.getKeyCode() == KeyEvent.KEYCODE_POWER) {
        i++;
        System.out.println("Power button pressed.");
        if (i == 2) {
            System.out.println("Power button pressed continuoulsy 3 times.");
            Toast.makeText(MainActivity.this, "Power button pressed " + i + " times.", Toast.LENGTH_SHORT).show();
        } else {
            System.out.println("Power button pressed continuoulsy " + i + " times.");
            Toast.makeText(MainActivity.this, "Power button pressed " + i + " times.", Toast.LENGTH_SHORT).show();
        }
    }
    return super.onKeyDown(keyCode, event);
}

我正在尝试使用上面的代码访问电源按钮事件.它适用于Volume_Up和Volume_Down键,但不适用于电源/锁定按钮.为什么会发生？建议一些示例或代码.

Answer 1

您无法覆盖应用程序中的电源按钮按下.但是当您按下电源按钮时,屏幕会打开/关闭.所以你可以使用广播接收器检测到这一点.

<receiver android:name=".MyBroadCastReciever">
<intent-filter>
    <action android:name="android.intent.action.SCREEN_OFF"/>
    <action android:name="android.intent.action.SCREEN_ON"/>
</intent-filter>
</receiver>

MyBroadCastReciever.java

public class MyBroadCastReciever extends BroadcastReceiver {

@Override
public void onReceive(Context context, Intent intent) {
    if (intent.getAction().equals(Intent.ACTION_SCREEN_OFF)) {
        //Take count of the screen off position
    } else if (intent.getAction().equals(Intent.ACTION_SCREEN_ON)) {
        //Take count of the screen on position
    }
}
}

希望这对你有所帮助.

注意: - 为了让我的广播接收器始终在Background中运行.我写了一个后台服务,它在后台连续启动并为我的广播接收器提供增强功能.

Answer 2

您应该将以下权限添加到清单文件中：

<uses-permission android:name="android.permission.PREVENT_POWER_KEY" />