如果在我的 android 应用程序中没有按下电源按钮 (x) 次，如何启动活动？

Question

还请解释它是如何工作的。当我的应用程序关闭时，这也应该有效。（它应该在后台运行）

Answer 1

您需要为此注册广播接收器
当应用程序在后台关闭时这项工作

public class MyReceiver extends BroadcastReceiver 
{
private static int countPowerOff = 0;

public MyReceiver ()
{

}

@Override
public void onReceive(Context context, Intent intent)
{
    if (intent.getAction().equals(Intent.ACTION_SCREEN_OFF))
    {    
        Log.e("In on receive", "In Method:  ACTION_SCREEN_OFF");
        countPowerOff++;
    }
    else if (intent.getAction().equals(Intent.ACTION_SCREEN_ON))
    {
        Log.e("In on receive", "In Method:  ACTION_SCREEN_ON");
    }
    else if(intent.getAction().equals(Intent.ACTION_USER_PRESENT))
    {
        Log.e("In on receive", "In Method:  ACTION_USER_PRESENT");
        if (countPowerOff > 2)
        {
            countPowerOff=0;
            Toast.makeText(context, "MAIN ACTIVITY IS BEING CALLED ", Toast.LENGTH_LONG).show();
            Intent i = new Intent(context, MainActivity.class);
            i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK|Intent.FLAG_ACTIVITY_CLEAR_TOP);
            context.startActivity(i);
        }
    }
  }
}