Power Key event in android?

Question

I want to listen to the power key event. How can i do this?

The code currently in use is:

@Override public boolean onKeyDown(int keyCode, KeyEvent event) { if(KeyEvent.KEYCODE_POWER == event.getKeyCode()){ Log.e("POWER", "pow"); return true;//If event is handled, falseif } return super.onKeyDown(keyCode, event); } 

And user permissions

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

I do not get any result.

I want to add a function when the user presses the power button or a long press on it may have an emergency call / Speed ​​dial.

Looking for a solution.

Answer 1

It matters if you write

 KeyEvent.KEYCODE_POWER == keyCode 

? I think you should write this, not

 KeyEvent.KEYCODE_POWER == event.getKeyCode() 

taken here: How to connect the power button in Android?

Answer 2

You should check your onKeyDown override function

 @Override public boolean onKeyDown(int keyCode, KeyEvent event) { if (keyCode == KeyEvent.KEYCODE_POWER) { // Do something here... return true; } return super.onKeyDown(keyCode, event); } 

and the same with onKeyLongPress if you use

Another way you would like to turn off the screen is to register the BroadcastReceiver with the action Intent.ACTION_SCREEN_OFF

Answer 3

 package app.test; import java.io.BufferedWriter; import java.io.FileWriter; import java.io.IOException; import java.text.SimpleDateFormat; import java.util.Date; import android.app.Activity; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.content.IntentFilter; import android.hardware.Sensor; import android.hardware.SensorEvent; import android.hardware.SensorEventListener; import android.hardware.SensorManager; import android.os.Bundle; import android.os.Environment; import android.os.PowerManager; import android.os.PowerManager.WakeLock; import android.provider.Settings; import android.util.Log; public class Test extends Activity implements SensorEventListener { private WakeLock mWakelock = null; private SensorManager mMgr; private Sensor mAccel; private BufferedWriter mLog; final private SimpleDateFormat mTimeFormat = new SimpleDateFormat("HH:mm:ss - "); private int mSavedTimeout; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); mMgr = (SensorManager) this.getSystemService(SENSOR_SERVICE); mAccel = mMgr.getDefaultSensor(Sensor.TYPE_ACCELEROMETER); try { String filename = Environment.getExternalStorageDirectory().getAbsolutePath() +"/accel.log"; mLog = new BufferedWriter(new FileWriter(filename, true)); } catch(Exception e) { e.printStackTrace(); finish(); } PowerManager pwrMgr = (PowerManager) this.getSystemService(POWER_SERVICE); mWakelock = pwrMgr.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "Accel"); mWakelock.acquire(); try { mSavedTimeout = Settings.System.getInt(getContentResolver(), Settings.System.SCREEN_OFF_TIMEOUT); } catch(Exception e) { mSavedTimeout = 120000; } Settings.System.putInt(getContentResolver(), Settings.System.SCREEN_OFF_TIMEOUT, 5000); } public BroadcastReceiver mReceiver = new BroadcastReceiver() { public void onReceive(Context context, Intent intent) { if (Intent.ACTION_SCREEN_OFF.equals(intent.getAction())) { writeLog("The screen has turned off"); mMgr.unregisterListener(Test.this); mMgr.registerListener(Test.this, mAccel, SensorManager.SENSOR_DELAY_NORMAL); } } }; @Override protected void onStart() { mMgr.registerListener(this, mAccel, SensorManager.SENSOR_DELAY_NORMAL); IntentFilter filter = new IntentFilter(Intent.ACTION_SCREEN_OFF); registerReceiver(mReceiver, filter); super.onStart(); } @Override protected void onStop() { mMgr.unregisterListener(this, mAccel); unregisterReceiver(mReceiver); try { mLog.flush(); } catch (IOException e) { } super.onStop(); } @Override protected void onDestroy() { try { mLog.flush(); mLog.close(); } catch(Exception e) { } Settings.System.putInt(getContentResolver(), Settings.System.SCREEN_OFF_TIMEOUT, mSavedTimeout); mWakelock.release(); super.onDestroy(); } public void onAccuracyChanged(Sensor sensor, int accuracy) { } public void onSensorChanged(SensorEvent event) { writeLog("Got a sensor event: " + event.values[0] + ", " + event.values[1] + ", " + event.values[2]); } private void writeLog(String str) { try { Date now = new Date(); mLog.write(mTimeFormat.format(now)); mLog.write(str); mLog.write("\n"); } catch(IOException ioe) { ioe.printStackTrace(); } } } 

Enjoyyyy