Detect device orientation when Activity orientation is locked

Question

In my project, I have to lock the orientation of an activity. (I cannot recreate the activity)

I want to display a message when the user change the orientation of th

Answer 1

It can also be solved with SensorManager. Here is a simple demo shows how to keep image orientation correct for locked activity to portrait:

MainActivity :

import android.content.Context;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.Surface;
import android.widget.ImageView;

public class MainActivity extends AppCompatActivity {
    private ImageView img;

    private SensorManager mSensorManager;
    private Sensor mOrientation;

    float value_0 = -10000;
    float value_1 = -10000;
    private SensorEventListener mOrientationSensorListener = new SensorEventListener() {
        int orientation = -1;

        @Override
        public void onSensorChanged(SensorEvent event) {
            int value ;
            if(value_0 == event.values[0] && value_1==event.values[1]){
                return;
            }
//            Log.d("values:", "values:" + event.values[0]+", "+event.values[1]);
            if (event.values[1] > 0 && event.values[0] == 0) {
                value = Surface.ROTATION_0;//portrait
                if (orientation != value) {
                    updateImageRotation(value);
                    Log.d("orientation", "portrait  + update");
                }
                orientation = value;
                Log.d("orientation", "portrait ");
            }


            if (event.values[1] < 0 && event.values[0] == 0) {
                value = Surface.ROTATION_180;//portrait reverse
                if (orientation != value) {
                    updateImageRotation(value);
                    Log.d("orientation", "portrait reverse + update");
                }
                orientation = value;
                Log.d("orientation", "portrait reverse");
            }

            if (event.values[0] > 0 && event.values[1] == 0) {
                value = Surface.ROTATION_90;//portrait reverse
                if (orientation != value) {
                    updateImageRotation(value);
                    Log.d("orientation", "landscape  + update");
                }
                orientation = value;
                Log.d("orientation", "landscape");
            }

            if (event.values[0] < 0 && event.values[1] == 0) {
                value = Surface.ROTATION_270;//portrait reverse
                if (orientation != value) {
                    updateImageRotation(value);
                    Log.d("orientation", "landscape  + update");
                }
                orientation = value;
                Log.d("orientation", "landscape reverse");
            }

            value_0=event.values[0];
            value_1=event.values[1];
        }

        @Override
        public void onAccuracyChanged(Sensor sensor, int accuracy) {

        }
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        img = (ImageView) findViewById(R.id.img);
        // Get sensor manager
        mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
        // Get the default sensor of specified type
        mOrientation = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
    }

    @Override
    protected void onResume() {
        super.onResume();
        if (mOrientation != null) {
            mSensorManager.registerListener(mOrientationSensorListener, mOrientation,
                    SensorManager.SENSOR_DELAY_GAME);
        }
    }

    @Override
    protected void onPause() {
        super.onPause();
        if (mOrientation != null) {
            mSensorManager.unregisterListener(mOrientationSensorListener);
        }
    }


    private void updateImageRotation(int degree) {

        switch (degree) {
            case Surface.ROTATION_0:
                img.setRotation(0);
                break;
            case Surface.ROTATION_90:
                img.setRotation(90);
                break;
            case Surface.ROTATION_180:
                img.setRotation(180);
                break;
            case Surface.ROTATION_270:
                img.setRotation(270);
                break;
        }
    }
}

In manifest. Orientation is locked to portrait and sensor is required as feature manifest.xml :

activity_main.xml :