Jameo Jameo - 20 days ago 4
Android Question

Get phone orientation when locked into one orientation

This could easily be a duplicate of another question, Im just struggling to figure out what to search for.

My camera app is locked in landscape mode (in the manifest) like this:

android:screenOrientation="landscape"


However, I want to still rotate some UI elements when the device is rotated into portrait (although android will still think its in landscape, but thats on purpose).

So I've tried this to check the orientation

int rotation = this.getWindowManager().getDefaultDisplay()
.getRotation();
int degrees = 0;
switch (rotation) {
case Surface.ROTATION_0:
Log.d("Rotation", "0");
break;
case Surface.ROTATION_90:
Log.d("Rotation", "90");
break;
case Surface.ROTATION_180:
Log.d("Rotation", "180");
break;
case Surface.ROTATION_270:
Log.d("Rotation", "270");
break;
}


And unfortunately it always returns 90, regardless of how I turn the phone. Is there a more robust way to get orientation, regardless of what Android "thinks" the orientation is?

Answer

So after I thought about it, I realized I could just implement a similar algorithm as what Android itself uses to figure out the orientation. I do it using the onSenseorChanged callback

public static final int UPSIDE_DOWN = 3;
public static final int LANDSCAPE_RIGHT = 4;
public static final int PORTRAIT = 1;
public static final int LANDSCAPE_LEFT = 2;
public int mOrientationDeg; //last rotation in degrees
public int mOrientationRounded; //last orientation int from above 
private static final int _DATA_X = 0;
private static final int _DATA_Y = 1;
private static final int _DATA_Z = 2;
private int ORIENTATION_UNKNOWN = -1;
@Override
public void onSensorChanged(SensorEvent event) 
{
    Log.d(TAG, "Sensor Changed");
    float[] values = event.values;
    int orientation = ORIENTATION_UNKNOWN;
    float X = -values[_DATA_X];
    float Y = -values[_DATA_Y];
    float Z = -values[_DATA_Z];        
    float magnitude = X*X + Y*Y;
    // Don't trust the angle if the magnitude is small compared to the y value
    if (magnitude * 4 >= Z*Z) {
        float OneEightyOverPi = 57.29577957855f;
        float angle = (float)Math.atan2(-Y, X) * OneEightyOverPi;
        orientation = 90 - (int)Math.round(angle);
        // normalize to 0 - 359 range
        while (orientation >= 360) {
            orientation -= 360;
        } 
        while (orientation < 0) {
            orientation += 360;
        }
    }
    //^^ thanks to google for that code
    //now we must figure out which orientation based on the degrees
    Log.d("Oreination", ""+orientation);
    if (orientation != mOrientationDeg) 
    {
        mOrientationDeg = orientation;
        //figure out actual orientation
        if(orientation == -1){//basically flat

        }
        else if(orientation <= 45 || orientation > 315){//round to 0
            tempOrientRounded = 1;//portrait
        }
        else if(orientation > 45 && orientation <= 135){//round to 90
            tempOrientRounded = 2; //lsleft
        }
        else if(orientation > 135 && orientation <= 225){//round to 180
            tempOrientRounded = 3; //upside down
        }
        else if(orientation > 225 && orientation <= 315){//round to 270
            tempOrientRounded = 4;//lsright
        }

    }

    if(mOrientationRounded != tempOrientRounded){
            //Orientation changed, handle the change here
        mOrientationRounded = tempOrientRounded;

    }
}

It looks more complecated than it is, but just know that it works(I'd say equally well as the system one works). Dont forget to register your sensor change event listener in onResume and onPause for accelerometer

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