TermApp/app/src/main/java/com/xypower/mpapp/v2/AutoFitGLView.java

package com.xypower.mpapp.v2;

import android.content.Context;
import android.opengl.GLSurfaceView;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;

public class AutoFitGLView extends GLSurfaceView implements View.OnTouchListener {

    private float mAspectRatio;

    public AutoFitGLView(Context context) {
        this(context, null);
    }

    public AutoFitGLView(Context context, AttributeSet attrs) {
        super(context, attrs);
        setOnTouchListener(this);
    }

    private TouchListener touchListener;

    public void setAspectRatio(int width, int height){
        mAspectRatio = (float)width / height;
        getHolder().setFixedSize(width, height);
        requestLayout();
    }

    @Override
    public boolean onTouch(View v, MotionEvent event) {
        final int actionMasked = event.getActionMasked();
        if (actionMasked != MotionEvent.ACTION_DOWN) {
            return false;
        }

        if (touchListener != null) {
            touchListener.onTouch(event, v.getWidth(), v.getHeight());
        }
        return false;
    }

    public interface TouchListener {
        void onTouch(MotionEvent event, int width, int height);
    }

    public void setTouchListener(TouchListener touchListener) {
        this.touchListener = touchListener;
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        int width = MeasureSpec.getSize(widthMeasureSpec);
        int height = MeasureSpec.getSize(heightMeasureSpec);
        if (mAspectRatio == 0) {
            setMeasuredDimension(width, height);
        }else {
            int newW,newH;
            float actualRatio;
            if (width > height) {
                actualRatio = mAspectRatio;
            }else {
                actualRatio = 1 / mAspectRatio;
            }

            if (width < height * actualRatio){
                newH = height;
                newW = (int) (height * actualRatio);
            }else {
                newW = width;
                newH = (int) (width / actualRatio);
            }
            setMeasuredDimension(newW, newH);

        }
    }
}