AspectRatioTextureView.java

import android.content.Context;
import android.os.Build;
import android.support.annotation.IntDef;
import android.support.annotation.RequiresApi;
import android.util.AttributeSet;
import android.view.TextureView;

import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;

/**
 * Created by LiJianxin on 2019/2/16.
 */
public class AspectRatioTextureView extends TextureView {

    private float videoAspectRatio;

    private @ResizeMode int resizeMode;

    @Documented
    @Retention(RetentionPolicy.SOURCE)
    @IntDef({
            RESIZE_FILL,
            RESIZE_FIT,
            RESIZE_CROP
    })
    public @interface ResizeMode {}

    public static final int RESIZE_FILL = 0;

    public static final int RESIZE_FIT = 1;

    public static final int RESIZE_CROP = 2;

    public AspectRatioTextureView(Context context) {
        super(context);
    }

    public AspectRatioTextureView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public AspectRatioTextureView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
    public AspectRatioTextureView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
    }

    public void setAspectRatio(float widthHeightRatio) {
        if (this.videoAspectRatio != widthHeightRatio) {
            this.videoAspectRatio = widthHeightRatio;
            requestLayout();
        }
    }

    /**
     * Sets the {@link ResizeMode}
     *
     * @param resizeMode The {@link ResizeMode}.
     */
    public void setResizeMode(@ResizeMode int resizeMode) {
        if (this.resizeMode != resizeMode) {
            this.resizeMode = resizeMode;
            requestLayout();
        }
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        if (videoAspectRatio <= 0) {
            // Aspect ratio not set.
            return;
        }

        int width = getMeasuredWidth();
        int height = getMeasuredHeight();

        float viewAspectRatio = (float) width / height;
        switch (resizeMode) {
            case RESIZE_FIT:
                if (videoAspectRatio > viewAspectRatio) {
                    height = (int) (width / videoAspectRatio);
                } else {
                    width = (int) (height * videoAspectRatio);
                }
                break;
            case RESIZE_CROP:
                if (videoAspectRatio > viewAspectRatio) {
                    width = (int) (height * videoAspectRatio);
                } else {
                    height = (int) (width / videoAspectRatio);
                }
            default:
            case RESIZE_FILL:
                break;
        }

        super.onMeasure(MeasureSpec.makeMeasureSpec(width, MeasureSpec.EXACTLY), MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY));

    }
}