An image view with an inner stroke overlaying the actual image

StrokeOverlayImageView.java

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.widget.ImageView;

public class StrokeOverlayImageView extends ImageView {

    private final int DEFAULT_BORDER_COLOR = 0x26000000;
    private final int DEFAULT_BORDER_WIDTH = 1; // width in pixels

    private Paint mBorderPaint;
    private Rect mBorderBounds;

    public StrokeOverlayImageView(Context context) {
        super(context);
        init();
    }

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

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

    private void init() {
        mBorderPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mBorderPaint.setStyle(Paint.Style.STROKE);
        mBorderPaint.setColor(DEFAULT_BORDER_COLOR);
        mBorderPaint.setStrokeWidth(DEFAULT_BORDER_WIDTH * 2); // the stroke is centered, so we multiply by two to have the right inner stroke width
        mBorderBounds = new Rect();
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        mBorderBounds.set(
            getPaddingLeft(),
            getPaddingTop(),
            getMeasuredWidth() - getPaddingRight(),
            getMeasuredHeight() - getPaddingBottom()
        );
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.drawRect(mBorderBounds, mBorderPaint);
    }
}