android - 如何在圆形 ImageView 周围绘制边框？

Question

我需要使用此类在 ImageView 周围绘制红色边框:

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.widget.ImageView;

public class RoundedImageView extends ImageView {

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

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

public RoundedImageView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
}

protected void onDraw(Canvas canvas) {
    float radius = 45.0f;
    Paint bp= new Paint();
    bp.setAntiAlias(true);
    canvas.drawARGB(0, 0, 0, 0);
    bp.setColor(Color.RED);
    bp.setStrokeWidth(16);


    Path clipPath = new Path();
    RectF rect = new RectF(0, 0, this.getWidth(), this.getHeight());
    clipPath.addRoundRect(rect, radius, radius, Path.Direction.CW);
    canvas.drawRoundRect(rect, radius, radius, bp);
    canvas.clipPath(clipPath);

    super.onDraw(canvas);
}
}

但是好像没有画边框？而且我不知道我做错了什么？

谁能帮忙吗？

谢谢

Answer 1

好吧，这就是我最后做的:

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

public class RoundedImageView extends ImageView {

private static final int PADDING = 8;
private static final float STROKE_WIDTH = 16f;

private Paint mBorderPaint;

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

public RoundedImageView(Context context, AttributeSet attrs) {
    this(context, attrs, 0);
    setPadding(PADDING, PADDING, PADDING, PADDING);
}

public RoundedImageView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    initBorderPaint();
}

private void initBorderPaint() {
    mBorderPaint = new Paint();
    mBorderPaint.setAntiAlias(true);
    mBorderPaint.setStyle(Paint.Style.STROKE);
    mBorderPaint.setColor(Color.WHITE);
    mBorderPaint.setStrokeWidth(STROKE_WIDTH);
}

@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    canvas.drawRect(PADDING, PADDING, getWidth() - PADDING, getHeight() - PADDING, mBorderPaint);
}
}

它没有按要求提供圆角，但也不是必须的。这只会在图像周围创建一个边框。