Android圆形的ImageView

最新推荐文章于 2024-07-11 02:04:57 发布

烤大蒜

最新推荐文章于 2024-07-11 02:04:57 发布

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分类专栏： Android 文章标签： Android imageview

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本文介绍了如何在Android中自定义ImageView实现圆形图片，并解决了使用默认方法导致的图片边缘模糊、无抗锯齿的问题。通过提供一个改进的自定义RoundImageView类的代码，展示了如何在onDraw()方法中应用 PorterDuffXfermode 模式来实现清晰的圆形图像。

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很对不住大家此代码有问题，这样做出来的原形imageview没有抗锯齿，到这图片边缘模糊效果如下：

由于项目需要图片要做成圆形的，只能自定义ImageView，下边自定义的ImageView效果如上图，边缘不抗锯齿，模糊

public class RoundImageView extends ImageView {

public RoundImageView(Context context) {
super(context);
// TODO Auto-generated constructor stub
}

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

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

@Override
protected void onDraw(Canvas canvas) {
Path clipPath = new Path();
int w = this.getWidth();
int h = this.getHeight();
clipPath.addCircle(w / 2, h / 2, w / 2, Path.Direction.CW);
canvas.clipPath(clipPath);
canvas.setDrawFilter(new PaintFlagsDrawFilter(0, Paint.ANTI_ALIAS_FLAG
| Paint.FILTER_BITMAP_FLAG));
super.onDraw(canvas);
}

}

所以不建议用上边的代码了：更改起自定义ImageView的代码，实现圆形ImageView的边缘抗锯齿：效果图如下：

我想大家看到效果了，圆形ImageView边缘已经不在模糊了；其自定义的ImageView的代码如下：

public class RoundImageView extends ImageView {

public RoundImageView(Context context) {
super(context);
// TODO Auto-generated constructor stub
}

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

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

@Override
protected void onDraw(Canvas canvas) {

Drawable drawable = getDrawable();

if (drawable == null) {
return;
}

if (getWidth() == 0 || getHeight() == 0) {
return;
}

Bitmap b = ((BitmapDrawable) drawable).getBitmap();
Bitmap bitmap = b.copy(Bitmap.Config.ARGB_8888, true);

int w = getWidth(), h = getHeight();

Bitmap roundBitmap = getCroppedBitmap(bitmap, w);
canvas.drawBitmap(roundBitmap, 0, 0, null);

}

public static Bitmap getCroppedBitmap(Bitmap bmp, int radius) {
Bitmap sbmp;
if (bmp.getWidth() != radius || bmp.getHeight() != radius)
sbmp = Bitmap.createScaledBitmap(bmp, radius, radius, false);
else
sbmp = bmp;
Bitmap output = Bitmap.createBitmap(sbmp.getWidth(), sbmp.getHeight(),
Config.ARGB_8888);
Canvas canvas = new Canvas(output);

final Paint paint = new Paint();
final Rect rect = new Rect(0, 0, sbmp.getWidth(), sbmp.getHeight());

paint.setAntiAlias(true);
paint.setFilterBitmap(true);
paint.setDither(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(Color.parseColor("#BAB399"));
canvas.drawCircle(sbmp.getWidth() / 2 + 0.7f,
sbmp.getHeight() / 2 + 0.7f, sbmp.getWidth() / 2 + 0.1f, paint);
paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
canvas.drawBitmap(sbmp, rect, rect, paint);

return output;
}

}