我有一个ImageView，我想让它带有圆角。
我使用了以下代码：
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle">
<solid android:color="@null"/>
<stroke android:width="1dp"
android:color="#ff000000"/>
<corners android:radius="62px"/>
</shape>
将这段代码设置为我的ImageView的背景。
虽然它能够工作，但是我放在ImageView上的源图片超出了边界，而且不能自适应到新形状。如何解决这个问题？
试试这个：
public class CustomImageView extends ImageView {
public static float radius = 18.0f;
public CustomImageView(Context context) {
super(context);
}
public CustomImageView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public CustomImageView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
@Override
protected void onDraw(Canvas canvas) {
//float radius = 36.0f;
Path clipPath = new Path();
RectF rect = new RectF(0, 0, this.getWidth(), this.getHeight());
clipPath.addRoundRect(rect, radius, radius, Path.Direction.CW);
canvas.clipPath(clipPath);
super.onDraw(canvas);
}
}
和
<your.pack.name.CustomImageView
android:id="@+id/selectIcon"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:scaleType="centerCrop" />
CustomImageView iconImage = (CustomImageView )findViewById(R.id.selectIcon);
iconImage.setImageBitmap(bitmap);
或者,
ImageView iv= new CustomImageView(this);
iv.setImageResource(R.drawable.pic);
奇怪的是，这里没有人提到来自Android Support Library v4的RoundedBitmapDrawable。对我来说，这是最简单的获得无边框圆角的方法。以下是使用示例:
RoundedBitmapDrawable roundedBitmapDrawable = RoundedBitmapDrawableFactory.create(getResources(), bitmap);
final float roundPx = (float) bitmap.getWidth() * 0.06f;
roundedBitmapDrawable.setCornerRadius(roundPx);
RoundedBitmapDrawable的边界>在不设置圆角半径的情况下查看结果。现在再设置圆角半径，再次查看结果！ - S.M.Mousavi编写一个函数，使用canvas将位图进行圆角处理。
public static Bitmap getRoundedCornerBitmap(Bitmap bitmap, int pixels) {
Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap
.getHeight(), Config.ARGB_8888);
Canvas canvas = new Canvas(output);
final int color = 0xff424242;
final Paint paint = new Paint();
final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
final RectF rectF = new RectF(rect);
final float roundPx = pixels;
paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(color);
canvas.drawRoundRect(rectF, roundPx, roundPx, paint);
paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
canvas.drawBitmap(bitmap, rect, rect, paint);
return output;
}
了解更多信息：这里
mPaint.setShadowLayer(radius, dX, dY, shadowColor);canvas.drawRoundRect(rect, cornerRadius, cornerRadius, mPaint); 并使用您的代码使位图角变圆，但是 shadow 和 bitmap 的角不同，我该怎么办？ - Vivek Thummar被接受的答案使用路径裁剪，但它不支持抗锯齿。请参见Romain Guy在他的帖子中的评论。"path clipping does not support antialiasing and you get jagged edges."
http://www.curious-creature.com/2012/12/11/android-recipe-1-image-with-rounded-corners/
有一个好的库（vinc3m1's RoundedImageView）可以在ImageView上支持圆角，但它只支持每个角相同的半径。因此，我做了一个可以在每个角上设置不同半径的库。
它不依赖于路径裁剪或重绘。它只是用canvas.drawPath()方法画一次。所以我最终得到了我想要的结果，就像下面这样。
对我而言，以下方法可以实现这个效果。 :)
该方法接受一个位图对象，并返回带有圆角的位图对象。roundPx是您想要的圆角像素数：
public static Bitmap getRoundedCornerBitmap(Bitmap bitmap) {
Bitmap output = Bitmap.createBitmap(bitmap.getWidth(),
bitmap.getHeight(), Config.ARGB_8888);
Canvas canvas = new Canvas(output);
final int color = 0xff424242;
final Paint paint = new Paint();
final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
final RectF rectF = new RectF(rect);
final float roundPx = 12;
paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(color);
canvas.drawRoundRect(rectF, roundPx, roundPx, paint);
paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
canvas.drawBitmap(bitmap, rect, rect, paint);
return output;
}
你可以使用这个库来代替ImageView，无需进行任何额外的编码。
private static Bitmap createRoundedRectBitmap(@NonNull Bitmap bitmap,
float topLeftCorner, float topRightCorner,
float bottomRightCorner, float bottomLeftCorner) {
Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(),
Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(output);
final int color = Color.WHITE;
final Paint paint = new Paint();
final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
final RectF rectF = new RectF(rect);
Path path = new Path();
float[] radii = new float[]{
topLeftCorner, bottomLeftCorner,
topRightCorner, topRightCorner,
bottomRightCorner, bottomRightCorner,
bottomLeftCorner, bottomLeftCorner
};
paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(color);
path.addRoundRect(rectF, radii, Path.Direction.CW);
canvas.drawPath(path, paint);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
canvas.drawBitmap(bitmap, rect, rect, paint);
return output;
}
然后将其与目标图像一起使用，如下所示：<FrameLayout
android:layout_width="100px"
android:layout_height="100px" >
<ImageView
android:id="@+id/targetImage"
android:layout_width="100px"
android:layout_height="100px"
android:src="@drawable/app_icon"
android:layout_gravity="center" />
<ImageView
android:id="@+id/boxImage"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:scaleType="fitXY"
android:src="@drawable/box" />
ImageView的父布局也是一个不错的解决方案。AppCompatImageView iconView = findViewById(R.id.thumbnail);
iconView.setClipToOutline(true);
<android.support.v7.widget.AppCompatImageView
android:id="@+id/thumbnail"
android:layout_width="80dp"
android:layout_height="80dp"
android:contentDescription="@string/thumbnail"
android:scaleType="centerInside"
android:background="@drawable/round_view" <!--here set the drawable as background -->
tools:src="@mipmap/ic_user" />
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<corners android:radius="10dp" />
</shape>
/**
* Creates new circular bitmap based on original one.
* @param newCornerRadius is optional
*/
fun Bitmap.toCircular(context: Context, newCornerRadius: Float? = null): RoundedBitmapDrawable {
return RoundedBitmapDrawableFactory.create(context.resources, this).apply {
isCircular = true
newCornerRadius?.let {
cornerRadius = it
}
}
}
Kotlin版本
fun Bitmap.roundCorner(pixels: Int): Bitmap {
val output: Bitmap = Bitmap.createBitmap(
width, height, Bitmap.Config.ARGB_8888
)
val canvas = Canvas(output)
val color = -0xbdbdbe
val paint = Paint()
val rect = Rect(0, 0, width, height)
val rectF = RectF(rect)
val roundPx = pixels.toFloat()
paint.isAntiAlias = true
canvas.drawARGB(0, 0, 0, 0)
paint.color = color
canvas.drawRoundRect(rectF, roundPx, roundPx, paint)
paint.xfermode = PorterDuffXfermode(PorterDuff.Mode.SRC_IN)
canvas.drawBitmap(this, rect, rect, paint)
return output
}
调用方式：
sourceBitmap.roundCorner(60)
ImageView设置padding应该可以解决这个问题。 - user2652394