在Android中,ImageView默认是一个矩形。如何使它成为一个圆角矩形(剪辑我的位图的所有4个角为圆角矩形)在ImageView?
请注意,从2021年起,只需使用ShapeableImageView
在Android中,ImageView默认是一个矩形。如何使它成为一个圆角矩形(剪辑我的位图的所有4个角为圆角矩形)在ImageView?
请注意,从2021年起,只需使用ShapeableImageView
当前回答
对于上面提到的乔治·沃尔特斯二世,我只是把他的答案扩展了一下,以支持不同的圆角。这可以进一步优化(一些目标矩形重叠),但不是很多。
我知道这个线程有点老了,但它是谷歌上关于如何在Android上圆角ImageViews的查询的顶级结果之一。
/**
* Use this method to scale a bitmap and give it specific rounded corners.
* @param context Context object used to ascertain display density.
* @param bitmap The original bitmap that will be scaled and have rounded corners applied to it.
* @param upperLeft Corner radius for upper left.
* @param upperRight Corner radius for upper right.
* @param lowerRight Corner radius for lower right.
* @param lowerLeft Corner radius for lower left.
* @param endWidth Width to which to scale original bitmap.
* @param endHeight Height to which to scale original bitmap.
* @return Scaled bitmap with rounded corners.
*/
public static Bitmap getRoundedCornerBitmap(Context context, Bitmap bitmap, float upperLeft,
float upperRight, float lowerRight, float lowerLeft, int endWidth,
int endHeight) {
float densityMultiplier = context.getResources().getDisplayMetrics().density;
// scale incoming bitmap to appropriate px size given arguments and display dpi
bitmap = Bitmap.createScaledBitmap(bitmap,
Math.round(endWidth * densityMultiplier),
Math.round(endHeight * densityMultiplier), true);
// create empty bitmap for drawing
Bitmap output = Bitmap.createBitmap(
Math.round(endWidth * densityMultiplier),
Math.round(endHeight * densityMultiplier), Config.ARGB_8888);
// get canvas for empty bitmap
Canvas canvas = new Canvas(output);
int width = canvas.getWidth();
int height = canvas.getHeight();
// scale the rounded corners appropriately given dpi
upperLeft *= densityMultiplier;
upperRight *= densityMultiplier;
lowerRight *= densityMultiplier;
lowerLeft *= densityMultiplier;
Paint paint = new Paint();
paint.setAntiAlias(true);
paint.setColor(Color.WHITE);
// fill the canvas with transparency
canvas.drawARGB(0, 0, 0, 0);
// draw the rounded corners around the image rect. clockwise, starting in upper left.
canvas.drawCircle(upperLeft, upperLeft, upperLeft, paint);
canvas.drawCircle(width - upperRight, upperRight, upperRight, paint);
canvas.drawCircle(width - lowerRight, height - lowerRight, lowerRight, paint);
canvas.drawCircle(lowerLeft, height - lowerLeft, lowerLeft, paint);
// fill in all the gaps between circles. clockwise, starting at top.
RectF rectT = new RectF(upperLeft, 0, width - upperRight, height / 2);
RectF rectR = new RectF(width / 2, upperRight, width, height - lowerRight);
RectF rectB = new RectF(lowerLeft, height / 2, width - lowerRight, height);
RectF rectL = new RectF(0, upperLeft, width / 2, height - lowerLeft);
canvas.drawRect(rectT, paint);
canvas.drawRect(rectR, paint);
canvas.drawRect(rectB, paint);
canvas.drawRect(rectL, paint);
// set up the rect for the image
Rect imageRect = new Rect(0, 0, width, height);
// set up paint object such that it only paints on Color.WHITE
paint.setXfermode(new AvoidXfermode(Color.WHITE, 255, AvoidXfermode.Mode.TARGET));
// draw resized bitmap onto imageRect in canvas, using paint as configured above
canvas.drawBitmap(bitmap, imageRect, imageRect, paint);
return output;
}
其他回答
你可以在你的布局中只使用ImageView,使用滑动,你可以使用这个方法应用圆角。
首先在你的gradle里写上,
compile 'com.github.bumptech.glide:glide:3.7.0'
对于有圆角的图像,
public void loadImageWithCorners(String url, ImageView view) {
Glide.with(context)
.load(url)
.asBitmap()
.centerCrop()
.placeholder(R.color.gray)
.error(R.color.gray)
.diskCacheStrategy(DiskCacheStrategy.SOURCE)
.into(new BitmapImageViewTarget(view) {
@Override
protected void setResource(Bitmap resource) {
RoundedBitmapDrawable circularBitmapDrawable =
RoundedBitmapDrawableFactory.create(context.getResources(), resource);
circularBitmapDrawable.setCornerRadius(32.0f); // radius for corners
view.setImageDrawable(circularBitmapDrawable);
}
});
}
调用方法:
loadImageWithCorners("your url","your imageview");
因为所有的答案对我来说都太复杂了,只是为了圆角,我想到了另一个解决方案,我认为值得分享,只是XML,以防你在图像周围有一些空间:
创建一个带有透明内容的带边框的形状,如下所示:
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<corners
android:radius="30dp" />
<stroke
android:color="#ffffffff"
android:width="10dp" />
</shape>
然后在RelativeLayout中,你可以先放置你的图像,然后在相同的位置上面的形状与另一个ImageView。封面形状的大小应与边框宽度相等。注意,要取一个较大的角半径,因为外半径已被定义,但内半径是覆盖你的图像。
希望它也能帮助到别人。
根据CQM请求编辑相关布局示例:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<ImageView
android:id="@+id/imageToShow"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/imgCorners"
android:layout_alignLeft="@+id/imgCorners"
android:layout_alignRight="@+id/imgCorners"
android:layout_alignTop="@+id/imgCorners"
android:background="#ffffff"
android:contentDescription="@string/desc"
android:padding="5dp"
android:scaleType="centerCrop" />
<ImageView
android:id="@+id/imgCorners"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:adjustViewBounds="true"
android:contentDescription="@string/desc"
android:src="@drawable/corners_white" />
</RelativeLayout>
有一个很酷的库可以让你塑造imageviews。
这里有一个例子:
<com.github.siyamed.shapeimageview.mask.PorterShapeImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
app:siShape="@drawable/shape_rounded_rectangle"
android:src="@drawable/neo"
app:siSquare="true"/>
形状定义:
<shape android:shape="rectangle" xmlns:android="http://schemas.android.com/apk/res/android">
<corners
android:topLeftRadius="18dp"
android:topRightRadius="18dp"
android:bottomLeftRadius="18dp"
android:bottomRightRadius="18dp" />
<solid android:color="@color/black" />
</shape>
结果:
我的ImageView圆角小部件的实现,(下||上)大小图像到所需的尺寸。它利用了CaspNZ的代码形式。
public class ImageViewRounded extends ImageView {
public ImageViewRounded(Context context) {
super(context);
}
public ImageViewRounded(Context context, AttributeSet attrs) {
super(context, attrs);
}
public ImageViewRounded(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
@Override
protected void onDraw(Canvas canvas) {
BitmapDrawable drawable = (BitmapDrawable) getDrawable();
if (drawable == null) {
return;
}
if (getWidth() == 0 || getHeight() == 0) {
return;
}
Bitmap fullSizeBitmap = drawable.getBitmap();
int scaledWidth = getMeasuredWidth();
int scaledHeight = getMeasuredHeight();
Bitmap mScaledBitmap;
if (scaledWidth == fullSizeBitmap.getWidth() && scaledHeight == fullSizeBitmap.getHeight()) {
mScaledBitmap = fullSizeBitmap;
} else {
mScaledBitmap = Bitmap.createScaledBitmap(fullSizeBitmap, scaledWidth, scaledHeight, true /* filter */);
}
Bitmap roundBitmap = ImageUtilities.getRoundedCornerBitmap(getContext(), mScaledBitmap, 5, scaledWidth, scaledHeight,
false, false, false, false);
canvas.drawBitmap(roundBitmap, 0, 0, null);
}
}
在glide库和RoundedBitmapDrawableFactory类的帮助下,很容易实现。您可能需要创建圆形占位符映像。
Glide.with(context)
.load(imgUrl)
.asBitmap()
.placeholder(R.drawable.placeholder)
.error(R.drawable.placeholder)
.into(new BitmapImageViewTarget(imgProfilePicture) {
@Override
protected void setResource(Bitmap resource) {
RoundedBitmapDrawable drawable = RoundedBitmapDrawableFactory.create(context.getResources(),
Bitmap.createScaledBitmap(resource, 50, 50, false));
drawable.setCornerRadius(10); //drawable.setCircular(true);
imgProfilePicture.setImageDrawable(drawable);
}
});