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
多亏了melanke,你可以使用一个自定义类并创建一个自定义循环ImageView。
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PorterDuff.Mode;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
public class MLRoundedImageView extends android.support.v7.widget.AppCompatImageView {
public MLRoundedImageView(Context context) {
super(context);
}
public MLRoundedImageView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public MLRoundedImageView(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) {
float smallest = Math.min(bmp.getWidth(), bmp.getHeight());
float factor = smallest / radius;
sbmp = Bitmap.createScaledBitmap(bmp, (int)(bmp.getWidth() / factor), (int)(bmp.getHeight() / factor), false);
} else {
sbmp = bmp;
}
Bitmap output = Bitmap.createBitmap(radius, radius,
Config.ARGB_8888);
Canvas canvas = new Canvas(output);
final int color = 0xffa19774;
final Paint paint = new Paint();
final Rect rect = new Rect(0, 0, radius, radius);
paint.setAntiAlias(true);
paint.setFilterBitmap(true);
paint.setDither(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(Color.parseColor("#BAB399"));
canvas.drawCircle(radius / 2 + 0.7f,
radius / 2 + 0.7f, radius / 2 + 0.1f, paint);
paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
canvas.drawBitmap(sbmp, rect, rect, paint);
return output;
}
}
然后在XML中使用它:
<your.package.name.MLRoundedImageView
..
/>
源
其他回答
我发现这两种方法在提出可行的解决方案时都非常有用。这是我的合成版本,它与像素无关,允许你有一些正方形的角,其余的角具有相同的半径(这是通常的用例)。 感谢以上两种解决方案:
public static Bitmap getRoundedCornerBitmap(Context context, Bitmap input, int pixels , int w , int h , boolean squareTL, boolean squareTR, boolean squareBL, boolean squareBR ) {
Bitmap output = Bitmap.createBitmap(w, h, Config.ARGB_8888);
Canvas canvas = new Canvas(output);
final float densityMultiplier = context.getResources().getDisplayMetrics().density;
final int color = 0xff424242;
final Paint paint = new Paint();
final Rect rect = new Rect(0, 0, w, h);
final RectF rectF = new RectF(rect);
//make sure that our rounded corner is scaled appropriately
final float roundPx = pixels*densityMultiplier;
paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(color);
canvas.drawRoundRect(rectF, roundPx, roundPx, paint);
//draw rectangles over the corners we want to be square
if (squareTL ){
canvas.drawRect(0, h/2, w/2, h, paint);
}
if (squareTR ){
canvas.drawRect(w/2, h/2, w, h, paint);
}
if (squareBL ){
canvas.drawRect(0, 0, w/2, h/2, paint);
}
if (squareBR ){
canvas.drawRect(w/2, 0, w, h/2, paint);
}
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
canvas.drawBitmap(input, 0,0, paint);
return output;
}
我重写了ImageView,把这个放进去,这样我就可以用xml定义它了。 您可能想在这里添加一些super调用所做的逻辑,但我已经对其进行了注释,因为它对我的情况没有帮助。
@Override
protected void onDraw(Canvas canvas) {
//super.onDraw(canvas);
Drawable drawable = getDrawable();
Bitmap b = ((BitmapDrawable)drawable).getBitmap() ;
Bitmap bitmap = b.copy(Bitmap.Config.ARGB_8888, true);
int w = getWidth(), h = getHeight();
Bitmap roundBitmap = CropImageView.getRoundedCornerBitmap( getContext(), bitmap,10 , w, h , true, false,true, false);
canvas.drawBitmap(roundBitmap, 0,0 , null);
}
希望这能有所帮助!
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:
这不是确切的答案,但它是一个类似的解决方案。它可能会帮助那些和我有同样遭遇的人。
我的图像是一个应用程序logo,它的背景是透明的,我正在应用XML渐变作为图像背景。我在imageView中添加了必要的padding/margin,然后添加了这个作为我的背景:
<?xml version="1.0" encoding="utf-8"?>
<!-- This file defines the gradient used on the background of the main activity. -->
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item>
<shape>
<gradient
android:type="linear"
android:startColor="@color/app_color_light_background"
android:endColor="@color/app_color_disabled"
android:angle="90" />
<!-- Round the top corners. -->
<corners
android:topLeftRadius="@dimen/radius_small"
android:topRightRadius="@dimen/radius_small" />
</shape>
</item>
</selector>
尝试材质组件库并使用ShapeableImageView。 大概是这样的:
Java:
imageView=new ShapeableImageView(context);
imageView.setShapeAppearanceModel(
imageView.getShapeAppearanceModel()
.toBuilder()
.setAllCornerSizes(20)
.build());
芬兰湾的科特林:
val imageView = ShapeableImageView(context)
imageView.setShapeAppearanceModel(
imageView.getShapeAppearanceModel()
.toBuilder()
.setAllCornerSizes(20f)
.build())
非常感谢第一个回答。下面是修改后的版本,将矩形图像转换为正方形(和圆形),填充颜色作为参数传递。
public static Bitmap getRoundedBitmap(Bitmap bitmap, int pixels, int color) {
Bitmap inpBitmap = bitmap;
int width = 0;
int height = 0;
width = inpBitmap.getWidth();
height = inpBitmap.getHeight();
if (width <= height) {
height = width;
} else {
width = height;
}
Bitmap output = Bitmap.createBitmap(width, height, Config.ARGB_8888);
Canvas canvas = new Canvas(output);
final Paint paint = new Paint();
final Rect rect = new Rect(0, 0, width, height);
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(inpBitmap, rect, rect, paint);
return output;
}