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
虽然前两个答案是可行的,但我希望再多描述一点。 比如说,ImageView所在的地方有一个活动或片段。您希望绘制图像并按比例缩放。然后你应该在onCreate或onCreateView中写入如下代码:
LinearLayout rootLayout = (LinearLayout) findViewById(R.id.rootLayout);
ImageView image = (ImageView) findViewById(R.id.image);
// Wait till an activity is visible and image can be measured.
rootLayout.post(new Runnable() {
@Override
public void run() {
// Setting ImageView height with aspect ratio.
Drawable drawable = ContextCompat.getDrawable(getActivity(), R.drawable.your_image);
int height = getImageViewHeight(drawable, image);
// Rounding image corners.
float radius = getResources().getDimension(R.dimen.your_radius_in_dp);
Bitmap bitmap = ((BitmapDrawable) drawable).getBitmap();
Bitmap result = getRoundedBitmap(bitmap, image.getWidth(), height, radius);
image.setImageBitmap(result);
}
});
其中设置新的图像高度为:
public static int getImageViewHeight(Drawable drawable, ImageView imageView) {
imageView.setImageDrawable(drawable);
int width = drawable.getIntrinsicWidth();
int height = 0;
if (width > 0) {
height = (drawable.getIntrinsicHeight() * imageView.getWidth()) / width;
imageView.getLayoutParams().height = height;
imageView.requestLayout();
}
return height;
}
然后,您应该编写一个方法来缩放图像并使其圆角。这里的width和height是位图的新维度(更小或更大)。在下面的例子中,我只圆角上的两个角。
private Bitmap getRoundedBitmap(Bitmap bitmap, int width, int height, float radius) {
// Create scaled bitmap.
Bitmap scaledBitmap = Bitmap.createScaledBitmap(bitmap, width, height, false);
BitmapShader shader = new BitmapShader(scaledBitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
Paint paint = new Paint();
paint.setAntiAlias(true);
paint.setShader(shader);
Bitmap result = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(result);
// First make all corners round.
canvas.drawRoundRect(new RectF(0, 0, width, height), radius, radius, paint);
// Then draw bottom rectangle.
canvas.drawRect(0, height - radius, radius, height, paint);
canvas.drawRect(width - radius, height - radius, width, height, paint);
return result;
}
其他回答
为了Glide 4.x.x
使用下面的简单代码
Glide
.with(context)
.load(uri)
.apply(
RequestOptions()
.circleCrop())
.into(imageView)
下面的代码创建一个圆角矩形布局对象,该对象围绕放置在其中的任何子对象绘制圆角矩形。它还演示了如何在不使用布局xml文件的情况下以编程方式创建视图和布局。
package android.example;
import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.util.TypedValue;
import android.view.ViewGroup.LayoutParams;
import android.widget.LinearLayout;
import android.widget.TextView;
public class MessageScreen extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
int mainBackgroundColor = Color.parseColor("#2E8B57");
int labelTextColor = Color.parseColor("#FF4500");
int messageBackgroundColor = Color.parseColor("#3300FF");
int messageTextColor = Color.parseColor("#FFFF00");
DisplayMetrics metrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(metrics);
float density = metrics.density;
int minMarginSize = Math.round(density * 8);
int paddingSize = minMarginSize * 2;
int maxMarginSize = minMarginSize * 4;
TextView label = new TextView(this);
/*
* The LayoutParams are instructions to the Layout that will contain the
* View for laying out the View, so you need to use the LayoutParams of
* the Layout that will contain the View.
*/
LinearLayout.LayoutParams labelLayoutParams = new LinearLayout.LayoutParams(
LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
label.setLayoutParams(labelLayoutParams);
label.setTextSize(TypedValue.COMPLEX_UNIT_SP, 18);
label.setPadding(paddingSize, paddingSize, paddingSize, paddingSize);
label.setText(R.string.title);
label.setTextColor(labelTextColor);
TextView message = new TextView(this);
RoundedRectangle.LayoutParams messageLayoutParams = new RoundedRectangle.LayoutParams(
LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);
/*
* This is one of the calls must made to force a ViewGroup to call its
* draw method instead of just calling the draw method of its children.
* This tells the RoundedRectangle to put some extra space around the
* View.
*/
messageLayoutParams.setMargins(minMarginSize, paddingSize,
minMarginSize, maxMarginSize);
message.setLayoutParams(messageLayoutParams);
message.setTextSize(TypedValue.COMPLEX_UNIT_SP, paddingSize);
message.setText(R.string.message);
message.setTextColor(messageTextColor);
message.setBackgroundColor(messageBackgroundColor);
RoundedRectangle messageContainer = new RoundedRectangle(this);
LinearLayout.LayoutParams messageContainerLayoutParams = new LinearLayout.LayoutParams(
LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);
messageContainerLayoutParams.setMargins(paddingSize, 0, paddingSize, 0);
messageContainer.setLayoutParams(messageContainerLayoutParams);
messageContainer.setOrientation(LinearLayout.VERTICAL);
/*
* This is one of the calls must made to force a ViewGroup to call its
* draw method instead of just calling the draw method of its children.
* This tells the RoundedRectangle to color the the exta space that was
* put around the View as well as the View. This is exterior color of
* the RoundedRectangle.
*/
messageContainer.setBackgroundColor(mainBackgroundColor);
/*
* This is one of the calls must made to force a ViewGroup to call its
* draw method instead of just calling the draw method of its children.
* This is the interior color of the RoundedRectangle. It must be
* different than the exterior color of the RoundedRectangle or the
* RoundedRectangle will not call its draw method.
*/
messageContainer.setInteriorColor(messageBackgroundColor);
// Add the message to the RoundedRectangle.
messageContainer.addView(message);
//
LinearLayout main = new LinearLayout(this);
LinearLayout.LayoutParams mainLayoutParams = new LinearLayout.LayoutParams(
LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);
main.setLayoutParams(mainLayoutParams);
main.setOrientation(LinearLayout.VERTICAL);
main.setBackgroundColor(mainBackgroundColor);
main.addView(label);
main.addView(messageContainer);
setContentView(main);
}
}
RoundedRectangle布局对象的类定义如下:
/**
* A LinearLayout that draws a rounded rectangle around the child View that was added to it.
*/
package android.example;
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.widget.LinearLayout;
/**
* A LinearLayout that has rounded corners instead of square corners.
*
* @author Danny Remington
*
* @see LinearLayout
*
*/
public class RoundedRectangle extends LinearLayout {
private int mInteriorColor;
public RoundedRectangle(Context p_context) {
super(p_context);
}
public RoundedRectangle(Context p_context, AttributeSet attributeSet) {
super(p_context, attributeSet);
}
// Listener for the onDraw event that occurs when the Layout is drawn.
protected void onDraw(Canvas canvas) {
Rect rect = new Rect(0, 0, getWidth(), getHeight());
RectF rectF = new RectF(rect);
DisplayMetrics metrics = new DisplayMetrics();
Activity activity = (Activity) getContext();
activity.getWindowManager().getDefaultDisplay().getMetrics(metrics);
float density = metrics.density;
int arcSize = Math.round(density * 10);
Paint paint = new Paint();
paint.setColor(mInteriorColor);
canvas.drawRoundRect(rectF, arcSize, arcSize, paint);
}
/**
* Set the background color to use inside the RoundedRectangle.
*
* @param Primitive int - The color inside the rounded rectangle.
*/
public void setInteriorColor(int interiorColor) {
mInteriorColor = interiorColor;
}
/**
* Get the background color used inside the RoundedRectangle.
*
* @return Primitive int - The color inside the rounded rectangle.
*/
public int getInteriorColor() {
return mInteriorColor;
}
}
在API 21的View类中添加了对圆形形状的剪切。
只要这样做:
创建一个可绘制的圆形形状,就像这样:
res - drawable round_outline xml。
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<corners android:radius="10dp" />
...
</shape>
设置drawable作为ImageView的背景: android:背景= " @drawable / round_outline” 根据这个文档,那么你所需要做的就是添加android:clipToOutline="true"
不幸的是,有一个错误,无法识别该XML属性。幸运的是,我们仍然可以在Java中设置剪辑:
在你的活动或片段中:
下面是它的样子:
注意:
此方法适用于任何可绘制的形状(不仅仅是圆角)。它会剪辑ImageView到你在Drawable xml中定义的任何形状轮廓。
关于ImageViews的特别说明
setClipToOutline()仅在视图的背景设置为可绘制的形状时才有效。如果此背景形状存在,视图将形状的轮廓作为剪切和阴影目的的边界。
这意味着,如果你想使用setClipToOutline()圆角的ImageView,你的图像必须设置使用android:src而不是android:background(因为背景必须设置为您的圆角形状)。如果你必须使用背景来设置你的图像而不是src,你可以使用这个解决方案:
创建一个布局,并将其背景设置为可绘制的形状 将布局包装在ImageView周围(没有填充) ImageView(包括布局中的任何其他内容)现在将以圆角布局形状显示。
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
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>