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
我已经通过自定义ImageView完成:
public class RoundRectCornerImageView extends ImageView {
private float radius = 18.0f;
private Path path;
private RectF rect;
public RoundRectCornerImageView(Context context) {
super(context);
init();
}
public RoundRectCornerImageView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public RoundRectCornerImageView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init();
}
private void init() {
path = new Path();
}
@Override
protected void onDraw(Canvas canvas) {
rect = new RectF(0, 0, this.getWidth(), this.getHeight());
path.addRoundRect(rect, radius, radius, Path.Direction.CW);
canvas.clipPath(path);
super.onDraw(canvas);
}
}
使用方法:
<com.mypackage.RoundRectCornerImageView
android:id="@+id/imageView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/image"
android:scaleType="fitXY" />
输出:
希望这对你有所帮助。
其他回答
罗曼盖伊就在那里。
缩小版如下。
Bitmap bitmap = ((BitmapDrawable) getResources().getDrawable(R.drawable.image)).getBitmap();
Bitmap bitmapRounded = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), bitmap.getConfig());
Canvas canvas = new Canvas(bitmapRounded);
Paint paint = new Paint();
paint.setAntiAlias(true);
paint.setShader(new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP));
canvas.drawRoundRect((new RectF(0.0f, 0.0f, bitmap.getWidth(), bitmap.getHeight())), 10, 10, paint);
imageView.setImageBitmap(bitmapRounded);
为什么不在draw()中进行剪辑?
以下是我的解决方案:
用剪切扩展RelativeLayout 将ImageView(或其他视图)放入布局中:
代码:
public class RoundRelativeLayout extends RelativeLayout {
private final float radius;
public RoundRelativeLayout(Context context, AttributeSet attrs) {
super(context, attrs);
TypedArray attrArray = context.obtainStyledAttributes(attrs,
R.styleable.RoundRelativeLayout);
radius = attrArray.getDimension(
R.styleable.RoundRelativeLayout_radius, 0);
}
private boolean isPathValid;
private final Path path = new Path();
private Path getRoundRectPath() {
if (isPathValid) {
return path;
}
path.reset();
int width = getWidth();
int height = getHeight();
RectF bounds = new RectF(0, 0, width, height);
path.addRoundRect(bounds, radius, radius, Direction.CCW);
isPathValid = true;
return path;
}
@Override
protected void dispatchDraw(Canvas canvas) {
canvas.clipPath(getRoundRectPath());
super.dispatchDraw(canvas);
}
@Override
public void draw(Canvas canvas) {
canvas.clipPath(getRoundRectPath());
super.draw(canvas);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int oldWidth = getMeasuredWidth();
int oldHeight = getMeasuredHeight();
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
int newWidth = getMeasuredWidth();
int newHeight = getMeasuredHeight();
if (newWidth != oldWidth || newHeight != oldHeight) {
isPathValid = false;
}
}
}
科特林
import android.graphics.BitmapFactory
import android.os.Bundle
import android.support.v4.graphics.drawable.RoundedBitmapDrawableFactory
import kotlinx.android.synthetic.main.activity_main.*
val bitmap = BitmapFactory.decodeResource(resources, R.drawable.myImage)
val rounded = RoundedBitmapDrawableFactory.create(resources, bitmap)
rounded.cornerRadius = 20f
profileImageView.setImageDrawable(rounded)
为了使ImageView成为圆形,我们可以改变拐角半径:
rounded.isCircular = true
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;
}
你可以很容易地使用roundedImageView库:
compile 'com.makeramen:roundedimageview:2.3.0'
然后:
<com.makeramen.roundedimageview.RoundedImageView
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/img_episode"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:elevation="7dp"
app:riv_border_color="@color/colorPrimary"
app:riv_border_width="1dip"
app:riv_corner_radius="10dip"
app:riv_mutate_background="true"
/>