这里使用ImageLoader

创建DisplayImageOptions:

DisplayImageOptions options = new DisplayImageOptions.Builder()
    // this will make circle, pass the width of image 
    .displayer(new RoundedBitmapDisplayer(getResources().getDimensionPixelSize(R.dimen.image_dimen_menu))) 
    .cacheOnDisc(true)
    .build();

imageLoader.displayImage(url_for_image,ImageView,options);

或者你也可以从Square上使用毕加索图书馆。

Picasso.with(mContext)
    .load(com.app.utility.Constants.BASE_URL+b.image)
    .placeholder(R.drawable.profile)
    .error(R.drawable.profile)
    .transform(new RoundedTransformation(50, 4))
    .resizeDimen(R.dimen.list_detail_image_size, R.dimen.list_detail_image_size)
    .centerCrop()
    .into(v.im_user);

你可以在这里下载RoundedTransformation文件 在这里

通过使用下面的代码，您可以改变顶部角半径

val image = findViewById<ImageView>(R.id.image)
val curveRadius = 20F

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {

    image.outlineProvider = object : ViewOutlineProvider() {

        @RequiresApi(Build.VERSION_CODES.LOLLIPOP)
        override fun getOutline(view: View?, outline: Outline?) {
            outline?.setRoundRect(0, 0, view!!.width, (view.height+curveRadius).toInt(), curveRadius)
        }
    }

    image.clipToOutline = true

}

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;
        }
    }

}

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"
  />

下面是一个覆盖imageView的简单示例，然后你也可以在布局设计器中使用它来预览。

public class RoundedImageView extends ImageView {

    public RoundedImageView(Context context) {
        super(context);
    }

    public RoundedImageView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public RoundedImageView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
    public RoundedImageView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
    }

    @Override
    public void setImageDrawable(Drawable drawable) {
        float radius = 0.1f;
        Bitmap bitmap = ((BitmapDrawable) drawable).getBitmap();
        RoundedBitmapDrawable rid = RoundedBitmapDrawableFactory.create(getResources(), bitmap);
        rid.setCornerRadius(bitmap.getWidth() * radius);
        super.setImageDrawable(rid);
    }
}

这是为了快速解决问题。半径用于所有角落，并基于位图宽度的百分比。

我只是覆盖了setImageDrawable，并使用支持v4方法绘制圆角位图。

用法:

<com.example.widgets.RoundedImageView
        android:layout_width="39dp"
        android:layout_height="39dp"
        android:src="@drawable/your_drawable" />

使用imageView和自定义imageView预览:

您可以尝试这个库- RoundedImageView

它是:

一个快速的ImageView，支持圆角，椭圆形和圆形。CircleImageView的完整超集。

我在我的项目中使用了它，它非常简单。