我有一个简单的解决办法。 通过右键单击软件包名称并选择new ->Image asset创建一个新的Image asset。 输入名称(任何名称)和路径(映像在系统中的位置)。 然后单击“下一步”和“完成”。 如果您输入图像名称为“img”，则在mipmap文件夹中自动创建一个名称为“img_round”的圆形图像。

然后，这样做:

<ImageView
        android:layout_width="100dp"
        android:layout_height="100dp"
        android:src="@mipmap/img_round"/>

您的预览可能仍然显示一个矩形图像。但如果你在你的设备上运行应用程序，它将是圆形的。

试试这个。

public class RoundedImageView extends android.support.v7.widget.AppCompatImageView {

    private int borderWidth = 4;
    private int viewWidth;
    private int viewHeight;
    private Bitmap image;
    private Paint paint;
    private Paint paintBorder;
    private BitmapShader shader;

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

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

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

    private void setup()
    {
        paint = new Paint();
        paint.setAntiAlias(true);

        paintBorder = new Paint();
        setBorderColor(Color.WHITE);
        paintBorder.setAntiAlias(true);
        this.setLayerType(LAYER_TYPE_SOFTWARE, paintBorder);

        paintBorder.setShadowLayer(4.0f, 0.0f, 2.0f, Color.WHITE);
    }

    public void setBorderWidth(int borderWidth)
    {
        this.borderWidth = borderWidth;
        this.invalidate();
    }

    public void setBorderColor(int borderColor)
    {
        if (paintBorder != null)
            paintBorder.setColor(borderColor);

        this.invalidate();
    }

    private void loadBitmap()
    {
        BitmapDrawable bitmapDrawable = (BitmapDrawable) this.getDrawable();

        if (bitmapDrawable != null)
            image = bitmapDrawable.getBitmap();
    }

    @SuppressLint("DrawAllocation")
    @Override
    public void onDraw(Canvas canvas)
    {
        loadBitmap();

        if (image != null)
        {
            shader = new BitmapShader(Bitmap.createScaledBitmap(image, canvas.getWidth(), canvas.getHeight(), false), Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
            paint.setShader(shader);
            int circleCenter = viewWidth / 2;
            canvas.drawCircle(circleCenter + borderWidth, circleCenter + borderWidth, circleCenter + borderWidth - 4.0f, paintBorder);
            canvas.drawCircle(circleCenter + borderWidth, circleCenter + borderWidth, circleCenter - 4.0f, paint);
        }
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
    {
        int width = measureWidth(widthMeasureSpec);
        int height = measureHeight(heightMeasureSpec, widthMeasureSpec);

        viewWidth = width - (borderWidth * 2);
        viewHeight = height - (borderWidth * 2);

        setMeasuredDimension(width, height);
    }

    private int measureWidth(int measureSpec)
    {
        int result = 0;
        int specMode = MeasureSpec.getMode(measureSpec);
        int specSize = MeasureSpec.getSize(measureSpec);

        if (specMode == MeasureSpec.EXACTLY)
        {
            result = specSize;
        }
        else
        {
            // Measure the text
            result = viewWidth;
        }

        return result;
    }

    private int measureHeight(int measureSpecHeight, int measureSpecWidth)
    {
        int result = 0;
        int specMode = MeasureSpec.getMode(measureSpecHeight);
        int specSize = MeasureSpec.getSize(measureSpecHeight);

        if (specMode == MeasureSpec.EXACTLY)
        {
            result = specSize;
        }
        else
        {
            result = viewHeight;
        }

        return (result + 2);
     }
 }

然后在布局中使用这个ImageView:

<com.app.Demo.RoundedImageView
     android:id="@+id/iv_profileImage"
     android:layout_width="70dp"
     android:layout_height="70dp"
     android:layout_centerHorizontal="true"
    />

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。

滑翔V4:

Glide.with(context).load(url).apply(RequestOptions.circleCropTransform()).into(imageView);

滑翔V3:

    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.setCircular(true);
                imgProfilePicture.setImageDrawable(drawable);
            }
        });

对于Picasso RoundedTransformation，这是一个非常好的解决方案，提供了一个额外的选择，在顶部或底部边缘的图像。

另一个想法是使用ImageView的clipToOutline属性。

这是一个布局示例:

<androidx.constraintlayout.widget.ConstraintLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <!-- Simple view to draw borders for an image,
         borders will be rounded because of the oval-shaped background. -->
    <View
        android:id="@+id/v_border"
        android:layout_width="50dp"
        android:layout_height="50dp"
        android:background="@drawable/shape_border"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <!-- Image itself: fits the border view, 
         a margin serves as a border width;
         the key point here - is a background shape which will clip the view to its forms. -->
    <ImageView
        android:id="@+id/iv_image"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:layout_margin="4dp"
        android:background="@drawable/shape_oval"
        android:src="@mipmap/ic_launcher"
        app:layout_constraintBottom_toBottomOf="@+id/v_border"
        app:layout_constraintEnd_toEndOf="@+id/v_border"
        app:layout_constraintStart_toStartOf="@+id/v_border"
        app:layout_constraintTop_toTopOf="@+id/v_border" />

</androidx.constraintlayout.widget.ConstraintLayout>

这是我们的shape_border可绘制对象:

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="oval">
    <solid android:color="#FF00FF" />
</shape>

和shape_oval drawable:

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="oval" />

你在代码中唯一要做的就是启用clipToOutline属性:

binding.ivImage.clipToOutline = true

当然，您甚至可以使用一些BindingAdapter来避免这一行代码。

您可以简单地使用CardView，而不需要任何外部库

  <androidx.cardview.widget.CardView
                    android:id="@+id/roundCardView"
                    android:layout_width="40dp"
                    android:layout_height="40dp"
                    android:layout_centerHorizontal="true"
                    android:elevation="0dp"
                    app:cardCornerRadius="20dp">

                    <ImageView
                        android:layout_width="40dp"
                        android:layout_height="40dp"
                        android:src="@drawable/profile" />
</androidx.cardview.widget.CardView>

@Jyotman Singh，答案非常好(对于坚实的背景)，所以我想通过分享可以根据你的需要重新着色的矢量绘图来增强它，而且这很方便，因为矢量整体形状是可伸缩的。

这是矩形-圆形状(@drawable/shape_round_profile_pic):

<?xml version="1.0" encoding="utf-8"?>
<vector xmlns:android="http://schemas.android.com/apk/res/android"
    android:viewportWidth="284"
    android:viewportHeight="284"
    android:width="284dp"
    android:height="284dp">
    <path
        android:pathData="M0 142L0 0l142 0 142 0 0 142 0 142 -142 0 -142 0zm165 137.34231c26.06742 -4.1212 52.67405 -17.543 72.66855 -36.65787 11.82805 -11.30768 20.55487 -22.85153 27.7633 -36.72531C290.23789 158.21592 285.62874 101.14121 253.48951 58.078079 217.58149 9.9651706 154.68849 -10.125717 98.348685 8.5190299 48.695824 24.95084 12.527764 67.047123 3.437787 118.98655 1.4806194 130.16966 1.511302 152.96723 3.4990422 164.5 12.168375 214.79902 47.646316 256.70775 96 273.76783c21.72002 7.66322 44.26673 9.48476 69 5.57448z"
        android:fillColor="#ffffff" /> // you can change frame color
</vector>

用法是一样的:

<FrameLayout
        android:layout_width="70dp"
        android:layout_height="70dp">

        <ImageView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="@drawable/YOUR_PICTURE" />

        <ImageView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="@drawable/shape_round_profile_pic"/>

    </FrameLayout>