我用shape = "oval"代替下面的"ring"。这对我很有效。为了保持图像在边界内，我使用<padding>并在<ImageView>中设置<adjustViewBounds>为true。我尝试过大小在50 x 50 px到200x200 px之间的图像。

你可以做一个简单的圆，有白色边框，透明内容的形状。

// res/drawable/circle.xml

<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:innerRadius="0dp"
    android:shape="ring"
    android:thicknessRatio="1.9"
    android:useLevel="false" >
    <solid android:color="@android:color/transparent" />

    <stroke
        android:width="10dp"
        android:color="@android:color/white" />
</shape>

然后制作一个可绘制的图层列表，并将其作为imageview的背景。

// res/drawable/img.xml

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

    <item android:drawable="@drawable/circle"/>    
    <item android:drawable="@drawable/ic_launcher"/>

</layer-list>

把它作为imageview的背景。

   <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="@drawable/img"/>

你会得到类似的东西。

实际上，你可以使用谷歌提供的支持库RoundedBitmapDrawableFactory类(这里和这里)，而不是使用第三方库:

Gradle:

implementation 'androidx.appcompat:appcompat:1.0.0-beta01'

MainActivity.kt

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        val originalDrawable = ContextCompat.getDrawable(this, R.drawable.avatar_1)!!
        val bitmap = convertDrawableToBitmap(originalDrawable)
        val drawable = RoundedBitmapDrawableFactory.create(resources, bitmap)
        drawable.setAntiAlias(true)
        drawable.cornerRadius = Math.max(bitmap.width, bitmap.height) / 2.0f
        avatarImageView.setImageDrawable(drawable)
    }

    companion object {
        @JvmStatic
        fun convertDrawableToBitmap(drawable: Drawable): Bitmap {
            if (drawable is BitmapDrawable)
                return drawable.bitmap
            // We ask for the bounds if they have been set as they would be most
            // correct, then we check we are  > 0
            val bounds = drawable.bounds
            val width = if (!bounds.isEmpty) bounds.width() else drawable.intrinsicWidth
            val height = if (!bounds.isEmpty) bounds.height() else drawable.intrinsicHeight
            // Now we check we are > 0
            val bitmap = Bitmap.createBitmap(if (width <= 0) 1 else width, if (height <= 0) 1 else height,
                    Bitmap.Config.ARGB_8888)
            val canvas = Canvas(bitmap)
            drawable.setBounds(0, 0, canvas.width, canvas.height)
            drawable.draw(canvas)
            return bitmap
        }
    }
}

xml res - - activity_main布局。

<FrameLayout
    xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent" tools:context=".MainActivity">

    <androidx.appcompat.widget.AppCompatImageView
        android:id="@+id/avatarImageView" android:layout_width="100dp" android:layout_height="100dp"
        android:layout_gravity="center"/>

</FrameLayout>

res - drawable avatar_1 xml。

<vector xmlns:android="http://schemas.android.com/apk/res/android" android:width="128dp" android:height="128dp"
        android:viewportHeight="128.0" android:viewportWidth="128.0">
    <path
        android:fillColor="#FF8A80" android:pathData="M0 0h128v128h-128z"/>
    <path
        android:fillColor="#FFE0B2"
        android:pathData="M36.3 94.8c6.4 7.3 16.2 12.1 27.3 12.4 10.7,-.3 20.3,-4.7 26.7,-11.6l.2.1c-17,-13.3,-12.9,-23.4,-8.5,-28.6 1.3,-1.2 2.8,-2.5 4.4,-3.9l13.1,-11c1.5,-1.2 2.6,-3 2.9,-5.1.6,-4.4,-2.5,-8.4,-6.9,-9.1,-1.5,-.2,-3 0,-4.3.6,-.3,-1.3,-.4,-2.7,-1.6,-3.5,-1.4,-.9,-2.8,-1.7,-4.2,-2.5,-7.1,-3.9,-14.9,-6.6,-23,-7.9,-5.4,-.9,-11,-1.2,-16.1.7,-3.3 1.2,-6.1 3.2,-8.7 5.6,-1.3 1.2,-2.5 2.4,-3.7 3.7l-1.8 1.9c-.3.3,-.5.6,-.8.8,-.1.1,-.2 0,-.4.2.1.2.1.5.1.6,-1,-.3,-2.1,-.4,-3.2,-.2,-4.4.6,-7.5 4.7,-6.9 9.1.3 2.1 1.3 3.8 2.8 5.1l11 9.3c1.8 1.5 3.3 3.8 4.6 5.7 1.5 2.3 2.8 4.9 3.5 7.6 1.7 6.8,-.8 13.4,-5.4 18.4,-.5.6,-1.1 1,-1.4 1.7,-.2.6,-.4 1.3,-.6 2,-.4 1.5,-.5 3.1,-.3 4.6.4 3.1 1.8 6.1 4.1 8.2 3.3 3 8 4 12.4 4.5 5.2.6 10.5.7 15.7.2 4.5,-.4 9.1,-1.2 13,-3.4 5.6,-3.1 9.6,-8.9 10.5,-15.2m-14.4,-49.8c.9 0 1.6.7 1.6 1.6 0 .9,-.7 1.6,-1.6 1.6,-.9 0,-1.6,-.7,-1.6,-1.6,-.1,-.9.7,-1.6 1.6,-1.6zm-25.7 0c.9 0 1.6.7 1.6 1.6 0 .9,-.7 1.6,-1.6 1.6,-.9 0,-1.6,-.7,-1.6,-1.6,-.1,-.9.7,-1.6 1.6,-1.6z"/>
    <path
        android:fillColor="#E0F7FA"
        android:pathData="M105.3 106.1c-.9,-1.3,-1.3,-1.9,-1.3,-1.9l-.2,-.3c-.6,-.9,-1.2,-1.7,-1.9,-2.4,-3.2,-3.5,-7.3,-5.4,-11.4,-5.7 0 0 .1 0 .1.1l-.2,-.1c-6.4 6.9,-16 11.3,-26.7 11.6,-11.2,-.3,-21.1,-5.1,-27.5,-12.6,-.1.2,-.2.4,-.2.5,-3.1.9,-6 2.7,-8.4 5.4l-.2.2s-.5.6,-1.5 1.7c-.9 1.1,-2.2 2.6,-3.7 4.5,-3.1 3.9,-7.2 9.5,-11.7 16.6,-.9 1.4,-1.7 2.8,-2.6 4.3h109.6c-3.4,-7.1,-6.5,-12.8,-8.9,-16.9,-1.5,-2.2,-2.6,-3.8,-3.3,-5z"/>
    <path
        android:fillColor="#444" android:pathData="M76.3,47.5 m-2.0, 0 a 2.0,2.0 0 1,1 4.0,0 a2.0,2.0 0 1,1 -4.0,0"/>
    <path
        android:fillColor="#444" android:pathData="M50.7,47.6 m-2.0, 0 a 2.0,2.0 0 1,1 4.0,0 a2.0,2.0 0 1,1 -4.0,0"/>
    <path
        android:fillColor="#444"
        android:pathData="M48.1 27.4c4.5 5.9 15.5 12.1 42.4 8.4,-2.2,-6.9,-6.8,-12.6,-12.6,-16.4 17.2 1.5 14.1,-9.4 14.1,-9.4,-1.4 5.5,-11.1 4.4,-11.1 4.4h-18.8c-1.7,-.1,-3.4 0,-5.2.3,-12.8 1.8,-22.6 11.1,-25.7 22.9 10.6,-1.9 15.3,-7.6 16.9,-10.2z"/>
</vector>

结果:

并且，假设你想在它上面添加一个边框，你可以使用下面的例子:

stroke_drawable.xml

<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="oval">
    <stroke
        android:width="4dp" android:color="@android:color/black"/>
</shape>

并添加android:前台="@drawable/stroke_drawable"到布局XML文件中的ImageView，你会得到这个:

不过，我不确定如何添加阴影(这将适用于较旧的Android版本)。使用FloatingActionButton(从“com.google.android. button”材料:材料"依赖)，我未能使位图填充FAB本身。如果它能起作用，那么使用它会更好。

编辑:如果你想添加立面阴影(可从API 21)，你可以改变一点我写的:

在布局XML文件内部:

<androidx.appcompat.widget.AppCompatImageView android:padding="4dp"
    android:id="@+id/avatarImageView" android:layout_width="100dp" android:layout_height="100dp" android:elevation="8dp"
    android:layout_gravity="center" android:background="@drawable/stroke_drawable" tools:srcCompat="@drawable/avatar_1"/>

CircularShadowViewOutlineProvider.kt

@TargetApi(Build.VERSION_CODES.LOLLIPOP)
class CircularShadowViewOutlineProvider : ViewOutlineProvider() {
    override fun getOutline(view: View, outline: Outline) {
        val size = Math.max(view.width, view.height)
        outline.setRoundRect(0, 0, size, size, size / 2f)
    }
}

在代码:

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP)
        avatarImageView.outlineProvider = CircularShadowViewOutlineProvider()

结果:

另一种不使用任何库的方法是使用ImageFilterView，并设置视图的圆百分比将使圆

app: roundPercent =“1”

  <androidx.constraintlayout.utils.widget.ImageFilterView
        android:id="@+id/ivProfile"
        android:layout_width="150dp"
        android:layout_height="150dp"
        android:src="@drawable/custom_button_1"
        app:roundPercent="1"
        android:scaleType="fitXY"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintBottom_toTopOf="@+id/etName"/>

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。

如果您希望将图像切割成圆形显示，可以这样做

public static Bitmap getCircularBitmap(Bitmap bitmap) {
        Bitmap output;

        if (bitmap.getWidth() > bitmap.getHeight()) {
            output = Bitmap.createBitmap(bitmap.getHeight(), bitmap.getHeight(), Bitmap.Config.ARGB_8888);
        } else {
            output = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getWidth(), Bitmap.Config.ARGB_8888);
        }

        Canvas canvas = new Canvas(output);

        final int color = 0xff424242;
        final Paint paint = new Paint();
        final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());

        float r = 0;

        if (bitmap.getWidth() > bitmap.getHeight()) {
            r = bitmap.getHeight() / 2;
        } else {
            r = bitmap.getWidth() / 2;
        }

        paint.setAntiAlias(true);
        canvas.drawARGB(0, 0, 0, 0);
        paint.setColor(color);
        canvas.drawCircle(r, r, r, paint);
        paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
        canvas.drawBitmap(bitmap, rect, rect, paint);
        return output;
    }