共三个文件，和一些自定义属性，根据自己的需求使用
先看一下效果，边框宽度颜色都可以设置，也可以改变其中某个角的度数


一：Corner注解
@Retention(RetentionPolicy.SOURCE)
@IntDef({
		Corner.TOP_LEFT, Corner.TOP_RIGHT,
		Corner.BOTTOM_LEFT, Corner.BOTTOM_RIGHT
})
public @interface Corner {
	int TOP_LEFT = 0;
	int TOP_RIGHT = 1;
	int BOTTOM_RIGHT = 2;
	int BOTTOM_LEFT = 3;
}

二：RoundedDrawable类
@SuppressWarnings("UnusedDeclaration")
public class RoundedDrawable extends Drawable {

	public static final String TAG = "RoundedDrawable";
	public static final int DEFAULT_BORDER_COLOR = Color.BLACK;

	private final RectF mBounds = new RectF();
	private final RectF mDrawableRect = new RectF();
	private final RectF mBitmapRect = new RectF();
	private final Bitmap mBitmap;
	private final Paint mBitmapPaint;
	private final int mBitmapWidth;
	private final int mBitmapHeight;
	private final RectF mBorderRect = new RectF();
	private final Paint mBorderPaint;
	private final Matrix mShaderMatrix = new Matrix();
	private final RectF mSquareCornersRect = new RectF();

	private Shader.TileMode mTileModeX = Shader.TileMode.CLAMP;
	private Shader.TileMode mTileModeY = Shader.TileMode.CLAMP;
	private boolean mRebuildShader = true;

	private float mCornerRadius = 0f;
	// [ topLeft, topRight, bottomLeft, bottomRight ]
	private final boolean[] mCornersRounded = new boolean[]{true, true, true, true};

	private boolean mOval = false;
	private float mBorderWidth = 0;
	private ColorStateList mBorderColor = ColorStateList.valueOf(DEFAULT_BORDER_COLOR);
	private ScaleType mScaleType = ScaleType.FIT_CENTER;

	public RoundedDrawable(Bitmap bitmap) {
		mBitmap = bitmap;

		mBitmapWidth = bitmap.getWidth();
		mBitmapHeight = bitmap.getHeight();
		mBitmapRect.set(0, 0, mBitmapWidth, mBitmapHeight);

		mBitmapPaint = new Paint();
		mBitmapPaint.setStyle(Paint.Style.FILL);
		mBitmapPaint.setAntiAlias(true);

		mBorderPaint = new Paint();
		mBorderPaint.setStyle(Paint.Style.STROKE);
		mBorderPaint.setAntiAlias(true);
		mBorderPaint.setColor(mBorderColor.getColorForState(getState(), DEFAULT_BORDER_COLOR));
		mBorderPaint.setStrokeWidth(mBorderWidth);
	}

	public static RoundedDrawable fromBitmap(Bitmap bitmap) {
		if (bitmap != null) {
			return new RoundedDrawable(bitmap);
		} else {
			return null;
		}
	}

	public static Drawable fromDrawable(Drawable drawable) {
		if (drawable != null) {
			if (drawable instanceof RoundedDrawable) {
				// just return if it's already a RoundedDrawable
				return drawable;
			} else if (drawable instanceof LayerDrawable) {
				LayerDrawable ld = (LayerDrawable) drawable;
				int num = ld.getNumberOfLayers();

				// loop through layers to and change to RoundedDrawables if possible
				for (int i = 0; i < num; i++) {
					Drawable d = ld.getDrawable(i);
					ld.setDrawableByLayerId(ld.getId(i), fromDrawable(d));
				}
				return ld;
			}

			// try to get a bitmap from the drawable and
			Bitmap bm = drawableToBitmap(drawable);
			if (bm != null) {
				return new RoundedDrawable(bm);
			}
		}
		return drawable;
	}

	public static Bitmap drawableToBitmap(Drawable drawable) {
		if (drawable instanceof BitmapDrawable) {
			return ((BitmapDrawable) drawable).getBitmap();
		}

		Bitmap bitmap;
		int width = Math.max(drawable.getIntrinsicWidth(), 2);
		int height = Math.max(drawable.getIntrinsicHeight(), 2);
		try {
			bitmap = Bitmap.createBitmap(width, height, Config.ARGB_8888);
			Canvas canvas = new Canvas(bitmap);
			drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
			drawable.draw(canvas);
		} catch (Throwable e) {
			e.printStackTrace();
			Log.w(TAG, "Failed to create bitmap from drawable!");
			bitmap = null;
		}

		return bitmap;
	}

	public Bitmap getSourceBitmap() {
		return mBitmap;
	}

	@Override
	public boolean isStateful() {
		return mBorderColor.isStateful();
	}

	@Override
	protected boolean onStateChange(int[] state) {
		int newColor = mBorderColor.getColorForState(state, 0);
		if (mBorderPaint.getColor() != newColor) {
			mBorderPaint.setColor(newColor);
			return true;
		} else {
			return super.onStateChange(state);
		}
	}

	private void updateShaderMatrix() {
		float scale;
		float dx;
		float dy;

		switch (mScaleType) {
			case CENTER:
				mBorderRect.set(mBounds);
				mBorderRect.inset(mBorderWidth / 2, mBorderWidth / 2);

				mShaderMatrix.reset();
				mShaderMatrix.setTranslate((int) ((mBorderRect.width() - mBitmapWidth) * 0.5f + 0.5f),
						(int) ((mBorderRect.height() - mBitmapHeight) * 0.5f + 0.5f));
				break;

			case CENTER_CROP:
				mBorderRect.set(mBounds);
				mBorderRect.inset(mBorderWidth / 2, mBorderWidth / 2);

				mShaderMatrix.reset();

				dx = 0;
				dy = 0;

				if (mBitmapWidth * mBorderRect.height() > mBorderRect.width() * mBitmapHeight) {
					scale = mBorderRect.height() / (float) mBitmapHeight;
					dx = (mBorderRect.width() - mBitmapWidth * scale) * 0.5f;
				} else {
					scale = mBorderRect.width() / (float) mBitmapWidth;
					dy = (mBorderRect.height() - mBitmapHeight * scale) * 0.5f;
				}

				mShaderMatrix.setScale(scale, scale);
				mShaderMatrix.postTranslate((int) (dx + 0.5f) + mBorderWidth / 2,
						(int) (dy + 0.5f) + mBorderWidth / 2);
				break;

			case CENTER_INSIDE:
				mShaderMatrix.reset();

				if (mBitmapWidth <= mBounds.width() && mBitmapHeight <= mBounds.height()) {
					scale = 1.0f;
				} else {
					scale = Math.min(mBounds.width() / (float) mBitmapWidth,
							mBounds.height() / (float) mBitmapHeight);
				}

				dx = (int) ((mBounds.width() - mBitmapWidth * scale) * 0.5f + 0.5f);
				dy = (int) ((mBounds.height() - mBitmapHeight * scale) * 0.5f + 0.5f);

				mShaderMatrix.setScale(scale, scale);
				mShaderMatrix.postTranslate(dx, dy);

				mBorderRect.set(mBitmapRect);
				mShaderMatrix.mapRect(mBorderRect);
				mBorderRect.inset(mBorderWidth / 2, mBorderWidth / 2);
				mShaderMatrix.setRectToRect(mBitmapRect, mBorderRect, Matrix.ScaleToFit.FILL);
				break;

			default:
			case FIT_CENTER:
				mBorderRect.set(mBitmapRect);
				mShaderMatrix.setRectToRect(mBitmapRect, mBounds, Matrix.ScaleToFit.CENTER);
				mShaderMatrix.mapRect(mBorderRect);
				mBorderRect.inset(mBorderWidth / 2, mBorderWidth / 2);
				mShaderMatrix.setRectToRect(mBitmapRect, mBorderRect, Matrix.ScaleToFit.FILL);
				break;

			case FIT_END:
				mBorderRect.set(mBitmapRect);
				mShaderMatrix.setRectToRect(mBitmapRect, mBounds, Matrix.ScaleToFit.END);
				mShaderMatrix.mapRect(mBorderRect);
				mBorderRect.inset(mBorderWidth / 2, mBorderWidth / 2);
				mShaderMatrix.setRectToRect(mBitmapRect, mBorderRect, Matrix.ScaleToFit.FILL);
				break;

			case FIT_START:
				mBorderRect.set(mBitmapRect);
				mShaderMatrix.setRectToRect(mBitmapRect, mBounds, Matrix.ScaleToFit.START);
				mShaderMatrix.mapRect(mBorderRect);
				mBorderRect.inset(mBorderWidth / 2, mBorderWidth / 2);
				mShaderMatrix.setRectToRect(mBitmapRect, mBorderRect, Matrix.ScaleToFit.FILL);
				break;

			case FIT_XY:
				mBorderRect.set(mBounds);
				mBorderRect.inset(mBorderWidth / 2, mBorderWidth / 2);
				mShaderMatrix.reset();
				mShaderMatrix.setRectToRect(mBitmapRect, mBorderRect, Matrix.ScaleToFit.FILL);
				break;
		}

		mDrawableRect.set(mBorderRect);
		mRebuildShader = true;
	}

	@Override
	protected void onBoundsChange(@NonNull Rect bounds) {
		super.onBoundsChange(bounds);

		mBounds.set(bounds);

		updateShaderMatrix();
	}

	@Override
	public void draw(@NonNull Canvas canvas) {
		if (mRebuildShader) {
			BitmapShader bitmapShader = new BitmapShader(mBitmap, mTileModeX, mTileModeY);
			if (mTileModeX == Shader.TileMode.CLAMP && mTileModeY == Shader.TileMode.CLAMP) {
				bitmapShader.setLocalMatrix(mShaderMatrix);
			}
			mBitmapPaint.setShader(bitmapShader);
			mRebuildShader = false;
		}

		if (mOval) {
			if (mBorderWidth > 0) {
				canvas.drawOval(mDrawableRect, mBitmapPaint);
				canvas.drawOval(mBorderRect, mBorderPaint);
			} else {
				canvas.drawOval(mDrawableRect, mBitmapPaint);
			}
		} else {
			if (any(mCornersRounded)) {
				float radius = mCornerRadius;
				if (mBorderWidth > 0) {
					canvas.drawRoundRect(mDrawableRect, radius, radius, mBitmapPaint);
					canvas.drawRoundRect(mBorderRect, radius, radius, mBorderPaint);
					redrawBitmapForSquareCorners(canvas);
					redrawBorderForSquareCorners(canvas);
				} else {
					canvas.drawRoundRect(mDrawableRect, radius, radius, mBitmapPaint);
					redrawBitmapForSquareCorners(canvas);
				}
			} else {
				canvas.drawRect(mDrawableRect, mBitmapPaint);
				if (mBorderWidth > 0) {
					canvas.drawRect(mBorderRect, mBorderPaint);
				}
			}
		}
	}

	private void redrawBitmapForSquareCorners(Canvas canvas) {
		if (all(mCornersRounded)) {
			// no square corners
			return;
		}

		if (mCornerRadius == 0) {
			return; // no round corners
		}

		float left = mDrawableRect.left;
		float top = mDrawableRect.top;
		float right = left + mDrawableRect.width();
		float bottom = top + mDrawableRect.height();
		float radius = mCornerRadius;

		if (!mCornersRounded[Corner.TOP_LEFT]) {
			mSquareCornersRect.set(left, top, left + radius, top + radius);
			canvas.drawRect(mSquareCornersRect, mBitmapPaint);
		}

		if (!mCornersRounded[Corner.TOP_RIGHT]) {
			mSquareCornersRect.set(right - radius, top, right, radius);
			canvas.drawRect(mSquareCornersRect, mBitmapPaint);
		}

		if (!mCornersRounded[Corner.BOTTOM_RIGHT]) {
			mSquareCornersRect.set(right - radius, bottom - radius, right, bottom);
			canvas.drawRect(mSquareCornersRect, mBitmapPaint);
		}

		if (!mCornersRounded[Corner.BOTTOM_LEFT]) {
			mSquareCornersRect.set(left, bottom - radius, left + radius, bottom);
			canvas.drawRect(mSquareCornersRect, mBitmapPaint);
		}
	}

	private void redrawBorderForSquareCorners(Canvas canvas) {
		if (all(mCornersRounded)) {
			// no square corners
			return;
		}

		if (mCornerRadius == 0) {
			return; // no round corners
		}

		float left = mDrawableRect.left;
		float top = mDrawableRect.top;
		float right = left + mDrawableRect.width();
		float bottom = top + mDrawableRect.height();
		float radius = mCornerRadius;
		float offset = mBorderWidth / 2;

		if (!mCornersRounded[Corner.TOP_LEFT]) {
			canvas.drawLine(left - offset, top, left + radius, top, mBorderPaint);
			canvas.drawLine(left, top - offset, left, top + radius, mBorderPaint);
		}

		if (!mCornersRounded[Corner.TOP_RIGHT]) {
			canvas.drawLine(right - radius - offset, top, right, top, mBorderPaint);
			canvas.drawLine(right, top - offset, right, top + radius, mBorderPaint);
		}

		if (!mCornersRounded[Corner.BOTTOM_RIGHT]) {
			canvas.drawLine(right - radius - offset, bottom, right + offset, bottom, mBorderPaint);
			canvas.drawLine(right, bottom - radius, right, bottom, mBorderPaint);
		}

		if (!mCornersRounded[Corner.BOTTOM_LEFT]) {
			canvas.drawLine(left - offset, bottom, left + radius, bottom, mBorderPaint);
			canvas.drawLine(left, bottom - radius, left, bottom, mBorderPaint);
		}
	}

	@Override
	public int getOpacity() {
		return PixelFormat.TRANSLUCENT;
	}

	@Override
	public int getAlpha() {
		return mBitmapPaint.getAlpha();
	}

	@Override
	public void setAlpha(int alpha) {
		mBitmapPaint.setAlpha(alpha);
		invalidateSelf();
	}

	@Override
	public ColorFilter getColorFilter() {
		return mBitmapPaint.getColorFilter();
	}

	@Override
	public void setColorFilter(ColorFilter cf) {
		mBitmapPaint.setColorFilter(cf);
		invalidateSelf();
	}

	@Override
	public void setDither(boolean dither) {
		mBitmapPaint.setDither(dither);
		invalidateSelf();
	}

	@Override
	public void setFilterBitmap(boolean filter) {
		mBitmapPaint.setFilterBitmap(filter);
		invalidateSelf();
	}

	@Override
	public int getIntrinsicWidth() {
		return mBitmapWidth;
	}

	@Override
	public int getIntrinsicHeight() {
		return mBitmapHeight;
	}

	/**
	 * @return the corner radius.
	 */
	public float getCornerRadius() {
		return mCornerRadius;
	}

	/**
	 * @param corner the specific corner to get radius of.
	 * @return the corner radius of the specified corner.
	 */
	public float getCornerRadius(@Corner int corner) {
		return mCornersRounded[corner] ? mCornerRadius : 0f;
	}

	/**
	 * Sets all corners to the specified radius.
	 *
	 * @param radius the radius.
	 * @return the {@link RoundedDrawable} for chaining.
	 */
	public RoundedDrawable setCornerRadius(float radius) {
		setCornerRadius(radius, radius, radius, radius);
		return this;
	}

	/**
	 * Sets the corner radius of one specific corner.
	 *
	 * @param corner the corner.
	 * @param radius the radius.
	 * @return the {@link RoundedDrawable} for chaining.
	 */
	public RoundedDrawable setCornerRadius(@Corner int corner, float radius) {
		if (radius != 0 && mCornerRadius != 0 && mCornerRadius != radius) {
			throw new IllegalArgumentException("Multiple nonzero corner radii not yet supported.");
		}

		if (radius == 0) {
			if (only(corner, mCornersRounded)) {
				mCornerRadius = 0;
			}
			mCornersRounded[corner] = false;
		} else {
			if (mCornerRadius == 0) {
				mCornerRadius = radius;
			}
			mCornersRounded[corner] = true;
		}

		return this;
	}

	/**
	 * Sets the corner radii of all the corners.
	 *
	 * @param topLeft     top left corner radius.
	 * @param topRight    top right corner radius
	 * @param bottomRight bototm right corner radius.
	 * @param bottomLeft  bottom left corner radius.
	 * @return the {@link RoundedDrawable} for chaining.
	 */
	public RoundedDrawable setCornerRadius(float topLeft, float topRight, float bottomRight,
										   float bottomLeft) {
		Set<Float> radiusSet = new HashSet<>(4);
		radiusSet.add(topLeft);
		radiusSet.add(topRight);
		radiusSet.add(bottomRight);
		radiusSet.add(bottomLeft);

		radiusSet.remove(0f);

		if (radiusSet.size() > 1) {
			throw new IllegalArgumentException("Multiple nonzero corner radii not yet supported.");
		}

		if (!radiusSet.isEmpty()) {
			float radius = radiusSet.iterator().next();
			if (Float.isInfinite(radius) || Float.isNaN(radius) || radius < 0) {
				throw new IllegalArgumentException("Invalid radius value: " + radius);
			}
			mCornerRadius = radius;
		} else {
			mCornerRadius = 0f;
		}

		mCornersRounded[Corner.TOP_LEFT] = topLeft > 0;
		mCornersRounded[Corner.TOP_RIGHT] = topRight > 0;
		mCornersRounded[Corner.BOTTOM_RIGHT] = bottomRight > 0;
		mCornersRounded[Corner.BOTTOM_LEFT] = bottomLeft > 0;
		return this;
	}

	public float getBorderWidth() {
		return mBorderWidth;
	}

	public RoundedDrawable setBorderWidth(float width) {
		mBorderWidth = width;
		mBorderPaint.setStrokeWidth(mBorderWidth);
		return this;
	}

	public int getBorderColor() {
		return mBorderColor.getDefaultColor();
	}

	public RoundedDrawable setBorderColor(@ColorInt int color) {
		return setBorderColor(ColorStateList.valueOf(color));
	}

	public ColorStateList getBorderColors() {
		return mBorderColor;
	}

	public RoundedDrawable setBorderColor(ColorStateList colors) {
		mBorderColor = colors != null ? colors : ColorStateList.valueOf(0);
		mBorderPaint.setColor(mBorderColor.getColorForState(getState(), DEFAULT_BORDER_COLOR));
		return this;
	}

	public boolean isOval() {
		return mOval;
	}

	public RoundedDrawable setOval(boolean oval) {
		mOval = oval;
		return this;
	}

	public ScaleType getScaleType() {
		return mScaleType;
	}

	public RoundedDrawable setScaleType(ScaleType scaleType) {
		if (scaleType == null) {
			scaleType = ScaleType.FIT_CENTER;
		}
		if (mScaleType != scaleType) {
			mScaleType = scaleType;
			updateShaderMatrix();
		}
		return this;
	}

	public Shader.TileMode getTileModeX() {
		return mTileModeX;
	}

	public RoundedDrawable setTileModeX(Shader.TileMode tileModeX) {
		if (mTileModeX != tileModeX) {
			mTileModeX = tileModeX;
			mRebuildShader = true;
			invalidateSelf();
		}
		return this;
	}

	public Shader.TileMode getTileModeY() {
		return mTileModeY;
	}

	public RoundedDrawable setTileModeY(Shader.TileMode tileModeY) {
		if (mTileModeY != tileModeY) {
			mTileModeY = tileModeY;
			mRebuildShader = true;
			invalidateSelf();
		}
		return this;
	}

	private static boolean only(int index, boolean[] booleans) {
		for (int i = 0, len = booleans.length; i < len; i++) {
			if (booleans[i] != (i == index)) {
				return false;
			}
		}
		return true;
	}

	private static boolean any(boolean[] booleans) {
		for (boolean b : booleans) {
			if (b) {
				return true;
			}
		}
		return false;
	}

	private static boolean all(boolean[] booleans) {
		for (boolean b : booleans) {
			if (b) {
				return false;
			}
		}
		return true;
	}

	public Bitmap toBitmap() {
		return drawableToBitmap(this);
	}
}

三：RoundedImageView类
@SuppressWarnings("UnusedDeclaration")
public class RoundedImageView extends AppCompatImageView {

	// Constants for tile mode attributes
	private static final int TILE_MODE_UNDEFINED = -2;
	private static final int TILE_MODE_CLAMP = 0;
	private static final int TILE_MODE_REPEAT = 1;
	private static final int TILE_MODE_MIRROR = 2;

	public static final String TAG = "RoundedImageView";
	public static final float DEFAULT_RADIUS = 0f;
	public static final float DEFAULT_BORDER_WIDTH = 0f;
	public static final Shader.TileMode DEFAULT_TILE_MODE = Shader.TileMode.CLAMP;
	private static final ScaleType[] SCALE_TYPES = {
			ScaleType.MATRIX,
			ScaleType.FIT_XY,
			ScaleType.FIT_START,
			ScaleType.FIT_CENTER,
			ScaleType.FIT_END,
			ScaleType.CENTER,
			ScaleType.CENTER_CROP,
			ScaleType.CENTER_INSIDE
	};

	private final float[] mCornerRadii =
			new float[] { DEFAULT_RADIUS, DEFAULT_RADIUS, DEFAULT_RADIUS, DEFAULT_RADIUS };

	private Drawable mBackgroundDrawable;
	private ColorStateList mBorderColor =
			ColorStateList.valueOf(RoundedDrawable.DEFAULT_BORDER_COLOR);
	private float mBorderWidth = DEFAULT_BORDER_WIDTH;
	private ColorFilter mColorFilter = null;
	private boolean mColorMod = false;
	private Drawable mDrawable;
	private boolean mHasColorFilter = false;
	private boolean mIsOval = false;
	private boolean mMutateBackground = false;
	private int mResource;
	private int mBackgroundResource;
	private ScaleType mScaleType;
	private Shader.TileMode mTileModeX = DEFAULT_TILE_MODE;
	private Shader.TileMode mTileModeY = DEFAULT_TILE_MODE;

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

	public RoundedImageView(Context context, AttributeSet attrs) {
		this(context, attrs, 0);
	}

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

		TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.RoundedImageView, defStyle, 0);

		int index = a.getInt(R.styleable.RoundedImageView_android_scaleType, -1);
		if (index >= 0) {
			setScaleType(SCALE_TYPES[index]);
		} else {
			// default scaletype to FIT_CENTER
			setScaleType(ScaleType.FIT_CENTER);
		}

		float cornerRadiusOverride =
				a.getDimensionPixelSize(R.styleable.RoundedImageView_riv_corner_radius, -1);

		mCornerRadii[Corner.TOP_LEFT] =
				a.getDimensionPixelSize(R.styleable.RoundedImageView_riv_corner_radius_top_left, -1);
		mCornerRadii[Corner.TOP_RIGHT] =
				a.getDimensionPixelSize(R.styleable.RoundedImageView_riv_corner_radius_top_right, -1);
		mCornerRadii[Corner.BOTTOM_RIGHT] =
				a.getDimensionPixelSize(R.styleable.RoundedImageView_riv_corner_radius_bottom_right, -1);
		mCornerRadii[Corner.BOTTOM_LEFT] =
				a.getDimensionPixelSize(R.styleable.RoundedImageView_riv_corner_radius_bottom_left, -1);

		boolean any = false;
		for (int i = 0, len = mCornerRadii.length; i < len; i++) {
			if (mCornerRadii[i] < 0) {
				mCornerRadii[i] = 0f;
			} else {
				any = true;
			}
		}

		if (!any) {
			if (cornerRadiusOverride < 0) {
				cornerRadiusOverride = DEFAULT_RADIUS;
			}
			for (int i = 0, len = mCornerRadii.length; i < len; i++) {
				mCornerRadii[i] = cornerRadiusOverride;
			}
		}

		mBorderWidth = a.getDimensionPixelSize(R.styleable.RoundedImageView_riv_border_width, -1);
		if (mBorderWidth < 0) {
			mBorderWidth = DEFAULT_BORDER_WIDTH;
		}

		mBorderColor = a.getColorStateList(R.styleable.RoundedImageView_riv_border_color);
		if (mBorderColor == null) {
			mBorderColor = ColorStateList.valueOf(RoundedDrawable.DEFAULT_BORDER_COLOR);
		}

		mMutateBackground = a.getBoolean(R.styleable.RoundedImageView_riv_mutate_background, false);
		mIsOval = a.getBoolean(R.styleable.RoundedImageView_riv_oval, false);

		final int tileMode = a.getInt(R.styleable.RoundedImageView_riv_tile_mode, TILE_MODE_UNDEFINED);
		if (tileMode != TILE_MODE_UNDEFINED) {
			setTileModeX(parseTileMode(tileMode));
			setTileModeY(parseTileMode(tileMode));
		}

		final int tileModeX =
				a.getInt(R.styleable.RoundedImageView_riv_tile_mode_x, TILE_MODE_UNDEFINED);
		if (tileModeX != TILE_MODE_UNDEFINED) {
			setTileModeX(parseTileMode(tileModeX));
		}

		final int tileModeY =
				a.getInt(R.styleable.RoundedImageView_riv_tile_mode_y, TILE_MODE_UNDEFINED);
		if (tileModeY != TILE_MODE_UNDEFINED) {
			setTileModeY(parseTileMode(tileModeY));
		}

		updateDrawableAttrs();
		updateBackgroundDrawableAttrs(true);

		if (mMutateBackground) {
			//noinspection deprecation
			super.setBackgroundDrawable(mBackgroundDrawable);
		}

		a.recycle();
	}

	private static Shader.TileMode parseTileMode(int tileMode) {
		switch (tileMode) {
			case TILE_MODE_CLAMP:
				return Shader.TileMode.CLAMP;
			case TILE_MODE_REPEAT:
				return Shader.TileMode.REPEAT;
			case TILE_MODE_MIRROR:
				return Shader.TileMode.MIRROR;
			default:
				return null;
		}
	}

	@Override
	protected void drawableStateChanged() {
		super.drawableStateChanged();
		invalidate();
	}

	@Override
	public ScaleType getScaleType() {
		return mScaleType;
	}

	@Override
	public void setScaleType(ScaleType scaleType) {
		assert scaleType != null;

		if (mScaleType != scaleType) {
			mScaleType = scaleType;

			switch (scaleType) {
				case CENTER:
				case CENTER_CROP:
				case CENTER_INSIDE:
				case FIT_CENTER:
				case FIT_START:
				case FIT_END:
				case FIT_XY:
					super.setScaleType(ScaleType.FIT_XY);
					break;
				default:
					super.setScaleType(scaleType);
					break;
			}

			updateDrawableAttrs();
			updateBackgroundDrawableAttrs(false);
			invalidate();
		}
	}

	@Override
	public void setImageDrawable(Drawable drawable) {
		mResource = 0;
		mDrawable = RoundedDrawable.fromDrawable(drawable);
		updateDrawableAttrs();
		super.setImageDrawable(mDrawable);
	}

	@Override
	public void setImageBitmap(Bitmap bm) {
		mResource = 0;
		mDrawable = RoundedDrawable.fromBitmap(bm);
		updateDrawableAttrs();
		super.setImageDrawable(mDrawable);
	}

	@Override
	public void setImageResource(@DrawableRes int resId) {
		if (mResource != resId) {
			mResource = resId;
			mDrawable = resolveResource();
			updateDrawableAttrs();
			super.setImageDrawable(mDrawable);
		}
	}

	@Override public void setImageURI(Uri uri) {
		super.setImageURI(uri);
		setImageDrawable(getDrawable());
	}

	private Drawable resolveResource() {
		Resources rsrc = getResources();
		if (rsrc == null) { return null; }

		Drawable d = null;

		if (mResource != 0) {
			try {
				d = rsrc.getDrawable(mResource);
			} catch (Exception e) {
				Log.w(TAG, "Unable to find resource: " + mResource, e);
				// Don't try again.
				mResource = 0;
			}
		}
		return RoundedDrawable.fromDrawable(d);
	}

	@Override
	public void setBackground(Drawable background) {
		setBackgroundDrawable(background);
	}

	@Override
	public void setBackgroundResource(@DrawableRes int resId) {
		if (mBackgroundResource != resId) {
			mBackgroundResource = resId;
			mBackgroundDrawable = resolveBackgroundResource();
			setBackgroundDrawable(mBackgroundDrawable);
		}
	}

	@Override
	public void setBackgroundColor(int color) {
		mBackgroundDrawable = new ColorDrawable(color);
		setBackgroundDrawable(mBackgroundDrawable);
	}

	private Drawable resolveBackgroundResource() {
		Resources rsrc = getResources();
		if (rsrc == null) { return null; }

		Drawable d = null;

		if (mBackgroundResource != 0) {
			try {
				d = rsrc.getDrawable(mBackgroundResource);
			} catch (Exception e) {
				Log.w(TAG, "Unable to find resource: " + mBackgroundResource, e);
				// Don't try again.
				mBackgroundResource = 0;
			}
		}
		return RoundedDrawable.fromDrawable(d);
	}

	private void updateDrawableAttrs() {
		updateAttrs(mDrawable, mScaleType);
	}

	private void updateBackgroundDrawableAttrs(boolean convert) {
		if (mMutateBackground) {
			if (convert) {
				mBackgroundDrawable = RoundedDrawable.fromDrawable(mBackgroundDrawable);
			}
			updateAttrs(mBackgroundDrawable, ScaleType.FIT_XY);
		}
	}

	@Override public void setColorFilter(ColorFilter cf) {
		if (mColorFilter != cf) {
			mColorFilter = cf;
			mHasColorFilter = true;
			mColorMod = true;
			applyColorMod();
			invalidate();
		}
	}

	private void applyColorMod() {
		// Only mutate and apply when modifications have occurred. This should
		// not reset the mColorMod flag, since these filters need to be
		// re-applied if the Drawable is changed.
		if (mDrawable != null && mColorMod) {
			mDrawable = mDrawable.mutate();
			if (mHasColorFilter) {
				mDrawable.setColorFilter(mColorFilter);
			}
			// TODO: support, eventually...
			//mDrawable.setXfermode(mXfermode);
			//mDrawable.setAlpha(mAlpha * mViewAlphaScale >> 8);
		}
	}

	private void updateAttrs(Drawable drawable, ScaleType scaleType) {
		if (drawable == null) { return; }

		if (drawable instanceof RoundedDrawable) {
			((RoundedDrawable) drawable)
					.setScaleType(scaleType)
					.setBorderWidth(mBorderWidth)
					.setBorderColor(mBorderColor)
					.setOval(mIsOval)
					.setTileModeX(mTileModeX)
					.setTileModeY(mTileModeY);

			if (mCornerRadii != null) {
				((RoundedDrawable) drawable).setCornerRadius(
						mCornerRadii[Corner.TOP_LEFT],
						mCornerRadii[Corner.TOP_RIGHT],
						mCornerRadii[Corner.BOTTOM_RIGHT],
						mCornerRadii[Corner.BOTTOM_LEFT]);
			}

			applyColorMod();
		} else if (drawable instanceof LayerDrawable) {
			// loop through layers to and set drawable attrs
			LayerDrawable ld = ((LayerDrawable) drawable);
			for (int i = 0, layers = ld.getNumberOfLayers(); i < layers; i++) {
				updateAttrs(ld.getDrawable(i), scaleType);
			}
		}
	}

	@Override
	@Deprecated
	public void setBackgroundDrawable(Drawable background) {
		mBackgroundDrawable = background;
		updateBackgroundDrawableAttrs(true);
		//noinspection deprecation
		super.setBackgroundDrawable(mBackgroundDrawable);
	}

	/**
	 * @return the largest corner radius.
	 */
	public float getCornerRadius() {
		return getMaxCornerRadius();
	}

	/**
	 * @return the largest corner radius.
	 */
	public float getMaxCornerRadius() {
		float maxRadius = 0;
		for (float r : mCornerRadii) {
			maxRadius = Math.max(r, maxRadius);
		}
		return maxRadius;
	}

	/**
	 * Get the corner radius of a specified corner.
	 *
	 * @param corner the corner.
	 * @return the radius.
	 */
	public float getCornerRadius(@Corner int corner) {
		return mCornerRadii[corner];
	}

	/**
	 * Set all the corner radii from a dimension resource id.
	 *
	 * @param resId dimension resource id of radii.
	 */
	public void setCornerRadiusDimen(@DimenRes int resId) {
		float radius = getResources().getDimension(resId);
		setCornerRadius(radius, radius, radius, radius);
	}

	/**
	 * Set the corner radius of a specific corner from a dimension resource id.
	 *
	 * @param corner the corner to set.
	 * @param resId the dimension resource id of the corner radius.
	 */
	public void setCornerRadiusDimen(@Corner int corner, @DimenRes int resId) {
		setCornerRadius(corner, getResources().getDimensionPixelSize(resId));
	}

	/**
	 * Set the corner radii of all corners in px.
	 *
	 * @param radius the radius to set.
	 */
	public void setCornerRadius(float radius) {
		setCornerRadius(radius, radius, radius, radius);
	}

	/**
	 * Set the corner radius of a specific corner in px.
	 *
	 * @param corner the corner to set.
	 * @param radius the corner radius to set in px.
	 */
	public void setCornerRadius(@Corner int corner, float radius) {
		if (mCornerRadii[corner] == radius) {
			return;
		}
		mCornerRadii[corner] = radius;

		updateDrawableAttrs();
		updateBackgroundDrawableAttrs(false);
		invalidate();
	}

	/**
	 * Set the corner radii of each corner individually. Currently only one unique nonzero value is
	 * supported.
	 *
	 * @param topLeft radius of the top left corner in px.
	 * @param topRight radius of the top right corner in px.
	 * @param bottomRight radius of the bottom right corner in px.
	 * @param bottomLeft radius of the bottom left corner in px.
	 */
	public void setCornerRadius(float topLeft, float topRight, float bottomLeft, float bottomRight) {
		if (mCornerRadii[Corner.TOP_LEFT] == topLeft
				&& mCornerRadii[Corner.TOP_RIGHT] == topRight
				&& mCornerRadii[Corner.BOTTOM_RIGHT] == bottomRight
				&& mCornerRadii[Corner.BOTTOM_LEFT] == bottomLeft) {
			return;
		}

		mCornerRadii[Corner.TOP_LEFT] = topLeft;
		mCornerRadii[Corner.TOP_RIGHT] = topRight;
		mCornerRadii[Corner.BOTTOM_LEFT] = bottomLeft;
		mCornerRadii[Corner.BOTTOM_RIGHT] = bottomRight;

		updateDrawableAttrs();
		updateBackgroundDrawableAttrs(false);
		invalidate();
	}

	public float getBorderWidth() {
		return mBorderWidth;
	}

	public void setBorderWidth(@DimenRes int resId) {
		setBorderWidth(getResources().getDimension(resId));
	}

	public void setBorderWidth(float width) {
		if (mBorderWidth == width) { return; }

		mBorderWidth = width;
		updateDrawableAttrs();
		updateBackgroundDrawableAttrs(false);
		invalidate();
	}

	@ColorInt
	public int getBorderColor() {
		return mBorderColor.getDefaultColor();
	}

	public void setBorderColor(@ColorInt int color) {
		setBorderColor(ColorStateList.valueOf(color));
	}

	public ColorStateList getBorderColors() {
		return mBorderColor;
	}

	public void setBorderColor(ColorStateList colors) {
		if (mBorderColor.equals(colors)) { return; }

		mBorderColor =
				(colors != null) ? colors : ColorStateList.valueOf(RoundedDrawable.DEFAULT_BORDER_COLOR);
		updateDrawableAttrs();
		updateBackgroundDrawableAttrs(false);
		if (mBorderWidth > 0) {
			invalidate();
		}
	}

	/**
	 * Return true if this view should be oval and always set corner radii to half the height or
	 * width.
	 *
	 * @return if this {@link RoundedImageView} is set to oval.
	 */
	public boolean isOval() {
		return mIsOval;
	}

	/**
	 * Set if the drawable should ignore the corner radii set and always round the source to
	 * exactly half the height or width.
	 *
	 * @param oval if this {@link RoundedImageView} should be oval.
	 */
	public void setOval(boolean oval) {
		mIsOval = oval;
		updateDrawableAttrs();
		updateBackgroundDrawableAttrs(false);
		invalidate();
	}

	public Shader.TileMode getTileModeX() {
		return mTileModeX;
	}

	public void setTileModeX(Shader.TileMode tileModeX) {
		if (this.mTileModeX == tileModeX) { return; }

		this.mTileModeX = tileModeX;
		updateDrawableAttrs();
		updateBackgroundDrawableAttrs(false);
		invalidate();
	}

	public Shader.TileMode getTileModeY() {
		return mTileModeY;
	}

	public void setTileModeY(Shader.TileMode tileModeY) {
		if (this.mTileModeY == tileModeY) { return; }

		this.mTileModeY = tileModeY;
		updateDrawableAttrs();
		updateBackgroundDrawableAttrs(false);
		invalidate();
	}

	/**
	 * If {@code true}, we will also round the background drawable according to the settings on this
	 * ImageView.
	 *
	 * @return whether the background is mutated.
	 */
	public boolean mutatesBackground() {
		return mMutateBackground;
	}

	/**
	 * Set whether the {@link RoundedImageView} should round the background drawable according to
	 * the settings in addition to the source drawable.
	 *
	 * @param mutate true if this view should mutate the background drawable.
	 */
	public void mutateBackground(boolean mutate) {
		if (mMutateBackground == mutate) { return; }

		mMutateBackground = mutate;
		updateBackgroundDrawableAttrs(true);
		invalidate();
	}
}

四：自定义的属性
<declare-styleable name="RoundedImageView">
        <attr name="riv_corner_radius" format="dimension" />
        <attr name="riv_corner_radius_top_left" format="dimension" />
        <attr name="riv_corner_radius_top_right" format="dimension" />
        <attr name="riv_corner_radius_bottom_left" format="dimension" />
        <attr name="riv_corner_radius_bottom_right" format="dimension" />
        <attr name="riv_border_width" format="dimension" />
        <attr name="riv_border_color" format="color" />
        <attr name="riv_mutate_background" format="boolean" />
        <attr name="riv_oval" format="boolean" />
        <attr name="android:scaleType" format="integer" />
        <attr name="riv_tile_mode" format="integer">
            <enum name="clamp" value="0" />
            <enum name="repeat" value="1" />
            <enum name="mirror" value="2" />
        </attr>
        <attr name="riv_tile_mode_x" format="integer">
            <enum name="clamp" value="0" />
            <enum name="repeat" value="1" />
            <enum name="mirror" value="2" />
        </attr>
        <attr name="riv_tile_mode_y" format="integer">
            <enum name="clamp" value="0" />
            <enum name="repeat" value="1" />
            <enum name="mirror" value="2" />
        </attr>
    </declare-styleable>

    
SwiftUI 中级之如何自定义圆角位置和度数 （2020年教程）
需求描述
我知道你可以使用 .cornerRadius（） 来设置 UI 视图为圆角，但有没有办法只输入特定角，如顶部。
解决方案
自定义
struct ContentView : View {
    var body: some View {

        Text("Hello World!")
            .foregroundColor(.white)
            .font(.largeTitle)
            .padding(20)
            .background(RoundedCorners(color: .blue, tl: 0, tr: 30, bl: 30, br: 0))
    }
}

struct RoundedCorners: View {
    var color: Color = .blue
    var tl: CGFloat = 0.0
    var tr: CGFloat = 0.0
    var bl: CGFloat = 0.0
    var br: CGFloat = 0.0

    var body: some View {
        GeometryReader { geometry in
            Path { path in

                let w = geometry.size.width
                let h = geometry.size.height

                // Make sure we do not exceed the size of the rectangle
                let tr = min(min(self.tr, h/2), w/2)
                let tl = min(min(self.tl, h/2), w/2)
                let bl = min(min(self.bl, h/2), w/2)
                let br = min(min(self.br, h/2), w/2)

                path.move(to: CGPoint(x: w / 2.0, y: 0))
                path.addLine(to: CGPoint(x: w - tr, y: 0))
                path.addArc(center: CGPoint(x: w - tr, y: tr), radius: tr, startAngle: Angle(degrees: -90), endAngle: Angle(degrees: 0), clockwise: false)
                path.addLine(to: CGPoint(x: w, y: h - br))
                path.addArc(center: CGPoint(x: w - br, y: h - br), radius: br, startAngle: Angle(degrees: 0), endAngle: Angle(degrees: 90), clockwise: false)
                path.addLine(to: CGPoint(x: bl, y: h))
                path.addArc(center: CGPoint(x: bl, y: h - bl), radius: bl, startAngle: Angle(degrees: 90), endAngle: Angle(degrees: 180), clockwise: false)
                path.addLine(to: CGPoint(x: 0, y: tl))
                path.addArc(center: CGPoint(x: tl, y: tl), radius: tl, startAngle: Angle(degrees: 180), endAngle: Angle(degrees: 270), clockwise: false)
            }
            .fill(self.color)
        }
    }
}

效果





SwiftUI 中级之如何自定义圆角位置和度数

参考资料
https://stackoverflow.com/questions/56760335/round-specific-corners-swiftui
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请关注我的专栏 SwiftUI教程与源码

写好了一个工具类

要在自己项目中build.gradle加入以下内容（导入Glide）


implementation('com.github.bumptech.glide:glide:4.7.1') {
        exclude group: "com.android.support"
}


可以自己设置圆角度数，也可以自动设置，如第5行，我写了20
public class GlideTool {

    @SuppressLint("CheckResult")
    public static void GlideRadius(Context context, String url, ImageView imageView) {
        //设置图片圆角角度
        RoundedCorners roundedCorners = new RoundedCorners(20);
        RequestOptions options = RequestOptions.bitmapTransform(roundedCorners).override(0, 0);
        Glide.with(context).load(url).apply(options).into(imageView);
    }

    @SuppressLint("CheckResult")
    public static void GlideRadius(Context context, String url, ImageView imageView, int radius) {
        //设置图片圆角角度
        RoundedCorners roundedCorners = new RoundedCorners(radius);
        RequestOptions options = RequestOptions.bitmapTransform(roundedCorners).override(0, 0);
        Glide.with(context).load(url).apply(options).into(imageView);
    }


}


其运行效果如下：

问题

最近在做毕业设计时有个自定义的PopWindow，布局用代码构建，其中就有用到GradientDrawable设置不同圆角的背景，在这里做下笔记。

效果



角度大小只是为了举例

实现

这里用的是Kotlin

val gd = GradientDrawable()
gd.cornerRadii = getCornerRadii(30F,8F,20F,5F)


private fun getCornerRadii(leftTop:Float,rightTop:Float,
                          leftBottom:Float,rightBottom:Float):FloatArray{
        //这里返回的一个浮点型的数组，一定要有8个元素，不然会报错
        return floatArrayOf(dp2px(leftTop), dp2px(leftTop), dp2px(rightTop),dp2px(rightTop),dp2px(rightBottom), dp2px(rightBottom),dp2px(leftBottom),dp2px(leftBottom))
}
private fun dp2px(dpVal: Float): Float {
    return TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,
           dpVal, mContext.resources.displayMetrics)
}