Android自定义ImageView实现圆角功能

<?xml version="1.0" encoding="utf-8"? 
<resources 
  <declare-styleable name="RoundCornerImageView" 
    <attr name="radius" format="dimension" / 
    <attr name="left_top_radius" format="dimension" / 
    <attr name="right_top_radius" format="dimension" / 
    <attr name="right_bottom_radius" format="dimension" / 
    <attr name="left_bottom_radius" format="dimension" / 
  </declare-styleable 
</resources 

public class RoundCornerImageView extends AppCompatImageView {
private float width, height;
private int defaultRadius = 0;
private int radius;
private int leftTopRadius;
private int rightTopRadius;
private int rightBottomRadius;
private int leftBottomRadius;
public RoundCornerImageView(Context context) {
this(context, null);
init(context, null);
}
public RoundCornerImageView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
init(context, attrs);
}
public RoundCornerImageView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init(context, attrs);
}
private void init(Context context, AttributeSet attrs) {
if (Build.VERSION.SDK_INT < 18) {
setLayerType(View.LAYER_TYPE_SOFTWARE, null);
}
// 读取配置
TypedArray array = context.obtainStyledAttributes(attrs, R.styleable.RoundCornerImageView);
radius = array.getDimensionPixelOffset(R.styleable.RoundCornerImageView_radius, defaultRadius);
leftTopRadius = array.getDimensionPixelOffset(R.styleable.RoundCornerImageView_left_top_radius, defaultRadius);
rightTopRadius = array.getDimensionPixelOffset(R.styleable.RoundCornerImageView_right_top_radius, defaultRadius);
rightBottomRadius = array.getDimensionPixelOffset(R.styleable.RoundCornerImageView_right_bottom_radius, defaultRadius);
leftBottomRadius = array.getDimensionPixelOffset(R.styleable.RoundCornerImageView_left_bottom_radius, defaultRadius);
//如果四个角的值没有设置，那么就使用通用的radius的值。
if (defaultRadius == leftTopRadius) {
leftTopRadius = radius;
}
if (defaultRadius == rightTopRadius) {
rightTopRadius = radius;
}
if (defaultRadius == rightBottomRadius) {
rightBottomRadius = radius;
}
if (defaultRadius == leftBottomRadius) {
leftBottomRadius = radius;
}
array.recycle();
}
@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
super.onLayout(changed, left, top, right, bottom);
width = getWidth();
height = getHeight();
}
@Override
protected void onDraw(Canvas canvas) {
//这里做下判断，只有图片的宽高大于设置的圆角距离的时候才进行裁剪
int maxLeft = Math.max(leftTopRadius, leftBottomRadius);
int maxRight = Math.max(rightTopRadius, rightBottomRadius);
int minWidth = maxLeft + maxRight;
int maxTop = Math.max(leftTopRadius, rightTopRadius);
int maxBottom = Math.max(leftBottomRadius, rightBottomRadius);
int minHeight = maxTop + maxBottom;
if (width  = minWidth && height   minHeight) {
Path path = new Path();
//四个角：右上，右下，左下，左上
path.moveTo(leftTopRadius, 0);
path.lineTo(width - rightTopRadius, 0);
path.quadTo(width, 0, width, rightTopRadius);
path.lineTo(width, height - rightBottomRadius);
path.quadTo(width, height, width - rightBottomRadius, height);
path.lineTo(leftBottomRadius, height);
path.quadTo(0, height, 0, height - leftBottomRadius);
path.lineTo(0, leftTopRadius);
path.quadTo(0, 0, leftTopRadius, 0);
canvas.clipPath(path);
}
super.onDraw(canvas);
}
}

<?xml version="1.0" encoding="utf-8"? 
<LinearLayout 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"
android:orientation="vertical"
tools:context="voicedemo.iflytek.com.roundimage.MainActivity" 
<voicedemo.iflytek.com.roundimage.RoundCornerImageView
android:id="@+id/iv_avatar"
android:layout_width="100dp"
android:layout_height="100dp"
android:layout_marginBottom="10dp"
android:layout_marginTop="50dp"
android:scaleType="centerCrop"
app:left_top_radius="20dp"
app:right_top_radius="20dp"
/ 
</LinearLayout 

public class MainActivity extends AppCompatActivity {
String avatarUrl = "19e9d4c0a8f1cd033ecac3692_th.jpg";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ImageView ivAvatar = findViewById(R.id.iv_avatar);
Glide.with(this).load(avatarUrl).into(ivAvatar);
}
}