在实践中，有时候会用到圆形图片展示（个人头像展示）及圆角展示，其实Glide加载ImageView能够实现这些：
Glide加载圆形图：
RequestOptions mRequestOptions = RequestOptions.circleCropTransform().diskCacheStrategy(DiskCacheStrategy.NONE)
.skipMemoryCache(true);
Glide.with(mContext).load(userInfo.getImage()).apply(mRequestOptions).into(mUserIcon);Glide加载圆角图：
RoundedCorners roundedCorners= new RoundedCorners(6);
RequestOptions options=RequestOptions.bitmapTransform(roundedCorners).override(300, 300);
Glide.with(context).load(files.getFilePath()).apply(options).into(mUserPhoto);但如果我们不想Glide加载呢，那么接下来我们自己简单去实现一个自定义ImageView吧，主要的实现起来是通过onDraw()方法中重新去绘制图片，简单定义一些属性。
先来个效果展示：
布局文件：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:ptr="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:background="#000"
android:orientation="vertical"
tools:context=".MainActivity">
<com.example.huowei.roundimagetest.RoundCornersImageView
android:layout_width="80dip"
android:layout_height="80dip"
android:layout_margin="20dip"
android:scaleType="centerCrop"
android:src="@mipmap/ic_launcher"
ptr:border_inside_color="#ffffff"
ptr:border_outside_color="#ffffff"
ptr:border_thickness="2.1dip" />
<com.example.huowei.roundimagetest.RoundCornersImageView
android:layout_width="80dip"
android:layout_height="80dip"
android:layout_margin="20dip"
android:scaleType="centerCrop"
android:src="@mipmap/ic_launcher"
ptr:border_inside_color="#ff0256"
ptr:border_outside_color="#fff000"
ptr:border_thickness="10dip" />
<com.example.huowei.roundimagetest.RoundCornersImageView
android:id="@+id/view"
android:layout_width="180dip"
android:layout_height="180dip"
android:layout_margin="20dip"
android:scaleType="fitXY"
android:src="@mipmap/ic_launcher"
ptr:is_round_corners="true"
ptr:roundHeight="3dip"
ptr:roundWidth="3dip" />
</LinearLayout>自定义属性：
<?xml version="1.0" encoding="utf-8"?>
<resources>
<declare-styleable name="roundCornersImageView">
<attr name="border_thickness" format="dimension" />
<attr name="border_inside_color" format="color" />
<attr name="border_outside_color" format="color"/>
<attr name="roundWidth" format="dimension" />
<attr name="roundHeight" format="dimension" />
<attr name="is_round_corners" format="boolean" />
</declare-styleable>
</resources>RoundCornersImageView：
public class RoundCornersImageView extends ImageView {
private Context mContext;
//默认的边框的宽度
private int mBorderThickness = 1;
// 如果只有其中一个有值，则只画一个圆形边框
private int mBorderOutsideColor = 0xffffff;
private int mBorderInsideColor = 0xffffff;
//默认颜色
private final int defaultColor = 0x000000;
// 控件默认长、宽
private int defaultWidth = 0;
private int defaultHeight = 0;
//默认圆角
private int roundWidth = 5;
private int roundHeight = 5;
//默认展示圆 为true展示圆角
private boolean mIsRoundCorners = false;
private Paint mPaint;
private Paint mPaint2;
public RoundCornersImageView(Context context) {
super(context);
mContext = context;
}
public RoundCornersImageView(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
mContext = context;
setCustomAttributes(attrs);
}
public RoundCornersImageView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
mContext = context;
setCustomAttributes(attrs);
}
/**
* 自定义属性
*
* @param attrs
*/
private void setCustomAttributes(AttributeSet attrs) {
TypedArray a = mContext.obtainStyledAttributes(attrs,
R.styleable.roundCornersImageView);
//圈的宽度
mBorderThickness = a.getDimensionPixelSize(
R.styleable.roundCornersImageView_border_thickness, 2);
//获取外层圈颜色
mBorderOutsideColor = a
.getColor(R.styleable.roundCornersImageView_border_outside_color,
defaultColor);
//获取内层圈颜色
mBorderInsideColor = a.getColor(
R.styleable.roundCornersImageView_border_inside_color, defaultColor);
//获取圆角
roundWidth = a.getDimensionPixelSize(R.styleable.roundCornersImageView_roundWidth, roundWidth);
roundHeight = a.getDimensionPixelSize(R.styleable.roundCornersImageView_roundHeight, roundHeight);
//设置是否展示圆角
mIsRoundCorners = a.getBoolean(R.styleable.roundCornersImageView_is_round_corners, mIsRoundCorners);
if (mIsRoundCorners) {
mPaint = new Paint();
mPaint.setColor(mContext.getResources().getColor(R.color.white));
mPaint.setAntiAlias(true);
mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_OUT));//SrcATop、DstATop
mPaint2 = new Paint();
mPaint2.setXfermode(null);
}
}
//绘制控件
@Override
protected void onDraw(Canvas canvas) {
Drawable drawable = getDrawable();
if (drawable == null) {
return;
}
//判断宽高
if (getWidth() == 0 || getHeight() == 0) {
return;
}
this.measure(0, 0);
if (drawable.getClass() == NinePatchDrawable.class)
return;
if (drawable instanceof ColorDrawable)
return;
//获取bitmap
// Bitmap bt = ((BitmapDrawable) drawable).getBitmap();
//因为图标是没有实例的 BitmapDrawable，所以上面的不能获取bitmap
Bitmap bt = Bitmap.createBitmap(drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);
Canvas canvasBit = new Canvas(bt);
//如果需要展示圆角的话直接为左右上下各个角截取就可以
if (mIsRoundCorners) {
super.onDraw(canvasBit);
drawLiftUp(canvasBit);
drawRightUp(canvasBit);
drawLiftDown(canvasBit);
drawRightDown(canvasBit);
canvas.drawBitmap(bt, 0, 0, mPaint2);
bt.recycle();
} else {
drawable.setBounds(0, 0, canvasBit.getWidth(), canvasBit.getHeight());
drawable.draw(canvasBit);
Bitmap bitmap = bt.copy(Bitmap.Config.ARGB_8888, true);
//赋值控件宽高
if (defaultWidth == 0) {
defaultWidth = getWidth();
}
if (defaultHeight == 0) {
defaultHeight = getHeight();
}
int radius = 0;
//判断两个边框的颜色
// 定义画两个边框，分别为外圆边框和内圆边框 必须先画外框 不然内框会被覆盖
if (mBorderInsideColor != defaultColor && mBorderOutsideColor != defaultColor) {
radius = (defaultWidth < defaultHeight ? defaultWidth : defaultHeight) / 2 - 2 * mBorderThickness;
// 画外圆 设置外框的宽度位置比内框多mBorderThickness的一半
drawCircleBorder(canvas, radius + mBorderThickness, mBorderOutsideColor);
// 画内圆
drawCircleBorder(canvas, radius + mBorderThickness / 2, mBorderInsideColor);
} else if (mBorderInsideColor != defaultColor && mBorderOutsideColor == defaultColor) {// 定义画一个边框
radius = (defaultWidth < defaultHeight ? defaultWidth
: defaultHeight) / 2 - mBorderThickness;
drawCircleBorder(canvas, radius + mBorderThickness / 2, mBorderInsideColor);
} else if (mBorderInsideColor == defaultColor && mBorderOutsideColor != defaultColor) {// 定义画一个边框
radius = (defaultWidth < defaultHeight ? defaultWidth
: defaultHeight) / 2 - mBorderThickness;
drawCircleBorder(canvas, radius + mBorderThickness / 2, mBorderOutsideColor);
} else {//没有边框
radius = (defaultWidth < defaultHeight ? defaultWidth
: defaultHeight) / 2;
}
//获取剪切后的bitmap
Bitmap croppedRoundBitmap = getCroppedRoundBitmap(bitmap, radius);
canvas.drawBitmap(croppedRoundBitmap, defaultWidth / 2 - radius, defaultHeight / 2 - radius, null);
}
}
/**
* 剪切左上角
*
* @param canvas
*/
private void drawLiftUp(Canvas canvas) {
Path path = new Path();
path.moveTo(0, roundHeight);
path.lineTo(0, 0);
path.lineTo(roundWidth, 0);
path.arcTo(new RectF(0, 0, roundWidth * 2, roundHeight * 2), -90, -90);
path.close();
canvas.drawPath(path, mPaint);
}
/**
* 剪切左下角
*
* @param canvas
*/
private void drawLiftDown(Canvas canvas) {
Path path = new Path();
path.moveTo(0, getHeight() - roundHeight);
path.lineTo(0, getHeight());
path.lineTo(roundWidth, getHeight());
path.arcTo(new RectF(0, getHeight() - roundHeight * 2, 0 + roundWidth * 2, getHeight()), 90, 90);
path.close();
canvas.drawPath(path, mPaint);
}
/**
* 剪切右下角
*
* @param canvas
*/
private void drawRightDown(Canvas canvas) {
Path path = new Path();
path.moveTo(getWidth() - roundWidth, getHeight());
path.lineTo(getWidth(), getHeight());
path.lineTo(getWidth(), getHeight() - roundHeight);
path.arcTo(new RectF(getWidth() - roundWidth * 2, getHeight() - roundHeight * 2, getWidth(), getHeight()), 0, 90);
path.close();
canvas.drawPath(path, mPaint);
}
/**
* 剪切右上角
*
* @param canvas
*/
private void drawRightUp(Canvas canvas) {
Path path = new Path();
path.moveTo(getWidth(), roundHeight);
path.lineTo(getWidth(), 0);
path.lineTo(getWidth() - roundWidth, 0);
path.arcTo(new RectF(getWidth() - roundWidth * 2, 0, getWidth(), 0 + roundHeight * 2), -90, 90);
path.close();
canvas.drawPath(path, mPaint);
}
/**
* 边缘画圆
*/
public void drawCircleBorder(Canvas canvas, int radius, int color) {
Paint paint = new Paint();
/* 去锯齿 */
paint.setAntiAlias(true);
paint.setFilterBitmap(true);
paint.setDither(true);
paint.setColor(color);
/* 设置paint的外框宽度 */
// paint.setStrokeWidth(10.0f);
canvas.drawCircle(defaultWidth / 2, defaultHeight / 2, radius, paint);
}
/**
* 获取裁剪后的圆形图片
*
* @param radius 半径
*/
public Bitmap getCroppedRoundBitmap(Bitmap bmp, int radius) {
Bitmap scaledSrcBmp;
int diameter = radius * 2;
// 为了防止宽高不相等，造成圆形图片变形，因此截取长方形中处于中间位置最大的正方形图片
int bmpWidth = bmp.getWidth();
int bmpHeight = bmp.getHeight();
int squareWidth = 0, squareHeight = 0;
int x = 0, y = 0;
Bitmap squareBitmap;
if (bmpHeight > bmpWidth) {// 高大于宽
squareWidth = squareHeight = bmpWidth;
x = 0;
y = (bmpHeight - bmpWidth) / 2;
// 截取正方形图片
squareBitmap = Bitmap.createBitmap(bmp, x, y, squareWidth,
squareHeight);
} else if (bmpHeight < bmpWidth) {// 宽大于高
squareWidth = squareHeight = bmpHeight;
x = (bmpWidth - bmpHeight) / 2;
y = 0;
squareBitmap = Bitmap.createBitmap(bmp, x, y, squareWidth,
squareHeight);
} else {
squareBitmap = bmp;
}
if (squareBitmap.getWidth() != diameter
|| squareBitmap.getHeight() != diameter) {
scaledSrcBmp = Bitmap.createScaledBitmap(squareBitmap, diameter,
diameter, true);
} else {
scaledSrcBmp = squareBitmap;
}
Bitmap output = Bitmap.createBitmap(scaledSrcBmp.getWidth(),
scaledSrcBmp.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(output);
Paint paint = new Paint();
Rect rect = new Rect(0, 0, scaledSrcBmp.getWidth(),
scaledSrcBmp.getHeight());
paint.setAntiAlias(true);
paint.setFilterBitmap(true);
paint.setDither(true);
canvas.drawARGB(0, 0, 0, 0);
canvas.drawCircle(scaledSrcBmp.getWidth() / 2,
scaledSrcBmp.getHeight() / 2, scaledSrcBmp.getWidth() / 2,
paint);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
canvas.drawBitmap(scaledSrcBmp, rect, rect, paint);
bmp = null;
squareBitmap = null;
scaledSrcBmp = null;
return output;
}
}
一个简单的圆形图片就 展示出来了....