实现自定义图片View圆形、圆角，椭圆

显示图片的时候为美观需要对图片进行形状上的处理，以下实现了3种，圆形。椭圆，矩形四个角带有弧度的

1、自定义ZQImageViewRoundOval.java 

 public class ZQImageViewRoundOval extends ImageView {

private Paint mPaint;

private int mWidth;

private int mHeight;

private int mRadius;// 圆半径

private RectF mRect;// 矩形凹行大小

private int mRoundRadius;// 圆角大小

private BitmapShader mBitmapShader;// 图形渲染

private Matrix mMatrix;

private int mType;// 记录是圆形还是圆角矩形

public static final int TYPE_CIRCLE = 0;// 圆形
public static final int TYPE_ROUND = 1;// 圆角矩形
public static final int TYPE_OVAL = 2;// 椭圆形
public static final int DEFAUT_ROUND_RADIUS = 10;// 默认圆角大小

public ZQImageViewRoundOval(Context context) {
this(context, null);
}

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

public ZQImageViewRoundOval(Context context, AttributeSet attrs,
int defStyle) {
super(context, attrs, defStyle);
initView();
}

private void initView() {
mPaint = new Paint();
mPaint.setAntiAlias(true);
mMatrix = new Matrix();
mRoundRadius = DEFAUT_ROUND_RADIUS;
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
// 如果是绘制圆形，则强制宽高大小一致
if (mType == TYPE_CIRCLE) {
mWidth = Math.min(getMeasuredWidth(), getMeasuredHeight());
mRadius = mWidth / 2;
setMeasuredDimension(mWidth, mWidth);
}
}

@Override
protected void onDraw(Canvas canvas) {

if (null == getDrawable()) {
return;
}
setBitmapShader();
if (mType == TYPE_CIRCLE) {
canvas.drawCircle(mRadius, mRadius, mRadius, mPaint);
} else if (mType == TYPE_ROUND) {
mPaint.setColor(Color.RED);
canvas.drawRoundRect(mRect, mRoundRadius, mRoundRadius, mPaint);
} else if (mType == TYPE_OVAL) {
canvas.drawOval(mRect, mPaint);
}
}

@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
mRect = new RectF(0, 0, getWidth(), getHeight());
}

/**
* 设置BitmapShader
*/
private void setBitmapShader() {
Drawable drawable = getDrawable();
if (null == drawable) {
return;
}
Bitmap bitmap = drawableToBitmap(drawable);
// 将bitmap作为着色器来创建一个BitmapShader
mBitmapShader = new BitmapShader(bitmap, Shader.TileMode.CLAMP,
Shader.TileMode.CLAMP);
float scale = 1.0f;
if (mType == TYPE_CIRCLE) {
// 拿到bitmap宽或高的小值
int bSize = Math.min(bitmap.getWidth(), bitmap.getHeight());
scale = mWidth * 1.0f / bSize;

} else if (mType == TYPE_ROUND || mType == TYPE_OVAL) {
// 如果图片的宽或者高与view的宽高不匹配，计算出需要缩放的比例；缩放后的图片的宽高，一定要大于我们view的宽高；所以我们这里取大值；
scale = Math.max(getWidth() * 1.0f / bitmap.getWidth(), getHeight()
* 1.0f / bitmap.getHeight());
}
// shader的变换矩阵，我们这里主要用于放大或者缩小
mMatrix.setScale(scale, scale);
// 设置变换矩阵
mBitmapShader.setLocalMatrix(mMatrix);
mPaint.setShader(mBitmapShader);

}
/**
* drawable转bitmap
* 
* @paramdrawable
* @return
*/
private Bitmap drawableToBitmap(Drawable drawable) {
if (drawable instanceof BitmapDrawable) {
BitmapDrawable bitmapDrawable = (BitmapDrawable) drawable;
return bitmapDrawable.getBitmap();
}
int w = drawable.getIntrinsicWidth();
int h = drawable.getIntrinsicHeight();
Bitmap bitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
drawable.setBounds(0, 0, w, h);
drawable.draw(canvas);
retur
4000
n bitmap;
}

/**
* 单位dp转单位px
*/
public int dpTodx(int dp) {

return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dp,
getResources().getDisplayMetrics());
}

public int getType() {
return mType;
}

/**
* 设置图片类型：圆形、圆角矩形、椭圆形
* 
* @param mType
*/
public void setType(int mType) {
if (this.mType != mType) {
this.mType = mType;
invalidate();
}
}

public int getRoundRadius() {
return mRoundRadius;
}

/**
* 设置圆角大小
* 
* @parammRoundRadius
*/
public void setRoundRadius(int mRoundRadius) {
if (this.mRoundRadius != mRoundRadius) {
this.mRoundRadius = mRoundRadius;
invalidate();
}
}

}

2、使用自定义view的地方需要设置背景  img_icon_shape.xml  这个是放在 drawable文件夹下的

3、Activity 中调用方法进行显示

ZQImageViewRoundOvalmImg_info_icon = (ZQImageViewRoundOval) findViewById(R.id.img_info_icon);
mImg_info_icon.setType(ZQImageViewRoundOval.TYPE_ROUND);

mImg_info_icon.setRoundRadius(10);// 矩形凹行大小

mImg_info_icon.setBackgroundResource(R.drawable.ic_launcher);

这里是显示本地的图片，也可以加载网络图片