CircleImageView-方式2

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MvpApp2
项目地址：Alex-Cin/MvpApp2
写一个圆形的ImageView 之前有一个通过paint.setXfermode方式去实现的，今天写一个更好地实现方式，国际惯例先看效果。

先看原图

搜狗截图20160730020147.png

CropType.leftTop

004.png

CropType.centerTop

002.png

CropType.center

003.png

最后看代码其实很简单，有错误请指出，谢谢

package github.alex.circleimageview;import android.content.Context;import android.graphics.Bitmap;import android.graphics.BitmapShader;import android.graphics.Canvas;import android.graphics.Matrix;import android.graphics.Paint;import android.graphics.Shader;import android.graphics.drawable.Drawable;import android.util.AttributeSet;import android.widget.ImageView;/** * 作者：alex * 时间：2016/7/29 13:48 * 博客地址：http://www.jianshu.com/users/c3c4ea133871/subscriptions */public class CircleImageView extends ImageView {    /**     * 绘图的Paint     */    private Paint paint;    /**     * 圆角的半径     */    private int radius;    /**     * 3x3 矩阵，主要用于缩小放大     */    private Matrix matrix;    /**     * 渲染图像，使用图像为绘制图形着色     */    private BitmapShader bitmapShader;    /**     * view的宽度     */    private int width;    private String cropType;    public CircleImageView(Context context) {        super(context);        initView();    }    public CircleImageView(Context context, AttributeSet attrs) {        super(context, attrs);        initView();    }    /**     * 初始化 视图     */    private void initView() {        matrix = new Matrix();        paint = new Paint();        paint.setAntiAlias(true);        radius = (int) dp2Px(10);        cropType = CropType.centerTop;    }    @Override    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {        super.onMeasure(widthMeasureSpec, heightMeasureSpec);        width = Math.min(getMeasuredWidth(), getMeasuredHeight());        radius = width / 2;        setMeasuredDimension(width, width);    }    @Override    protected void onDraw(Canvas canvas) {        // super.onDraw(canvas);        if (getDrawable() == null) {            return;        }        initBitmapShader();        canvas.drawCircle(radius, radius, radius, paint);    }    /**     * 初始化BitmapShader     */    private void initBitmapShader() {        Drawable drawable = getDrawable();        if (drawable == null) {            return;        }        Bitmap bmp = drawable2Bitmap(drawable);        bitmapShader = new BitmapShader(bmp, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);        int bSize = Math.min(bmp.getWidth(), bmp.getHeight());        float scale = width * 1.0f / bSize;        matrix.setScale(scale, scale);        bitmapShader.setLocalMatrix(matrix);        paint.setShader(bitmapShader);    }    /**     * drawable转bitmap     *     * @param drawable     * @return     */    private Bitmap drawable2Bitmap(Drawable drawable) {        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);        if ((w >= h) && CropType.centerTop.equals(cropType)) {            canvas.translate((h - w) * 0.5F, 0);        } else if ((w >= h) && CropType.center.equals(cropType)) {            canvas.translate((h - w) * 0.5F, 0);        } else if ((w < h) && CropType.center.equals(cropType)) {            canvas.translate(0, (w - h) * 0.5F);        }        drawable.draw(canvas);        return bitmap;    }    public static final class CropType {        public static final String leftTop = "起点在左上角";        public static final String centerTop = "起点水平居中&垂直置顶";        public static final String center = "起点在图片中心";    }    /**     * 数据转换: dp---->px     */    private float dp2Px(float dp) {        return dp * getContext().getResources().getDisplayMetrics().density;    }}

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