自定义圆角的ImageView 还可以实现图片的圆形、椭圆形展示。

来源：互联网发布：windows文档加密编辑：程序博客网时间：2024/05/16 08:47
为了达到美观的效果，项目中的所有图片显示都是圆角显示。然而Android的ImageView没有圆角属性，而让UI把所有图片都处理成圆角，也不合适。这里采用自定义的方法来自定义一个支持圆角的ImageView，然后在布局中引用这个类来布局就可以了。同时，该自定义ImageView还支持绘制圆形和椭圆形的ImageView。可以根据实际需要来选择。这个代码是网上找的和大家一起分享下
import android.content.Context;import android.graphics.*;import android.graphics.Bitmap.Config;import android.graphics.PorterDuff.Mode;import android.graphics.drawable.Drawable;import android.util.AttributeSet;import android.util.Log;import android.widget.ImageView;import java.lang.ref.WeakReference;/** * 使用Xfermode渲染方案实现圆角矩形、椭圆ImageView * @author caizhiming * */public class XCRoundImageViewByXfermode extends ImageView{    //数据定义    private Paint mPaint;      private Xfermode mXfermode = new PorterDuffXfermode(Mode.DST_IN);      private Bitmap mMaskBitmap; //用来做    private int mRoundBorderRadius;//圆角大小    private int mType;//类型：圆形、圆角或椭圆        private WeakReference<Bitmap> mBufferBitmap;//使用缓存技术，避免每次都执行onDraw    public static final int TYPE_CIRCLE = 1;//圆形    public static final int TYPE_ROUND = 2;//圆角矩形    public static final int TYPE_OVAL = 3;//椭圆形    private static final int DEFAULT_ROUND_BORDER_RADIUS = 10;//默认圆角大小         //构造方法    public XCRoundImageViewByXfermode(Context context){        this(context, null);    }    public XCRoundImageViewByXfermode(Context context, AttributeSet attrs) {        super(context, attrs);        // TODO Auto-generated constructor stub                mPaint = new Paint();        mPaint.setAntiAlias(true);//设置消除锯齿        mType = TYPE_ROUND;        mRoundBorderRadius = DEFAULT_ROUND_BORDER_RADIUS;    }    /**     * 测量view的大小     */    @Override    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {        // TODO Auto-generated method stub        super.onMeasure(widthMeasureSpec, heightMeasureSpec);        //如果类型是圆形，则强制设置view的宽高一致，取宽高的较小值         if(mType == TYPE_CIRCLE){            int width = Math.min(getMeasuredWidth(),getMeasuredHeight());            setMeasuredDimension(width, width);        }    }    /**     * 绘制view的内容     */    @Override    protected void onDraw(Canvas canvas) {        // TODO Auto-generated method stub        //从缓存中取出bitmap        Bitmap bmp = (mBufferBitmap == null ? null:mBufferBitmap.get());        if(bmp == null || bmp.isRecycled()){            //如果没有缓存存在的情况            //获取drawable            Drawable drawable = getDrawable();            //获取drawable的宽高            int dwidth = drawable.getIntrinsicWidth();            int dheight = drawable.getIntrinsicHeight();            Log.v("czm","dwidth="+dwidth+",width="+getWidth());            if(null != drawable){                bmp = Bitmap.createBitmap(getWidth(), getHeight(),                          Config.ARGB_8888);                 float scale = 1.0f;                //创建画布                Canvas drawCanvas = new Canvas(bmp);                //按照bitmap的宽高，以及view的宽高，计算缩放比例；因为设置的src宽高                //比例可能和imageview的宽高比例不同，这里我们不希望图片失真；                                  if(mType == TYPE_CIRCLE)                  {//如果是圆形                      scale = getWidth() * 1.0F / Math.min(dwidth, dheight);                  }else if (mType == TYPE_ROUND || mType == TYPE_OVAL)                  {//如果是圆角矩形或椭圆                     // 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 / dwidth, getHeight()                              * 1.0f / dheight);                  }                Log.v("czm","scale="+scale);                //根据缩放比例，设置bounds，即相当于做缩放图片                  drawable.setBounds(0, 0, (int)(scale * dwidth), (int)(scale * dheight));                drawable.draw(drawCanvas);                //获取bitmap，即圆形、圆角或椭圆的bitmap                if(mMaskBitmap == null || mMaskBitmap.isRecycled()){                    mMaskBitmap = getDrawBitmap();                }                //为paint设置Xfermode 渲染模式                mPaint.reset();                mPaint.setFilterBitmap(false);                mPaint.setXfermode(mXfermode);                //绘制不同形状                drawCanvas.drawBitmap(mMaskBitmap, 0, 0,mPaint);                mPaint.setXfermode(null);                                //将准备好的bitmap绘制出来                  canvas.drawBitmap(bmp, 0, 0, null);                  //bitmap缓存起来，避免每次调用onDraw，分配内存                  mBufferBitmap = new WeakReference<Bitmap>(bmp);             }                    }else{            //如果缓存还存在的情况            mPaint.setXfermode(null);              canvas.drawBitmap(bmp, 0.0f, 0.0f, mPaint);              return;         }    }    /**     * 绘制不同的图形Bitmap     */    private Bitmap getDrawBitmap(){        Bitmap bitmap = Bitmap.createBitmap(getWidth(), getHeight(),                  Config.ARGB_8888);        Canvas canvas = new Canvas(bitmap);          Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);          paint.setColor(Color.BLACK);            if(mType == TYPE_CIRCLE)        {//绘制圆形             canvas.drawCircle(getWidth() / 2, getWidth() / 2, getWidth() / 2,                      paint);         }else if(mType == TYPE_ROUND)          {//绘制圆角矩形            canvas.drawRoundRect(new RectF(0, 0, getWidth(), getHeight()),                      mRoundBorderRadius, mRoundBorderRadius, paint);          }else if(mType == TYPE_OVAL ){         //绘制椭圆            canvas.drawOval(new RectF(0, 0, getWidth(), getHeight()), mPaint);        }          return bitmap;      }    /**     * 因为使用了缓存技术，所以需要在invalidate中做些回收释放资源的处理     */    @Override    public void invalidate() {        // TODO Auto-generated method stub        mBufferBitmap = null;        if(mMaskBitmap != null){            mMaskBitmap.recycle();            mMaskBitmap = null;        }        super.invalidate();    }        public int getRoundBorderRadius() {        return mRoundBorderRadius;    }    public void setRoundBorderRadius(int mRoundBorderRadius) {        if(this.mRoundBorderRadius != mRoundBorderRadius){            this.mRoundBorderRadius = mRoundBorderRadius;            invalidate();        }    }    public int getType() {        return this.mType;    }    public void setType(int mType) {        if(this.mType != mType){            this.mType = mType;            invalidate();        }    }}
效果如图
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