Android 圆角边框的实现方式汇总

<?xml version="1.0" encoding="utf-8"?><shape xmlns:android="http://schemas.android.com/apk/res/android"><!-- 设置填充颜色 为白色 --><solid android:color="#FFFFFF" /><!-- 设置几何图形四个角的弧度 --><corners android:radius="10dp"/><!-- 设置几何形状绘制边框 红色边框 --><stroke android:color="#CD2626"android:width="2dp"/></shape>

package com.ice.cornersdemo;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.RectF;import android.graphics.Shader;import android.graphics.drawable.BitmapDrawable;import android.graphics.drawable.ColorDrawable;import android.graphics.drawable.Drawable;import android.util.AttributeSet;import android.widget.ImageView;/*** 自定义带圆角的ImageView* Created by ice on 14-8-6.*/public class CornersImageView extends ImageView{private Bitmap mBitmap;private BitmapShader mBitmapShader;private final Matrix mShaderMatrix = new Matrix();private final Paint mBitmapPaint = new Paint();private final RectF mDrawableRect = new RectF();private float mDrawableRadius;private int mBitmapWidth;private int mBitmapHeight;private static final Bitmap.Config BITMAP_CONFIG = Bitmap.Config.ARGB_8888;private static final int COLORDRAWABLE_DIMENSION = 1;public CornersImageView(Context context){super(context);}public CornersImageView(Context context, AttributeSet attrs){this(context, attrs, 0);}public CornersImageView(Context context, AttributeSet attrs, int defStyle){super(context, attrs, defStyle);init();}private void init() {if (mBitmap == null){return;}mBitmapShader = new BitmapShader(mBitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);// 设置抗锯齿mBitmapPaint.setAntiAlias(true);// 使用位图平铺的渲染效果mBitmapPaint.setShader(mBitmapShader);mBitmapWidth = mBitmap.getWidth();mBitmapHeight = mBitmap.getHeight();mDrawableRect.set(0, 0, mBitmapWidth, mBitmapHeight);// 获取图片展示的圆形半径mDrawableRadius = Math.min(mDrawableRect.width()/2, mDrawableRect.height()/2);invalidate();}@Overridepublic void draw(Canvas canvas){if (getDrawable() == null){return;}canvas.drawCircle(getWidth()/2, getHeight()/2, mDrawableRadius, mBitmapPaint);}@Overridepublic void setImageBitmap(Bitmap bm) {super.setImageBitmap(bm);mBitmap = bm;init();}@Overridepublic void setImageDrawable(Drawable drawable) {super.setImageDrawable(drawable);mBitmap = getBitmapFromDrawable(drawable);init();}@Overridepublic void setImageResource(int resId) {super.setImageResource(resId);mBitmap = getBitmapFromDrawable(getDrawable());init();}/*** 将Drawable转换成Bitmap对象* @param drawable* @return*/private Bitmap getBitmapFromDrawable(Drawable drawable) {if (drawable == null) {return null;}if (drawable instanceof BitmapDrawable) {return ((BitmapDrawable) drawable).getBitmap();}try {Bitmap bitmap;if (drawable instanceof ColorDrawable) {bitmap = Bitmap.createBitmap(COLORDRAWABLE_DIMENSION, COLORDRAWABLE_DIMENSION,BITMAP_CONFIG);} else {bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight(),BITMAP_CONFIG);}Canvas canvas = new Canvas(bitmap);drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());drawable.draw(canvas);return bitmap;} catch (OutOfMemoryError e) {return null;}}}

/*** 将方形图片剪切成圆图* @param bitmap* @return*/public static Bitmap getCircleBitmap(Bitmap bitmap) {Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Config.ARGB_8888);Canvas canvas = new Canvas(output);Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());RectF rectF = new RectF(rect);Paint paint = new Paint();paint.setAntiAlias(true); // 防止边缘的锯齿paint.setFilterBitmap(true); // 对位图进行滤波处理canvas.drawOval(rectF, paint); // 根据rectF 绘制一个椭圆/圆形// 设置两张图片相交时的显示模式为 SRC_INpaint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));canvas.drawBitmap(bitmap, rect, rectF, paint);return output;}