用自定义的RoundImageView来实现圆形图片（可加边框）

本文的控件来自：http://blog.csdn.net/alan_biao/article/details/17379925

这个控件不同于之前介绍过的那个框架，这个仅仅能过将图片裁剪为圆形，没能弄成椭圆，也没有android:scaleType属性。但他可以提供两重边框，对于简单的使用来说，是完全够用的。

使用方式和之前一样，首先先配置attrs.xml

    <!--
        border_thickness         设置边框的宽度
        border_inside_color     设置内边框的颜色
        border_outside_color     设置外边框的颜色
        内外边框如果只设置一个的话，则认为只显示一个边框。
     -->
    <declare-styleable name="RoundImageView">
        <attr name="border_thickness" format="dimension" />
        <attr name="border_inside_color" format="color" />
        <attr name="border_outside_color" format="color" />
    </declare-styleable> 

然后建立类RoundImageView.java

package com.eva.views;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.PorterDuff.Mode;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.NinePatchDrawable;
import android.util.AttributeSet;
import android.widget.ImageView;

/**
 * 圆形ImageView，可设置最多两个宽度不同且颜色不同的圆形边框。
 * 来源的博客：http://blog.csdn.net/alan_biao/article/details/17379925
 * @author Alan
 */
public class RoundImageView extends ImageView {
    private int mBorderThickness = 0;
    private Context mContext;
    private int defaultColor = 0xFFFFFFFF;
    // 如果只有其中一个有值，则只画一个圆形边框
    private int mBorderOutsideColor = 0;//图片的外边界
    private int mBorderInsideColor = 0;//图片的内边界
    // 控件默认长、宽
    private int defaultWidth = 0;
    private int defaultHeight = 0;

    public RoundImageView(Context context) {
        super(context);
        mContext = context;
    }

    public RoundImageView(Context context, AttributeSet attrs) {
        super(context, attrs);
        mContext = context;
        setCustomAttributes(attrs);
    }

    public RoundImageView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        mContext = context;
        setCustomAttributes(attrs);
    }

    private void setCustomAttributes(AttributeSet attrs) {
        TypedArray a = mContext.obtainStyledAttributes(attrs,R.styleable.RoundImageView);
        //边界的宽度
        mBorderThickness = a.getDimensionPixelSize(
                R.styleable.RoundImageView_border_thickness, 0);
        //外边界的颜色
        mBorderOutsideColor = a.getColor(
                R.styleable.RoundImageView_border_outside_color,defaultColor);
        //内边界的颜色
        mBorderInsideColor = a.getColor(
                R.styleable.RoundImageView_border_inside_color, defaultColor);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        Drawable drawable = getDrawable();
        if (drawable == null) {
            return;
        }

        if (getWidth() == 0 || getHeight() == 0) {
            return;
        }
        this.measure(0, 0);
        if (drawable.getClass() == NinePatchDrawable.class)
            return;
        Bitmap b = ((BitmapDrawable) drawable).getBitmap();
        Bitmap bitmap = b.copy(Bitmap.Config.ARGB_8888, true);
        if (defaultWidth == 0) {
            defaultWidth = getWidth();
        }
        if (defaultHeight == 0) {
            defaultHeight = getHeight();
        }
        // 保证重新读取图片后不会因为图片大小而改变控件宽、高的大小（针对宽、高为wrap_content布局的imageview，但会导致margin无效）
        // if (defaultWidth != 0 && defaultHeight != 0) {
        // LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
        // defaultWidth, defaultHeight);
        // setLayoutParams(params);
        // }

        int radius = 0;
        if (mBorderInsideColor != defaultColor
                && mBorderOutsideColor != defaultColor) {// 定义画两个边框，分别为外圆边框和内圆边框
            radius = (defaultWidth < defaultHeight ? defaultWidth
                    : defaultHeight) / 2 - 2 * mBorderThickness;
            // 画内圆
            drawCircleBorder(canvas, radius + mBorderThickness / 2,
                    mBorderInsideColor);
            // 画外圆
            drawCircleBorder(canvas, radius + mBorderThickness
                    + mBorderThickness / 2, mBorderOutsideColor);
        } 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;
        }
        Bitmap roundBitmap = getCroppedRoundBitmap(bitmap, radius);
        canvas.drawBitmap(roundBitmap, defaultWidth / 2 - radius, defaultHeight
                / 2 - radius, null);
    }

    /**
     * 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(), 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(Mode.SRC_IN));
        canvas.drawBitmap(scaledSrcBmp, rect, rect, paint);
        // bitmap回收(recycle导致在布局文件XML看不到效果)
        // bmp.recycle();
        // squareBitmap.recycle();
        // scaledSrcBmp.recycle();
        bmp = null;
        squareBitmap = null;
        scaledSrcBmp = null;
        return output;
    }

    /**
     * 边缘画圆
     */
    private 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　style　为STROKE：空心 */
        paint.setStyle(Paint.Style.STROKE);
        /* 设置paint的外框宽度 */
        paint.setStrokeWidth(mBorderThickness);
        canvas.drawCircle(defaultWidth / 2, defaultHeight / 2, radius, paint);
    }

}

最后，在布局文件中设置该控件（需要添加命名空间）

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:pv="http://schemas.android.com/apk/res/com.eva.views"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#d6d6d6"
    android:orientation="vertical" >

    <com.eva.views.RoundImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/kale"
        android:layout_marginTop="16dp"
        android:layout_gravity="center_horizontal"

        pv:border_thickness="3dp"
        pv:border_inside_color="#50c0e9"/>

    <com.eva.views.RoundImageView
        android:id="@+id/image_id"
        android:layout_width="150dp"
        android:layout_height="150dp"
        android:src="@drawable/kale"
        android:layout_marginTop="16dp"
        android:layout_gravity="center_horizontal"  

        pv:border_thickness="4dp"
        pv:border_inside_color="#50c0e9"
        pv:border_outside_color="#ffc641"/>

    <com.eva.views.RoundImageView
        android:layout_width="100dp"
        android:layout_height="100dp"
        android:src="@drawable/kale"
        android:layout_marginTop="16dp"
        android:layout_gravity="center_horizontal"    

        pv:border_thickness="3dp"
        pv:border_inside_color="#d6d6d6"
        pv:border_outside_color="#ffc641"/>

</LinearLayout>

我们在代码中可以和用ImageView一样来设置图片

        RoundImageView imageView = (RoundImageView)findViewById(R.id.image_id);
        imageView.setImageDrawable(getResources().getDrawable(R.drawable.saber));
        imageView.setImageResource(R.drawable.saber);