原地址：http://blog.csdn.net/nupt123456789/article/details/24886451?utm_source=tuicool&utm_medium=referral
1.自定义圆形控件github地址：https://github.com/hdodenhof/CircleImageView
主要的类：
[java] view plain copy package de.hdodenhof.circleimageview; import edu.njupt.zhb.main.R; import android.content.Context; import android.content.res.TypedArray; import android.graphics.Bitmap; import android.graphics.BitmapShader; import android.graphics.Canvas; import android.graphics.Color; 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; public class CircleImageView extends ImageView { private static final ScaleType SCALE_TYPE = ScaleType.CENTER_CROP; private static final Bitmap.Config BITMAP_CONFIG = Bitmap.Config.ARGB_8888; private static final int COLORDRAWABLE_DIMENSION = 1; private static final int DEFAULT_BORDER_WIDTH = 0; private static final int DEFAULT_BORDER_COLOR = Color.BLACK; private final RectF mDrawableRect = new RectF(); private final RectF mBorderRect = new RectF(); private final Matrix mShaderMatrix = new Matrix(); private final Paint mBitmapPaint = new Paint(); private final Paint mBorderPaint = new Paint(); private int mBorderColor = DEFAULT_BORDER_COLOR; private int mBorderWidth = DEFAULT_BORDER_WIDTH; private Bitmap mBitmap; private BitmapShader mBitmapShader; private int mBitmapWidth; private int mBitmapHeight; private float mDrawableRadius; private float mBorderRadius; private boolean mReady; private boolean mSetupPending; public CircleImageView(Context context) { super(context); } public CircleImageView(Context context, AttributeSet attrs) { this(context, attrs, 0); } public CircleImageView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); super.setScaleType(SCALE_TYPE); TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.CircleImageView, defStyle, 0); mBorderWidth = a.getDimensionPixelSize(R.styleable.CircleImageView_border_width, DEFAULT_BORDER_WIDTH); mBorderColor = a.getColor(R.styleable.CircleImageView_border_color, DEFAULT_BORDER_COLOR); a.recycle(); mReady = true; if (mSetupPending) { setup(); mSetupPending = false; } } @Override public ScaleType getScaleType() { return SCALE_TYPE; } @Override public void setScaleType(ScaleType scaleType) { if (scaleType != SCALE_TYPE) { throw new IllegalArgumentException(String.format("ScaleType %s not supported.", scaleType)); } } @Override protected void onDraw(Canvas canvas) { if (getDrawable() == null) { return; } canvas.drawCircle(getWidth() / 2, getHeight() / 2, mDrawableRadius, mBitmapPaint); canvas.drawCircle(getWidth() / 2, getHeight() / 2, mBorderRadius, mBorderPaint); } @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) { super.onSizeChanged(w, h, oldw, oldh); setup(); } public int getBorderColor() { return mBorderColor; } public void setBorderColor(int borderColor) { if (borderColor == mBorderColor) { return; } mBorderColor = borderColor; mBorderPaint.setColor(mBorderColor); invalidate(); } public int getBorderWidth() { return mBorderWidth; } public void setBorderWidth(int borderWidth) { if (borderWidth == mBorderWidth) { return; } mBorderWidth = borderWidth; setup(); } @Override public void setImageBitmap(Bitmap bm) { super.setImageBitmap(bm); mBitmap = bm; setup(); } @Override public void setImageDrawable(Drawable drawable) { super.setImageDrawable(drawable); mBitmap = getBitmapFromDrawable(drawable); setup(); } @Override public void setImageResource(int resId) { super.setImageResource(resId); mBitmap = getBitmapFromDrawable(getDrawable()); setup(); } 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; } } private void setup() { if (!mReady) { mSetupPending = true; return; } if (mBitmap == null) { return; } mBitmapShader = new BitmapShader(mBitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP); mBitmapPaint.setAntiAlias(true); mBitmapPaint.setShader(mBitmapShader); mBorderPaint.setStyle(Paint.Style.STROKE); mBorderPaint.setAntiAlias(true); mBorderPaint.setColor(mBorderColor); mBorderPaint.setStrokeWidth(mBorderWidth); mBitmapHeight = mBitmap.getHeight(); mBitmapWidth = mBitmap.getWidth(); mBorderRect.set(0, 0, getWidth(), getHeight()); mBorderRadius = Math.min((mBorderRect.height() - mBorderWidth) / 2, (mBorderRect.width() - mBorderWidth) / 2); mDrawableRect.set(mBorderWidth, mBorderWidth, mBorderRect.width() - mBorderWidth, mBorderRect.height() - mBorderWidth); mDrawableRadius = Math.min(mDrawableRect.height() / 2, mDrawableRect.width() / 2); updateShaderMatrix(); invalidate(); } private void updateShaderMatrix() { float scale; float dx = 0; float dy = 0; mShaderMatrix.set(null); if (mBitmapWidth * mDrawableRect.height() > mDrawableRect.width() * mBitmapHeight) { scale = mDrawableRect.height() / (float) mBitmapHeight; dx = (mDrawableRect.width() - mBitmapWidth * scale) * 0.5f; } else { scale = mDrawableRect.width() / (float) mBitmapWidth; dy = (mDrawableRect.height() - mBitmapHeight * scale) * 0.5f; } mShaderMatrix.setScale(scale, scale); mShaderMatrix.postTranslate((int) (dx + 0.5f) + mBorderWidth, (int) (dy + 0.5f) + mBorderWidth); mBitmapShader.setLocalMatrix(mShaderMatrix); } } 自定义的属性：res/values/attrs.xml
[html] view plain copy <?xml version="1.0" encoding="utf-8"?> <resources> <declare-styleable name="CircleImageView"> <attr name="border_width" format="dimension" /> <attr name="border_color" format="color" /> </declare-styleable> </resources> 使用时的布局文件：
[html] view plain copy <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" > <RelativeLayout android:layout_width="match_parent" android:layout_height="0dp" android:layout_weight="1" android:padding="@dimen/base_padding" android:background="@color/light"> <de.hdodenhof.circleimageview.CircleImageView android:layout_width="160dp" android:layout_height="160dp" android:layout_centerInParent="true" android:src="@drawable/demo" app:border_width="2dp" app:border_color="@color/dark" /> </RelativeLayout> <RelativeLayout android:layout_width="match_parent" android:layout_height="0dp" android:layout_weight="1" android:padding="@dimen/base_padding" android:background="@color/dark"> <de.hdodenhof.circleimageview.CircleImageView android:layout_width="160dp" android:layout_height="160dp" android:layout_centerInParent="true" android:src="@drawable/lena" app:border_width="2dp" app:border_color="@color/light" /> </RelativeLayout> </LinearLayout> 效果：
Demo下载：http://download.csdn.NET/detail/nuptboyzhb/7284553
注意：有些开发者可能也发现了，如果我们需要一个圆形的ImageButton的话，其实，我们没有必要自己写。如果ImageButton的图标是固定不变的，我们完全可以让设计师给我设计一个圆形的图片，然后直接设置再ImageButton上就可以了。但是，请注意，我们这里的圆形ImageView是自定义控件，也即是：无论你设置的图片是什么样的，显示出来的就是圆的。比如：易信中用户头像的设置，无论用户拍什么的照片，显示出来都是一个圆的。
拓展阅读：
还有一个更加强大的RoundedImageView，还支持圆角，椭圆等等。
https://github.com/vinc3m1/RoundedImageView
