Android使用CircleImageView实现圆形头像的方法

有时我们在应用中会用到圆形头像，下面是利用CircleImageView实现圆形头像的演示，下面效果和代码，效果如图

实现起来也比较简单，先在项目中建一个circleimageview包用来存放CircleImageView类，待会直接把CircleImageView类复制到包里就可以使用了

然后，再建一个attrs.xml，其代码相当简单，定义了圆形边框宽度和颜色

<?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>

然后是在自己应用的Activity的布局文件中使用CircleImageView了

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
 xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:tools="http://schemas.android.com/tools"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 tools:context="com.example.icontest.MainActivity">
 <circleimageview.CircleImageView
   xmlns:app="http://schemas.android.com/apk/res-auto"
   android:id="@+id/circleImageView"
   android:layout_width="100dp"
   android:layout_height="100dp"
   android:layout_centerHorizontal="true"
   android:src="@mipmap/ic_launcher"
   app:border_width="2dp"
   app:border_color="#ccc"
    />
</RelativeLayout>

注意的是要写上circleimageview.CircleImageView这个全路径，还要指定

xmlns:app="http://schemas.android.com/apk/res-auto"

这个就是根据上面整个布局的

xmlns:android="http://schemas.android.com/apk/res/android"

来的，把res/android改为res-auto即可，然后再指定border_width和border_color两个属性即可
然后再Activity中就直接可以利用id找到它了

CircleImageView icon;
icon= (CircleImageView) findViewById(R.id.circleImageView);

最后是CircleImageView类的代码，这个网上随便就能找到，不过这里还是贴出来吧

package circleimageview;
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.net.Uri;
import android.util.AttributeSet;
import android.widget.ImageView;
import com.example.icontest.R;
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 = 2;
 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);
  init();
 }
 public CircleImageView(Context context, AttributeSet attrs) {
  this(context, attrs, 0);
 }
 public CircleImageView(Context context, AttributeSet attrs, int defStyle) {
  super(context, attrs, defStyle);
  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();
  init();
 }
 private void init() {
  super.setScaleType(SCALE_TYPE);
  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
 public void setAdjustViewBounds(boolean adjustViewBounds) {
  if (adjustViewBounds) {
    throw new IllegalArgumentException("adjustViewBounds not supported.");
  }
 }
 @Override
 protected void onDraw(Canvas canvas) {
  if (getDrawable() == null) {
    return;
  }
  canvas.drawCircle(getWidth() / 2, getHeight() / 2, mDrawableRadius, mBitmapPaint);
  if (mBorderWidth != 0) {
    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();
 }
 @Override
 public void setImageURI(Uri uri) {
  super.setImageURI(uri);
  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);
 }
}

来源：http://blog.csdn.net/qq_33245265/article/details/52356884