android开源系列：CircleImageView自定义圆形控件的使用

1.自定义圆形控件github地址： https://github.com/hdodenhof/CircleImageView
主要的类：

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

使用时的布局文件：

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。