在项目中，我们经常会用到圆形图片，但是android本身又没有提供，那我只能我们自己来完成。
第一种方式，自定义CircleImageView:
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;
// 圆形边框的厚度默认值。
// 如果是0，则没有天蓝色渐变的边框。
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;
private final Paint mFlagBackgroundPaint = new Paint();
private final TextPaint mFlagTextPaint = new TextPaint();
private String mFlagText;
private boolean mShowFlag = false;
private Rect mFlagTextBounds = new Rect();
Shader mSweepGradient = null;
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);
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.save();
canvas.rotate(20, getWidth() / 2, getHeight() / 2);
canvas.drawCircle(getWidth() / 2, getHeight() / 2, mBorderRadius,
mBorderPaint);
canvas.restore();
}
if (mShowFlag && mFlagText != null) {
canvas.drawArc(mBorderRect, 40, 100, false, mFlagBackgroundPaint);
mFlagTextPaint.getTextBounds(mFlagText, 0, mFlagText.length(),
mFlagTextBounds);
canvas.drawText(mFlagText, getWidth() / 2,
(float) ((3 + Math.cos((float) (Math.PI * 5 / 18)))
* getHeight() / 4 + mFlagTextBounds.height() / 3),
mFlagTextPaint);
}
}
@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);
mFlagBackgroundPaint.setColor(Color.BLACK & 0x66FFFFFF);
mFlagBackgroundPaint.setFlags(TextPaint.ANTI_ALIAS_FLAG);
mFlagTextPaint.setFlags(TextPaint.ANTI_ALIAS_FLAG);
mFlagTextPaint.setTextAlign(Align.CENTER);
mFlagTextPaint.setColor(Color.WHITE);
mFlagTextPaint
.setTextSize(getResources().getDisplayMetrics().density * 18);
mSweepGradient = new SweepGradient(getWidth() / 2, getHeight() / 2,
new int[] { Color.rgb(255, 255, 255), Color.rgb(1, 209, 255) },
null);
mBorderPaint.setShader(mSweepGradient);
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);
}
public void setShowFlag(boolean show) {
mShowFlag = show;
invalidate();
}
public void setFlagText(String text) {
mFlagText = text;
invalidate();
}
}
使用的时候，切记不要引用成V4报下的CircleImageView！！
另一篇文章分享的第二种方式：把图片修剪为圆形，这样给我们视觉上的效果是一样
我们时常会用到圆形图片，那么，是对图片进行裁剪，还是自定义圆形的ImageView，如果没有特殊要求的话，我们肯定选择前者，原因很简单，因为简单！！直接上源码，就是这么粗暴任性~~~
public static Bitmap createCircleImage(Bitmap source) {
int length = source.getWidth() < source.getHeight() ? source.getWidth() : source.getHeight();
Paint paint = new Paint();
paint.setAntiAlias(true);
Bitmap target = Bitmap.createBitmap(length, length, Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(target);
canvas.drawCircle(length / 2, length / 2, length / 2, paint);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
canvas.drawBitmap(source, 0, 0, paint);
return target;
}
只需要输入bitmap，然后就给你返回圆形的bitmap，然后设置到ImageView中，是不是很简单。
这里另外提一点，如果从ImageView中拿出来bitmap，只需要一行代码：
//从ImageView中获取bitmap
Bitmap bm =((BitmapDrawable) ( imageView).getDrawable()).getBitmap();
