Android开发圆形ImageView实现

效果图如下

1、自定义属性，在value文件夹下新建attrs文件，声明如下属性

<declare-styleable name="CircleImageView">    <attr name="border_color" format="color"/>    <attr name="border_width" format="dimension"/></declare-styleable>

2、继承ImageView ，重写构造和ondraw方法

public class CircleImageView extends AppCompatImageView {  private int borderColor;  private int borderWidth;  private final static int DEFAULT_COLOR = Color.BLACK;  private final static int DEFAULT_BORDER_WIDTH = 0;  private Paint mPaint;  public CircleImageView(Context context) {    this(context,null);  }  public CircleImageView(Context context, @Nullable AttributeSet attrs) {    this(context, attrs,0);  }  public CircleImageView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {    super(context, attrs, defStyleAttr);    TypedArray typedArray = context.obtainStyledAttributes(attrs,R.styleable.CircleImageView);    borderColor = typedArray.getColor(R.styleable.CircleImageView_border_color, DEFAULT_COLOR);    borderWidth = typedArray.getDimensionPixelSize(R.styleable.CircleImageView_border_width, DEFAULT_BORDER_WIDTH);    borderWidth = dp2px(context,borderWidth);    mPaint = new Paint();    typedArray.recycle();  }  public int dp2px(Context ctx,int dp) {    float scale = ctx.getResources().getDisplayMetrics().density;    return (int) (dp * scale + 0.5);  }  @Override  protected void onDraw(Canvas canvas) {    Drawable drawable = getDrawable();    if (drawable != null && drawable instanceof BitmapDrawable) {      Bitmap bitmap = ((BitmapDrawable)drawable).getBitmap();      Bitmap circleBitmap = getCircleBitmap(bitmap);      Rect srcRect = new Rect(0,0,circleBitmap.getWidth(),circleBitmap.getHeight());      Rect dstRect = new Rect(0,0,getWidth(),getHeight());      mPaint.reset();      canvas.drawBitmap(circleBitmap,srcRect,dstRect,mPaint);    }else {        super.onDraw(canvas);    }  }  private Bitmap getCircleBitmap(Bitmap bitmap) {    Bitmap circleBitmap = Bitmap.createBitmap(bitmap.getWidth(),bitmap.getHeight(),Bitmap.Config.ARGB_8888);    Canvas canvas = new Canvas(circleBitmap);    mPaint.setAntiAlias(true);    canvas.drawARGB(0,255,255,255);    mPaint.setColor(borderColor);    int radius = bitmap.getWidth() < bitmap.getHeight()? bitmap.getWidth():bitmap.getHeight();    canvas.drawCircle(radius/2,radius/2,radius/2-borderWidth,mPaint);    mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));    Rect rect = new Rect(0,0,bitmap.getWidth(),bitmap.getHeight());    canvas.drawBitmap(bitmap,rect,rect,mPaint);    mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_OVER));    canvas.drawCircle(radius/2,radius/2,radius / 2,mPaint);    return circleBitmap;  }}

3、引入CircleImageView

<com.mydemo.view.CircleImageView    android:layout_width="100dp"    android:layout_height="100dp"    android:src='/images/loading.gif' data-original="@drawable/logo"    app:border_color="#ffff00"    app:border_width="1dp"    />

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原标题：Android开发圆形ImageView实现

关键词：Android