EyeView.java

package com.cheng.animationstudy.customview.ucbrowser;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.os.Build;
import android.util.AttributeSet;
import android.widget.FrameLayout;

/**
 * 仿UC浏览器下拉动画中的眼睛
 */
public class EyeView extends FrameLayout {
    
    private Paint mPaint;
    private Bitmap mBitmap;
    
    public EyeView(Context context) {
        super(context);
        init();
    }

    public EyeView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    public EyeView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init();
    }

    private void init() {
        setDrawingCacheEnabled(true);
        if (Build.VERSION.SDK_INT >= 11) {
            setLayerType(LAYER_TYPE_SOFTWARE, null);
        }
        mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
    }

    @Override
    protected void dispatchDraw(Canvas canvas) {
        super.dispatchDraw(canvas);
        if (mBitmap != null) {
            mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));
            canvas.drawBitmap(mBitmap, 0, 0, mPaint);
            mPaint.setXfermode(null);
        }
    }

    public void setRadius(int radius) {
        if (mBitmap!=null && !mBitmap.isRecycled()) {
            mBitmap.recycle();
        }
        mBitmap = Bitmap.createBitmap(getWidth(), getHeight(), Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(mBitmap);
        canvas.drawCircle(getWidth() / 2f, getHeight() / 2f, radius, mPaint);
        invalidate();
    }
}