自定义View中代码流程问题？

具体代码在最下方给出

点击 CHECK 后 就是图二的效果
但是不太明白他这个绘制过程所以用Log.e调试 还是没看懂
点击包含这个View的activity时 log打印为

不明白为什么是两次onDraw的打印

然后点击CHECK Log.e打印为(只发了一部分截图)

不明白为什么 又打印了两次onDraw
然后进行sendEmptyMessageDelayed的递归操作(不知道有没有说错)
在invalidate前后分别设置log
然后每次在handleMessage中判断的时候 为什么 又要打印onDraw(还是两次)

E/AAA: onDraw E/AAA: onDraw E/AAA: invalidate 1 + 0 E/AAA: invalidate 1 + 1 E/AAA: Count=1

public class CheckView extends View {private static final int ANIM_NULL = 0; //动画状态-没有 private static final int ANIM_CHECK = 1;//动画状态-开启 private static final int ANIM_UNCHECK = 2;//动画状态-结束private Context mContext; // 上下文 private int mWidth, mHeight;// 宽高 private Handler mHandler; // handlerprivate Paint mPaint; private Bitmap okBitmap;private int animCurrentPage = -1; // 当前页码 private int animMaxPage = 13; // 总页数 private int animDuration = 500; // 动画时长 private int animState = ANIM_NULL;// 动画状态private boolean isCheck = false;// 是否只选中状态public CheckView(Context context, AttributeSet attrs) { super(context, attrs); Log.e("AAA","构造方法CheckView + 0"); init(context); Log.e("AAA","构造方法CheckView + 1"); }/*** 初始化* @param context*/ private void init(Context context) { mContext = context;mPaint = new Paint(); mPaint.setColor(0xffFF5317);//设置画笔颜色 mPaint.setStyle(Paint.Style.FILL);//设置画笔风格 mPaint.setAntiAlias(true);//抗锯齿okBitmap = BitmapFactory.decodeResource(mContext.getResources(), R.drawable.checkes);//从资源文件获取BitmapmHandler = new Handler() { @Override public void handleMessage(Message msg) { super.handleMessage(msg); if (animCurrentPage < animMaxPage && animCurrentPage >= 0) {// 点击之前-1 <13 && -1>=0 点击后 0 < 13 && 0 >=0 Log.e("AAA","invalidate 1 + 0"); invalidate();//重绘 ==> 调用onDraw方法，重绘View中变化的部分 Log.e("AAA","invalidate 1 + 1");if (animState == ANIM_NULL)// 动画状态==没有 return; if (animState == ANIM_CHECK) {//动画状态==开启animCurrentPage++;//当前页数++ } else if (animState == ANIM_UNCHECK) {//动画状态==关闭 animCurrentPage--;//当前页数-- } this.sendEmptyMessageDelayed(0, animDuration / animMaxPage); Log.e("AAA", "Count=" + animCurrentPage); } else { if (isCheck) { //isCheck==false animCurrentPage = animMaxPage - 1;// -1 = 13-1 } else { animCurrentPage = -1; } Log.e("AAA","invalidate 2 + 0"); invalidate();//重绘ondraw中 使用invalidate 非UI线程中 使用 postInvalidate Log.e("AAA","invalidate 2 + 1"); animState = ANIM_NULL;// 动画状态==没有 } } }; } /*** View大小确定* @param w* @param h* @param oldw* @param oldh*/ @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) { super.onSizeChanged(w, h, oldw, oldh); mWidth = w; mHeight = h; Log.e("AAA","onSizeChanged"); }/*** 绘制内容* @param canvas*/ @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); Log.e("AAA","onDraw"); // 移动坐标系到画布中央 canvas.translate(mWidth / 2, mHeight / 2);// 绘制背景圆形 canvas.drawCircle(0, 0, 240, mPaint);// 得出图像边长 int sideLength = okBitmap.getHeight();// 得到图像选区 和 实际绘制位置 Rect src = new Rect(sideLength * animCurrentPage, 0, sideLength * (animCurrentPage + 1), sideLength); Rect dst = new Rect(-200, -200, 200, 200);// 绘制 canvas.drawBitmap(okBitmap, src, dst, null); } /*** 选择*/ public void check() { if (animState != ANIM_NULL || isCheck) return; animState = ANIM_CHECK; animCurrentPage = 0; Log.e("AAA","check + 1"); mHandler.sendEmptyMessageDelayed(0, animDuration / animMaxPage);// (0,500/13) isCheck = true; Log.e("AAA","check + 2"); }/*** 取消选择*/ public void unCheck() { if (animState != ANIM_NULL || (!isCheck)) return; animSt优艾设计网_Photoshop交流ate = ANIM_UNCHECK; animCurrentPage = animMaxPage - 1; mHandler.sendEmptyMessageDelayed(0, animDuration / animMaxPage); isCheck = false; }/*** 设置动画时长* @param animDuration*/ public void setAnimDuration(int animDuration) { if (animDuration <= 0) return; this.animDuration = animDuration; }/*** 设置背景圆形颜色* @param color*/ public void setBackgroundColor(int color){ mPaint.setColor(color); } }

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