android - 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;           // handler

    private 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Bitmap

        mHandler = 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;
        animState = 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);
    }
}

伊谢尔伦2773 Tage vor377

android - 自定义View中代码流程问题

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