[游戏开发]Android自定义View实现Loading动态图

最近家里的宽带业务到期，客服打电话说之前的套餐没了，新套餐普遍涨价，就选了一个+20元绑定一个摄像头的套餐，前两天师傅上门安装了摄像头，我手机上下载一个“小翼管家”就能在手机上实时看家里情况。话说，这种收费服务就是抢劫呀！

回到正题，“小翼管家”App做的一般，不过打开摄像头一刻，loading动画倒是让我挺有兴趣，于是决定在摸鱼的时间动手仿一个......画六边形实在有点麻烦，还要计算角度，没那么多时间，我还要打王者......就用圆角矩形代替了......

package com.example.myapplication;

import android.animation.ValueAnimator;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;

public class LoadingView extends View {

    private Paint paint;
    private int width;
    private int height;
    private RectF r1, r2, r3, r4, r5, r6, r7, r8, r9;
    private RectF R1, R2, R3, R4, R5, R6, R7, R8, R9;
    private int count;
    private ValueAnimator animator;
    private boolean fading;

    public LoadingView(Context context) {
        super(context);
        init();
    }

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

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

    private void init() {
        paint = new Paint(Paint.ANTI_ALIAS_FLAG);
        paint.setStyle(Paint.Style.FILL);
        paint.setColor(Color.parseColor("#f9cb9c"));
        reset();
    }

    private void reset() {
        r1 = new RectF();
        r2 = new RectF();
        r3 = new RectF();
        r4 = new RectF();
        r5 = new RectF();
        r6 = new RectF();
        r7 = new RectF();
        r8 = new RectF();
        r9 = new RectF();
    }

    private ValueAnimator.AnimatorUpdateListener listener = new ValueAnimator.AnimatorUpdateListener() {
        @Override
        public void onAnimationUpdate(ValueAnimator animation) {
            float fraction = (float) animation.getAnimatedValue();
            float temp = fraction;
            if (count > 9) {
                count = 1;
                fading = !fading;
            }
            if (fading) {
                temp = 1 - fraction;
            }
            switch (count) {
                case 1:
                    r1 = getTemp(temp);
                    break;
                case 2:
                    r2 = getTemp(temp);
                    break;
                case 3:
                    r3 = getTemp(temp);
                    break;
                case 4:
                    r4 = getTemp(temp);
                    break;
                case 5:
                    r5 = getTemp(temp);
                    break;
                case 6:
                    r6 = getTemp(temp);
                    break;
                case 7:
                    r7 = getTemp(temp);
                    break;
                case 8:
                    r8 = getTemp(temp);
                    break;
                case 9:
                    r9 = getTemp(temp);
                    break;
            }
            invalidate();
            if (fraction == 0) {
                start();
            }
        }
    };

    @Override
    public void onWindowFocusChanged(boolean hasWindowFocus) {
        super.onWindowFocusChanged(hasWindowFocus);
        if (hasWindowFocus) {
            start();
        } else {
            stop();
        }
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        int wmode = MeasureSpec.getMode(widthMeasureSpec);
        int wsize = MeasureSpec.getSize(widthMeasureSpec);
        int hmode = MeasureSpec.getMode(heightMeasureSpec);
        int hsize = MeasureSpec.getSize(heightMeasureSpec);

        if (wmode == MeasureSpec.AT_MOST && hmode == MeasureSpec.AT_MOST) {
            setMeasuredDimension(64, 64);
        } else if (wmode == MeasureSpec.AT_MOST) {
            setMeasuredDimension(64, hsize);
        } else if (hmode == MeasureSpec.AT_MOST) {
            setMeasuredDimension(wsize, 64);
        }
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        width = (w - 4) / 3;
        height = (h - 4) / 3;
        R1 = new RectF(1, 1, 1 + width, 1 + height);
        R2 = new RectF(1 + R1.right, R1.top, 1 + R1.right + width, R1.bottom);
        R3 = new RectF(1 + R2.right, R1.top, 1 + R2.right + width, R1.bottom);
        R8 = new RectF(1, 1 + R1.bottom, R1.right, 1 + R1.bottom + height);
        R9 = new RectF(1 + R8.right, R8.top, 1 + R8.right + width, R8.bottom);
        R4 = new RectF(1 + R9.right, R8.top, 1 + R9.right + width, R8.bottom);
        R7 = new RectF(1, 1 + R8.bottom, R1.right, 1 + R8.bottom + height);
        R6 = new RectF(1 + R7.right, R7.top, 1 + R7.right + width, R7.bottom);
        R5 = new RectF(1 + R6.right, R7.top, 1 + R6.right + width, R7.bottom);
    }

    private void start() {
        count++;
        animator = ValueAnimator.ofFloat(1, 0);
        animator.setDuration(500);
        animator.addUpdateListener(listener);
        animator.start();
    }

    private void stop() {
        animator.cancel();
        animator.removeUpdateListener(listener);
        animator = null;
        fading = false;
        count = 0;
        reset();
        invalidate();
    }

    private RectF getTemp(float fraction) {
        RectF temp = new RectF();
        RectF rectF = getRect();
        temp.left = rectF.left + width / 2 * fraction;
        temp.top = rectF.top + height / 2 * fraction;
        temp.right = rectF.right - width / 2 * fraction;
        temp.bottom = rectF.bottom - height / 2 * fraction;
        return temp;
    }

    private RectF getRect() {
        switch (count) {
            case 1:
                return R1;
            case 2:
                return R2;
            case 3:
                return R3;
            case 4:
                return R4;
            case 5:
                return R5;
            case 6:
                return R6;
            case 7:
                return R7;
            case 8:
                return R8;
            case 9:
                return R9;
        }
        return R1;
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        float r = width / 4;
        canvas.drawRoundRect(r1, r, r, paint);
        canvas.drawRoundRect(r2, r, r, paint);
        canvas.drawRoundRect(r3, r, r, paint);
        canvas.drawRoundRect(r4, r, r, paint);
        canvas.drawRoundRect(r5, r, r, paint);
        canvas.drawRoundRect(r6, r, r, paint);
        canvas.drawRoundRect(r7, r, r, paint);
        canvas.drawRoundRect(r8, r, r, paint);
        canvas.drawRoundRect(r9, r, r, paint);
    }
}