Android初级进阶之自定义View之SafeVeiw 有更新!

  aohanyao

前言

Android初级进阶之自定义View之SafeVeiw

SafeView

这是我模仿的一个效果,要不断的进步,就要不断的学习。主要实现的效果是一个转动的效果和一个3D触摸效果。请看效果图(录制的图片有点大):
效果图

知识点

  1. Canvas
    1. Paint
    2. Shader
    3. Camera(不是相机)
    4. Animator

分析

整个View看上去是有四个圆组成,内中心的圆对边上有一个小圆,圆上面还有小尾巴。其实主要的原理是使用ValueAnimator来发散一个圆周的值,也就是360度,然后每次发散后旋转画布就能得到上面的效果。

技术点

  1. android.graphics.Camera是Android官方提供的3D效果组件,使用起来十分的简单,关键在于理解其中的x,y,z轴。(有空再写一篇Camera的使用)
  2. Sharder 阴影渲染
    1. 本View中主要使用了LinearGradient和RadialGradient。
      1. LinearGradient为线性渐变,在这里主要是用来画小圆的尾巴。
      2. RadialGradient为径向渐变,从圆心向外四周扩散,在这里是用来画中心圆的效果。
  3. Animator 自3.0后推出的属性动画,本文主要使用ValueAnimator。

CODE

1.初始化 && Measure

将一些全局的值在构方法中进行初始化并且测量View的宽高等。


  		mPaint = new Paint();
        mPaint.setAntiAlias(true);
        mPaint.setStrokeCap(Paint.Cap.ROUND);// 圆角笔触
        mLeftLinearGradient = new LinearGradient(0, 0, mCy - OFFSET, mCy - OFFSET, 0xddffffff, 0x00000000, Shader.TileMode.CLAMP);//左边的尾巴
        mRightLinearGradient = new LinearGradient(mCy - OFFSET, mCy / 2, 0, mCy / 2, 0xddffffff, 0x00000000, Shader.TileMode.CLAMP);//右边的尾巴

2.绘制所有的背景圆

圆的颜色是从中心开始不断的淡化的,其实这只要更改透明度就可以完成这样的效果

/**
 * @param canvas
 * @param radius 直径
 * @param angle  当前角度
 */
private void canvasCircle(Canvas canvas, int radius, float angle) {
    float percentage = angle / 360f;//当前角度百分比
    mPaint.setColor(0xddffffff);
    mPaint.setStyle(Paint.Style.STROKE);
    mPaint.setStrokeWidth(1.5f);
    //绘制中心圆圈
    canvas.drawCircle(radius, radius, radius - OFFSET, mPaint);
    mPaint.setStyle(Paint.Style.FILL);
    mPaint.setColor(0x22ffffff);


    if (aninatopValue >= 90) {
        //绘制第二圆圈
        canvas.drawCircle(radius, radius, radius - OFFSET + 40 * percentage, mPaint);
    }
    mPaint.setColor(0x11ffffff);
    if (aninatopValue >= 180) {
        //绘制第三圆圈
        canvas.drawCircle(radius, radius, radius - OFFSET + 80 * percentage, mPaint);
    }
    if (aninatopValue >= 270) {
        //绘制第四圆圈
        canvas.drawCircle(radius, radius, radius - OFFSET + 120 * percentage, mPaint);
    }
    if (aninatopValue <= 90) {// 初始状态下绘制所有的圆圈
        mPaint.setColor(0x22ffffff);
        canvas.drawCircle(radius, radius, radius - OFFSET + 40, mPaint);
        mPaint.setColor(0x11ffffff);
        canvas.drawCircle(radius, radius, radius - OFFSET + 80, mPaint);
        canvas.drawCircle(radius, radius, radius - OFFSET + 120, mPaint);
    }
    mPaint.setColor(0xff1782dd);//绘制中心圆为背景颜色
    canvas.drawCircle(radius, radius, radius - OFFSET, mPaint);
    mPaint.setColor(0x55ffffff);
    //渲染 得到中心的 凹凸效果
    RadialGradient radialGradient = new RadialGradient(radius, radius, radius - OFFSET, new int[]{0x00000000, 0xffffffff}, null, Shader.TileMode.CLAMP);
    mPaint.setShader(radialGradient);
    canvas.drawCircle(radius, radius, radius - OFFSET, mPaint);
}

效果图:

绘制完所有的圆

3.绘制中间的文字

/**
 * //绘制文字
 *
 * @param canvas
 * @param radius
 */
private void canvasText(Canvas canvas, int radius) {
    mPaint.setShader(null);//文字颜色
    mPaint.setColor(0x88ffffff);//转换字体
    mPaint.setTextSize(DensityUtils.sp2px(getContext(), 14));
    mPaint.setStrokeWidth(2);
    mPaint.setStyle(Paint.Style.STROKE);
    String safeText = "已防御次数";
    canvas.drawText(safeText, radius - mPaint.measureText(safeText) / 2, (radius - mPaint.measureText(String.valueOf(safeText)) / 2), mPaint);
    mPaint.setStyle(Paint.Style.FILL);
    mPaint.setColor(0xffffffff);
    mPaint.setTextSize(DensityUtils.sp2px(getContext(), 30));
    mPaint.setStrokeWidth(2);
    canvas.drawText(String.valueOf(safeCount), radius - mPaint.measureText(String.valueOf(safeCount)) / 2, radius + radius / 4, mPaint);
}

绘制完所有的圆

4.绘制左右两个圆点并旋转

到这里,基本绘制就已经完成了,只要加上角度的计算和动画部分,这个View就能够动起来了。

/**
 * 绘制旋转部分
 */
private void canvasRotate(Canvas canvas, int radius, float angle) {
    //旋转画布
    canvas.rotate(angle, radius, radius);
    //移动坐标到中心
    canvas.translate(radius, radius);
    mPaint.setShader(null);
    //左边的圆
    mPaint.setColor(Color.WHITE);
    mPaint.setStyle(Paint.Style.FILL);
    mPaint.setStrokeWidth(5);
    canvas.drawCircle(-radius + OFFSET, 0, 10, mPaint);
    //右边的圆
    canvas.drawCircle(radius - OFFSET, 0, 10, mPaint);
    mPaint.setStyle(Paint.Style.STROKE);
    mPaint.setStrokeWidth(8);
    //绘制坐标的圆的尾巴
    RectF mRectF = new RectF(-radius + OFFSET, -radius + OFFSET, radius - OFFSET, radius - OFFSET);
    mPaint.setShader(mRightLinearGradient);
    canvas.drawArc(mRectF, 15, 180 - 15, false, mPaint);
    mPaint.setShader(mLeftLinearGradient);
    canvas.drawArc(mRectF, 180 + 15, 180 - 15, false, mPaint);
    //合并画布
    canvas.restore();
}

绘制完所有的圆

5.动画与角度

/**
 * 开始
 */
private void startLoopAnimator() {
    //发散350度
    motionAnimator = ValueAnimator.ofFloat(360f).setDuration(1500);
    //线性差值器
    motionAnimator.setInterpolator(new LinearInterpolator());
    //永远循环
    motionAnimator.setRepeatCount(ValueAnimator.INFINITE);
    motionAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
        @Override
        public void onAnimationUpdate(ValueAnimator animation) {
            safeCount++;
            aninatopValue = (float) animation.getAnimatedValue();
            postInvalidate();
        }
    });
    motionAnimator.start();
}

绘制完所有的圆

最后

源码

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