Android自定义View——贝塞尔曲线实现水波纹进度球

效果图

这里写图片描述

原理分析

首先需要了解的水波纹实现效果,可以在博客的自定义View专题找到,其实现原理如下

  • 利用贝塞尔曲线绘制屏幕外和屏幕内的sin曲线
  • 利用path将sin曲线的左下角和右下角连接起来成为一块区域
  • 通过不断的平移sin曲线,然后平移完一个周期则重新回到原点

这里写图片描述

实现步骤

绘制实现的步骤如下

  • 裁剪画布为圆形
  • 绘制圆形边框
  • 绘制波浪区域
  • 绘制进度文字
  • 自动增长进度

1、初始化变量

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public class WaveView extends View {
//View的宽高
private int width;
private int height;
//View的画笔
private Paint wavePaint;
private Paint textPaint;
private Paint circlePaint;
//波浪的路径
private Path path;
//sin曲线的长度:一个周期长度
private int cycle = 160;
//每次平移的长度,为四分之一个周期
private int translateX = cycle / 4;
//sin曲线振幅的高度
private int waveHeight = 80;
//sin曲线的起点坐标
private Point startPoint;
//当前波浪的进度
private int progress = 0;
//当前波浪的速度
private int waveSpeech = 150;
//是否启用了自动增长进度
private boolean isAutoIncrease = false;
public WaveView(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
initPaint(context);
}
public WaveView(Context context) {
super(context);
initPaint(context);
}
private void initPaint(Context context) {
path = new Path();
wavePaint = new Paint();
wavePaint.setAntiAlias(true);
wavePaint.setStyle(Paint.Style.FILL);
wavePaint.setColor(Color.parseColor("#1998FA"));
circlePaint = new Paint();
circlePaint.setStrokeWidth(5);
circlePaint.setStyle(Paint.Style.STROKE);
circlePaint.setAntiAlias(true);
circlePaint.setColor(Color.parseColor("#1998FA"));
textPaint = new Paint();
textPaint.setAntiAlias(true);
textPaint.setTextSize(50);
textPaint.setColor(Color.BLUE);
}
}

2、获取宽和高

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@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
//由于是一个圆形,所以取的值是宽高的最小值
width = measureSize(400, widthMeasureSpec);
height = measureSize(400, heightMeasureSpec);
width = Math.min(width, height);
height = Math.min(width, height);
setMeasuredDimension(width, height);
//初始化起点,为屏幕外的一个周期
startPoint = new Point(-cycle * 4, 0);
}
/**
* 测量宽高
*
* @param defaultSize
* @param measureSpec
* @return
*/
private int measureSize(int defaultSize, int measureSpec) {
int result = defaultSize;
int mode = MeasureSpec.getMode(measureSpec);
int size = MeasureSpec.getSize(measureSpec);
switch (mode) {
case MeasureSpec.UNSPECIFIED:
result = defaultSize;
break;
case MeasureSpec.AT_MOST:
case MeasureSpec.EXACTLY:
result = size;
break;
}
return result;
}

3、绘制图形

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@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
//设置内间距
setPadding(20, 20, 20, 20);
//裁剪画布为圆形
clipCicle(canvas);
//绘制圆形边框
drawCicleBorder(canvas);
//绘制波浪区域
drawWavePath(canvas);
//绘制进度文字
drawProcessText(canvas);
//自动增长进度
if (isAutoIncrease) {
if (progress >= 100) {
progress = 0;
} else {
progress++;
}
}
//更新UI
postInvalidateDelayed(waveSpeech);
}
/**
* 裁剪画布为圆形
*
* @param canvas
*/
private void clipCicle(Canvas canvas) {
Path circlePath = new Path();
circlePath.addCircle(width / 2, height / 2, width / 2, Path.Direction.CW);
canvas.clipPath(circlePath);
}
/**
* 绘制圆形边框
*
* @param canvas
*/
private void drawCicleBorder(Canvas canvas) {
canvas.drawPaint(circlePaint);
canvas.drawCircle(width / 2, height / 2, width / 2, circlePaint);
}
/**
* 绘制波浪区域
*
* @param canvas
*/
private void drawWavePath(Canvas canvas) {
//根据进度改变起点坐标的y值
startPoint.y = (int) ((1 - (progress / 100.0)) * (height / 2 + width / 2));
Log.e("TAG", "startPoint.y:" + startPoint.y);
//移动区域起点
path.moveTo(startPoint.x, startPoint.y);
int j = 1;
//循环绘制正弦曲线区域,循环两个周期
for (int i = 1; i <= 8; i++) {
if (i % 2 == 0) {
//波峰
path.quadTo(startPoint.x + (cycle * j), startPoint.y + waveHeight,
startPoint.x + (cycle * 2) * i, startPoint.y);
} else {
//波谷
path.quadTo(startPoint.x + (cycle * j), startPoint.y - waveHeight,
startPoint.x + (cycle * 2) * i, startPoint.y);
}
j += 2;
}
//绘制封闭的区域
path.lineTo(width, height);//右下角
path.lineTo(startPoint.x, height);//左下角
path.lineTo(startPoint.x, startPoint.y);//起点
path.close();
//绘制区域
canvas.drawPath(path, wavePaint);
path.reset();
//一开始的起点是在-160,160 = 40 + 40 + 40 + 40,走完一个周期则回到原点
if (startPoint.x + translateX >= 0) {
startPoint.x = -cycle * 4;
} else {
startPoint.x += translateX;
}
}
/**
* 绘制进度文字
*
* @param canvas
*/
private void drawProcessText(Canvas canvas) {
//画布的大小
Rect targetRect = new Rect(0, 0, width, height);
Paint.FontMetricsInt fontMetrics = textPaint.getFontMetricsInt();
int baseline = (targetRect.bottom + targetRect.top - fontMetrics.bottom - fontMetrics.top) / 2;
// 下面这行是实现水平居中,drawText对应改为传入targetRect.centerX()
textPaint.setTextAlign(Paint.Align.CENTER);
canvas.drawText(progress + "%", targetRect.centerX(), baseline, textPaint);
}

4、提供对外API

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/**
* 开启自动增长
*/
public void startIncrease() {
isAutoIncrease = true;
invalidate();
}
/**
* 设置当前进度
*
* @param progress 进度
*/
public void setProgress(int progress) {
if (progress > 100 || progress < 0)
throw new RuntimeException(getClass().getName() + "请设置[0,100]之间的值");
this.progress = progress;
invalidate();
}
/**
* 通过动画设置当前进度
*
* @param targetProcess 进度 <=100
* @param duration 动画时长
*/
public void setProgress(final int targetProcess, int duration) {
if (progress > 100 || progress < 0)
throw new RuntimeException(getClass().getName() + "请设置[0,100]之间的值");
ValueAnimator progressAnimator = ValueAnimator.ofInt(progress, targetProcess);
progressAnimator.setDuration(duration);
progressAnimator.setTarget(progress);
progressAnimator.setInterpolator(new LinearInterpolator());
progressAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
setProgress((Integer) animation.getAnimatedValue());
}
});
progressAnimator.start();
}
/**
* 获取当前进度
*
* @return
*/
public int getProgress() {
return progress;
}

5、使用API

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public class WaterWaveActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_water_wave);
// API三选一即可
// 设置当前进度条
((WaveView) findViewById(R.id.wv)).setProgress(50);
// 在10秒钟内将进度条增长到50%
((WaveView) findViewById(R.id.wv)).setProgress(50, 10000);
// 自动增长进度从0到100
((WaveView) findViewById(R.id.wv)).startIncrease();
}
}

6、源码下载

水波纹进度球View下载

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