Android编程使用自定义View实现水波进度效果示例

public class WaterWaveView extends View {  //边框宽度  private int STROKE_WIDTH;  //组件的宽，高  private int width, height;    private float max, progress;    private Paint progressPaint;  //波纹振幅与半径之比。(建议设置：<0.1)  private static final float A = 0.05f;  //绘制文字的画笔  private Paint textPaint;  //绘制边框的画笔  private Paint circlePaint;    private int centerX, centerY;  //内圆所在的矩形  private RectF circleRectF;  public WaterWaveView(Context context) {    super(context);    init();  }  public WaterWaveView(Context context, AttributeSet attrs) {    super(context, attrs);    init();  }  public WaterWaveView(Context context, AttributeSet attrs, int defStyleAttr) {    super(context, attrs, defStyleAttr);    init();  }  //初始化  private void init() {    progressPaint = new Paint();    progressPaint.setColor(Color.parseColor("#77cccc88"));    progressPaint.setAntiAlias(true);    textPaint = new Paint();    textPaint.setColor(Color.WHITE);    textPaint.setAntiAlias(true);    circlePaint = new Paint();    circlePaint.setStyle(Paint.Style.STROKE);    circlePaint.setAntiAlias(true);    circlePaint.setColor(Color.parseColor("#33333333"));    autoRefresh();  }  @Override  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {    super.onMeasure(widthMeasureSpec, heightMeasureSpec);    if (width == 0 || height == 0) {      width = getWidth();      height = getHeight();      //计算圆弧半径和圆心点      int circleRadius = Math.min(width, height) >> 1;      STROKE_WIDTH = circleRadius / 10;      circlePaint.setStrokeWidth(STROKE_WIDTH);      centerX = width / 2;      centerY = height / 2;      VALID_RADIUS = circleRadius - STROKE_WIDTH;      RADIANS_PER_X = (float) (Math.PI / VALID_RADIUS);      circleRectF = new RectF(centerX - VALID_RADIUS, centerY - VALID_RADIUS,          centerX + VALID_RADIUS, centerY + VALID_RADIUS);    }  }  private Rect textBounds = new Rect();  //x方向偏移量  private int xOffset;  @Override  protected void onDraw(Canvas canvas) {    super.onDraw(canvas);    //绘制圆形边框    canvas.drawCircle(centerX, centerY, VALID_RADIUS + (STROKE_WIDTH >> 1), circlePaint);    //绘制水波曲线    canvas.drawPath(getWavePath(xOffset), progressPaint);    //绘制文字    textPaint.setTextSize(VALID_RADIUS >> 1);    String text1 = String.valueOf(progress);    //测量文字长度    float w1 = textPaint.measureText(text1);    //测量文字高度    textPaint.getTextBounds("8", 0, 1, textBounds);    float h2 = textBounds.height();    float extraW = textPaint.measureText("8") / 3;    canvas.drawText(text1, centerX - w1 / 2 - extraW, centerY + h2 / 2, textPaint);    textPaint.setTextSize(VALID_RADIUS / 6);    textPaint.getTextBounds("M", 0, 1, textBounds);    float h3 = textBounds.height();    canvas.drawText("M", centerX + w1 / 2 - extraW + 5, centerY - (h2 / 2 - h3), textPaint);    String text3 = "共" + String.valueOf(max) + "M";    float w3 = textPaint.measureText(text3, 0, text3.length());    textPaint.getTextBounds("M", 0, 1, textBounds);    float h4 = textBounds.height();    canvas.drawText(text3, centerX - w3 / 2, centerY + (VALID_RADIUS >> 1) + h4 / 2, textPaint);    String text4 = "流量剩余";    float w4 = textPaint.measureText(text4, 0, text4.length());    textPaint.getTextBounds(text4, 0, text4.length(), textBounds);    float h5 = textBounds.height();    canvas.drawText(text4, centerX - w4 / 2, centerY - (VALID_RADIUS >> 1) + h5 / 2, textPaint);  }  //绘制水波的路径  private Path wavePath;  //每一个像素对应的弧度数  private float RADIANS_PER_X;  //去除边框后的半径（即内圆半径）  private int VALID_RADIUS;    private Path getWavePath(int xOffset) {    if (wavePath == null) {      wavePath = new Path();    } else {      wavePath.reset();    }    float[] startPoint = new float[2]; //波浪线起点    float[] endPoint = new float[2]; //波浪线终点    for (int i = 0; i <= VALID_RADIUS * 2; i += 2) {      float x = centerX - VALID_RADIUS + i;      float y = (float) (centerY + VALID_RADIUS * (1.0f + A) * 2 * (0.5f - progress / max)          + VALID_RADIUS * A * Math.sin((xOffset + i) * RADIANS_PER_X));      //只计算内圆内部的点，边框上的忽略      if (calDistance(x, y, centerX, centerY) > VALID_RADIUS) {        if (x < centerX) {          continue; //左边框,继续循环        } else {          break; //右边框,结束循环        }      }      //第1个点      if (wavePath.isEmpty()) {        startPoint[0] = x;        startPoint[1] = y;        wavePath.moveTo(x, y);      } else {        wavePath.lineTo(x, y);      }      endPoint[0] = x;      endPoint[1] = y;    }    if (wavePath.isEmpty()) {      if (progress / max >= 0.5f) {        //满格        wavePath.moveTo(centerX, centerY - VALID_RADIUS);        wavePath.addCircle(centerX, centerY, VALID_RADIUS, Path.Direction.CW);      } else {        //空格        return wavePath;      }    } else {      //添加圆弧部分      float startDegree = calDegreeByPosition(startPoint[0], startPoint[1]); //0~180      float endDegree = calDegreeByPosition(endPoint[0], endPoint[1]); //180~360      wavePath.arcTo(circleRectF, endDegree - 360, startDegree - (endDegree - 360));    }    return wavePath;  }  private float calDistance(float x1, float y1, float x2, float y2) {    return (float) Math.sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2));  }  //根据当前位置，计算出进度条已经转过的角度。  private float calDegreeByPosition(float currentX, float currentY) {    float a1 = (float) (Math.atan(1.0f * (centerX - currentX) / (currentY - centerY)) / Math.PI * 180);    if (currentY < centerY) {      a1 += 180;    } else if (currentY > centerY && currentX > centerX) {      a1 += 360;    }    return a1 + 90;  }  public void setMax(int max) {    this.max = max;    invalidate();  }  //直接设置进度值（同步）  public void setProgressSync(float progress) {    this.progress = progress;    invalidate();  }    private void autoRefresh() {    new Thread(new Runnable() {      @Override      public void run() {        while (!detached) {          xOffset += (VALID_RADIUS >> 4);          SystemClock.sleep(100);          postInvalidate();        }      }    }).start();  }  //标记View是否已经销毁  private boolean detached = false;  @Override  protected void onDetachedFromWindow() {    super.onDetachedFromWindow();    detached = true;  }}