Android开发实现绘制淘宝收益图折线效果示例

本文实例讲述了Android开发实现绘制淘宝收益图折线效果。分享给大家供大家参考，具体如下：

实现的效果我一会贴上，我先说下原理，我们知道要实现在canvas上画线，不就是要搞一个paint嘛，然后首先肯定要设置下paint的属性，那么画文字呢，不就是Textpaint吗，对，就是这么简单，接下来怎么画，折线图主要分为X轴和y轴，x轴表示日期，y表示收益，好，说道这里，大家应该知道怎么去做了，下面直接贴代码

这个方法是，画x,y坐标系的，以及上面的日期和收益了

private void drawCoordinate(Canvas canvas) {
  //坐标系画笔
  Paint coordinatePaint = new Paint();
  coordinatePaint.setAntiAlias(true);
  coordinatePaint.setStrokeWidth(1);
  coordinatePaint.setColor(getResources().getColor(R.color.c5));
  //坐标系文字画笔
  TextPaint coordinateTextPaint = new TextPaint();
  coordinateTextPaint.setAntiAlias(true);
  coordinateTextPaint.setTextSize(scaleTextSize);
  coordinateTextPaint.setAntiAlias(true);
  coordinateTextPaint.setColor(scaleTextColor);
  coordinateTextPaint.setTextAlign(Align.CENTER);
  //水平的刻度线
  float verticalScaleStep = getVerticalScaleStep();
  coordinateTextPaint.setTextAlign(Align.RIGHT);
  float textHeight = getTextHeight(coordinateTextPaint, "8");
  for (int i = 0; i < maxVerticalScaleValue; i++) {
    float y = getHeight() - bottomPadding - (verticalScaleStep * i);
    canvas.drawLine(leftPadding, y, getWidth() - rightPadding, y, coordinatePaint);
    canvas.drawText(i + "", leftPadding - 13, y + textHeight / 2, coordinateTextPaint);
  }
  //垂直的刻度线
  float horizontalScaleStep = getHorizontalScaleStep();
  for (int i = 0; i < line.getSize(); i++) {
    float x = leftPadding + (horizontalScaleStep * i);
    if (i == 0) {
      canvas.drawLine(x, topPadding, x, getHeight() - bottomPadding, coordinatePaint);
    }
    coordinateTextPaint.setColor(mTouchIndex == i ? verticalLineColor : scaleTextColor);
    coordinateTextPaint.setTextAlign(i == 0 ? Align.LEFT : Align.CENTER);
    canvas.drawText(line.getPoint(i).getX(), x, getHeight() - bottomPadding + textHeight + 10, coordinateTextPaint);
  }
}

但是产品有个需求啊，就是点击当前日期可以查看我的收益，并且在交汇点上展示出来

private void drawCurve(Canvas canvas) {
  Paint curvePaint = new Paint();//曲线画笔
  curvePaint.setColor(curveColor);
  curvePaint.setAntiAlias(true);
  curvePaint.setStrokeWidth(curveStrokeWidth);
  float horizontalScaleStep = getHorizontalScaleStep();
  float lastXPixels = 0, newYPixels = 0;
  float lastYPixels = 0, newXPixels = 0;
  float useHeight = getHeight() - bottomPadding - topPadding;
  for (int i = 0; i < line.getSize(); i++) {
    float yPercent = line.getPoint(i).getY() / maxVerticalScaleValue;
    if (i == 0) {
      lastXPixels = leftPadding + i * horizontalScaleStep;
      lastYPixels = getHeight() - bottomPadding - useHeight * yPercent;
    } else {
      newXPixels = leftPadding + i * horizontalScaleStep;
      newYPixels = getHeight() - bottomPadding - useHeight * yPercent;
      canvas.drawLine(lastXPixels, lastYPixels, newXPixels, newYPixels, curvePaint);
      lastXPixels = newXPixels;
      lastYPixels = newYPixels;
    }
    line.getPoint(i).fLineX = lastXPixels;
    line.getPoint(i).fLineY = lastYPixels;
  }
}

点击交汇点，有文字提示说明，

private void drawTipRect(Canvas canvas) {
  if (mTouchIndex == -1) return;
  LinePoint point = line.getPoint(mTouchIndex);
  float x = point.fLineX;
  float y = point.fLineY;
  // 描绘竖线
  Paint paint = new TextPaint();
  PathEffect effects = new DashPathEffect(new float[]{5, 5, 5, 5}, 1);
  paint.setPathEffect(effects);
  paint.setAntiAlias(true);
  paint.setStrokeWidth(verticalLineStrokeWidth);
  paint.setColor(verticalLineColor);
  canvas.drawLine(x, topPadding, x, getHeight() - bottomPadding, paint);
  //描绘交汇圆点
  paint.setPathEffect(null);
  paint.setStyle(Paint.Style.FILL_AND_STROKE);
  paint.setColor(Color.WHITE);
  canvas.drawCircle(x, y, circleRadius, paint);
  paint.setStyle(Paint.Style.STROKE);
  paint.setColor(circleColor);
  paint.setStrokeWidth(circleStrokeWidth);
  canvas.drawCircle(x, y, circleRadius, paint);
  float midY = (topPadding + getHeight() - bottomPadding) / 2;
  float midX = (leftPadding + getWidth() - rightPadding) / 2;
  //描绘圆角矩形
  TextPaint textPaint = new TextPaint();
  textPaint.setTextSize(tipTextSize);
  textPaint.setTextAlign(Align.CENTER);
  textPaint.setColor(tipTextColor);
  textPaint.setAntiAlias(true);
  String label = tipPrefix + point.getY();
  float textWidth = textPaint.measureText(label) + 15;
  float textHeight = getTextHeight(textPaint, label) + 8;
  float hMargin = 10;//水平间距
  float vMargin = 8;//垂直间距
  float w = textWidth + hMargin * 2;//宽
  float h = textHeight + vMargin * 2;//高
  RectF rect = new RectF();
  if (x > midX) {
    rect.right = x - hMargin;
    rect.left = x - w;
  } else {
    rect.left = x + hMargin;
    rect.right = x + w;
  }
  if (y > midY) {
    rect.top = y - h;
    rect.bottom = y - vMargin;
  } else {
    rect.bottom = y + h;
    rect.top = y + vMargin;
  }
  Paint roundRectPaint = new Paint();
  roundRectPaint.setColor(tipRectColor);
  roundRectPaint.setStyle(Paint.Style.FILL);
  roundRectPaint.setAntiAlias(true);
  canvas.drawRoundRect(rect, 3, 3, roundRectPaint);
  // 描绘圆角矩形中间的文字
  float roundTextX = (rect.left + rect.right) / 2;
  float roundTextY = (rect.top + rect.bottom + getTextHeight(textPaint, label)) / 2;
  canvas.drawText(label, roundTextX, roundTextY, textPaint);
}

好了核心的代码就这么多了，由于我们把它当做的是控件再用，那么我们在初始化的时候，肯定会引入一些自定义的样式表，

private void initViews(AttributeSet attrs, int defStyle) {
  TypedArray typedArray = getContext().obtainStyledAttributes(attrs, R.styleable.LineGraph, defStyle, 0);
  scaleTextSize = typedArray.getDimension(R.styleable.LineGraph_scale_text_size, 20);
  scaleTextColor = typedArray.getColor(R.styleable.LineGraph_scale_text_color, getResources().getColor(R.color.c5));
  tipRectColor = typedArray.getColor(R.styleable.LineGraph_tip_rect_color, getResources().getColor(R.color.c8));
  tipTextSize = typedArray.getDimension(R.styleable.LineGraph_tip_text_size, 22);
  tipTextColor = typedArray.getColor(R.styleable.LineGraph_tip_text_color, getResources().getColor(R.color.c12));
  curveStrokeWidth = typedArray.getDimension(R.styleable.LineGraph_curve_stroke_width, 4);
  curveColor = typedArray.getColor(R.styleable.LineGraph_curve_color, getResources().getColor(R.color.c8));
  verticalLineStrokeWidth = typedArray.getDimension(R.styleable.LineGraph_vertical_line_stroke_width, 2);
  verticalLineColor = typedArray.getColor(R.styleable.LineGraph_vertical_line_color, getResources().getColor(R.color.c8));
  circleStrokeWidth = typedArray.getDimensionPixelSize(R.styleable.LineGraph_circle_stroke_width, 3);
  circleColor = typedArray.getColor(R.styleable.LineGraph_circle_color, getResources().getColor(R.color.c8));
  circleRadius = typedArray.getDimensionPixelSize(R.styleable.LineGraph_circle_radius, 7);
  typedArray.recycle();
  bottomPadding = dip2px(getContext(), 20);
  topPadding = dip2px(getContext(), 10);
  leftPadding = dip2px(getContext(), 20);
  rightPadding = dip2px(getContext(), 10);
}

样式表文件我就不多说了，行如下面的格式，

<declare-styleable name="LineGraph">
  <attr name="scale_text_size" format="dimension" />
  <attr name="scale_text_color" format="color" />
  <attr name="tip_text_size" format="dimension" />
  <attr name="tip_text_color" format="color" />
  <attr name="tip_rect_color" format="color" />
  <attr name="curve_stroke_width" format="dimension" />
  <attr name="curve_color" format="color" />
  <attr name="vertical_line_stroke_width" format="dimension" />
  <attr name="vertical_line_color" format="color" />
  <attr name="circle_stroke_width" format="dimension" />
  <attr name="circle_color" format="color" />
  <attr name="circle_radius" format="dimension" />
</declare-styleable>

最后贴上个效果图：

git下载地址：https://github.com/xiangzhihong/lineview

或者点击此处本站下载。

更多关于Android相关内容感兴趣的读者可查看本站专题：《Android图形与图像处理技巧总结》、《Android开发入门与进阶教程》、《Android调试技巧与常见问题解决方法汇总》、《Android基本组件用法总结》、《Android视图View技巧总结》、《Android布局layout技巧总结》及《Android控件用法总结》

希望本文所述对大家Android程序设计有所帮助。