Android开发实现绘制淘宝收益图折线效果示例

2019-10-22 18:22:30

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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：

Android,绘制,淘宝收益图,折线