Android开发X Y轴Board的绘制教程示例
目录
- 正文
- 1. X轴的绘制
- 2. Y轴的绘制
- 绘制RightYAxisLabel
- 3. Board 绘制
正文
上篇大致介绍了RecyclerChart能够绘制的图表,以及一些特有的功能。从这节开始具体地介绍图表的绘制,本节先介绍RcyclerChart中一些图表的相关辅助的绘制,X、Y轴,以及Board的绘制。
上一章节有介绍绘制的逻辑都在ItemDecoration中实现的,而各种图表基本都有X、Y轴、Board相关的绘制,所以把他们的相关逻辑抽象到上层的基类BaseChartItemDecoration, 包含 YAxisRender、XAxisRender、BarBoardRender三个绘制的Render中显示相关的绘制逻辑,子类的相关的X、Y轴及Board 的相关绘制可以override单独实现, 泛型参数 BaseChartAttrs, BaseYAxis 根据具体的图表传递不同的类给Render进行绘制。
X、Y轴相对而言并不属于单个ItemView的附属,属于整个Chart的附属,所以单独地让RecyclerView设置Padding,然后利用padding的空间绘制X、Y轴,以BarChartRecyclerView为例:
1. X轴的绘制
ReycylerView中每个Item Model 为 RecyclerEntry, 其中包含一个字段 type, 会根据当前的位置设定一个值。
public static final int TYPE_XAXIS_FIRST = 1;//一个月 public static final int TYPE_XAXIS_SECOND = 2;//7天的线,需要drawText public static final int TYPE_XAXIS_THIRD = 3;//最小刻度的线 public static final int TYPE_XAXIS_SPECIAL = 4;//同时是月线以及7日分隔线 public long timestamp; public int type; public LocalDate localDate;
例如,绘制一天步数的一个图表,每半小时一根柱子,一共48根BarChart, 其中要 0点、6点、12点、18点、24点要显示X轴坐标,则以上几个位置对应的type值设置为 TYPE_XAXIS_SECOND, 普通的设置为 TYPE_XAXIS_THIRD, 一般的设置为 TYPE_XAXIS_THIRD,在创建RecyclerEntry 的list绑定到Adapter的时候设定。绘制X轴时,drawLine 以及drawLabel 都会依照这个 Entry里的Type来设定,具体绘制相关的Color、size、position等都设定在 BaseAttrs 中, 例如一下绘制X轴的网格线:
//绘制网格 纵轴线 final public void drawVerticalLine(Canvas canvas, RecyclerView parent, XAxis xAxis) { if (!mBarChartAttrs.enableXAxisGridLine){ return; } BaseBarChartAdapter mAdapter = (BaseBarChartAdapter) parent.getAdapter(); List<BarEntry> entries = mAdapter.getEntries(); int parentTop = parent.getPaddingTop(); int parentBottom = parent.getHeight() - parent.getPaddingBottom(); int parentLeft = parent.getPaddingLeft(); final int childCount = parent.getChildCount(); mTextPaint.setTextSize(xAxis.getTextSize()); int parentRight = parent.getWidth() - parent.getPaddingRight(); for (int i = 0; i < childCount; i++) { final View child = parent.getChildAt(i); int adapterPosition = parent.getChildAdapterPosition(child); if (adapterPosition == RecyclerView.NO_POSITION){ continue; } int type = parent.getAdapter().getItemViewType(adapterPosition); final int x = child.getRight(); if (x > parentRight || x < parentLeft) {//超出的时候就不要画了 continue; } if (type == BarEntry.TYPE_XAXIS_FIRST || type == BarEntry.TYPE_XAXIS_SPECIAL) { if (mBarChartAttrs.enableXAxisFirstGridLine){ boolean isNextSecondType = isNearEntrySecondType(entries, xAxis, child.getWidth(), adapterPosition); mLinePaint.setColor(xAxis.firstDividerColor); Path path = new Path(); if (isNextSecondType) { path.moveTo(x, parentBottom - mBarChartAttrs.contentPaddingBottom); } else { path.moveTo(x, parentBottom); } path.lineTo(x, parentTop); canvas.drawPath(path, mLinePaint); } } else if (type == BarEntry.TYPE_XAXIS_SECOND) { if (mBarChartAttrs.enableXAxisSecondGridLine){ //拿到child 的布局信息 PathEffect pathEffect = new DashPathEffect(new float[]{5, 5, 5, 5}, 1); mDashPaint.setPathEffect(pathEffect); mDashPaint.setColor(xAxis.secondDividerColor); Path path = new Path(); path.moveTo(x, parentBottom - DisplayUtil.dip2px(1)); path.lineTo(x, parentTop); canvas.drawPath(path, mDashPaint); } } else if (type == BarEntry.TYPE_XAXIS_THIRD) { if (mBarChartAttrs.enableXAxisThirdGridLine){ //拿到child 的布局信息。 绘制同上。 。。。 canvas.drawPath(path, mDashPaint); } } } }
关于XAxis 坐标的绘制,通过ValueFormatter 来获取Label,这样可以将Label的文本内容显示交给设定ValueFormatter的提供者,ValueFormatter借用的MPChart里的概念。这里通过每个Entry中的type属性以及x, timestamp等相关属性,自己的需求来控制Label.
//绘制X坐标 final public void drawXAxis(Canvas canvas, RecyclerView parent, XAxis xAxis) { if (!mBarChartAttrs.enableXAxisLabel){ return; } int parentBottom = parent.getHeight() - parent.getPaddingBottom(); int parentLeft = parent.getPaddingLeft(); final int childCount = parent.getChildCount(); mTextPaint.setTextSize(xAxis.getTextSize()); int parentRight = parent.getWidth() - parent.getPaddingRight(); for (int i = 0; i < childCount; i++) { final View child = parent.getChildAt(i); final int xLeft = child.getLeft(); final int xRight = child.getRight(); BarEntry barEntry = (BarEntry) child.getTag(); String dateStr = xAxis.getValueFormatter().getBarLabel(barEntry); if (!TextUtils.isEmpty(dateStr)) { int childWidth = child.getWidth(); float txtWidth = mTextPaint.measureText(dateStr); float txtXLeft = 0; float txtY = parentBottom - DisplayUtil.dip2px(1); if (childWidth > txtWidth) {//柱状图的宽度比较大的时候,文字居中 float distance = childWidth - txtWidth; txtXLeft = xLeft + distance / 2; } else { txtXLeft = xRight - xAxis.labelTxtPadding - txtWidth; } float txtXRight = txtXLeft + txtWidth; int length = dateStr.length(); if (DecimalUtil.bigOrEquals(txtXLeft, parentLeft) && DecimalUtil.smallOrEquals(txtXRight, parentRight)) {//中间位置 canvas.drawText(dateStr, txtXLeft, txtY, mTextPaint); } else if (txtXLeft < parentLeft && txtXRight > parentLeft) {//处理左边界 int displayLength = (int) ((txtXRight - parentLeft) / txtWidth * length); int index = length - displayLength; canvas.drawText(dateStr, index, length, parentLeft, txtY, mTextPaint); } else if (txtXRight > parentRight && txtXLeft < parentRight) {//处理右边界 int displayLength = (int) ((parentRight - txtXLeft + 1) / txtWidth * length); int endIndex = displayLength; if (endIndex < length) { endIndex += 1; } canvas.drawText(dateStr, 0, endIndex, txtXLeft, txtY, mTextPaint); } } } }
2. Y轴的绘制
Y轴的具体 Left、Right的绘制可以根据ChartAttrs中的设置来控制具体显示哪一种。上面有提到X/Y/Board的绘制会受RecyclerView中的padding来限制绘制的区域大小,然后具体的Y轴网格线绘制几格,每格的Label显示均由YAxis来控制,特殊的需求也支持自定义,之前有介绍过MPChart图表中Y轴的这个计算,需要跟具体的业务数据相关联。得到了YAxis的labelCount 以及具体的Label List 之后,绘制就非常简单了。
//绘制 Y轴刻度线 横的网格线 public void drawHorizontalLine(Canvas canvas, RecyclerView parent, T yAxis) { int left = parent.getPaddingLeft(); int right = parent.getWidth() - parent.getPaddingRight(); mLinePaint.setColor(yAxis.getGridColor()); int top = parent.getPaddingTop(); int bottom = parent.getHeight() - parent.getPaddingBottom(); float distance = bottom - mBarChartAttrs.contentPaddingBottom - mBarChartAttrs.contentPaddingTop - top; int lineNums = yAxis.getLabelCount(); float lineDistance = distance / lineNums; float gridLine = top + mBarChartAttrs.contentPaddingTop; for (int i = 0; i <= lineNums; i++) { if (i > 0) { gridLine = gridLine + lineDistance; } Path path = new Path(); path.moveTo(left, gridLine); path.lineTo(right, gridLine); boolean enable = false; if (i == lineNums && mBarChartAttrs.enableYAxisZero) { enable = true; } else { enable = mBarChartAttrs.enableYAxisGridLine;//允许画 Y轴刻度 } if (enable) { canvas.drawPath(path, mLinePaint); } } }
绘制RightYAxisLabel
//绘制右边的刻度 public void drawRightYAxisLabel(Canvas canvas, RecyclerView parent, T yAxis) { if (mBarChartAttrs.enableRightYAxisLabel) { int right = parent.getWidth(); int top = parent.getPaddingTop(); int bottom = parent.getHeight() - parent.getPaddingBottom(); mTextPaint.setTextSize(yAxis.getTextSize()); String longestStr = yAxis.getLongestLabel(); float yAxisWidth = mTextPaint.measureText(longestStr) + mBarChartAttrs.recyclerPaddingRight; int paddingRight = computeYAxisWidth(parent.getPaddingRight(), yAxisWidth); //设置 recyclerView的 BarChart 内容区域 parent.setPadding(parent.getPaddingLeft(), parent.getPaddingTop(), paddingRight, parent.getPaddingBottom()); float topLocation = top + mBarChartAttrs.contentPaddingTop; float containerHeight = bottom - mBarChartAttrs.contentPaddingBottom - topLocation; float itemHeight = containerHeight / yAxis.getLabelCount(); //通过YAxis获取 具体的label List. HashMap<Float, Float> yAxisScaleMap = yAxis.getYAxisScaleMap(topLocation, itemHeight, yAxis.getLabelCount()); float txtX = right - parent.getPaddingRight() + yAxis.labelHorizontalPadding; for (Map.Entry<Float, Float> entry : yAxisScaleMap.entrySet()) { float yAxisScaleLocation = entry.getKey(); float yAxisScaleValue = entry.getValue(); String labelStr = yAxis.getValueFormatter().getFormattedValue(yAxisScaleValue); float txtY = yAxisScaleLocation + yAxis.labelVerticalPadding; canvas.drawText(labelStr, txtX, txtY, mTextPaint); } } }
3. Board 绘制
Board的绘制相对而言就简单了,只需根据mBarChartAttrs 中的属性值,以及RecyclerView的padding值,以及绘制颜色背景等绘制即可。
final public void drawBarBorder(@NonNull Canvas canvas, @NonNull RecyclerView parent) { if (mBarChartAttrs.enableBarBorder) { RectF rectF = new RectF(); float start = parent.getPaddingLeft(); float top = parent.getPaddingTop(); float end = parent.getRight() - parent.getPaddingRight(); //底部有0的刻度是不是不用画,就画折线了。 float bottom = parent.getHeight() - parent.getPaddingBottom() - mBarChartAttrs.contentPaddingBottom; rectF.set(start, top, end, bottom); mBarBorderPaint.setStrokeWidth(mBarChartAttrs.barBorderWidth); canvas.drawRect(rectF, mBarBorderPaint); } }
至此本章节介绍完毕,相对而言还是比较简单的,YAxis中的label 的计算等,可以参考我代码里面的Case。
以上就是Android开发X Y轴Board的绘制教程示例的详细内容,更多关于Android Board绘制X Y轴的资料请关注我们其它相关文章!