MPAndroidChart 教程：动态和实时数据 Dynamic & Realtime Data（八）

来源：互联网发布：金税盘重装后数据没了编辑：程序博客网时间：2024/05/17 08:14

其余文章索引：
MPAndroidChart 教程：概述
MPAndroidChart 教程：开始 Getting Started（一）
MPAndroidChart 教程：与图表进行手势交互 Interaction with the Chart（二）
MPAndroidChart 教程：坐标轴，X轴，Y轴，Labels（三）
MPAndroidChart 教程：设置数据，设置颜色（四）
MPAndroidChart 教程：数据格式器 ValueFormatter（五）
MPAndroidChart 教程：图表的具体设置 Specific chart settings（六）
MPAndroidchart 教程：图例 Legend（七）
MPAndroidChart 教程：动态和实时数据 Dynamic & Realtime Data（八）
MPAndroidChart 教程：修改视窗 Modifying the Viewport（九）
MPAndroidChart 教程：动画 Animations（十）
MPAndroidChart 教程：MarkerView（十一）
MPAndroidChart 教程：ChartData类，ChartData子类， DataSet类，DataSet子类（十二）
时间仓促，难免有错误，有的话希望大家在评论中指出，谢谢。
源码：范例代码在线查看或下载

一、概述

在 MPAndroidChart 1.6.3 版本得以实现，在更新版本不断得到提高。

存在各种方法为图表动态地增加新的数据或移除数据

允许添加或删除 Entry 对象到现有的 DataSet 。
允许添加或删除 Entry 对象到已存在的 ChartData 的DataSet 。

二、动态添加数据

DataSet 类和所有子类：

addEntry(Entry e) : 添加的 Entry 对象到 DataSet 。

ChartData 类和所有子类：

addEntry(Entry e, int dataSetIndex) : 添加 Entry 到 DataSet 的指定索引处。
addDataSet(DataSet d) : 添加 DataSet 对象到 ChartData 。
除此之外，也有用于动态remove数据的方法。

二、动态移除数据

DataSet 类和所有子类：

public boolean removeFirst() : 删除该 DataSet 的第一个 Entry 项( 索引0 )。如果成功返回true，否则为false。
public boolean removeLast() : 删除该 DataSet 的最后一个 Entry 项( 索引大小-1 )。如果成功返回true，否则为false。
public boolean removeEntry(Entry e) : 从 DataSet 中移除给定的 Entry 对象。如果成功返回true 。
public boolean removeEntry(int xIndex) : 从 DataSet 中移除给定索引对应的 Entry 对象。如果成功返回true 。

ChartData 类和所有子类：

public boolean removeEntry(Entry e, int dataSetIndex) : 移除给定索引对应的 DataSet 中给定的 Entry 对象。如果成功，返回true。
public boolean removeEntry(int xIndex, int dataSetIndex) : 移除给定索引对应的 DataSet 中给定索引对应的 Entry 对象。如果成功，返回true。
public boolean removeDataSet(DataSet d) : 从该 ChartData 对象中移除给定的 DataSet 对象。如果成功，返回true。
public boolean removeDataSet(int index) : 从该 ChartData 对象中移除给定索引对应的 DataSet 对象。如果成功，返回true。

三、记住

动态添加或移除数据后，调用invalidate()刷新图表之前必须调用 notifyDataSetChanged() .

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"> <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// more code ...</span> exampleData.addEntry(...); chart.notifyDataSetChanged(); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// let the chart know it's data changed</span> chart.invalidate(); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// refresh</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li></ul>

注： moveViewTo(...) 方法会自动调用 invalidate()

四、DynamicalAddingActivity.java

下面有6个演示动态添加(删除)数据的小例子：

addEntry() , removeLastEntry() , addDataSet() ,
removeLastDataSet() , clearChart() 和 setEmptyLineData() .

点击查看 DynamicalAddingActivity.java 源码

1. addEntry()

为最后一个 DataSet 添加一个y值随机的 Entry，一开始如果没有 DataSet 则新增一个 DataSet .
1) 效果图：

2) 对应代码如下：

<code class="hljs cs has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">addEntry</span>(View view) {        LineData lineData = mChart.getData();        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (lineData != <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>) {            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> indexLast = getLastDataSetIndex(lineData);            LineDataSet lastSet = lineData.getDataSetByIndex(indexLast);            <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// set.addEntry(...); // can be called as well</span>            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (lastSet == <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>) {                lastSet = createLineDataSet();                lineData.addDataSet(lastSet);            }            <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 这里要注意，x轴的index是从零开始的</span>            <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 假设index=2，那么getEntryCount()就等于3了</span>            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> count = lastSet.getEntryCount();            <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// add a new x-value first 这行代码不能少</span>            lineData.addXValue(count + <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">""</span>);            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">float</span> yValues = (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">float</span>) (Math.random() * <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">100</span>);            <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 位最后一个DataSet添加entry</span>            lineData.addEntry(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Entry(yValues, count), indexLast);            mChart.notifyDataSetChanged();            mChart.moveViewTo(yValues, count, YAxis.AxisDependency.LEFT);            Log.d(TAG, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"set.getEntryCount()="</span> + lastSet.getEntryCount()                    + <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">" ; indexLastDataSet="</span> + indexLast);        }    }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li></ul>

2. removeLastEntry()

移除最后一个 DataSet 的最后一个 Entry 。在效果图中你会发现，即使没有 Entry 了，继续点击”removeLastEntry”按钮程序也不会crash掉。
1) 效果图：

2) 对应代码如下：

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">removeLastEntry</span>(View view) {        LineData lineData = mChart.getLineData();        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (lineData != <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>) {            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> indexLastDataSet = lineData.getDataSetCount() - <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>;            LineDataSet lastDataSet = lineData.getDataSetByIndex(indexLastDataSet);            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (lastDataSet != <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>) {                Entry lastEntry = lastDataSet.getEntryForXIndex(                        lastDataSet.getEntryCount() - <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>);                lineData.removeEntry(lastEntry, indexLastDataSet);                <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// or remove by index</span>                <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// mData.removeEntry(xIndex, dataSetIndex);</span>                mChart.notifyDataSetChanged();                mChart.invalidate();            }        }    }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li></ul>

3. addDataSet()

动态添加一个 DataSet，可以添加N多个 DataSet ，没发现有上限。
下面的效果图同时也演示了前面的为最后一个 DataSet 添加一个y值随机的 Entry 和移除最后一个 DataSet 的最后一个 Entry 。
1) 效果图：

2) 对应代码如下：

<code class="hljs cs has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">addDataSet</span>(View view) {        LineData lineData = mChart.getLineData();        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (lineData != <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>) {            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> count = (lineData.getDataSetCount() + <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>);            <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// create 10 y-value</span>            ArrayList<Entry> yValueList = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> ArrayList<>();            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (lineData.getXValCount() == <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>) {                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span> (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> i = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>; i < <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">10</span>; i++) {                    lineData.addXValue((i + <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>) + <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">""</span>);                }            }            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span> (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> i = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>; i < lineData.getXValCount(); i++) {                yValueList.add(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Entry((<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">float</span>) (Math.random() * <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">100</span>f), i));            }            LineDataSet <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">set</span> = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> LineDataSet(yValueList, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"DataSet "</span> + count);            <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 求余，防止数组越界异常</span>            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> colorIndex = count % mColors.length;            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">set</span>.setColor(mColors[colorIndex]);            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">set</span>.setCircleColor(mColors[colorIndex]);            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">set</span>.setValueTextColor(mColors[colorIndex]);            lineData.addDataSet(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">set</span>);            mChart.notifyDataSetChanged();            mChart.invalidate();        }    }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li></ul>

4. removeLastDataSet()

移除最后一个DataSet 。
在效果图中你会发现，即使没有 DataSet 了，继续点击”removeLastDataSet”程序也不会crash掉。
1) 效果图：

2) 对应代码如下：

<code class="hljs cs has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">removeLastDataSet</span>(View view) {        LineData lineData = mChart.getData();        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (lineData != <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>) {            lineData.removeDataSet(lineData.getDataSetCount() - <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>);            mChart.notifyDataSetChanged();            mChart.invalidate();        }    }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li></ul>

5. clearChart() 和 setEmptyLineData()

清空图表和为图表设置一个空的LineData.
在效果图中你会发现，clearChart() 后，点击”addDataSet”图表并没有新增 DataSet 的响应，clear 后要 setEmptyLineData() 才能addDataSet()。
1) 效果图：

2) 对应代码如下：

<code class="hljs cs has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 清空图表</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">clearChart</span>(View view) {        mChart.clear();    }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li></ul>

<code class="hljs cs has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 为图表设置一个空的LineData</span>    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">setEmptyLineData</span>(View view) {        mChart.setData(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> LineData());        mChart.invalidate();    }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li></ul>

RealtimeDataActivity

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