android - How to plot real time line graph

Question

I am creating sound meter app in android I want to show values in line graph on real time anyone please tell me how I can do it?

Answer 1

时间操作请看android.text.format.Time http://developer.android.com/reference/android/text/format/Time.html

这是那里的官方示例代码：

Time time = new Time();
time.set(4, 10, 2007);  // set the date to Nov 4, 2007, 12am
time.normalize(false);       // this sets isDst = 1
time.monthDay += 1;     // changes the date to Nov 5, 2007, 12am
millis = time.toMillis(false);   // millis is Nov 4, 2007, 11pm
millis = time.toMillis(true);    // millis is Nov 5, 2007, 12am

现在为了显示图表，没有现成的类，所以你必须自己通过覆盖类的Draw()函数来绘制它View，或者搜索一个库来做到这一点，例如：http ://android-graphview.org/

Answer 2

使用 AChartEngine 时，您只需将新值添加到系列并调用mChartView.repaint()，以便使用新更新刷新图表。

Answer 3

在 onCreate(...) 中：

GraphView graphView = new LineGraphView(this, "Amplitude");
graphView.setScrollable(true);
graphView.setViewPort(0, 30); // the x range you want to show without scrolling
GraphViewSeries graphSeries = new GraphViewSeries(new GraphViewDataInterface[0]);
graphView.addSeries(graphSeries);
setContentView(graphView);
//or add your graphView to the Activity's view as appropriate

然后，当您获得新值时：

graphSeries.appendData(new GraphView.GraphViewData(xValue, yValue), true, 300); 
//where 300 is the maximum number of values to keep

新值将出现在右侧，GraphView 将自动滚动以在图表上显示最新数据。