我正在使用Graph View
库(4.0.1)对加速计传感器进行采样并实时显示图表。
应用程序运行良好,但图表错误:
如图所示,Z轴(品红色)的值为~9.8但在图中它显示为~15,Y轴(绿色)的值为0.2但在图中我们在零下与X轴相同的想法。
这是我的代码:
SensorManager sensorManager;
TextView tvX, tvY, tvZ;
GraphView graph;
LineGraphSeries<DataPoint> seriesX, seriesY, seriesZ;
long startTime;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_runtime_graph);
tvX = (TextView) findViewById(R.id.tvAcc_X); // color : blue
tvY = (TextView) findViewById(R.id.tvAcc_Y); // color : green
tvZ = (TextView) findViewById(R.id.tvAcc_Z); // color : magenta
graph = (GraphView) findViewById(R.id.graph);
seriesX = new LineGraphSeries<>();
seriesY = new LineGraphSeries<>();
seriesZ = new LineGraphSeries<>();
seriesX.setColor(Color.BLUE);
seriesY.setColor(Color.GREEN);
seriesZ.setColor(Color.MAGENTA);
graph.addSeries(seriesX);
graph.addSeries(seriesY);
graph.addSeries(seriesZ);
startTime = System.nanoTime() / 100000000;
sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER), SensorManager.SENSOR_DELAY_NORMAL);
}
@Override
public void onSensorChanged(SensorEvent event)
{
tvX.setText(String.valueOf(event.values[0]));
tvY.setText(String.valueOf(event.values[1]));
tvZ.setText(String.valueOf(event.values[2]));
updateGraph((event.timestamp / 100000000) - startTime,
event.values[0], event.values[1], event.values[2]);
}
void updateGraph (final long timestamp, final float x, final float y, final float z)
{
runOnUiThread(new Runnable() {
@Override
public void run() {
seriesX.appendData(new DataPoint(timestamp, x), true, 40);
seriesY.appendData(new DataPoint(timestamp, y), true, 40);
seriesZ.appendData(new DataPoint(timestamp, z), true, 40);
}
});
}
我发现问题发生在scrollToEnd
字段设置为true
时,否则图表是正确的。
我发现的另一个问题可能相关,当scroolToEnd
为真时,轴不会更新。
有没有办法解决这个问题? 谢谢!
答案 0 :(得分:3)
logcat显示为什么scrollToEnd在你的情况下不起作用:
GraphView: scrollToEnd works only with manual x axis bounds
设置x轴边界手册,在create方法中添加此代码
Viewport vp = graph.getViewport();
vp.setXAxisBoundsManual(true);
vp.setMinX(0);
vp.setMaxX(1000);
但代码还有另一个问题: System.nanoTime()和 event.timestamp 是不同的时间格式
System.nanoTime() // current value of system timer in nanoseconds
event.timestamp // nanoseconds since device uptime
记录不完善:SensorEvent timestamp