Thanks VizGuy. That sounds simple enough and it works for a while --
but after calling draw() a few times, the gauges disappear.
Here is my sample app using the 5 gauges like those from the Showcase.
Am I doing something wrong? or is there a bug in the Viz library?
package com.company.gaugetest.client;
import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.core.client.GWT;
import com.google.gwt.user.client.Random;
import com.google.gwt.user.client.Timer;
import com.google.gwt.user.client.ui.RootPanel;
import com.google.gwt.visualization.client.AjaxLoader;
import com.google.gwt.visualization.client.DataTable;
import com.google.gwt.visualization.client.AbstractDataTable.ColumnType;
import com.google.gwt.visualization.client.visualizations.Gauge;
/**
* Entry point classes define <code>onModuleLoad()</code>.
*/
public class GaugeTest implements EntryPoint
{
private Gauge gauge;
private Gauge.Options options;
public void onModuleLoad()
{
Runnable onLoadCallback = new Runnable() {
public void run()
{
RootPanel rootPanel = RootPanel.get();
options = Gauge.Options.create();
options.setWidth(400);
options.setHeight(240);
options.setGaugeRange(0, 24);
options.setGreenRange(0, 6);
options.setYellowRange(6,12);
options.setRedRange(12, 24);
final DataTable data = getData();
Timer timer = new Timer() {
public void run()
{
// Randomly pick one gauge to update with a
random number.
int index = Random.nextInt(4);
int num = Random.nextInt(24);
data.setValue(index, 1, num);
GWT.log("Next for " + index + " is " + num, null);
gauge.draw(data, options);
}
};
gauge = new Gauge(data, options);
rootPanel.add(gauge);
timer.scheduleRepeating(2000);
}
};
AjaxLoader.loadVisualizationApi(onLoadCallback, Gauge.PACKAGE);
}
private DataTable getData()
{
final DataTable data = DataTable.create();
data.addColumn(ColumnType.STRING, "Task");
data.addColumn(ColumnType.NUMBER, "Hours per Day");
data.addRows(5);
data.setValue(0, 0, "Work");
data.setValue(0, 1, 11);
data.setValue(1, 0, "Eat");
data.setValue(1, 1, 2);
data.setValue(2, 0, "Commute");
data.setValue(2, 1, 2);
data.setValue(3, 0, "Watch TV");
data.setValue(3, 1, 2);
data.setValue(4, 0, "Sleep");
data.setValue(4, 1, 7);
return data;
}
}
VizGuy wrote:
> This can be done easily.
>
> All you have to do is to call the draw() function of the same chart
> again, with a new data. This will cause the needle to move to the new
> place.
>
> Notice that if you are using a query to get the data from a remote
> data source, you can set the query to have a refresh interval and so
> it will automatically send for a new data and if it was changed, the
> function that you originally set to be called when the query is back,
> we be called again.
>
> Regards,
> VizGuy
>
>
> On Tue, Jan 13, 2009 at 9:34 AM, TomHj <[email protected]
> <mailto:[email protected]>> wrote:
>
>
> I'm investigating whether I can use the Google Visualization API with
> the GWT wrapper within my GWT app to display a dashboard of gauges.
> The gauges would display things like memory utilization, disk usage,
> etc. I need to be able to update the gauges on the fly (so the
> needles are repositioned without redrawing the entire gauge).
>
> I can't tell if the Gauge visualization supports that updating to
> reflect new data. If so, how is it done?
>
> thanks,
> Tom
>
>
>
>
> >
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