CODEWITHSUNDEEP
javaandroidgraphview
Arthur Fyon
Arthur Fyon

Reputation: 21

How to fix the limit of x axis with GraphView

I want to develop an app which communicates with BLE sensors at 100 Hz and to plot real time data using GraphView. I want to plot data in an "ECG way of doing", by having always the same fixed x axis and the curve which plots during time and come back on the left of the graph if the plot has reached the right end of the graph. I managed to receive data and to plot it but I have two concerns:

Here is some code snippets to help you understand what I have done wrong.

LineGraphSeries<DataPoint> series;
private int time = 0;
private int maxDataPoints = 200;

In OnCreate function

mDataGraph = (GraphView) findViewById(R.id.graph_data);
mDataGraph.getGridLabelRenderer().setHorizontalLabelsVisible(false);
mDataGraph.getGridLabelRenderer().setVerticalLabelsVisible(false);
mDataGraph.getGridLabelRenderer().setHighlightZeroLines(true);
mDataGraph.getGridLabelRenderer().setGridStyle(GridLabelRenderer.GridStyle.NONE);
mDataGraph.getViewport().setDrawBorder(true);
mDataGraph.setKeepScreenOn(true);

series = new LineGraphSeries<DataPoint>();
mDataGraph.addSeries(series);

// customize a little bit viewport
Viewport viewport = mDataGraph.getViewport();
viewport.setXAxisBoundsManual(true);
viewport.setMinX(0);
viewport.setMaxX(maxDataPoints);
viewport.setScalable(true);
viewport.setScrollable(true);

My function to handle data texts and plots

private void displayData(String data) {
    if (data != null) {
        mDataField.setText(data);
        int dataNumber = Integer.parseInt(data);
        // Reset graph
        if (time == maxDataPoints){
            mDataGraph.removeAllSeries();
            series = new LineGraphSeries<DataPoint>();
            mDataGraph.addSeries(series);
            time = 0;
        }
        series.appendData(new DataPoint(time, dataNumber), true, maxDataPoints);
        time ++;
    }
}

Note that my template is the Bluetooth Le Gatt one.

It is the first time I use this forum and I code in android studio (and even in java), so I hope that my explanations are clear and that someone can help me.

Thanks to take time to read this.

Regards, Arthur.

Upvotes: 1

Views: 385

Answers (1)

Arthur Fyon
Arthur Fyon

Reputation: 21

I was able to fix it by setting scrollToEnd to false in the appendData function... Was so easy.

Regards, Arthur.

Upvotes: 1

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