MPAndroidChart - issues with setVisibleYRange, does not work for setting higher values

Question

Working with MPandroiChart i have encounterd a problem, i am adding dynamical data and am trying to have the chart fit the highest data at all times, using "setVisibleYRange()" seems to work fine when i need to narrow down the view but does not seem to work when i need the view to expand again after narrowing it down, based on the mpandroidChart example i have made a simple test activity that shows my point:

    public class DynamicalAddingActivityTest extends Activity implements OnChartValueSelectedListener {

    private LineChart mChart;

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_linechart_noseekbar);

        mChart = (LineChart) findViewById(R.id.chart1);
        mChart.setOnChartValueSelectedListener(this);
        mChart.setDrawGridBackground(false);
        mChart.setDescription("");





          // add an empty data object
            mChart.setData(new LineData());
    //        mChart.getXAxis().setDrawLabels(false);
    //        mChart.getXAxis().setDrawGridLines(false);
        mChart.invalidate();
        for(int i = 0; i<10; i++){
            addEntry();
        }

        mChart.setVisibleYRange(2, AxisDependency.LEFT);
        mChart.invalidate();

        findViewById(R.id.add).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                addEntry();
            }
        });

        findViewById(R.id.change).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                EditText t = (EditText) findViewById(R.id.edit);
                int vis = Integer.valueOf(t.getText().toString());
                mChart.setVisibleYRange(vis, AxisDependency.LEFT);
                mChart.notifyDataSetChanged();
                mChart.invalidate();
            }
        });
    }

    int[] mColors = ColorTemplate.VORDIPLOM_COLORS;

    private void addEntry() {

        LineData data = mChart.getData();

        if(data != null) {

            LineDataSet set = data.getDataSetByIndex(0);
            // set.addEntry(...); // can be called as well

            if (set == null) {
                set = createSet();
                data.addDataSet(set);
            }

            // add a new x-value first
            data.addXValue(set.getEntryCount() + "");

            // choose a random dataSet
            int randomDataSetIndex = (int) (Math.random() * data.getDataSetCount());

            data.addEntry(new Entry((float) (Math.random() * 10), set.getEntryCount()), randomDataSetIndex);

            // let the chart know it's data has changed
            mChart.notifyDataSetChanged();

//            mChart.setVisibleXRange(6);
//            mChart.setVisibleYRange(30, AxisDependency.LEFT);
//            
//            // this automatically refreshes the chart (calls invalidate())
//            mChart.moveViewTo(data.getXValCount()-7, 55f, AxisDependency.LEFT);

            // redraw the chart
            mChart.invalidate();   
        }
    }

    private void removeLastEntry() {

        LineData data = mChart.getData();

        if(data != null) {

            LineDataSet set = data.getDataSetByIndex(0);

            if (set != null) {

                Entry e = set.getEntryForXIndex(set.getEntryCount() - 1);

                data.removeEntry(e, 0);
                // or remove by index
                // mData.removeEntry(xIndex, dataSetIndex);

                mChart.notifyDataSetChanged();
                mChart.invalidate();
            }
        }
    }

    private void addDataSet() {

        LineData data = mChart.getData();

        if(data != null) {

            int count = (data.getDataSetCount() + 1);

            // create 10 y-vals
            ArrayList<Entry> yVals = new ArrayList<Entry>();

            if(data.getXValCount() == 0) {
                // add 10 x-entries
                for (int i = 0; i < 10; i++) {
                    data.addXValue("" + (i+1));
                }
            }

            for (int i = 0; i < data.getXValCount(); i++) {
                yVals.add(new Entry((float) (Math.random() * 50f) + 50f * count, i));
            }

            LineDataSet set = new LineDataSet(yVals, "DataSet " + count);
            set.setLineWidth(2.5f);
            set.setCircleSize(4.5f);

            int color = mColors[count % mColors.length];

            set.setColor(color);
            set.setCircleColor(color);
            set.setHighLightColor(color);
            set.setValueTextSize(10f);
            set.setValueTextColor(color);

            data.addDataSet(set);
            mChart.notifyDataSetChanged();
            mChart.invalidate();   
        }
    }

    private void removeDataSet() {

        LineData data = mChart.getData();

        if(data != null) {

            data.removeDataSet(data.getDataSetByIndex(data.getDataSetCount() - 1));

            mChart.notifyDataSetChanged();
            mChart.invalidate();   
        }
    }

    @Override
    public void onValueSelected(Entry e, int dataSetIndex, Highlight h) {
        Toast.makeText(this, e.toString(), Toast.LENGTH_SHORT).show();
    }

    @Override
    public void onNothingSelected() {

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.dynamical, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

        switch (item.getItemId()) {
            case R.id.actionAddEntry:
                addEntry();
                Toast.makeText(this, "Entry added!", Toast.LENGTH_SHORT).show();
                break;
            case R.id.actionRemoveEntry:
                removeLastEntry();
                Toast.makeText(this, "Entry removed!", Toast.LENGTH_SHORT).show();
                break;
            case R.id.actionAddDataSet:
                addDataSet();
                Toast.makeText(this, "DataSet added!", Toast.LENGTH_SHORT).show();
                break;
            case R.id.actionRemoveDataSet:
                removeDataSet();
                Toast.makeText(this, "DataSet removed!", Toast.LENGTH_SHORT).show();
                break;
            case R.id.actionAddEmptyLineData:
                mChart.setData(new LineData());
                mChart.invalidate();
                Toast.makeText(this, "Empty data added!", Toast.LENGTH_SHORT).show();
                break;
            case R.id.actionClear:
                mChart.clear();
                Toast.makeText(this, "Chart cleared!", Toast.LENGTH_SHORT).show();
                break;
        }

        return true;
    }

    private LineDataSet createSet() {

        LineDataSet set = new LineDataSet(null, "DataSet 1");
        set.setLineWidth(2.5f);
        set.setCircleSize(4.5f);
        set.setColor(Color.rgb(240, 99, 99));
        set.setCircleColor(Color.rgb(240, 99, 99));
        set.setHighLightColor(Color.rgb(190, 190, 190));
        set.setAxisDependency(AxisDependency.LEFT);
        set.setValueTextSize(10f);

        return set;
    }
}

with this xml:

    <?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <com.github.mikephil.charting.charts.LineChart
        android:id="@+id/chart1"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:layout_alignParentTop="true">

        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="change"
            android:gravity="top|left"
            android:id="@+id/change"
            />

        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="add"
            android:gravity="top|center_horizontal"
            android:id="@+id/add"
            />

        <EditText
            android:inputType="number"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:gravity="top|right"
            android:id="@+id/edit"/>



    </LinearLayout>



</RelativeLayout>

So, when i try to type in a value greater then the one i have set before "setVisibleYRange()" does not seem to work, however it does work if a set a value lower then the one set before.

any ideas on why this is? am i missing something? @PhilJay

Answer 1

Yes you are missing something.

This is not a "zoom" method. It's only purpose is to restrain the maximum visible range of values displayed on the y-axis.

If the current visible range is 100, and then setVisibleYRange(50) is called, the visible range will be reduced to 50 since the current range of 100 is no longer allowed. If then setVisibleYRange(100) is called, nothing has to change, because the current visible range of 50 is well in the allowed bounds. If you then start zooming out, it will stop at range 100.