The ValueFormatter interface

The ValueFormatter interface can be used to create custom-made formatter classes that allow to format values within the chart (from DataSets) or values from the YAxis in a specific way.

For using the ValueFormatter, simply create a new class and let it implement the interface and return whatever you want to be displayed from the getFormattedValue(float value) method.

Example of a custom formatter

public class MyValueFormatter implements ValueFormatter {

    private DecimalFormat mFormat;
    
    public MyValueFormatter() {
        mFormat = new DecimalFormat("###,###,##0.0"); // use one decimal
    }
    
    @Override
    public String getFormattedValue(float value) {
        return mFormat.format(value) + " $"; // append a dollar-sign
    }
}

Then, set your formatter to the YAxis, ChartData or DataSet object:

// usage on axis
yAxis.setValueFormatter(new MyValueFormatter());

// usage on whole data object
lineData.setValueFormatter(new MyValueFormatter());

// usage on individual dataset object
lineDataSet.setValueFormatter(new MyValueFormatter());

Predefined Formatters

• LargeValueFormatter: Can be used for formatting large values > "1.000". It will turn values like "1.000" into "1k", "1.000.000" will be "1m" (million), and "1.000.000.000" will be "1b" (billion). It does not support numbers with decimal digits like "1.000,5".
• PercentFormatter: Used for displaying a "%" sign after each value with 1 decimal digit. Especially useful for the PieChart.