This example demonstrates how to use LogarithmicNumericAxis with SciChart Android. This axis type can be used as XAxis or YAxis of the SciChartSurface in order to add a Logarithmic scale to an Android Chart. Axis labels are formatted using Scientific notation with Superscript.

Tips!

You can set LogarithmicBase when you need to change logarithmic base of the axis, e.g. Log10, LogE, Log2.

// example_single_chart_fragment.xml

<?xml version="1.0" encoding="utf-8"?><!--*************************************************************************-->
<!-- SCICHART® Copyright SciChart Ltd. 2011-2016. All rights reserved. -->
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<!-- Web: http://www.scichart.com -->
<!-- Support: support@scichart.com -->
<!-- Sales:   sales@scichart.com -->
<!--  -->
<!-- example_single_chart_fragment.xml is part of the SCICHART® Examples. Permission is hereby granted -->
<!-- to modify, create derivative works, distribute and publish any part of this source -->
<!-- code whether for commercial, private or personal use. -->
<!--  -->
<!-- The SCICHART® examples are distributed in the hope that they will be useful, but -->
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<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <com.scichart.charting.visuals.SciChartSurface
        android:id="@+id/chart"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" />

</LinearLayout>

// LogarithmicAxisFragment.java

//******************************************************************************
// SCICHART® Copyright SciChart Ltd. 2011-2017. All rights reserved.
//
// Web: http://www.scichart.com
// Support: support@scichart.com
// Sales:   sales@scichart.com
//
// LogarithmicAxisFragment.java is part of the SCICHART® Examples. Permission is hereby granted
// to modify, create derivative works, distribute and publish any part of this source
// code whether for commercial, private or personal use.
//
// The SCICHART® examples are distributed in the hope that they will be useful, but
// without any warranty. It is provided "AS IS" without warranty of any kind, either
// expressed or implied.
//******************************************************************************

package com.scichart.examples.fragments;

import android.app.Dialog;
import android.content.Context;
import android.view.View;
import android.view.animation.DecelerateInterpolator;
import android.widget.AdapterView;
import android.widget.CompoundButton;
import android.widget.Spinner;

import com.scichart.charting.model.AxisCollection;
import com.scichart.charting.model.dataSeries.XyDataSeries;
import com.scichart.charting.visuals.SciChartSurface;
import com.scichart.charting.visuals.axes.IAxis;
import com.scichart.charting.visuals.axes.ILogarithmicNumericAxis;
import com.scichart.charting.visuals.axes.ScientificNotation;
import com.scichart.charting.visuals.pointmarkers.EllipsePointMarker;
import com.scichart.charting.visuals.pointmarkers.IPointMarker;
import com.scichart.charting.visuals.renderableSeries.FastLineRenderableSeries;
import com.scichart.core.framework.UpdateSuspender;
import com.scichart.drawing.utility.ColorUtil;
import com.scichart.examples.R;
import com.scichart.examples.components.SpinnerStringAdapter;
import com.scichart.examples.data.DataManager;
import com.scichart.examples.data.DoubleSeries;
import com.scichart.examples.fragments.base.ExampleBaseFragment;
import com.scichart.examples.utils.ItemSelectedListenerBase;
import com.scichart.examples.utils.ViewSettingsUtil;
import com.scichart.examples.utils.widgetgeneration.ImageViewWidget;
import com.scichart.examples.utils.widgetgeneration.Widget;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import butterknife.BindView;

public class LogarithmicAxisFragment extends ExampleBaseFragment {

    private double selectedLogBase = 10d;

    private boolean isXLogAxis, isYLogAxis;
    private IAxis xAxis, yAxis;

    @BindView(R.id.chart)
    SciChartSurface surface;

    @Override
    public List<Widget> getToolbarItems() {
        return new ArrayList<Widget>() {
            {
                add(new ImageViewWidget.Builder().setId(R.drawable.example_toolbar_settings).setListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        openSettingsDialog();
                    }
                }).build());
            }
        };
    }

    @Override
    protected int getLayoutId() {
        return R.layout.example_single_chart_fragment;
    }

    @Override
    protected void initExample() {
        xAxis = generateLogarithmicAxis();
        yAxis = generateLogarithmicAxis();
        isXLogAxis = isYLogAxis = true;

        final XyDataSeries<Double, Double> dataSeries1 = sciChartBuilder.newXyDataSeries(Double.class, Double.class).withSeriesName("Curve A").build();
        final XyDataSeries<Double, Double> dataSeries2 = sciChartBuilder.newXyDataSeries(Double.class, Double.class).withSeriesName("Curve B").build();
        final XyDataSeries<Double, Double> dataSeries3 = sciChartBuilder.newXyDataSeries(Double.class, Double.class).withSeriesName("Curve C").build();

        final DoubleSeries ds1Points = DataManager.getInstance().getExponentialCurve(1.8, 100);
        final DoubleSeries ds2Points = DataManager.getInstance().getExponentialCurve(2.25, 100);
        final DoubleSeries ds3Points = DataManager.getInstance().getExponentialCurve(3.59, 100);

        dataSeries1.append(ds1Points.xValues, ds1Points.yValues);
        dataSeries2.append(ds2Points.xValues, ds2Points.yValues);
        dataSeries3.append(ds3Points.xValues, ds3Points.yValues);

        final int line1Color = ColorUtil.argb(0xFF, 0xFF, 0xFF, 0x00);
        final int line2Color = ColorUtil.argb(0xFF, 0x27, 0x9B, 0x27);
        final int line3Color = ColorUtil.argb(0xFF, 0xFF, 0x19, 0x19);

        final IPointMarker pointMarker1 = sciChartBuilder.newPointMarker(new EllipsePointMarker())
                .withSize(5)
                .withFill(line1Color)
                .build();
        final IPointMarker pointMarker2 = sciChartBuilder.newPointMarker(new EllipsePointMarker())
                .withSize(5)
                .withFill(line2Color)
                .build();
        final IPointMarker pointMarker3 = sciChartBuilder.newPointMarker(new EllipsePointMarker())
                .withSize(5)
                .withFill(line3Color)
                .build();

        final FastLineRenderableSeries line1 = sciChartBuilder.newLineSeries()
                .withStrokeStyle(line1Color)
                .withPointMarker(pointMarker1)
                .withDataSeries(dataSeries1)
                .build();
        final FastLineRenderableSeries line2 = sciChartBuilder.newLineSeries()
                .withStrokeStyle(line2Color)
                .withPointMarker(pointMarker2)
                .withDataSeries(dataSeries2)
                .build();
        final FastLineRenderableSeries line3 = sciChartBuilder.newLineSeries()
                .withStrokeStyle(line3Color)
                .withPointMarker(pointMarker3)
                .withDataSeries(dataSeries3)
                .build();

        UpdateSuspender.using(surface, new Runnable() {
            @Override
            public void run() {
                Collections.addAll(surface.getXAxes(), xAxis);
                Collections.addAll(surface.getYAxes(), yAxis);
                Collections.addAll(surface.getRenderableSeries(), line1, line2, line3);
                Collections.addAll(surface.getChartModifiers(), sciChartBuilder.newModifierGroupWithDefaultModifiers().build());

                sciChartBuilder.newAnimator(line1).withSweepTransformation().withInterpolator(new DecelerateInterpolator()).withDuration(3000).withStartDelay(350).start();
                sciChartBuilder.newAnimator(line2).withSweepTransformation().withInterpolator(new DecelerateInterpolator()).withDuration(3000).withStartDelay(350).start();
                sciChartBuilder.newAnimator(line3).withSweepTransformation().withInterpolator(new DecelerateInterpolator()).withDuration(3000).withStartDelay(350).start();
            }
        });

        surface.zoomExtents();
    }

    private IAxis generateLinearAxis() {
        return sciChartBuilder.newNumericAxis()
                .withTextFormatting("#.#E+0")
                .withScientificNotation(ScientificNotation.Normalized)
                .withGrowBy(0.1, 0.1)
                .withDrawMajorBands(false)
                .build();
    }

    private IAxis generateLogarithmicAxis() {
        return sciChartBuilder.newLogarithmicNumericAxis()
                .withTextFormatting("#.#E+0")
                .withScientificNotation(ScientificNotation.LogarithmicBase)
                .withLogarithmicBase(selectedLogBase)
                .withGrowBy(0.1, 0.1)
                .withDrawMajorBands(false)
                .build();
    }

    private void openSettingsDialog() {
        final Dialog dialog = ViewSettingsUtil.createSettingsPopup(getActivity(), R.layout.example_log_axis_popup_layout);

        Context context = dialog.getContext();

        final SpinnerStringAdapter logBaseModesAdapter = new SpinnerStringAdapter(context, R.array.log_base_modes);
        final Spinner logBaseModesSpinner = (Spinner) dialog.findViewById(R.id.log_base_spinner);
        logBaseModesSpinner.setAdapter(logBaseModesAdapter);
        logBaseModesSpinner.setSelection(2);
        logBaseModesSpinner.setOnItemSelectedListener(new ItemSelectedListenerBase() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                switch (position){
                    case 0: selectedLogBase = 2d; break;
                    case 1: selectedLogBase = 5d; break;
                    case 2: selectedLogBase = 10d; break;
                    case 3: selectedLogBase = Math.E; break;
                }

                trySetLogBaseForAxis(xAxis, selectedLogBase);
                trySetLogBaseForAxis(yAxis, selectedLogBase);
            }
        });

        ViewSettingsUtil.setUpSwitchCompat(dialog, R.id.use_log_on_x_axis_checkbox, isXLogAxis, new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                isXLogAxis = isChecked;
                xAxis = isXLogAxis ? generateLogarithmicAxis() : generateLinearAxis();

                UpdateSuspender.using(surface, new Runnable() {
                    @Override
                    public void run() {
                        final AxisCollection xAxes = surface.getXAxes();

                        xAxes.clear();
                        xAxes.add(xAxis);
                    }
                });
            }
        });

        ViewSettingsUtil.setUpSwitchCompat(dialog, R.id.use_log_on_y_axis_checkbox, isYLogAxis, new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                isYLogAxis = isChecked;
                yAxis = isYLogAxis ? generateLogarithmicAxis() : generateLinearAxis();

                UpdateSuspender.using(surface, new Runnable() {
                    @Override
                    public void run() {
                        final AxisCollection yAxes = surface.getYAxes();

                        yAxes.clear();
                        yAxes.add(yAxis);
                    }
                });
            }
        });

        dialog.show();
    }

    private static void trySetLogBaseForAxis(IAxis axis, double logBase) {
        if(axis instanceof ILogarithmicNumericAxis)
            ((ILogarithmicNumericAxis)axis).setLogarithmicBase(logBase);
    }
}

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