HalfPieChartActivity.java

package com.xxmassdeveloper.mpchartexample;

import android.content.Intent;
import android.graphics.Color;
import android.graphics.Typeface;
import android.net.Uri;
import android.os.Bundle;
import android.text.SpannableString;
import android.text.style.ForegroundColorSpan;
import android.text.style.RelativeSizeSpan;
import android.text.style.StyleSpan;
import android.util.DisplayMetrics;
import android.view.Menu;
import android.view.MenuItem;
import android.view.WindowManager;
import android.widget.RelativeLayout;

import com.github.mikephil.charting.animation.Easing;
import com.github.mikephil.charting.charts.PieChart;
import com.github.mikephil.charting.components.Legend;
import com.github.mikephil.charting.data.PieData;
import com.github.mikephil.charting.data.PieDataSet;
import com.github.mikephil.charting.data.PieEntry;
import com.github.mikephil.charting.formatter.PercentFormatter;
import com.github.mikephil.charting.utils.ColorTemplate;
import com.xxmassdeveloper.mpchartexample.notimportant.DemoBase;

import java.util.ArrayList;

@SuppressWarnings("SameParameterValue")
public class HalfPieChartActivity extends DemoBase {

    private PieChart chart;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);
        setContentView(R.layout.activity_piechart_half);

        setTitle("HalfPieChartActivity");

        chart = findViewById(R.id.chart1);
        chart.setBackgroundColor(Color.WHITE);

        moveOffScreen();

        chart.setUsePercentValues(true);
        chart.getDescription().setEnabled(false);

        chart.setCenterTextTypeface(tfLight);
        chart.setCenterText(generateCenterSpannableText());

        chart.setDrawHoleEnabled(true);
        chart.setHoleColor(Color.WHITE);

        chart.setTransparentCircleColor(Color.WHITE);
        chart.setTransparentCircleAlpha(110);

        chart.setHoleRadius(58f);
        chart.setTransparentCircleRadius(61f);

        chart.setDrawCenterText(true);

        chart.setRotationEnabled(false);
        chart.setHighlightPerTapEnabled(true);

        chart.setMaxAngle(180f); // HALF CHART
        chart.setRotationAngle(180f);
        chart.setCenterTextOffset(0, -20);

        setData(4, 100);

        chart.animateY(1400, Easing.EaseInOutQuad);

        Legend l = chart.getLegend();
        l.setVerticalAlignment(Legend.LegendVerticalAlignment.TOP);
        l.setHorizontalAlignment(Legend.LegendHorizontalAlignment.CENTER);
        l.setOrientation(Legend.LegendOrientation.HORIZONTAL);
        l.setDrawInside(false);
        l.setXEntrySpace(7f);
        l.setYEntrySpace(0f);
        l.setYOffset(0f);

        // entry label styling
        chart.setEntryLabelColor(Color.WHITE);
        chart.setEntryLabelTypeface(tfRegular);
        chart.setEntryLabelTextSize(12f);
    }

    private void setData(int count, float range) {

        ArrayList<PieEntry> values = new ArrayList<>();

        for (int i = 0; i < count; i++) {
            values.add(new PieEntry((float) ((Math.random() * range) + range / 5), parties[i % parties.length]));
        }

        PieDataSet dataSet = new PieDataSet(values, "Election Results");
        dataSet.setSliceSpace(3f);
        dataSet.setSelectionShift(5f);

        dataSet.setColors(ColorTemplate.MATERIAL_COLORS);
        //dataSet.setSelectionShift(0f);

        PieData data = new PieData(dataSet);
        data.setValueFormatter(new PercentFormatter());
        data.setValueTextSize(11f);
        data.setValueTextColor(Color.WHITE);
        data.setValueTypeface(tfLight);
        chart.setData(data);

        chart.invalidate();
    }

    private SpannableString generateCenterSpannableText() {

        SpannableString s = new SpannableString("MPAndroidChart\ndeveloped by Philipp Jahoda");
        s.setSpan(new RelativeSizeSpan(1.7f), 0, 14, 0);
        s.setSpan(new StyleSpan(Typeface.NORMAL), 14, s.length() - 15, 0);
        s.setSpan(new ForegroundColorSpan(Color.GRAY), 14, s.length() - 15, 0);
        s.setSpan(new RelativeSizeSpan(.8f), 14, s.length() - 15, 0);
        s.setSpan(new StyleSpan(Typeface.ITALIC), s.length() - 14, s.length(), 0);
        s.setSpan(new ForegroundColorSpan(ColorTemplate.getHoloBlue()), s.length() - 14, s.length(), 0);
        return s;
    }

    private void moveOffScreen() {

        DisplayMetrics displayMetrics = new DisplayMetrics();
        getWindowManager().getDefaultDisplay().getMetrics(displayMetrics);

        int height = displayMetrics.heightPixels;

        int offset = (int)(height * 0.65); /* percent to move */

        RelativeLayout.LayoutParams rlParams =
                (RelativeLayout.LayoutParams) chart.getLayoutParams();
        rlParams.setMargins(0, 0, 0, -offset);
        chart.setLayoutParams(rlParams);
    }

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

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

        switch (item.getItemId()) {
            case R.id.viewGithub: {
                Intent i = new Intent(Intent.ACTION_VIEW);
                i.setData(Uri.parse("https://github.com/PhilJay/MPAndroidChart/blob/master/MPChartExample/src/com/xxmassdeveloper/mpchartexample/HalfPieChartActivity.java"));
                startActivity(i);
                break;
            }
        }

        return true;
    }

    @Override
    public void saveToGallery() { /* Intentionally left empty */ }
}