MPChartExample/src/com/xxmassdeveloper/mpchartexample/HalfPieChartActivity.java

package com.xxmassdeveloper.mpchartexample;

import android.graphics.Color;
import android.graphics.Point;
import android.graphics.Typeface;
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.view.Display;
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.components.Legend.LegendPosition;
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;

public class HalfPieChartActivity extends DemoBase {

    private PieChart mChart;

    @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);

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

        moveOffScreen();

        mChart.setUsePercentValues(true);
        mChart.setDescription("");

        mChart.setCenterTextTypeface(mTfLight);
        mChart.setCenterText(generateCenterSpannableText());

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

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

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

        mChart.setDrawCenterText(true);

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

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

        setData(4, 100);

        mChart.animateY(1400, Easing.EasingOption.EaseInOutQuad);

        Legend l = mChart.getLegend();
        l.setPosition(LegendPosition.ABOVE_CHART_CENTER);
        l.setXEntrySpace(7f);
        l.setYEntrySpace(0f);
        l.setYOffset(0f);

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

    private void setData(int count, float range) {

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

        for (int i = 0; i < count; i++) {
            values.add(new PieEntry((float) ((Math.random() * range) + range / 5), mParties[i % mParties.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(mTfLight);
        mChart.setData(data);

        mChart.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() {

        Display display = getWindowManager().getDefaultDisplay();
        int height = display.getHeight();  // deprecated

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

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