add: pie chart information for screen-reader

Author: ish-joshi

MPChartLib/src/main/java/com/github/mikephil/charting/charts/CandleStickChart.java

@@ -44,6 +44,6 @@ public CandleData getCandleData() {
 
     @Override
     public String getAccessibilityDescription() {
-        return "This is a candlestick";
+        return "This is a candlestick chart";
     }
 }

MPChartLib/src/main/java/com/github/mikephil/charting/charts/LineChart.java

@@ -5,9 +5,12 @@
 import android.util.AttributeSet;
 
 import com.github.mikephil.charting.data.LineData;
+import com.github.mikephil.charting.formatter.IAxisValueFormatter;
 import com.github.mikephil.charting.interfaces.dataprovider.LineDataProvider;
 import com.github.mikephil.charting.renderer.LineChartRenderer;
 
+import java.util.Locale;
+
 /**
  * Chart that draws lines, surfaces, circles, ...
  *
@@ -50,6 +53,25 @@ protected void onDetachedFromWindow() {
 
     @Override
     public String getAccessibilityDescription() {
-        return "This is a line chart";
+        LineData lineData = getLineData();
+
+        int numberOfPoints = lineData.getEntryCount();
+
+        // Min and max values...
+        IAxisValueFormatter yAxisValueFormmater = getAxisLeft().getValueFormatter();
+        String minVal = yAxisValueFormmater.getFormattedValue(lineData.getYMin(), null);
+        String maxVal = yAxisValueFormmater.getFormattedValue(lineData.getYMax(), null);
+
+        // Data range...
+        IAxisValueFormatter xAxisValueFormatter = getXAxis().getValueFormatter();
+        String minRange = xAxisValueFormatter.getFormattedValue(lineData.getXMin(), null);
+        String maxRange = xAxisValueFormatter.getFormattedValue(lineData.getXMax(), null);
+
+        String entries = numberOfPoints == 1 ? "entry" : "entries";
+
+        return String.format(Locale.getDefault(), "The line chart has %d %s. " +
+                        "The minimum value is %s and maximum value is %s." +
+                        "Data ranges from %s to %s.",
+                numberOfPoints, entries, minVal, maxVal, minRange, maxRange);
     }
 }

MPChartLib/src/main/java/com/github/mikephil/charting/charts/PieChart.java

@@ -6,18 +6,22 @@
 import android.graphics.Paint;
 import android.graphics.RectF;
 import android.graphics.Typeface;
+import android.text.TextUtils;
 import android.util.AttributeSet;
 
 import com.github.mikephil.charting.components.XAxis;
 import com.github.mikephil.charting.data.PieData;
+import com.github.mikephil.charting.data.PieEntry;
 import com.github.mikephil.charting.highlight.Highlight;
 import com.github.mikephil.charting.highlight.PieHighlighter;
 import com.github.mikephil.charting.interfaces.datasets.IPieDataSet;
 import com.github.mikephil.charting.renderer.PieChartRenderer;
 import com.github.mikephil.charting.utils.MPPointF;
 import com.github.mikephil.charting.utils.Utils;
 
+import java.util.ArrayList;
 import java.util.List;
+import java.util.Locale;
 
 /**
  * View that represents a pie chart. Draws cake like slices.
@@ -804,6 +808,24 @@ protected void onDetachedFromWindow() {
 
     @Override
     public String getAccessibilityDescription() {
-        return "This is a pie chart";
+
+        PieData pieData = getData();
+
+        int entryCount = pieData.getEntryCount();
+
+        StringBuilder builder = new StringBuilder();
+
+        builder.append(String.format(Locale.getDefault(), "The pie chart has %d entries.",
+                entryCount));
+
+        for (int i = 0; i < entryCount; i++) {
+            PieEntry entry = pieData.getDataSet().getEntryForIndex(i);
+            float percentage = (entry.getValue() / pieData.getYValueSum()) * 100;
+            builder.append(String.format(Locale.getDefault(), "%s has %.2f percent pie taken",
+                    (TextUtils.isEmpty(entry.getLabel()) ? "No Label" : entry.getLabel()),
+                    percentage));
+        }
+
+        return builder.toString();
     }
 }