add: stub message and verified it is read by screenreader

Author: ish-joshi

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

@@ -275,4 +275,9 @@ public void setRoundedBarRadius(float mRoundedBarRadius) {
         this.mDrawRoundedBars = true;
         init();
     }
+
+    @Override
+    public String getAccessibilityDescription() {
+        return "This is a bar chart";
+    }
 }

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

@@ -40,4 +40,9 @@ protected void init() {
     public BubbleData getBubbleData() {
         return mData;
     }
+
+    @Override
+    public String getAccessibilityDescription() {
+        return "This is bubble chart";
+    }
 }

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

@@ -41,4 +41,9 @@ protected void init() {
     public CandleData getCandleData() {
         return mData;
     }
+
+    @Override
+    public String getAccessibilityDescription() {
+        return "This is a candlestick";
+    }
 }

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

@@ -21,6 +21,7 @@
 import android.view.View;
 import android.view.ViewGroup;
 import android.view.ViewParent;
+import android.view.accessibility.AccessibilityEvent;
 
 import com.github.mikephil.charting.animation.ChartAnimator;
 import com.github.mikephil.charting.animation.Easing.EasingFunction;
@@ -170,6 +171,11 @@ public abstract class Chart<T extends ChartData<? extends IDataSet<? extends Ent
 	private float mExtraTopOffset = 0.f, mExtraRightOffset = 0.f, mExtraBottomOffset = 0.f, mExtraLeftOffset = 0.f;
 
 	/**
+     * Tag for logging accessibility related content
+     */
+    private String TAG = "abilityTag";
+
+    /**
 	 * default constructor for initialization in code
 	 */
 	public Chart(Context context) {
@@ -1654,6 +1660,22 @@ public void setUnbindEnabled(boolean enabled) {
 
     // region accessibility
 
+    /**
+     *
+     * @return accessibility description must be created for each chart
+     */
+    public abstract String getAccessibilityDescription();
+
+    @Override
+    public boolean dispatchPopulateAccessibilityEvent(AccessibilityEvent event) {
+
+        boolean completed = super.dispatchPopulateAccessibilityEvent(event);
+        Log.d(TAG, "Dispatch called for Chart <View> and completed as " + completed);
+
+        event.getText().add(getAccessibilityDescription());
+
+        return true;
+    }
 
     // endregion
 }

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

@@ -266,4 +266,8 @@ protected void drawMarkers(Canvas canvas) {
 		}
 	}
 
+    @Override
+    public String getAccessibilityDescription() {
+        return "This is a combined chart";
+    }
 }

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

@@ -47,4 +47,9 @@ protected void onDetachedFromWindow() {
         }
         super.onDetachedFromWindow();
     }
+
+    @Override
+    public String getAccessibilityDescription() {
+        return "This is a line chart";
+    }
 }

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

@@ -801,4 +801,9 @@ protected void onDetachedFromWindow() {
         }
         super.onDetachedFromWindow();
     }
+
+    @Override
+    public String getAccessibilityDescription() {
+        return "This is a pie chart";
+    }
 }

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

@@ -382,4 +382,9 @@ public float getYChartMin() {
     public float getYRange() {
         return mYAxis.mAxisRange;
     }
+
+    @Override
+    public String getAccessibilityDescription() {
+        return "This is a Radar chart";
+    }
 }

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

@@ -74,4 +74,9 @@ public static ScatterShape[] getAllDefaultShapes() {
             return new ScatterShape[]{SQUARE, CIRCLE, TRIANGLE, CROSS, X, CHEVRON_UP, CHEVRON_DOWN};
         }
     }
+
+    @Override
+    public String getAccessibilityDescription() {
+        return "This is scatter chart";
+    }
 }