fix(android): crash in ListView on API 21 (#13262)

* fix(android): crash in ListView on API 21

default listDivider on API 21 is instance of NinePatchDrawable, not a GradientDrawable

fix #13261

* fix(android): hide default separator when separatorStyle is SEPARATOR_STYLE_NONE

* docs(api): fix ListView example

* docs(api): add warning about separatorHeight usage on Android API below 23

Co-authored-by: Hans Knöchel <hansemannn@users.noreply.github.com>

android/modules/ui/src/java/ti/modules/titanium/ui/widget/TiUIListView.java

@@ -8,6 +8,7 @@
 
 import android.content.Context;
 import android.content.res.TypedArray;
+import android.graphics.drawable.Drawable;
 import android.graphics.drawable.GradientDrawable;
 import android.view.View;
 import android.view.ViewGroup;
@@ -214,7 +215,9 @@ private void processProperty(String name, Object value)
 				? TiConvert.toTiDimension(heightString, TiDimension.TYPE_HEIGHT)
 				.getAsPixels((View) getNativeView().getParent()) : 0;
 
-			if (name.equals(TiC.PROPERTY_SEPARATOR_COLOR)
+			if (height == 0) {
+				this.listView.setSeparator(0, height);
+			} else if (name.equals(TiC.PROPERTY_SEPARATOR_COLOR)
 				|| properties.containsKey(TiC.PROPERTY_SEPARATOR_COLOR)) {
 				String colorString = properties.getString(TiC.PROPERTY_SEPARATOR_COLOR);
 				if (name.equals(TiC.PROPERTY_SEPARATOR_COLOR)) {
@@ -227,10 +230,12 @@ private void processProperty(String name, Object value)
 
 			} else {
 				final TypedArray divider = context.obtainStyledAttributes(new int[] { android.R.attr.listDivider });
-				final GradientDrawable defaultDrawable = (GradientDrawable) divider.getDrawable(0);
+				final Drawable defaultDrawable = divider.getDrawable(0);
 
 				// Set platform default separator.
-				defaultDrawable.setSize(0, height);
+				if (defaultDrawable instanceof GradientDrawable) {
+					((GradientDrawable) defaultDrawable).setSize(0, height);
+				}
 				this.listView.setSeparator(defaultDrawable);
 				divider.recycle();
 			}

apidoc/Titanium/UI/ListView.yml

@@ -758,6 +758,8 @@ properties:
     description: |
         Height of the ListView separator, in platform-specific units. If undefined, default native height will be used.
         Numerical inputs are treated as pixels. For example, 3 and "3px" are equivalent.
+        On Android API < 23 you must specify <Titanium.UI.ListView.separatorStyle> and
+        <Titanium.UI.ListView.separatorColor> for this property to work.
     type: [String, Number]
     since: "4.1.0"
     platforms: [android]
@@ -1367,8 +1369,8 @@ examples:
             {properties: { title: 'Carrots'}},
             {properties: { title: 'Potatoes'}},
         ];
-        sections.push(vegSection);
         var vegSection = Ti.UI.createListSection({ headerTitle: 'Vegetables', items: vegDataSet});
+        sections.push(vegSection);
 
         listView.sections = sections;
         win.add(listView);