fix(label): text wrapping inside flexbox layout (#121)

* fix(ios-label): fix text wrapping in iOS 11
* fix(android): fix label text wrapping inside flexbox layout

android/widgets/src/main/java/org/nativescript/widgets/FlexboxLayout.java

@@ -1071,9 +1071,24 @@ public class FlexboxLayout extends ViewGroup {
                     } else {
                         accumulatedRoundError = rawCalculatedWidth - roundedCalculatedWidth;
                     }
-                    child.measure(MeasureSpec.makeMeasureSpec(roundedCalculatedWidth, MeasureSpec.EXACTLY),
+
-                            MeasureSpec.makeMeasureSpec(child.getMeasuredHeight(),
+                    int childWidthMeasureSpec = MeasureSpec.makeMeasureSpec(roundedCalculatedWidth, MeasureSpec.EXACTLY);
-                                    MeasureSpec.EXACTLY));
+
+                    // NOTE: for controls that support internal content wrapping (e.g. TextView) reducing the width
+                    // might result in increased height e.g. text that could be shown on one line for larger
+                    // width needs to be wrapped in two when width is reduced.
+                    // As a result we cannot unconditionally measure with EXACTLY the current measured height
+                    int childHeightMeasureSpec = getChildMeasureSpec(this.getMeasuredHeightAndState(),
+                            getPaddingTop() + getPaddingBottom() + lp.topMargin
+                                    + lp.bottomMargin, lp.height < 0 ? LayoutParams.WRAP_CONTENT : lp.height);
+
+                    child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
+
+                    // make sure crossSize is up-to-date as child calculated height might have increased
+                    flexLine.mCrossSize = Math.max(
+                            flexLine.mCrossSize,
+                            child.getMeasuredHeight() + lp.topMargin + lp.bottomMargin
+                    );
                 }
                 flexLine.mMainSize += child.getMeasuredWidth() + lp.leftMargin + lp.rightMargin;
             } else {

ios/TNSWidgets/TNSWidgets/TNSLabel.m

@@ -12,13 +12,27 @@
 
 
 - (CGRect)textRectForBounds:(CGRect)bounds limitedToNumberOfLines:(NSInteger)numberOfLines {
-    CGSize size = [super textRectForBounds:bounds limitedToNumberOfLines:numberOfLines].size;
+    // UILabel.textRectForBounds:limitedToNumberOfLines: returns rect with CGSizeZero when empty
-    return CGRectMake(
+    if (self.text.length == 0) {
+        return [super textRectForBounds:bounds limitedToNumberOfLines:numberOfLines];
+    }
+
+    // 1. Subtract the insets (border thickness & padding)
+    // 2. Calculate the original label bounds
+    // 3. Add the insets again
+    UIEdgeInsets insets = UIEdgeInsetsMake(self.borderThickness.top + self.padding.top,
+                                           self.borderThickness.left + self.padding.left,
+                                           self.borderThickness.bottom + self.padding.bottom,
+                                           self.borderThickness.right + self.padding.right);
+
+    CGRect rect = [super textRectForBounds:UIEdgeInsetsInsetRect(bounds, insets) limitedToNumberOfLines:numberOfLines];
+
+    UIEdgeInsets inverseInsets = UIEdgeInsetsMake(-(self.borderThickness.top + self.padding.top),
                                                   -(self.borderThickness.left + self.padding.left),
-                      - (self.borderThickness.right + self.padding.right),
+                                                  -(self.borderThickness.bottom + self.padding.bottom),
-                      size.width + self.borderThickness.left + self.padding.left + self.padding.right + self.borderThickness.right,
+                                                  -(self.borderThickness.right + self.padding.right));
-                      size.height + self.borderThickness.top + self.padding.top + self.padding.bottom + self.borderThickness.bottom
+
-                      );
+    return UIEdgeInsetsInsetRect(rect, inverseInsets);
 }
 
 -(void)drawTextInRect:(CGRect)rect {