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Merge pull request #951 from Hixie/dropdown-cancel

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Canceling a dropdown menu selects null value
This commit is contained in:
Ian Hickson 2015-12-15 17:09:12 -08:00
commit b378d9670b
1 changed files with 25 additions and 7 deletions
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32
packages/flutter/lib/src/material/dropdown.dart
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@ -95,7 +95,10 @@ class _DropDownMenu<T> extends StatusTransitionComponent {
padding: _kMenuHorizontalPadding,
child: route.items[itemIndex]
),
onTap: () => Navigator.pop(context, route.items[itemIndex].value)
onTap: () => Navigator.pop(
context,
new _DropDownRouteResult<T>(route.items[itemIndex].value)
)
)
));
}
@ -143,9 +146,24 @@ class _DropDownMenu<T> extends StatusTransitionComponent {
}
}
class _DropDownRoute<T> extends PopupRoute<T> {
// We box the return value so that the return value can be null. Otherwise,
// canceling the route (which returns null) would get confused with actually
// returning a real null value.
class _DropDownRouteResult<T> {
const _DropDownRouteResult(this.result);
final T result;
bool operator ==(dynamic other) {
if (other is! _DropDownRouteResult)
return false;
final _DropDownRouteResult<T> typedOther = other;
return result == typedOther.result;
}
int get hashCode => result.hashCode;
}
class _DropDownRoute<T> extends PopupRoute<_DropDownRouteResult<T>> {
_DropDownRoute({
Completer<T> completer,
Completer<_DropDownRouteResult<T>> completer,
this.items,
this.selectedIndex,
this.rect,
@ -246,7 +264,7 @@ class _DropDownButtonState<T> extends State<DropDownButton<T>> {
void _handleTap() {
final RenderBox renderBox = indexedStackKey.currentContext.findRenderObject();
final Rect rect = renderBox.localToGlobal(Point.origin) & renderBox.size;
final Completer completer = new Completer<T>();
final Completer completer = new Completer<_DropDownRouteResult<T>>();
Navigator.push(context, new _DropDownRoute<T>(
completer: completer,
items: config.items,
@ -254,11 +272,11 @@ class _DropDownButtonState<T> extends State<DropDownButton<T>> {
rect: _kMenuHorizontalPadding.inflateRect(rect),
elevation: config.elevation
));
completer.future.then((T newValue) {
if (!mounted)
completer.future.then((_DropDownRouteResult<T> newValue) {
if (!mounted || newValue == null)
return;
if (config.onChanged != null)
config.onChanged(newValue);
config.onChanged(newValue.result);
});
}