build method
Widget build (BuildContext context)
override
Describes the part of the user interface represented by this widget.
The framework calls this method when this widget is inserted into the tree in a given BuildContext and when the dependencies of this widget change (e.g., an InheritedWidget referenced by this widget changes). This method can potentially be called in every frame and should not have any side effects beyond building a widget.
The framework replaces the subtree below this widget with the widget returned by this method, either by updating the existing subtree or by removing the subtree and inflating a new subtree, depending on whether the widget returned by this method can update the root of the existing subtree, as determined by calling Widget.canUpdate.
Typically implementations return a newly created constellation of widgets that are configured with information from this widget's constructor and from the given BuildContext.
The given BuildContext contains information about the location in the tree at which this widget is being built. For example, the context provides the set of inherited widgets for this location in the tree. A given widget might be built with multiple different BuildContext arguments over time if the widget is moved around the tree or if the widget is inserted into the tree in multiple places at once.
The implementation of this method must only depend on:
- the fields of the widget, which themselves must not change over time, and
- any ambient state obtained from the
context
using BuildContext.dependOnInheritedWidgetOfExactType.
If a widget's build method is to depend on anything else, use a StatefulWidget instead.
See also:
- StatelessWidget, which contains the discussion on performance considerations.
Implementation
@override
Widget build(BuildContext context) {
return Scaffold(
resizeToAvoidBottomInset: false,
// header for the widget
appBar: AppBar(
backgroundColor: Theme.of(context).primaryColor,
elevation: 0.9,
centerTitle: true,
// header title
title: Text(
AppLocalizations.of(context)!.strictTranslate('Share News'),
style: Theme.of(context).textTheme.titleLarge!.copyWith(
fontWeight: FontWeight.w600,
fontSize: 20,
),
),
leading: IconButton(
//TODO: showing the null pointer exception
key: const Key('add_post_icon_button1'),
color: Theme.of(context).iconTheme.color,
icon: const Icon(Icons.menu),
onPressed: () => drawerKey!.currentState!.openDrawer(),
),
// button to upload the post.
actions: [
TextButton(
key: const Key('add_post_text_btn1'),
onPressed: () => model.uploadPost(),
child: Text(
AppLocalizations.of(context)!.strictTranslate("Post"),
style: Theme.of(context).textTheme.headlineSmall!.copyWith(
fontWeight: FontWeight.w600,
color: Theme.of(context).colorScheme.secondary,
),
),
),
],
),
body: BaseView<AddPostViewModel>(
onModelReady: (m) {
m.initialise();
model = m;
},
builder: (context, model, child) => SingleChildScrollView(
child: Column(
children: <Widget>[
ListTile(
leading: const CircleAvatar(radius: 25),
title: Text(model.userName),
subtitle: Text(
AppLocalizations.of(context)!.strictTranslate(model.orgName),
),
),
// renders icon button to upload post files.
Row(
children: <Widget>[
// button to select the photo from gallery.
IconButton(
key: const Key('add_post_icon_button2'),
onPressed: () => model.getImageFromGallery(),
icon: const Icon(Icons.photo),
),
// button to capture the image.
IconButton(
key: const Key('add_post_icon_button3'),
onPressed: () => model.getImageFromGallery(camera: true),
icon: const Icon(Icons.camera_alt),
),
// button to select file
IconButton(
key: const Key('add_post_icon_button4'),
onPressed: () {},
icon: const Icon(Icons.file_upload),
),
// button to add hastags to the post.
TextButton(
key: const Key('add_post_text_btn2'),
onPressed: () {},
child: Text(
'# ${AppLocalizations.of(context)!.strictTranslate("Add hashtag")}',
style: Theme.of(context).textTheme.titleLarge,
),
),
],
),
const Divider(),
Padding(
padding: const EdgeInsets.symmetric(horizontal: 16.0),
child: TextField(
controller: model.titleController,
// input field to write the description of the post.
decoration: InputDecoration(
border: InputBorder.none,
focusedBorder: InputBorder.none,
enabledBorder: InputBorder.none,
errorBorder: InputBorder.none,
disabledBorder: InputBorder.none,
hintText: AppLocalizations.of(context)!.strictTranslate(
"Enter the title of your post",
),
label: Text(
AppLocalizations.of(context)!.strictTranslate(
"Title",
),
),
),
),
),
const Divider(),
Padding(
padding: const EdgeInsets.symmetric(horizontal: 16.0),
child: TextField(
controller: model.controller,
maxLines: null,
// input field to write the description of the post.
decoration: InputDecoration(
border: InputBorder.none,
focusedBorder: InputBorder.none,
enabledBorder: InputBorder.none,
errorBorder: InputBorder.none,
disabledBorder: InputBorder.none,
hintText: AppLocalizations.of(context)!.strictTranslate(
"Write here what do you want to share",
),
),
),
),
// if the image for the post is added then render button to remove it.
model.imageFile != null
// ignore: sized_box_for_whitespace
? Container(
height: 230,
padding: const EdgeInsets.all(8.0),
child: Stack(
children: [
Image.file(
model.imageFile!,
fit: BoxFit.cover,
width: MediaQuery.of(context).size.width,
),
Positioned(
right: 5,
top: 5,
child: IconButton(
onPressed: () => model.removeImage(),
icon: const Icon(
Icons.cancel,
color: Colors.black,
),
),
)
],
),
)
: Container(),
],
),
),
),
);
}