Files
2023-10-11 15:05:12 +03:00

163 lines
5.1 KiB
Plaintext

---
id: customize_text_messages
title: Message List View
---
Customizing Text Messages
### Introduction
Every application provides a unique look and feel to their own messaging interface including and not
limited to fonts, colors, and shapes.
This guide details how to customize message text in the `StreamMessageListView` / `StreamMessageWidget` in the
Stream Chat Flutter UI SDK.
:::note
This guide is specifically for the `StreamMessageListView` but if you intend to display a `StreamMessageWidget`
separately, follow the same process without the `.copyWith` and use the default constructor instead.
:::
### Basics of customizing a `StreamMessageWidget`
First, add a `StreamMessageListView` in the appropriate place where you intend to display messages from a
channel.
```dart
StreamMessageListView(
...
)
```
Now, we use the `messageBuilder` parameter to build a custom message. The builder function also provides
the default implementation of the `StreamMessageWidget` so that we can change certain aspects of the widget
without redoing all of the default parameters.
:::note
In earlier versions of the SDK, some `StreamMessageWidget` parameters were exposed directly through the `StreamMessageListView`,
however, this quickly becomes hard to maintain as more parameters and customizations are added to the
`StreamMessageWidget`. Newer version utilise a cleaner interface to change the parameters by supplying a
default message implementation as aforementioned.
:::
```dart
StreamMessageListView(
...
messageBuilder: (context, messageDetails, messageList, defaultWidget) {
return defaultWidget;
},
)
```
We use `.copyWith()` to customize the widget:
```dart
StreamMessageListView(
...
messageBuilder: (context, messageDetails, messageList, defaultWidget) {
return defaultWidget.copyWith(
...
);
},
)
```
### Customizing text
If you intend to simply change the theme for the text, you need not recreate the whole widget. The
`StreamMessageWidget` has a `messageTheme` parameter that allows you to pass the theme for most aspects
of the message.
```dart
StreamMessageListView(
...
messageBuilder: (context, messageDetails, messageList, defaultWidget) {
return defaultWidget.copyWith(
messageTheme: StreamMessageThemeData(
...
messageTextStyle: TextStyle(),
),
);
},
)
```
If you want to replace the entire text widget in the `StreamMessageWidget`, you can use the `textBuilder`
parameter which provides a builder for creating a widget to substitute the default text.parameter
```dart
StreamMessageListView(
...
messageBuilder: (context, messageDetails, messageList, defaultWidget) {
return defaultWidget.copyWith(
textBuilder: (context, message) {
return Text(message.text ?? '');
},
);
},
)
```
### Adding Hashtags
To add elements like hashtags, we can override the `textBuilder` in the StreamMessageWidget:
```dart
StreamMessageListView(
...
messageBuilder: (context, messageDetails, messageList, defaultWidget) {
return defaultWidget.copyWith(
textBuilder: (context, message) {
final text = _replaceHashtags(message.text)?.replaceAll('\n', '\\\n');
final messageTheme = StreamChatTheme.of(context).ownMessageTheme;
if (text == null) return const SizedBox();
return MarkdownBody(
data: text,
onTapLink: (
String link,
String? href,
String title,
) {
// Do something with tapped hashtag
},
styleSheet: MarkdownStyleSheet.fromTheme(
Theme.of(context).copyWith(
textTheme: Theme.of(context).textTheme.apply(
bodyColor: messageTheme.messageTextStyle?.color,
decoration: messageTheme.messageTextStyle?.decoration,
decorationColor: messageTheme.messageTextStyle?.decorationColor,
decorationStyle: messageTheme.messageTextStyle?.decorationStyle,
fontFamily: messageTheme.messageTextStyle?.fontFamily,
),
),
).copyWith(
a: messageTheme.messageLinksStyle,
p: messageTheme.messageTextStyle,
),
);
},
);
},
)
String? _replaceHashtags(String? text) {
if (text == null) return null;
final exp = RegExp(r"\B#\w\w+");
String result = text;
exp.allMatches(text).forEach((match){
text = text!.replaceAll(
'${match.group(0)}', '[${match.group(0)}](${match.group(0)?.replaceAll(' ', '')})');
});
return result;
}
```
We can replace the hashtags using RegEx and add links for the MarkdownBody which is done here in the
`_replaceHashtags()` function.
Inside the textBuilder, we use the `flutter_markdown` package to build our hashtags as links.
![](../../assets/hashtag_example.jpg)