- \n
- Allows you to programmatically set, get, and modify text<\/li>\n
- Provides selection control (cursor position, text selection)<\/li>\n
- Gives access to the current text value at any time<\/li>\n
- Can be used to clear text, set initial values, or format text<\/li>\n
- Requires manual disposal to prevent memory leaks<\/li>\n<\/ul>\n
Example:<\/strong><\/p>\n
class MyWidget extends StatefulWidget {\r\n @override\r\n _MyWidgetState createState() => _MyWidgetState();\r\n}\r\n\r\nclass _MyWidgetState extends State<MyWidget> {\r\n final TextEditingController _controller = TextEditingController();\r\n\r\n @override\r\n void dispose() {\r\n _controller.dispose(); \/\/ Important: dispose to prevent memory leaks\r\n super.dispose();\r\n }\r\n\r\n @override\r\n Widget build(BuildContext context) {\r\n return TextField(\r\n controller: _controller,\r\n decoration: InputDecoration(hintText: 'Enter text'),\r\n );\r\n }\r\n}<\/pre>\nonChanged<\/h2>\n
onChanged is a callback function that gets triggered every time the text in the field changes. It’s a simpler, more reactive approach.<\/p>\n
Key features:<\/b><\/p>\n
- \n
- Immediately responds to text changes<\/li>\n
- Receives the current text value as a parameter<\/li>\n
- No need for manual disposal<\/li>\n
- Good for simple validation or real-time filtering<\/li>\n
- More functional programming approach<\/li>\n<\/ul>\n
Example:<\/strong><\/p>\n
TextField(\r\n onChanged: (String value) {\r\n print('Current text: $value');\r\n \/\/ Handle text change\r\n },\r\n decoration: InputDecoration(hintText: 'Enter text'),\r\n)\r\n<\/pre>\nWhen to use which?<\/span><\/h2>\n
When to use which?<\/h2>\n
Use TextEditingController when:<\/p>\n
- \n
- You need to programmatically control the text (set, clear, format)<\/li>\n
- You need to access text value from multiple places in your code<\/li>\n
- You need cursor\/selection control<\/li>\n
- You’re building complex forms<\/li>\n
- You need to persist text across widget rebuilds<\/li>\n<\/ul>\n
Use onChanged when:<\/p>\n
- \n
- You only need to react to text changes<\/li>\n
- You’re doing simple validation or filtering<\/li>\n
- You want a more straightforward, callback-based approach<\/li>\n
- You don’t need to manipulate the text programmatically<\/li>\n<\/ul>\n
Can you use both together?<\/h2>\n
Yes! You can use both approaches simultaneously:<\/p>\n
final TextEditingController _controller = TextEditingController();<\/code><\/p>\nTextField(\r\n controller: _controller,\r\n onChanged: (String value) {\r\n \/\/ React to changes\r\n print('Text changed: $value');\r\n },\r\n decoration: InputDecoration(hintText: 'Enter text'),\r\n)<\/pre>\nThis gives you the flexibility of programmatic control while also allowing you to react to changes in real-time.<\/p>\n
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