Flutter ramka uchun qo'llanma 1-bob. Flutterga kirish Flutter nima. O'rnatish

Yuqori tugma

ElevatedButton vidjeti tugmani ifodalaydi, uning asosiy vazifasi bosilganda javob berish va ba'zi harakatlarni bajarishdir.

Ushbu vidjetda ikkita konstruktor mavjud. Birinchi konstruktor:

1 2	ElevatedButton({Key key, @required VoidCallback onPressed, VoidCallback onLongPress, ButtonStyle style, FocusNode focusNode, bool autofocus: false, Clip clipBehavior: Clip.none, @required Widget child})

Keling, ba'zi parametrlarni ko'rib chiqaylik:
kalit: buyumning kaliti
onPressed: bosilganda chaqiriladigan harakatni tavsiflaydi
onLongPress: uzoq bosilganda chaqiriladigan harakatni tavsiflaydi
uslub: tugma uslubi
focusNode: klaviatura fokuslarini qabul qilish va klaviatura hodisalarini boshqarish uchun ishlatiladigan ob'ekt
avtofokus: tugma sukut bo'yicha fokusni olish-olmasligini bildiradi
clipBehavior: tugma mazmuni qanday qirqib olinishini belgilaydi
bola: boshqa vidjet sifatida tugma mazmuni (odatda tugmachadagi yorliq)
Ikkinchi konstruktor piktogramma parametridan vidjet ko'rinishidagi belgini qo'shimcha ravishda qo'shish imkonini beradi:

1 2	ElevatedButton.icon({Key key, @required VoidCallback onPressed, VoidCallback onLongPress, ButtonStyle style, FocusNode focusNode, bool autofocus, Clip clipBehavior, @required Widget icon, @required Widget label})

Eng oddiy ElevatedButtonni yaratish:

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import 'package:flutter/material.dart';   void main() {   runApp(MaterialApp(     home:  Scaffold(       body: ElevatedButton(           child:Text("Click", style: TextStyle(fontSize: 22),)       ),       appBar: AppBar(title:Text("METANIT.COM")),     )   )); }

Skrinshotdan ko'rinib turibdiki, tugma sukut bo'yicha faol emas, chunki biz uni bosilganda chaqirish uchun amal o'rnatmaganmiz - ya'ni onPressed parametri.

Bu parametr mohiyatan hech narsa qaytarmaydigan va parametrlarni olmaydigan bo'sh Funktsiyani () ifodalaydi. Masalan, biz hatto bo'sh funksiyadan ham foydalanishimiz mumkin:

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ElevatedButton(   child: Text("Click", style: TextStyle(fontSize: 22)),   onPressed:(){} )

Oddiy misol sifatida, tugmani bosish orqali konsolga ma'lum bir qatorni chiqaramiz:

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import 'package:flutter/material.dart';   void main() {   runApp(MaterialApp(     home:  Scaffold(       body: ElevatedButton(           child: Text("Click", style: TextStyle(fontSize: 22)),           onPressed:(){ print("Clicked!!!");}       ),       appBar: AppBar(title: Text("METANIT.COM")),)   )); }

Chop etish () funksiyasi tugma bosilganda konsolga ma'lumot chiqaradi:

Yo'nalish vidjeti

Ba'zi konteynerlarga ElevatedButtonni joylashtirishda xatolikka duch kelishimiz mumkin

1	No Directionality widget found.

Bunday holda, siz asosiy konteynerni Yo'nalish vidjetiga o'rashingiz mumkin:

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import 'package:flutter/material.dart';   int count = 0; void main() {   runApp(Directionality(       textDirection: TextDirection.rtl,       child: Container(     color: Colors.white,     padding: EdgeInsets.only(top:25),     child: ElevatedButton(         child:Text("Click", textDirection: TextDirection.ltr)     )),   )); }

Yoki MaterialApp kabi yoʻnalishni bilvosita qoʻllaydigan boshqa vidjetlardan foydalaning.