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.