Using if statement to show a container in flutter-CodePudding

I have this certain issue so there is a URL in my flutter app where,

String URL = "www.abcd/page=$number";
int number = 1;

And a button with onTap where,

Inkwell(child:Container(child: Text("Next")),
 onTap :()=> setState({
            number  )}

Sorry I typed those codes manually maybe there is some syntax error. So basically I want the user to tap on the next button the page number in the link increases by 1, but I want to iterate an 'if' function, when number> 1 then show a button where the page decrements by one and if number<1 then I don't want the container to show.

So is there any way to achieve it?

CodePudding user response：

Use a ternary operator

condition ? if True : if False

In your case use it on the on the button that decrements by 1.

number>1 ? shows Button : shows empty Sizedbox

number>1 
       ? InkWell(
        onTap: (() {
          setState(() {
            number--;
          });}),
        child: Container(
          height: 30,
          color: Colors.red[100],
          child: Text('Previous'),
          )) 
        : SizedBox(),

CodePudding user response：

You can use if statement as shown below.

import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);
  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      debugShowCheckedModeBanner: false,
      home: SafeArea(child: MyHome()),
    );
  }
}

class MyHome extends StatefulWidget {
  const MyHome({super.key});

  @override
  State<MyHome> createState() => _MyHomeState();
}

class _MyHomeState extends State<MyHome> {
  int number = 1;
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Column(mainAxisAlignment: MainAxisAlignment.spaceEvenly, children: [
        Text('URL www.abcd/page=$number'),
        Row(
          mainAxisAlignment: MainAxisAlignment.spaceAround,
          children: [
            InkWell(
              child: const Text("Next"),
              onTap: () {
                setState(() {
                  number  ;
                });
              },
            ),
            if (number > 1)
              InkWell(
                child: const Text("Previous"),
                onTap: () {
                  setState(() {
                    number--;
                  });
                },
              ),
          ],
        ),
      ]),
    );
  }
}