Question

我有这个小部件数组，但我需要能够动态添加更多项目如何通过函数向此小部件数组添加更多项？

  List<Widget> _tabScroll() => [
    Tab(
      child: Container(
        decoration: BoxDecoration(
          borderRadius: BorderRadius.circular(20),
          border: Border.all(color: Colors.grey[300], width: 1),
          color: Colors.grey[100]
        ),
        padding: EdgeInsets.fromLTRB(12.0, 5.0, 12.0, 5.0),
        child: Text(_tab1),
      ),
    ),
    Tab(
      child: Container(
        decoration: BoxDecoration(
          borderRadius: BorderRadius.circular(20),
          border: Border.all(color: Colors.grey[300], width: 1),
          color: Colors.grey[100]
        ),
        padding: EdgeInsets.fromLTRB(12.0, 5.0, 12.0, 5.0),
        child: Text(_tab2),
      ),
    ),
    Tab(
      child: Container(
        decoration: BoxDecoration(
          borderRadius: BorderRadius.circular(20),
          border: Border.all(color: Colors.grey[300], width: 1),
          color: Colors.grey[100]
        ),
        padding: EdgeInsets.fromLTRB(12.0, 5.0, 12.0, 5.0),
        child: Text(_tab3),
      ),
    ),
  ];

这是标签的控制器

  TabBar _tabBarLabel() => TabBar(
    tabs: _tabScroll(),
  );

Answer 1

替换您的吸气剂

List<Tab> get tabs => [
  Tab(...),
  Tab(...),
  Tab(...),
];

带有实例变量

List<Tab> tabs = [
  Tab(...),
  Tab(...),
  Tab(...),
];

并使用

tabs.add(Tab(...));

Answer 2

由于您将要处理代码中的列表，因此这里有一些其他简单的列表操作可能会为您提供帮助。我在这里创建了一个dartpad文件，以便您可以使用它们，并且我标记了两个将对您的特定问题有帮助： https://dartpad.dev/a6f78b9ad58a589e7415d9b1625950b6

// Create firstList and add object to the end of firstList 
// THIS ONE will help you with your initial question
      List<String> firstList = ['Chicago', 'Santiago', 'São Paulo'];
      firstList.add('Tokyo'); 

// Adds to firstList at index number.(indexed from zero)
// THIS ONE will also help you with your initial question, but if you 
//    want to be more precise with where you insert your element
      firstList.insert(2, 'Mexico City'); 

// Create secondList and add entire secondList to end of firstList
// THIS ONE will help with your initial question if you decide to make 
// changes in bulk. (build secondList first with your changes, and add it to 
// your initial list all at once.
      List<String> secondList = ['Stockholm', 'Moscow', 'Paris']; 
      firstList.addAll(secondList); 

// Create thirdList and add to firstList at index "0" in firstList
// THIS ONE will help you with your initial question if you need to create
// a list ahead of time and insert it at a specific place all at once.
      List<String> thirdList = ['New York', 'San José', 'Buenos Aires']; 
      firstList.insertAll(0,thirdList); 

// Removes specific object in firstList
      firstList.remove("San José"); 

// Removes object at specific index in firstList
      firstList.removeAt(0); 

// Removes last object in firstList
      firstList.removeLast(); 

// Removes everything between 5 and 7 (where 7 is not inclusive) in firstList
      firstList.removeRange(5,7); 

// Find the index of a given object in firstList
      int bestCity = firstList.indexOf("Chicago"); 

// Finds index of first object that meets some criteria (in this case, starts with S);
      var firstS = firstList.indexWhere((city)=>city.startsWith("S")); 

// Same as the previous, but instead of starting at zero, it starts with the index of the included integer
      var secondS = firstList.indexWhere((city)=>city.startsWith("S"), firstS + 1);

将新项目添加到List <Widget>

2 个答案: