app 底部导航设置

bottomNavigationBar: BottomNavigationBar(
  type: BottomNavigationBarType.fixed,
  currentIndex: _currentIndex,
  onTap: (index) {
    setState(() => _currentIndex = index);
  },
  selectedItemColor: Color(0xFF009946),
  unselectedItemColor: Colors.grey,
  selectedFontSize: 12.0,     // 选中项文字大小
  unselectedFontSize: 12.0,
  showSelectedLabels: true,
  showUnselectedLabels: true,
  items: [
    BottomNavigationBarItem(
      icon: _currentIndex == 0 ? Image.asset('assets/images/home1.png' , width: 18,) : Image.asset('assets/images/home0.png' ,width: 18,),
      label: '首页',
    ),
     BottomNavigationBarItem(
      icon:_currentIndex == 1 ? Image.asset('assets/images/car1.png' , width: 18,) : Image.asset('assets/images/car0.png' ,width: 18,),
      label: '搜索',
    ),
     BottomNavigationBarItem(
      icon: _currentIndex == 2 ? Image.asset('assets/images/about1.png' , width: 18,) : Image.asset('assets/images/about0.png' ,width: 18,),
      label: '我的',
    ),
    BottomNavigationBarItem(
      icon: _currentIndex == 3 ? Image.asset('assets/images/pone1.png' , width: 18,) : Image.asset('assets/images/pone0.png' ,width: 18,),
      label: '我的',
    ),
  ],
),