如何解决使用 androidx.navigation 时由 Activity 重置的工具栏标题
使用 androidx.navigation 在 namespace Permisson
{
/// <summary>
/// An empty page that can be used on its own or navigated to within a Frame.
/// </summary>
public sealed partial class MainPage : Page
{
public viewmodel viewmodel { get; set; }
public MainPage()
{
this.InitializeComponent();
this.viewmodel = new viewmodel();
}
private void Button_Click(object sender,RoutedEventArgs e)
{
var v = viewmodel.DataRef[0];
v.Val = 9;
}
private void Button_Click_1(object sender,RoutedEventArgs e)
{
var v = viewmodel.DataRef[1];
v.Val = 10;
}
}
public class viewmodel
{
private ObservableCollection<ValWrapper> dataRef = new ObservableCollection<ValWrapper>()
{
new ValWrapper {Val=22,Brush=new SolidColorBrush (Colors.Green),IsUpdate = false },new ValWrapper {Val=25,IsUpdate = false},new ValWrapper {Val=35,new ValWrapper {Val=45,new ValWrapper {Val=55,new ValWrapper {Val=65,IsUpdate = false }
};
public ObservableCollection<ValWrapper> DataRef { get { return dataRef; } }
}
public class ColorConverter : IValueConverter
{
public object Convert(object value,Type targettype,object parameter,string language)
{
var color = new SolidColorBrush();
if ((bool)value)
{
color.Color = Colors.Red;
}
else
{
color.Color = Colors.Green;
}
return color;
}
public object ConvertBack(object value,string language)
{
throw new NotImplementedException();
}
}
public class ValWrapper : INotifyPropertyChanged
{
private int val;
private SolidColorBrush brush;
public SolidColorBrush Brush
{
get { return brush; }
set
{
brush = value;
RaisePropertyChanged();
}
}
private int _tempValue;
public int Val
{
get { return val; }
set
{
if(_tempValue != value && _tempValue != 0)
{
IsUpdate = true;
}
val = value;
RaisePropertyChanged();
_tempValue = val;
}
}
private bool _isUpdate;
public bool IsUpdate
{
set
{
_isUpdate = value;
RaisePropertyChanged();
}
get
{
return _isUpdate;
}
}
public event PropertyChangedEventHandler PropertyChanged;
public void RaisePropertyChanged([CallerMemberName] string propertyname = null)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
{
handler(this,new PropertyChangedEventArgs(propertyname));
}
}
}
}
中使用 android.label 时会自动设置工具栏标题。这工作正常，直到发生配置更改（例如旋转设备）。在此之后，工具栏标题将重置为应用标题。
在旋转后导航的 nav_graph 设置标题后，Activity 似乎正在重新设置 Activity.onPostCreate() 中的标题。
解决方法
您必须设置带有导航图和支持操作栏的工具栏。
val appCompat = requireActivity() as AppCompatActivity
appCompat.setSupportActionBar(toolbar)
appCompat.setupActionBarWithNavController(navController)
查看 this 了解更多信息。
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