Xamarin - 从 MainActivity 调用片段方法

Question

我有一个带有 3 个选项卡片段的视图寻呼机。 tabFragment1 类的代码(注意：V4Fragment = Android.Support.V4.App.Fragment(：

class tabFragment1 : V4Fragment
{
public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle saved)
{
var v = inflater.Inflate(Resource.Layout.tabLayout1, container, false);
// Set weather icon
ImageView iv_icon = v.FindViewById<ImageView>(Resource.Id.iv_icon);
iv_icon.SetImageResource(Resource.Drawable.ic_weather_cloudy_white_48dp);
Snackbar.Make(container, "tabFragment; onCreateView()", Snackbar.LengthLong).Show();
//UpdateContent(v);
return v;
}
public void UpdateContent(View v)
{
// Sample values to read
string locationCode = "528454";
// Mapping views
TextView tv_currentConditions = v.FindViewById<TextView>(Resource.Id.currentConditions);
TextView tv_currentTemperature = v.FindViewById<TextView>(Resource.Id.currentTemperature);
TextView tv_currentRealFeel = v.FindViewById<TextView>(Resource.Id.currentRealFeel);
TextView tv_minMaxTemperature = v.FindViewById<TextView>(Resource.Id.minMaxTemperature);
// Update view from database
tv_currentConditions.Text = Sql.ReadValue(locationCode,"currentConditions");
tv_currentTemperature.Text = Sql.ReadValue(locationCode, "currentTemperature") + "°C";
tv_currentRealFeel.Text = GetString(Resource.String.feelLike) + " " + Sql.ReadValue(locationCode, "currentRealFeel") + "°C";
tv_minMaxTemperature.Text = Sql.ReadValue(locationCode, "minTemperature") + " " + Sql.ReadValue(locationCode, "maxTemperature") + "°C";
}
}

所以，我想从 MainActivity 方法调用 UpdateContent(( 方法：

public void UpdateCurrentTab()
{
ViewPager viewPager = FindViewById<ViewPager>(Resource.Id.viewpager);
int currentItem = viewPager.CurrentItem;
Snackbar.Make(drawerLayout, "CALL TO UPDATE Tab " + currentItem, Snackbar.LengthLong).Show();
View fView = viewPager.GetChildAt(currentItem);
if (currentItem == 1) { tabFragment1.UpdateContent(fView); }
}

它工作正常(因为我看到每次选择选项卡时都会在 Snackbar 中出现正确的 itemID(，但在 if 子句下的最后一行......

if (currentItem == 1) { tabFragment1.UpdateContent(fView); }

。我看到Visual Studio错误弹出窗口说，那

非静态字段、方法或属性"tabFragment1.UpdateContent(fView("需要对象引用

解决问题的最佳方法是什么？谢谢

Answer 1

>public void UpdateContent(View v)是对象的方法而不是类型的方法。因此，要使用它，您需要创建tabFragment1对象并调用它的方法。或者，您可以将UpdateContent(View v)的声明更改为static UpdateContent(View v)并将其调用为 type 的方法。

更改声明：

public static void UpdateContent(View v)
{
// Put here your code from question       
}

并使用：

public void UpdateCurrentTab()
{
ViewPager viewPager = FindViewById<ViewPager>(Resource.Id.viewpager);
int currentItem = viewPager.CurrentItem;
Snackbar.Make(drawerLayout, "CALL TO UPDATE Tab " + currentItem, Snackbar.LengthLong).Show();
View fView = viewPager.GetChildAt(currentItem);
if (currentItem == 1) 
{ 
// Now it's a type's method not object's
tabFragment1.UpdateContent(fView); 
}
}