[英]Xamarin - call fragment method from MainActivity
我有一個帶有3個標簽片段的viewPager。 tabFragment1類的代碼(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";
}
}
因此,我想從MainActivity方法中調用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(因為我看到每次選擇選項卡時我都會在Snackbar中看到正確的itemID),但是在if子句下的最后一行...
if (currentItem == 1) { tabFragment1.UpdateContent(fView); }
...我看到Visual Studio錯誤彈出窗口說,
非靜態字段,方法或屬性'tabFragment1.UpdateContent(fView)'需要對象引用
解決問題的最佳方法是什么? 謝謝
public void UpdateContent(View v)
是對象的方法,而不是類型的方法。 因此,要使用它,您需要創建tabFragment1
對象並調用它的方法。 或者,您可以將UpdateContent(View v)
聲明更改為static UpdateContent(View v)
並將其作為類型的方法進行調用。
更改聲明:
public static void UpdateContent(View v)
{
// Put here your code from question
}
並使用:
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);
}
}
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