Android SDK equivlent for viewWillAppear (iOS)

androidoncreatesharedpreferencestextviewviewwillappear

Situation

I have a fairly simple app with 2 "layouts" using SharedPreferences.

Main.xml
Settings.xml

Main has a textView that uses getString from SharedPreferences. Also a button to open Settings.

Settings has a spinner and a button to save to SharedPreferences.

The textView gets updated when the App loads as I am calling setText() inside onCreate(Bundle savedInstanceState)

Problem

When I open Settings and update the SharedPreferences, I use the Back button to get back to Main.

Since I am calling setText() inside onCreate() the textView does not update again until I exit the app and open the app again to main.

What method do I need to use to update the textView after coming back from Settings?

My request is similar to the viewWillAppear() for iOS.

Best Answer

onCreate() is only called once when the activity first starts. If you want to update text whenever the activity becomes active you can use onResume() instead. More information on the Activity lifecycle can be found here.

Related Solutions

Python – way to run Python on Android

One way is to use Kivy:

Open source Python library for rapid development of applications that make use of innovative user interfaces, such as multi-touch apps.

Kivy runs on Linux, Windows, OS X, Android and iOS. You can run the same [python] code on all supported platforms.

Kivy Showcase app

Android – How to close/hide the Android soft keyboard programmatically

You can force Android to hide the virtual keyboard using the InputMethodManager, calling hideSoftInputFromWindow, passing in the token of the window containing your focused view.

// Check if no view has focus:
View view = this.getCurrentFocus();
if (view != null) {  
    InputMethodManager imm = (InputMethodManager)getSystemService(Context.INPUT_METHOD_SERVICE);
    imm.hideSoftInputFromWindow(view.getWindowToken(), 0);
}

This will force the keyboard to be hidden in all situations. In some cases, you will want to pass in InputMethodManager.HIDE_IMPLICIT_ONLY as the second parameter to ensure you only hide the keyboard when the user didn't explicitly force it to appear (by holding down the menu).

Note: If you want to do this in Kotlin, use: context?.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager

Kotlin Syntax

// Only runs if there is a view that is currently focused
this.currentFocus?.let { view ->
    val imm = getSystemService(Context.INPUT_METHOD_SERVICE) as? InputMethodManager
    imm?.hideSoftInputFromWindow(view.windowToken, 0)
}