I'm developing an Android app with Kotlin.

For example I have an access token which I get on my LoginActivity and I need this access token on each activity to call API. I know that I could use putExtra() and getExtra(), but it doesn't make sense to write this code for each new activity.

Is there a way to create a global variable or something like static class which will be accessible for all activities in app?

What is the right Android approach for that?

CodePudding user response：

I think an object or companion object is what you are looking for.

Be warned is is possible for an instance of an object to be garbage collected without your control. I would recommend creating a BaseActivity class that all your Activities inherit from and override the following methods.

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    savedInstanceState?.let {
        MyObject.refreshFromBundle(it)
    }
}

override fun onSaveInstanceState(outState: Bundle) {
    MyObject.populateBundle(outState)
    super.onSaveInstanceState(outState)
}

Then in your object have the following functions

fun refreshFromBundle(bundle: Bundle) {
    // Get info from bundle and populate your variables
}

fun populateBundle(bundle: Bundle) {
    // Put info from variables into the bundle
}

More info on why it is necessary here

CodePudding user response：

You can use a simple class.

public class Important{
   private static String key = "";
   public static void setKey(String key){
       this.key = key;
   }
   public static String getKey(){
       return key;
   }
}

Create this class under in your package. When you get your key just call Important.setKey("key"). Then you can get your key anytime anywhere by calling Important.getKey()