Android Global Variables: Best Practices

There are several ways to create global variables in Android.

1. Use the Application class: Create a class that inherits from Application, then register this class in the AndroidManifest.xml file. Define global variables within this class and provide public get and set methods to access these variables throughout the entire application.

public class MyApplication extends Application {
    private String globalVariable;

    public String getGlobalVariable() {
        return globalVariable;
    }

    public void setGlobalVariable(String globalVariable) {
        this.globalVariable = globalVariable;
    }
}

Register the Application class in the AndroidManifest.xml file.

<application
    android:name=".MyApplication"
    ...

1. Utilizing SharedPreferences: store data in SharedPreferences to access it throughout the entire application. Global variables can be retrieved and set using the get and put methods of the SharedPreferences class.

SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(context);
SharedPreferences.Editor editor = preferences.edit();
editor.putString("globalVariable", "value");
editor.apply();

String globalVariable = preferences.getString("globalVariable", "");

1. Using static variables: Define static variables in a class, and then access and modify these global variables through static methods of the class.

public class GlobalVariable {
    public static String globalVariable;
}

GlobalVariable.globalVariable = "value";
String value = GlobalVariable.globalVariable;

These methods allow for the creation of global variables to be selected based on specific needs.