Add main/java/com/example/musicwork/Data.java

main/java/com/example/musicwork/Data.java

@@ -0,0 +1,19 @@
+package com.example.musicwork;
+
+import android.app.Application;
+
+public class Data extends Application{
+    private String username;
+
+    public String getUsername(){
+        return this.username;
+    }
+    public void setUsername(String c){
+        this.username= c;
+    }
+    @Override
+    public void onCreate(){
+        username = "null";
+        super.onCreate();
+    }
+}