Home / Questions / 67600
Accepted
Dimoreno
Asked: 2020-05-05 22:21:24 +0800 CST 2020-05-05 22:21:24 +0800 CST

Error comparing values ​​in Android (if)

  • 772

I have the following Activity which starts a service of type service in android for it inside my Activity class I have the following

Intent i_service = new Intent(getApplicationContext(), MyService.class);
        i_service.putExtra("nombre_clase", "Mapas");
        startService(i_service);

and in my class MyService.class I have the following: 

 public int onStartCommand(Intent intent, int flags, int startId) {
        Log.d(var,"servicio stratcomand");
        String nombre_clase = intent.getStringExtra("nombre_clase");
        Log.d("bbbbbbbbbb", "valor: "+nombre_clase);
        if(nombre_clase == "Mapas"){
            Log.d("aaaaaaaaaaa", "valor: "+nombre_clase);
        }else{
            Log.d("aaaaaaaaaaa", "noo error ");
        }
        return super.onStartCommand(intent, flags, startId);
    }

Before entering the condition I print the class_name variable which does not present any error, but when I want it to print the value of the same variable within the condition I always get the message "no error", since the value "Maps" if it exists.

What I want to know is how do I solve this problem, in advance I thank you

java

2 Answers

  1. Best Answer

    The problem is that you are not comparing type objects Stringcorrectly.

    You must use the method equals, otherwise what you are comparing are objects and not their content and, therefore, they will always be different.

    This would be the correct code:

       public int onStartCommand(Intent intent, int flags, int startId) {
        Log.d(var,"servicio stratcomand");
        String nombre_clase = intent.getStringExtra("nombre_clase");
        Log.d("bbbbbbbbbb", "valor: "+nombre_clase);
        if("Mapas".equals(nombre_clase)){
            Log.d("aaaaaaaaaaa", "valor: "+nombre_clase);
        }else{
            Log.d("aaaaaaaaaaa", "noo error ");
        }
        return super.onStartCommand(intent, flags, startId);
    }

    I've put "Mapas".equals(nombre_clase)instead of nombre_clase.equals("Mapas")to avoid possibles NullPointerExceptionsince you don't explicitly check if the value is null.

    • 4

  2. In the language Javathe function is used equals()to compare Strings, the operator should NEVER be used ==.

       // if(nombre_clase == "Mapas"){
    if(nombre_clase.equals("Mapas")){
        Log.d("aaaaaaaaaaa", "valor: "+nombre_clase);
    }else{
        Log.d("aaaaaaaaaaa", "noo error ");
    }

    You could also use equalsIgnoreCase(), which performs a case-insensitive comparison, for example:

    If you nombre_clasehave the value of "maps":

    nombre_clase = "mapas"

    This comparison would have a value false:

    nombre_clase.equals("Mapas")

    instead if you use equalsIgnoreCase(), it would have a value true:

    nombre_clase.equalsIgnoreCase("Mapas")
    • 0