If statement doesn't work well Android

Question

I have a app that every time you open it, the app reads a file saved into the internal storage and prints something. Then it updates the file.

String filename = "myfile";
String restore = "";
FileOutputStream outputStream;
FileInputStream inputStream;

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    restore = read();
    System.out.println("Before if statement the restore value is: " + restore);
    if(restore == "test3"){
                restore = "test4";
                System.out.println("I' m saving: " +restore);
                save(restore);
            }
            if(restore == "test2"){
                restore = "test3";
                System.out.println("I'm saving: " +restore);
                save(restore);
            }
           if(restore2 == "test1"){
                restore = "test2";
                System.out.println("I'm saving  " +restore);
                save(restore);
            }
}
 public String read() {
    try {
        inputStream = openFileInput(filename);
        StringBuilder builder = new StringBuilder();
        String restore2 = null;
        int ch;
        while((ch = inputStream.read()) != -1){
            builder.append((char)ch);
        }
       System.out.println(builder.toString());
        if(builder.toString() != null) {
            restore2 = builder.toString();
            System.out.println("Restore 2 value is: " + restore2);
        }
        inputStream.close();
        return restore2;

    } catch (Exception e) {
        e.printStackTrace();
        return "test1";
    }

 }

private void save(String salvare) {
    try {
    outputStream = openFileOutput(filename, Context.MODE_PRIVATE);
    outputStream.write(salvare.getBytes());
        System.out.println("I saved: " + salvare);
    outputStream.close();
} catch (Exception e) {
    e.printStackTrace();
}
}

When I open the application for the first time, everything goes well and I get:

Before if statement the restore value is test1 I'm saving test1 I saved test 1

When I reopen my app, The read() function works well because I get

Before if statement the restore value is test2

But I don't get I'm saving test2. This means that the second if statement seems to be useless. Looking at my log cat I don't get any type of error. What can be the problem?

What?? That is another problem – Alessio Trecani May 12 '15 at 17:31 — Alessio Trecani, May 12 '15 at 17:31
Replace all your "==" with ".equals". – Gagan May 12 '15 at 17:32 — Gagan, May 12 '15 at 17:32

score 5 · Answer 1 · answered May 12 '15 at 17:31

5

Strings in Java are objects. Therefore, they should be compared with the equals method, not the == operator (which checks identity).

E.g.:

if (restore.equals("test3")) {

answered May 12 '15 at 17:31

Mureinik

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Oh thanks man: I tough it was right because it didn't give me error for the first time. – Alessio Trecani May 12 '15 at 17:34

If statement doesn't work well Android

1 Answers1