If statement being skipped during execution

Question

I am having a problem with this piece of code. The if statement on line 6 is being ignored during execution. I have stepped through the code at this point and the value of the variable file[position] is "subjects.dat". However, it is skipping over the steps in this and going to the related else statement. Any ideas why??

dialogButton.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {
                if (markComplete.isChecked()) {
                    String toDelete;
                    String[] files = fileList();
                    if (files[position] == "subjects.dat") { //the error occurs at this line
                        toDelete = files[position + 1];
                        boolean deleted = deleteFile(toDelete);
                        if (deleted) {
                            dialog.dismiss();
                        } else {
                            // Do nothing
                        }
                    } else {                            
                        toDelete = files[position];                     
                        boolean deleted = deleteFile(toDelete);
                        if (deleted) {
                            dialog.dismiss();
                        } else {
                            //Do nothing
                        }   
                    }

                }                   
            }

Thanks!

because it is evaluated to false as String comparisons are not done this way — njzk2, Feb 11 '13 at 16:49
This might be one of the most common java error, along with `if (var = 2)` ;) — nicopico, Feb 11 '13 at 16:53

score 6 · Accepted Answer · answered Feb 11 '13 at 16:48

6

You need to use .equals() to compare the actual value of two strings - otherwise you're checking if they're the same object.

if (files[position].equals("subjects.dat")) { 
    // do stuff
}

answered Feb 11 '13 at 16:48

thegrinner

11,546
5
41
64

@RohitJain whoops, fixed. – thegrinner Feb 11 '13 at 16:49

score 1 · Answer 2 · answered Feb 11 '13 at 16:48

1

Always check String equality using equals() method. == operator cheks if two refrenece variables point to the same object.

answered Feb 11 '13 at 16:48

PermGenError

45,977
8
87
106

score 1 · Answer 3 · answered Feb 11 '13 at 16:53

Strings are objects in java and when you use "==", you compare the references (pointers), which usually are different (usually because for short strings some optimization is made). Long story short, use

string.equals(anotherString)

instead of

string == anotherString

score 0 · Answer 4 · answered Feb 11 '13 at 16:54

0

String - use .equals(). == will never give you true since the objects are different.

Instead of files[position] == "subjects.dat" use files[position].equals("subjects.dat")

answered Feb 11 '13 at 16:54

user1744361

14

If statement being skipped during execution

4 Answers4

Linked