Difference between this.mCtx and mCtx Android

Question

If I create a class that looks like this:

public class TagManager {
private final Context mCtx;

public TagManager (Context ctx) {
    this.mCtx = ctx;
}

}

What is the difference between using

this.mCtx = ctx;

versus

mCtx = ctx;

As far as I can tell they both do the same thing but I can't find any discussion of it.

Check this http://docs.oracle.com/javase/tutorial/java/javaOO/thiskey.html out. — Qw4z1, Sep 02 '12 at 15:22
Also see this http://stackoverflow.com/a/6547327/1166813 answer, since it is the same for variables and methods. — Qw4z1, Sep 02 '12 at 15:24

score 4 · Accepted Answer · edited Sep 02 '12 at 15:35

4

For sure it's the same. It's just a matter of CodeStyle - it's up to you to select what you like more.

The only reasonable case to make this.* is when your argument and member variable have the same name. For example

    private final Context ctx;
    public TagManager (Context ctx) {
        this.ctx = ctx;
    }

However, Android Code Style tells us to use m*** prefix for member variables, so this situation should rare happen in your classes.

Good luck

edited Sep 02 '12 at 15:35

Alex Coleman

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answered Sep 02 '12 at 15:14

AlexN

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Good answer, thanks. Gave it to you because you threw in the m*** prefix info :) – easycheese Sep 02 '12 at 15:25

score 2 · Answer 2 · answered Sep 02 '12 at 15:15

Within an instance method or a constructor, this is a reference to the current object — the object whose method or constructor is being called

public class Point {
    public int x = 0;
    public int y = 0;

    //constructor
    public Point(int x, int y) {
        this.x = x;
        this.y = y;
    }
}

this.x on the example refer to public int x no int x

score 1 · Answer 3 · answered Sep 02 '12 at 15:15

Consider this:

public class foo {
private final int bla = 1;

public int blabla () {
    int bla = 2;
    return bla;//this will return 2
}

/

public class foo {
private final int bla = 1;

public int blabla () {
    int bla = 2;
    return this.bla;//this will return 1
}

Difference between this.mCtx and mCtx Android

3 Answers3