TextView中的“ this”的角色textView = new TextView（this）;

Question

I am new to Android programming. I want to know that in this code what does the this in

TextView textView = new TextView(this); 

this would point to which class or method? I copied this code from here .

Answer 1

The reason you need this when creating a TextView is because one of the the constructors of TextView (the one that you're calling) takes a Context object as a parameter.

That basically means you must give TextView a Context in order to create it.

Where do you get this context from? Well, an activity is a kind of context ( Activity is a subclass of Context )! And you're creating the TextView in an activity class right? So just use this activity as the context!

Got it? Use this activity as the context for the TextView ! That's why you put this in there. this refers to the object that the code is currently running on.

Since this refers to an object created from the class, you can't use this in a static method because a the code in a static method does not run on any object.

Another use of this is in constructors:

class MyClass {
    private int a, b;

    public MyClass(int a, int b) {
        this.a = a;
        this.b = b;
    }
}

Since the compiler can't know which a or b you mean, you must add this to refer the a that's in the class.

Answer 2

this refers to the current object's instance that was invoked or initialized.

See: What does "this" mean?