Why I have to pass Bundle to Fragment in Android

Question

We usually use below style when we pass parameter to the fragment

public static MyFragment newInstance() {
    MyFragment fragment = new MyFragment();
    String myVariable = "My variable string";
    Bundle bundle = new Bundle();
    bundle.putString("myVariable", myVariable);
    fragment.setArguments(bundle);
    return fragment;
}

What happens when we use getter setter method:

private String myVariable;
public String getMyVariable() {
    return myVariable;
}
public void setMyVariable(String myVariable) {
    this.myVariable = myVariable;
}
public static MyFragment newInstance() {
    MyFragment fragment = new MyFragment();
    String passVariable = "My variable string";
    fragment.setMyVariable(passVariable);
    return fragment;
}


public void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    String passVariable = getMyVariable();

}

When I test with the second way, there is no problem occurs. So why we have to use the first way?

I also saw the post "Why use bundle to pass data to fragment?". They said "it's easier for the system to restore its values when the fragment is re-instantiated" But I tested in case the fragment is popped from stack, the variable is still remained.

Take a look at [this](http://stackoverflow.com/q/37765613/6950238) question, — Andrii Omelchenko, Oct 31 '16 at 12:32

score 2 · Accepted Answer · answered Oct 31 '16 at 12:29

2

If the framework needs to recreate your fragment, the data you have set with your second setter method is lost.

Argument bundles persist to recreated fragments.

answered Oct 31 '16 at 12:29

laalto

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Does the variable always loses or it will be loss sometimes? I tested in case the fragment is popped from stack, the variable is still remained. – hoc nguyen Oct 31 '16 at 13:00
It is lost when the fragment is recreated. One common source for recreation is device orientation changes. – laalto Oct 31 '16 at 13:32
Oh Thank you. I missed this case – hoc nguyen Oct 31 '16 at 15:49

Why I have to pass Bundle to Fragment in Android

1 Answers1