Getting arguments from a bundle

问题

I'm trying to pass arguments from my Activity to a Fragment and I'm using this code:

@Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_detail);

        String message = getIntent().getStringExtra(Intent.EXTRA_TEXT);

        DetailActivityFragment fragment = new DetailActivityFragment();

        Bundle bundle = new Bundle();
        bundle.putString(INTENT_EXTRA, message);

        fragment.setArguments(bundle);
    }

I'm getting the value of the message variable through an Intent Extra and that works fine, so far.
Then I'm passing it as an argument to my fragment but then, when I call getArguments() from that specific Fragment it returns a null Bundle.
Does anybody have a solution to this?

@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        Bundle bundle = getArguments();

        if (bundle != null && bundle.containsKey(DetailActivity.INTENT_EXTRA)) {
            forecast = bundle.getString(DetailActivity.INTENT_EXTRA);
        } else if (bundle == null) {
            Toast.makeText(getActivity(), "Error", Toast.LENGTH_LONG).show();
        }

    }

The upper method displays a Toast message "Error" when I run the app...

回答1:

This is a correct approach

Send (in the Activity):

final FragmentTransaction ft = getSupportFragmentManager().beginTransaction();

final DetailActivityFragment  frg = new DetailActivityFragment ();
ft.replace(R.id.container, frg);

final Bundle bdl = new Bundle();
bdl.putString("yourKey", "Some Value");
frg.setArguments(bdl);

ft.commit();

Receive (in the Fragment):

final Bundle bdl = getArguments();

String str = "";
try
{
    str = bdl.getString("yourKey");
}
catch(final Exception e)
{
    // Do nothing
}

回答2:

The best way to use arguments with your fragment is to use the newInstance function of the fragment.Create a static method that gets your params and pass them in the fragment through the new instance function as below:

public static myFragment newInstance(String param1, String param2) {
    myFragment fragment = new myFragment ();
    Bundle args = new Bundle();
    args.putString(ARG_PARAM1, param1);
    args.putString(ARG_PARAM2, param2);
    fragment.setArguments(args);
    return fragment;
}

And then on create set your global arguments:

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    if (getArguments() != null) {
        mParam1 = getArguments().getString(ARG_PARAM1);
        mParam2 = getArguments().getString(ARG_PARAM2);
    }
}

on your main activity you will create the fragment like

myFragment __myFragment = myFragment.newInstance("test","test");

That should work

来源：https://stackoverflow.com/questions/30846973/getting-arguments-from-a-bundle

标签

android

android-intent

android-fragments