在使用具有不同片段/布局的视图寻呼机时如何传递片段参数？

Question

Objective : To use fragment arguments to pass along the string value from a TextView to a new fragments TextView , BUT while using a ViewPager with different layouts/fragments in the FragmentPagerAdapter .

Problem : The new fragment never receives the fragments arguments from the previous fragment.

My Set up : I have my Activity hosting the ViewPager and FragmentPagerAdapter . I have overridden FragmentPagerAdapters getItem(int position) method to create a new fragment instance depending on the current position of the ViewPager . Right now I only have two Fragments in my adapter, but will be adding more after getting over this obstacle. I am using the newInstance() technique to pass along the Fragment 's arguments, but nothing is ever passed.

Pertinent Code :

My FragmentPagerAdapter code:

//this is a variable that I pass in as the newInstanct() methods parameter,
// I update   this variable from my fragments constantly
public static String fragmentArgumentsValue = "";

mViewPager.setAdapter(new FragmentPagerAdapter(fm) {


            @Override
            public int getCount() {

                return NUMBER_OF_VIEWS;
            }

            @Override
            public Fragment getItem(int position) {
                switch (position) {
                case 0:
                    Log.d(TAG, "---In getPosition(), position 0---");

                    return Frag1
                            .newInstance(fragmentArgumentsValue);

                case 1:
                    Log.d(TAG, "---In getPosition(), position 1---");

                    return frag2
                            .newInstance(fragmentArgumentsValue);

                default:
                    Log.d(TAG, "---In getPosition(), DEFAULT---");

                    return frag1
                            .newInstance(fragmentArgumentsValue);
                }

            }
        });

One of the fragments newInstance() method:

public static Fragment newInstance(String fragmentArgumentsValue) {
    Frag1 f = new Frag1();
    Bundle bun = new Bundle();
    bun.putString(KEY_FRAGMENT_ARGUMENTS_STRING, fragmentArgumentsValue);
    f.setArguments(bun);
    return f;
}

Getting the fragments arguments:

String argString = getArguments().getString(
        KEY_FRAGMENT_ARGUMENTS_STRING);
if (argString.length() != 0) {
    Log.d(TAG, "Trying to set the frag args to:" + argString);
    mWorkingTextView.setText("" + argString);
} else {
    Log.d(TAG, "Couldn't set frag args to: " + argString);
}

What I've Tried : I've tried giving the Activity that hosts the ViewPager and FragmentPagerAdapter a static variable that I constantly update in each one of my fragments , I include the static variable in the fragment.newInstance(staticVariableInActivity) method, but this doesn't seem to work. I've also tried using the ViewPager callback viewPager.setOnPageChangeListener() I had overridden the onPageSelected(int pos) and tried to pass the fragment arguments there, nevertheless it didn't work... so please help me SO!!!

My thoughts : I do not have the different fragments and layouts in an ArrayList or any list for that matter, I just instantiate the Fragments via the newInstance() method depending on the positions of the FragementPagerAdapter , could this be a problem? Should I create a singleton list of the layouts/fragments ? So I can change the values of the Fragments TextViews via the singleton list? (excuse me if that's a dumb or not possible thing to do).

Note : I am am saving away the TextViews values via public void onSaveInstanceState(Bundle outState) to handle screen rotations. Could this be a problem?

Answer 1

Alright so I this link will help in the communication between fragments: Communication with other Fragments .

You need to define a interface that the Activity will implement and the fragments will use to send data onward to the activity, and the activity will then find the fragment by tag doing something like this:

frag = (Fragment2) getSupportFragmentManager()
                    .findFragmentByTag(
                            "android:switcher:" + R.id.viewPager + ":2");

and then update the fragment by calling a public method implemented within the fragment.

The link provided will help greatly, it is from the Android Development website.

Answer 2

Adds the bundle inside your Adapter.

example in the constructor of the adapter :

      public ViewPagerAdapter(Context context, FragmentManager fm) {
        super(fm);
        fragments.add(TileFragments.newInstance());
        Bundle bundleFeatures = new Bundle();
        bundleFeatures.putString(ContentName.FEATURES.toString(),ContentName.FEATURES.toString());

        fragments.get(0).setArguments(bundleFeatures);

    }