将数据从一个滑动标签传递到另一个Null值

Question

我尝试将参数传递给视图页中的另一个选项卡。但价值不传递。我在onTabSelected()函数中编写了代码。但是，只出现空值。请帮帮我。遵循我的代码。

MainActivity

public class MainActivity extends FragmentActivity implements
        ActionBar.TabListener  {
    private ViewPager viewPager;
    private TabsPagerAdapter mAdapter;
    private ActionBar actionBar;
    // Tab titles
    private String[] tabs = { "Top Rated", "Games", "Movies" };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        // Initilization
        viewPager = (ViewPager) findViewById(R.id.pager);
        actionBar = getActionBar();
        mAdapter = new TabsPagerAdapter(getSupportFragmentManager());
        viewPager.setAdapter(mAdapter);
        //actionBar.setHomeButtonEnabled(false);
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
        // Adding Tabs
        for (String tab_name : tabs) {
        actionBar.addTab(actionBar.newTab().setText(tab_name)
                    .setTabListener(this));
        }  

    }
    @Override
    public void onTabReselected(Tab tab, FragmentTransaction ft) {
    }
    @Override
    public void onTabSelected(Tab tab, FragmentTransaction ft) {
        // on tab selected
        // show respected fragment view
        Bundle bundle=new Bundle();
        bundle.putString("name", "From Activity");
        //set Fragmentclass Arguments
        MoviesFragment fragobj=new MoviesFragment();
        fragobj.setArguments(bundle);
        viewPager.setCurrentItem(tab.getPosition());
    }
    @Override
    public void onTabUnselected(Tab tab, FragmentTransaction ft) {
    }
}

MoviesFragments

public class MoviesFragment extends Fragment {
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        String strtext=getArguments().getString("name"); // ERROR in NULLPointerExecption
        View rootView = inflater.inflate(R.layout.fragment_movies, container, false);
        TextView text=(TextView) rootView.findViewById(R.id.text1);
        text.setText("Movie");
        return rootView;
    }
}

我尝试这个代码，但strtext错误发生在NullPointerException

Answer 1

你需要这样做:

 @Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction ft) {
    // on tab selected
    // show respected fragment view
    //set Fragmentclass Arguments
    MoviesFragment preInitializedFragment = (MoviesFragment) getSupportFragmentManager().findFragmentByTag(MoviesFragment.class.getName());
    if (preInitializedFragment == null) {
        Bundle bundle=new Bundle();
        bundle.putString("name", "From Activity");
        MoviesFragment mFragment=new MoviesFragment();
        mFragment.setArguments(bundle);
        ft.add(android.R.id.content, mFragment, MoviesFragment.class.getName());
    } else {
        ft.attach(preInitializedFragment);
    }
}