actionBar.setHomeButtonEnabled给出片段中的错误，因为空指针异常 [英] actionBar.setHomeButtonEnabled gives error in fragment as null pointer exception

问题描述

我正在尝试在片段中创建可滑动选项卡.因此在viewpager中添加选项卡，但这给了我错误 当actionBar.setHomeButtonEnabled(false)作为null指针异常无法进行instastaite活动时.我试图解决过去两天的问题，但无法解决.请帮助我解决它.请找到我的Fragment类.

I am trying to create swipeable tabs in fragment.So add tab in viewpager.But it gives me error when actionBar.setHomeButtonEnabled(false) as null pointer exception unable instastaite activity.I am try to resolved issue from past two days but unable do it.Please help me resolved it.please find my Fragment class.

公共类HomeFragment扩展了Fragment的实现 ActionBar.TabListener {

public class HomeFragment extends Fragment implements ActionBar.TabListener{

View FaramentView;
private FragmentActivity context;

private ViewPager viewPager;
private TabsPagerAdapter mAdapter;
private ActionBar actionBar;
// Tab titles
private String[] tabs = { "Top Rated", "Games", "Movies" };


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
    FaramentView = inflater.inflate(R.layout.home_fragment, null, false); 

    return FaramentView;

}

@Override public void onAttach(Activity activity) {

    context = (FragmentActivity) activity;


    super.onAttach(activity);
}

@TargetApi(Build.VERSION_CODES.HONEYCOMB) @Override
public void onActivityCreated(Bundle savedInstanceState) 
{

    super.onActivityCreated(savedInstanceState);
    // Initilization
            viewPager = (ViewPager) FaramentView.findViewById(R.id.pager);
             actionBar = context.getActionBar();

            mAdapter = new TabsPagerAdapter(context.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));
            }

            /**
             * on swiping the viewpager make respective tab selected
             * */
            viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {

                @Override
                public void onPageSelected(int position) {
                    // on changing the page
                    // make respected tab selected
                    actionBar.setSelectedNavigationItem(position);
                }

                @Override
                public void onPageScrolled(int arg0, float arg1, int arg2) {
                }

                @Override
                public void onPageScrollStateChanged(int arg0) {
                }
            });
}

public LayoutInflater getSystemService(String layoutInflaterService) {
    // TODO Auto-generated method stub
    return null;
}

@Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
    // TODO Auto-generated method stub

}

@Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
    // TODO Auto-generated method stub

}

@Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
    // TODO Auto-generated method stub

}  

}

推荐答案

在活动下的Android清单文件中添加

In your Android manifest file under activity add

android:theme="@android:style/Theme.Holo"

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