按下后退按鈕時重啟片段類

Question

我有一個片段是標簽視圖的一部分。 當我按下后退按鈕時，我想重新啟動此片段。 但我不知道如何更新它。 我嘗試了這樣的代碼： 在活動中重新啟動片段，但它不起作用。

這是一個檢測后退按鈕的代碼：

    @Override
public void onResume() {

    super.onResume();

    getView().setFocusableInTouchMode(true);
    getView().requestFocus();
    getView().setOnKeyListener(new View.OnKeyListener() {
        @Override
        public boolean onKey(View v, int keyCode, KeyEvent event) {

            if (event.getAction() == KeyEvent.ACTION_UP && keyCode == KeyEvent.KEYCODE_BACK){

                // handle back button




                return true;

            }

            return false;
        }
    });
}

這是一個片段類按鈕：

public class MoviesFragment extends Fragment {

  static ListView list;


static String[] numbers_text = new String[] { "one", "two", "three", "four",
        "five", "six", "seven", "eight", "nine", "ten", "eleven",
        "twelve", "thirteen", "fourteen", "fifteen" };
String[] songs = new String[] { "1", "2", "3", "4", "5", "6", "7",
        "8", "9", "10", "11", "12", "13", "14", "15" };



MainCustomList adapter;




@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {



    View view = inflater.inflate(R.layout.fragment_movies, container, false);

    adapter = new MainCustomList(this.getActivity(), numbers_text);
         list=(ListView) view.findViewById(R.id.list);
         list.setAdapter(adapter);


         return view;
}

主要：

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));
    }

    /**
     * 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) {
        }
    });
}

@Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
}

@Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
    // on tab selected
    // show respected fragment view
    viewPager.setCurrentItem(tab.getPosition());
}

@Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
}

 }

Answer 1

使用此代碼：

YourFragmentClass fragment = (YourFragmentClass) 
getFragmentManager().findFragmentById(R.id.your_fragment_container_id)

getFragmentManager().beginTransaction()
                    .detach(fragment)
                    .attach(fragment)
                    .commit();

這將導致您的fragment的OnCreateView方法再次被調用並刷新其布局。

更新：

使用Support Library ，您可以通過以下方式訪問您的片段：

int YOUR_FRAGMENT_POSITION = 2; // in your case you wanna access the 3rd fragment, 0 indexed

YourFragmentClass fragment = (YourFragmentClass) getSupportFragmentManager().getFragments().get(YOUR_FRAGMENT_POSITION);

並使用上面相同的代碼段：

getSupportFragmentManager().beginTransaction()
                        .detach(fragment)
                        .attach(fragment)
                        .commit();

如果您嘗試通過PagerAdapter訪問您的fragment ，您最終可能會遇到IllegalStateException ，告訴您該片段未能保存其state 。