How to navigate in fragments?

Question

So I am using Tabs and seeking for this kind of navigation:

tab1 -- > inside 1 -- > inside2

tab2 -- > inside 3 -- > inside 4

tab3 -- > inside 5

inside I mean that it should open a new layout and class.

My project main class is this:

public class TabsFragmentActivity extends SherlockFragmentActivity implements
        TabHost.OnTabChangeListener {

    private TabHost mTabHost;
    private HashMap<String, TabInfo> mapTabInfo = new HashMap<String, TabInfo>();
    private TabInfo mLastTab = null;
    private static Context mContext;

    private class TabInfo {
        private String tag;
        private Class clss;
        private Bundle args;
        private Fragment fragment;

        TabInfo(String tag, Class clazz, Bundle args) {
            this.tag = tag;
            this.clss = clazz;
            this.args = args;
        }
    }

    class TabFactory implements TabContentFactory {

        private final Context mContext;

        public TabFactory(Context context) {
            mContext = context;
        }

        public View createTabContent(String tag) {
            View v = new View(mContext);
            v.setMinimumWidth(0);
            v.setMinimumHeight(0);
            return v;
        }
    }

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // Step 1: Inflate layout
        setContentView(R.layout.tabs_fragment_activity);

        mContext = this;

        // Step 2: Setup TabHost
        initialiseTabHost(savedInstanceState);

        if (savedInstanceState != null) {
            mTabHost.setCurrentTabByTag(savedInstanceState.getString("tab")); 
        }

        addNavaigationBar();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        //Add Action item with title
            menu.add("some")
            .setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM | MenuItem.SHOW_AS_ACTION_WITH_TEXT);

        return super.onCreateOptionsMenu(menu);
    }

    public void addNavaigationBar() {
        // Create Action Bar sherlock
        ActionBar navigation_bar = getSupportActionBar();

        // Setting standart navigation bar view
        navigation_bar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);

        navigation_bar.setDisplayShowTitleEnabled(true);
        navigation_bar.setTitle("Test");

        // Override Action items to navigation bar. Calls onCreateOptionsMenu
        // invalidateOptionsMenu();
    }

    protected void onSaveInstanceState(Bundle outState) {
        outState.putString("tab", mTabHost.getCurrentTabTag()); // save the tab
                                                                // selected
        super.onSaveInstanceState(outState);
    }

    /**
     * Step 2: Setup TabHost
     */
    private void initialiseTabHost(Bundle args) {
        mTabHost = (TabHost) findViewById(android.R.id.tabhost);

        mTabHost.setup();

        TabInfo tabInfo = null;

        TabsFragmentActivity.addTab(this, this.mTabHost, this.mTabHost
                .newTabSpec("Tab1").setIndicator("Tab 1"),
                (tabInfo = new TabInfo("Tab1", Tab1Fragment.class, args)));

        this.mapTabInfo.put(tabInfo.tag, tabInfo);


        TabsFragmentActivity.addTab(this, this.mTabHost, this.mTabHost
                .newTabSpec("Tab2").setIndicator("Tab 2"),
                (tabInfo = new TabInfo("Tab2", Tab2Fragment.class, args)));

        this.mapTabInfo.put(tabInfo.tag, tabInfo);

        TabsFragmentActivity.addTab(this, this.mTabHost, this.mTabHost
                .newTabSpec("Tab3").setIndicator("Tab 3"),
                (tabInfo = new TabInfo("Tab3", Tab3Fragment.class, args)));

        this.mapTabInfo.put(tabInfo.tag, tabInfo);
        // Default to first tab
        this.onTabChanged("Tab1");
        //
        mTabHost.setOnTabChangedListener(this);
    }

    private static void addTab(TabsFragmentActivity activity, TabHost tabHost,
            TabHost.TabSpec tabSpec, TabInfo tabInfo) {
        // Attach a Tab view factory to the spec
        tabSpec.setContent(activity.new TabFactory(activity));

        String tag = tabSpec.getTag();
        //getTabWidget()

        View view = prepareTabView(activity, R.id.tab_bar_icon);
        tabSpec.setIndicator(view);

        // Check to see if we already have a fragment for this tab, probably
        // from a previously saved state. If so, deactivate it, because our
        // initial state is that a tab isn't shown.
        tabInfo.fragment = activity.getSupportFragmentManager().findFragmentByTag(tag);

        if (tabInfo.fragment != null && !tabInfo.fragment.isDetached()) {

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

            ft.detach(tabInfo.fragment);

            ft.commit();

            activity.getSupportFragmentManager().executePendingTransactions();
        }
        tabHost.addTab(tabSpec);
    }

    private static View prepareTabView(Context context, int drawable){
        //inflate(R.layout.tab_indicator, android.R.id.tabs, false)
        View tabIndicator = LayoutInflater.from(context).inflate(R.layout.tab_indicator, null);
        ImageView icon = (ImageView) tabIndicator.findViewById(R.id.tab_bar_icon);
        icon.setImageResource(R.drawable.ic_launcher);
        return tabIndicator;

    }

    public void onTabChanged(String tag) {
        TabInfo newTab = this.mapTabInfo.get(tag);

        if (mLastTab != newTab) {
            FragmentTransaction ft = this.getSupportFragmentManager()
                    .beginTransaction();
            if (mLastTab != null) {
                if (mLastTab.fragment != null) {
                    ft.detach(mLastTab.fragment);
                }
            }
            if (newTab != null) {
                if (newTab.fragment == null) {
                    newTab.fragment = Fragment.instantiate(this,
                            newTab.clss.getName(), newTab.args);
                    ft.add(R.id.realtabcontent, newTab.fragment, newTab.tag);
                } else {
                    ft.attach(newTab.fragment);
                }
            }

            mLastTab = newTab;
            ft.commit();
            this.getSupportFragmentManager().executePendingTransactions();
        }
    }

}

This create 3 Tabs with there content. Here is how look Tab1 fragment class (other look similar) :

public class Tab1Fragment extends SherlockFragment {
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        if (container == null) {
            // We have different layouts, and in one of them this
            // fragment's containing frame doesn't exist.  The fragment
            // may still be created from its saved state, but there is
            // no reason to try to create its view hierarchy because it
            // won't be displayed.  Note this is not needed -- we could
            // just run the code below, where we would create and return
            // the view hierarchy; it would just never be used.
            return null;
        }
        LinearLayout theLayout = (LinearLayout)inflater.inflate(R.layout.tab_frag1_layout, container, false);
        // Register for the Button.OnClick event
        Button b = (Button)theLayout.findViewById(R.id.frag1_button);
        b.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

**//Here i want open a new window but don't change pressed tab and when press back it should go back at this window**
            }
        });
        return theLayout;
    }
}

I write on button press what I want.

I can't open a new fragment or activity inside this fragment ?

How I should do navigation inside fragments ?

Answer 1

I like to let my host Activity handle all transitions, so what I do in my fragments is create an interface to handle navigation. For example, you could add this interface to your Tab1Fragment:

public interface Callback {
    public void onButtonBClicked();
}

Then in your TabsFragmentActivity, implement Tab1Fragment.Callback, which will require you to implement onButtonBClicked(). Here's an example of how you could implement this method:

@Override
public void onButtonBClicked() {

    Fragment anotherFragment = Fragment.instantiate(this, AnotherFragment.class.getName());
    FragmentTransaction ft = getFragmentManager().beginTransaction();
    ft.add(R.id.realtabcontent, anotherFragment);
    ft.addToBackStack(null);
    ft.commit();
}

Almost done. Next, you need to do is get a reference to this callback in your fragment. This is typically achieved in the onAttached() method. For example:

@Override
public void onAttach(Activity activity) {

    super.onAttach(activity);
    try {
        mCallback = (Callback) activity;
    }
    catch (ClassCastException e) {
        throw new ClassCastException(activity.toString() + " must implement " + Callback.class.getName());
    }
}

And, finally, in your OnClickListener, call mCallback.onButtonBClicked().