Question

I’m using fragments and have created a tabhost with 3 tabs and placed a button in the first tab. My question is can I change to the second tab from the button I created? Here’s my code:

 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;
        }

    }

    /**
     * 
     * @author mwho
     * 
     */
    class TabFactory implements TabContentFactory {

        private final Context mContext;

        /**
         * @param context
         */
        public TabFactory(Context context) {
            mContext = context;
        }

        /**
         * (non-Javadoc)
         * 
         * @see android.widget.TabHost.TabContentFactory#createTabContent(java.lang.String)
         */
        public View createTabContent(String tag) {
            View v = new View(mContext);
            v.setMinimumWidth(0);
            v.setMinimumHeight(0);
            return v;
        }

    }

    /**
     * (non-Javadoc)
     * 
     * @see android.support.v4.app.FragmentActivity#onCreate(android.os.Bundle)
     */
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.tabs_layout);
        initialiseTabHost(savedInstanceState);
        if (savedInstanceState != null) {
            mTabHost.setCurrentTabByTag(savedInstanceState.getString("tab")); // set
                                                                                // the
                                                                                // tab
                                                                                // as
                                                                                // per
                                                                                // the
                                                                                // saved
                                                                                // state
        }
    }

    /**
     * (non-Javadoc)
     * 
     * @see android.support.v4.app.FragmentActivity#onSaveInstanceState(android.os.Bundle)
     */
    protected void onSaveInstanceState(Bundle outState) {
        outState.putString("tab", mTabHost.getCurrentTabTag()); // save the tab
                                                                // selected
        super.onSaveInstanceState(outState);
    }

    /**
     * Initialise the Tab Host
     */
    private void initialiseTabHost(Bundle args) {
        mTabHost = (TabHost) findViewById(android.R.id.tabhost);
        mTabHost.setup();
        TabInfo tabInfo = null;
        ElastoTabsActivity.addTab(this, this.mTabHost, this.mTabHost
                .newTabSpec("Tab1").setIndicator("Home"),
                (tabInfo = new TabInfo("Tab1", HomeTab.class, args)));
        this.mapTabInfo.put(tabInfo.tag, tabInfo);
        ElastoTabsActivity.addTab(this, this.mTabHost, this.mTabHost
                .newTabSpec("Tab2").setIndicator("Taping Prep"),
                (tabInfo = new TabInfo("Tab2", Tab2Fragment.class, args)));
        this.mapTabInfo.put(tabInfo.tag, tabInfo);
        ElastoTabsActivity.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);
    }

    /**
     * @param activity
     * @param tabHost
     * @param tabSpec
     * @param clss
     * @param args
     */
    private static void addTab(ElastoTabsActivity 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();

        // 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);
    }

    /**
     * (non-Javadoc)
     * 
     * @see android.widget.TabHost.OnTabChangeListener#onTabChanged(java.lang.String)
     */
    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();
        }
    }

Thanks!

Answer 1

Did you have a chance to read the TabHost documentary before writing your code? Because you are already using a function in your code to change the tabs.

The only thing you have to do is to implement it inside your button’s onClick listener. If you don’t know how to handle button clicks, there is a vast of examples on the web.