Problem mit TabHost

TheMs · 18. Januar 2014

Hallo Leute ,

ich bin neu hier - und kenn mich auch noch nicht allzu gut mit Java - Android - Stuff aus...

Aaalso zu meinem Problem:
Ich habe ein Projekt mit NavigationDrawerFragment an der linken Seite und bei einem Item soll ein Fragment geöffnet werden, welches ein TabHost mit TabWidget und ViewPager enthält. Das klappt auch alles wunderbar, wenn ich allerdings dann wieder ein anderes Item aus der Navigation auswähle und wieder zurück zum TabHost wechsele, will das Ganze nicht mehr so funktionieren - die 3 Tabs werden zwar angezeigt, allerdings nicht der Inhalt des Ersten - bei Wechseln auf dritten Tab wird der Inhalt des dritten angezeigt und wenn man wieder zum ersten Tab wechselt auch dessen Inhalt. Der Inhalt des 2. Tabs wird allerdings nicht angezeigt.

Habt ihr irgendeine Idee, woran das liegen könnte?

Hier mal meine Codes:

MainActivity.java:

Java

package com.example.app;


import android.app.Activity;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.content.Context;
import android.os.Build;
import android.os.Bundle;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.support.v4.widget.DrawerLayout;
import android.widget.ArrayAdapter;
import android.widget.TextView;


public class MainActivity extends ActionBarActivity implements NavigationDrawerFragment.NavigationDrawerCallbacks {


	/**
 	* Fragment managing the behaviors, interactions and presentation of the navigation drawer.
 	*/
	private NavigationDrawerFragment mNavigationDrawerFragment;


	/**
 	* Used to store the last screen title. For use in {@link #restoreActionBar()}.
 	*/
	private CharSequence mTitle;


	@Override
	protected void onCreate(Bundle savedInstanceState) {
    	super.onCreate(savedInstanceState);
    	setContentView(R.layout.activity_main);


    	mNavigationDrawerFragment = (NavigationDrawerFragment)
            	getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);
    	mTitle = getTitle();


    	// Set up the drawer.
    	mNavigationDrawerFragment.setUp(
            	R.id.navigation_drawer,
            	(DrawerLayout) findViewById(R.id.drawer_layout));
	}


	@Override
	public void onNavigationDrawerItemSelected(int position) {
    	// update the main content by replacing fragments
    	Fragment fragment = null;


    	if(position != 2)
        	fragment = PlaceholderFragment.newInstance(position + 1);
    	else
        	fragment = new TabHostFragment();
    	FragmentManager fragmentManager = getSupportFragmentManager();
    	fragmentManager.beginTransaction()
            	.replace(R.id.container, fragment)
            	.commit();
	}


	public void onSectionAttached(int number) {
    	switch (number) {
        	case 1:
            	mTitle = getString(R.string.title_section1);
            	break;
        	case 2:
            	mTitle = getString(R.string.title_section2);
            	break;
        	case 3:
            	mTitle = getString(R.string.title_section3);
            	break;
    	}
	}


	public void restoreActionBar() {
    	ActionBar actionBar = getSupportActionBar();
    	actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
    	actionBar.setDisplayShowTitleEnabled(true);
    	actionBar.setTitle(mTitle);
	}




	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
    	if (!mNavigationDrawerFragment.isDrawerOpen()) {
        	// Only show items in the action bar relevant to this screen
        	// if the drawer is not showing. Otherwise, let the drawer
        	// decide what to show in the action bar.
        	getMenuInflater().inflate(R.menu.main, menu);
        	restoreActionBar();
        	return true;
    	}
    	return super.onCreateOptionsMenu(menu);
	}


	@Override
	public boolean onOptionsItemSelected(MenuItem item) {
    	// Handle action bar item clicks here. The action bar will
    	// automatically handle clicks on the Home/Up button, so long
    	// as you specify a parent activity in AndroidManifest.xml.
    	int id = item.getItemId();
    	if (id == R.id.action_settings) {
        	return true;
    	}
    	return super.onOptionsItemSelected(item);
	}


	/**
 	* A placeholder fragment containing a simple view.
 	*/
	public static class PlaceholderFragment extends Fragment {
    	/**
     	* The fragment argument representing the section number for this
     	* fragment.
     	*/
    	private static final String ARG_SECTION_NUMBER = "section_number";


    	/**
     	* Returns a new instance of this fragment for the given section
     	* number.
     	*/
    	public static PlaceholderFragment newInstance(int sectionNumber) {
        	PlaceholderFragment fragment = new PlaceholderFragment();
        	Bundle args = new Bundle();
        	args.putInt(ARG_SECTION_NUMBER, sectionNumber);
        	fragment.setArguments(args);
        	return fragment;
    	}


    	public PlaceholderFragment() {
    	}


    	@Override
    	public View onCreateView(LayoutInflater inflater, ViewGroup container,
            	Bundle savedInstanceState) {
        	View rootView = inflater.inflate(R.layout.fragment_main, container, false);
        	TextView textView = (TextView) rootView.findViewById(R.id.section_label);
        	textView.setText(Integer.toString(getArguments().getInt(ARG_SECTION_NUMBER)));
        	return rootView;
    	}


    	@Override
    	public void onAttach(Activity activity) {
        	super.onAttach(activity);
        	((MainActivity) activity).onSectionAttached(
                	getArguments().getInt(ARG_SECTION_NUMBER));
    	}
	}


}

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NavigationDrawerFragment.java:

Java

package com.example.app;


import android.support.v7.app.ActionBarActivity;;
import android.app.Activity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.support.v4.app.ActionBarDrawerToggle;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.content.SharedPreferences;
import android.content.res.Configuration;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;


public class NavigationDrawerFragment extends Fragment {


	/**
 	* Remember the position of the selected item.
 	*/
	private static final String STATE_SELECTED_POSITION = "selected_navigation_drawer_position";


	/**
 	* Per the design guidelines, you should show the drawer on launch until the user manually
 	* expands it. This shared preference tracks this.
 	*/
	private static final String PREF_USER_LEARNED_DRAWER = "navigation_drawer_learned";


	/**
 	* A pointer to the current callbacks instance (the Activity).
 	*/
	private NavigationDrawerCallbacks mCallbacks;


	/**
 	* Helper component that ties the action bar to the navigation drawer.
 	*/
	private ActionBarDrawerToggle mDrawerToggle;


	private DrawerLayout mDrawerLayout;
	private ListView mDrawerListView;
	private View mFragmentContainerView;


	private int mCurrentSelectedPosition = 0;
	private boolean mFromSavedInstanceState;
	private boolean mUserLearnedDrawer;


	public NavigationDrawerFragment() {
	}


	@Override
	public void onCreate(Bundle savedInstanceState) {
    	super.onCreate(savedInstanceState);


    	// Read in the flag indicating whether or not the user has demonstrated awareness of the
    	// drawer. See PREF_USER_LEARNED_DRAWER for details.
    	SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(getActivity());
    	mUserLearnedDrawer = sp.getBoolean(PREF_USER_LEARNED_DRAWER, false);


    	if (savedInstanceState != null) {
        	mCurrentSelectedPosition = savedInstanceState.getInt(STATE_SELECTED_POSITION);
        	mFromSavedInstanceState = true;
    	}


    	// Select either the default item (0) or the last selected item.
    	selectItem(mCurrentSelectedPosition);
	}


	@Override
	public void onActivityCreated (Bundle savedInstanceState) {
    	super.onActivityCreated(savedInstanceState);
    	// Indicate that this fragment would like to influence the set of actions in the action bar.
    	setHasOptionsMenu(true);
	}


	@Override
	public View onCreateView(LayoutInflater inflater, ViewGroup container,
        	Bundle savedInstanceState) {
    	mDrawerListView = (ListView) inflater.inflate(
            	R.layout.fragment_navigation_drawer, container, false);
    	mDrawerListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        	@Override
        	public void onItemClick(AdapterView&lt;?&gt; parent, View view, int position, long id) {
            	selectItem(position);
        	}
    	});
    	mDrawerListView.setAdapter(new ArrayAdapter&lt;String&gt;(
            	getActionBar().getThemedContext(),
            	android.R.layout.simple_list_item_activated_1,
            	android.R.id.text1,
            	new String[]{
                    	getString(R.string.title_section1),
                    	getString(R.string.title_section2),
                    	getString(R.string.title_section3),
            	}));
    	mDrawerListView.setItemChecked(mCurrentSelectedPosition, true);
    	return mDrawerListView;
	}


	public boolean isDrawerOpen() {
    	return mDrawerLayout != null && mDrawerLayout.isDrawerOpen(mFragmentContainerView);
	}


	/**
 	* Users of this fragment must call this method to set up the navigation drawer interactions.
 	*
 	* @param fragmentId   The android:id of this fragment in its activity's layout.
 	* @param drawerLayout The DrawerLayout containing this fragment's UI.
 	*/
	public void setUp(int fragmentId, DrawerLayout drawerLayout) {
    	mFragmentContainerView = getActivity().findViewById(fragmentId);
    	mDrawerLayout = drawerLayout;


    	// set a custom shadow that overlays the main content when the drawer opens
    	mDrawerLayout.setDrawerShadow(R.drawable.drawer_shadow, GravityCompat.START);
    	// set up the drawer's list view with items and click listener


    	ActionBar actionBar = getActionBar();
    	actionBar.setDisplayHomeAsUpEnabled(true);
    	actionBar.setHomeButtonEnabled(true);


    	// ActionBarDrawerToggle ties together the the proper interactions
    	// between the navigation drawer and the action bar app icon.
    	mDrawerToggle = new ActionBarDrawerToggle(
            	getActivity(),                	/* host Activity */
            	mDrawerLayout,                	/* DrawerLayout object */
            	R.drawable.ic_drawer,         	/* nav drawer image to replace 'Up' caret */
            	R.string.navigation_drawer_open,  /* "open drawer" description for accessibility */
            	R.string.navigation_drawer_close  /* "close drawer" description for accessibility */
    	) {
        	@Override
        	public void onDrawerClosed(View drawerView) {
            	super.onDrawerClosed(drawerView);
            	if (!isAdded()) {
                	return;
            	}


            	getActivity().supportInvalidateOptionsMenu(); // calls onPrepareOptionsMenu()
        	}


        	@Override
        	public void onDrawerOpened(View drawerView) {
            	super.onDrawerOpened(drawerView);
            	if (!isAdded()) {
                	return;
            	}


            	if (!mUserLearnedDrawer) {
                	// The user manually opened the drawer; store this flag to prevent auto-showing
                	// the navigation drawer automatically in the future.
                	mUserLearnedDrawer = true;
                	SharedPreferences sp = PreferenceManager
                        	.getDefaultSharedPreferences(getActivity());
                	sp.edit().putBoolean(PREF_USER_LEARNED_DRAWER, true).apply();
            	}


            	getActivity().supportInvalidateOptionsMenu(); // calls onPrepareOptionsMenu()
        	}
    	};


    	// If the user hasn't 'learned' about the drawer, open it to introduce them to the drawer,
    	// per the navigation drawer design guidelines.
    	if (!mUserLearnedDrawer && !mFromSavedInstanceState) {
        	mDrawerLayout.openDrawer(mFragmentContainerView);
    	}


    	// Defer code dependent on restoration of previous instance state.
    	mDrawerLayout.post(new Runnable() {
        	@Override
        	public void run() {
            	mDrawerToggle.syncState();
        	}
    	});


    	mDrawerLayout.setDrawerListener(mDrawerToggle);
	}


	private void selectItem(int position) {
    	mCurrentSelectedPosition = position;
    	if (mDrawerListView != null) {
        	mDrawerListView.setItemChecked(position, true);
    	}
    	if (mDrawerLayout != null) {
        	mDrawerLayout.closeDrawer(mFragmentContainerView);
    	}
    	if (mCallbacks != null) {
        	mCallbacks.onNavigationDrawerItemSelected(position);
    	}
	}


	@Override
	public void onAttach(Activity activity) {
    	super.onAttach(activity);
    	try {
        	mCallbacks = (NavigationDrawerCallbacks) activity;
    	} catch (ClassCastException e) {
        	throw new ClassCastException("Activity must implement NavigationDrawerCallbacks.");
    	}
	}


	@Override
	public void onDetach() {
    	super.onDetach();
    	mCallbacks = null;
	}


	@Override
	public void onSaveInstanceState(Bundle outState) {
    	super.onSaveInstanceState(outState);
    	outState.putInt(STATE_SELECTED_POSITION, mCurrentSelectedPosition);
	}


	@Override
	public void onConfigurationChanged(Configuration newConfig) {
    	super.onConfigurationChanged(newConfig);
    	// Forward the new configuration the drawer toggle component.
    	mDrawerToggle.onConfigurationChanged(newConfig);
	}


	@Override
	public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
    	// If the drawer is open, show the global app actions in the action bar. See also
    	// showGlobalContextActionBar, which controls the top-left area of the action bar.
    	if (mDrawerLayout != null && isDrawerOpen()) {
        	inflater.inflate(R.menu.global, menu);
        	showGlobalContextActionBar();
    	}
    	super.onCreateOptionsMenu(menu, inflater);
	}


	@Override
	public boolean onOptionsItemSelected(MenuItem item) {
    	if (mDrawerToggle.onOptionsItemSelected(item)) {
        	return true;
    	}


    	if (item.getItemId() == R.id.action_example) {
        	Toast.makeText(getActivity(), "Example action.", Toast.LENGTH_SHORT).show();
        	return true;
    	}


    	return super.onOptionsItemSelected(item);
	}


	/**
 	* Per the navigation drawer design guidelines, updates the action bar to show the global app
 	* 'context', rather than just what's in the current screen.
 	*/
	private void showGlobalContextActionBar() {
    	ActionBar actionBar = getActionBar();
    	actionBar.setDisplayShowTitleEnabled(true);
    	actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
    	actionBar.setTitle(R.string.app_name);
	}


	private ActionBar getActionBar() {
    	return ((ActionBarActivity) getActivity()).getSupportActionBar();
	}


	/**
 	* Callbacks interface that all activities using this fragment must implement.
 	*/
	public static interface NavigationDrawerCallbacks {
    	/**
     	* Called when an item in the navigation drawer is selected.
     	*/
    	void onNavigationDrawerItemSelected(int position);
	}
}

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TabHostFragment.java

Java

package com.example.app;


import android.support.v4.app.Fragment;
import android.os.Bundle;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TabHost;


import java.util.ArrayList;
import java.util.List;


/**
 * Created by Michael on 17.01.14.
 */
public class TabHostFragment extends Fragment implements TabHost.OnTabChangeListener, ViewPager.OnPageChangeListener {


	MyPageAdapter pageAdapter;
	private ViewPager mViewPager;
	private TabHost mTabHost;


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


    	mViewPager = (ViewPager) view.findViewById(R.id.viewpager);


    	// Tab Initialization
    	initialiseTabHost(view);


    	// Fragments and ViewPager Initialization
    	List&lt;Fragment&gt; fragments = getFragments();
    	pageAdapter = new MyPageAdapter(getActivity().getSupportFragmentManager(), fragments);
    	mViewPager.setAdapter(pageAdapter);
    	mViewPager.setOnPageChangeListener(this);


    	return view;
	}


	@Override
	public void onDestroy() {
    	super.onDestroy();
	}


	// Method to add a TabHost
	private static void AddTab(MainActivity activity, TabHost tabHost, TabHost.TabSpec tabSpec) {
    	tabSpec.setContent(new MyTabFactory(activity));
    	tabHost.addTab(tabSpec);
	}


	// Manages the Tab changes, synchronizing it with Pages
	public void onTabChanged(String tag) {
    	int pos = this.mTabHost.getCurrentTab();
    	this.mViewPager.setCurrentItem(pos);
	}


	@Override
	public void onPageScrollStateChanged(int arg0) {
	}


	// Manages the Page changes, synchronizing it with Tabs
	@Override
	public void onPageScrolled(int arg0, float arg1, int arg2) {
    	int pos = this.mViewPager.getCurrentItem();
    	this.mTabHost.setCurrentTab(pos);
	}


	@Override
	public void onPageSelected(int arg0) {
	}


	private List&lt;Fragment&gt; getFragments(){
    	List&lt;Fragment&gt; fList = new ArrayList&lt;Fragment&gt;();


    	Fragment f1 = MainActivity.PlaceholderFragment.newInstance(0);
    	Fragment f2 = MainActivity.PlaceholderFragment.newInstance(1);
    	Fragment f3 = MainActivity.PlaceholderFragment.newInstance(2);
    	fList.add(f1);
    	fList.add(f2);
    	fList.add(f3);


    	return fList;
	}


	// Tabs Creation
	private void initialiseTabHost(View view) {
    	mTabHost = (TabHost) view.findViewById(android.R.id.tabhost);
    	mTabHost.setup();


    	// TODO Put here your Tabs
    	AddTab((MainActivity) getActivity(), mTabHost, mTabHost.newTabSpec("Tab1").setIndicator("Tab1"));
    	AddTab((MainActivity) getActivity(), mTabHost, mTabHost.newTabSpec("Tab2").setIndicator("Tab2"));
    	AddTab((MainActivity) getActivity(), mTabHost, mTabHost.newTabSpec("Tab3").setIndicator("Tab3"));


    	mTabHost.setOnTabChangedListener(this);
	}
}

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MyTabFactory.java:

Java

package com.example.app;


/**
 * Created by Michael on 17.01.14.
 */
import android.content.Context;
import android.view.View;
import android.widget.TabHost.TabContentFactory;


public class MyTabFactory implements TabContentFactory {


	private final Context mContext;


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


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

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MyPageAdapter.java:

Java

package com.example.app;


/**
 * Created by Michael on 17.01.14.
 */


import java.util.List;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;


public class MyPageAdapter extends FragmentPagerAdapter {
	private List&lt;Fragment&gt; fragments;


	public MyPageAdapter(FragmentManager fm, List&lt;Fragment&gt; fragments) {
    	super(fm);
    	this.fragments = fragments;
	}


	@Override
	public Fragment getItem(int position) {
    	return this.fragments.get(position);
	}


	@Override
	public int getCount() {
    	return this.fragments.size();
	}
}

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fragment_tabhost.xml:

HTML

&lt;LinearLayout xmlns:android="SPAMSCHUTZ://schemas.android.com/apk/res/android"
	xmlns:tools="SPAMSCHUTZ://schemas.android.com/tools"
	android:layout_width="match_parent"
	android:layout_height="match_parent"
	tools:context=".MainActivity" &gt;


	&lt;TabHost
    	android:id="@android:id/tabhost"
    	android:layout_width="fill_parent"
    	android:layout_height="wrap_content" &gt;


    	&lt;LinearLayout
        	android:layout_width="fill_parent"
        	android:layout_height="wrap_content"
        	android:orientation="vertical" &gt;


        	&lt;TabWidget
            	android:id="@android:id/tabs"
            	android:orientation="horizontal"
            	android:layout_width="fill_parent"
            	android:layout_height="wrap_content"
            	android:layout_weight="0" /&gt;


        	&lt;FrameLayout
            	android:id="@android:id/tabcontent"
            	android:layout_width="0dp"
            	android:layout_height="0dp"
            	android:layout_weight="0" /&gt;


        	&lt;android.support.v4.view.ViewPager
            	android:id="@+id/viewpager"
            	android:layout_width="fill_parent"
            	android:layout_height="wrap_content"
            	android:layout_gravity="bottom" /&gt;


    	&lt;/LinearLayout&gt;
	&lt;/TabHost&gt;


&lt;/LinearLayout&gt;

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fragment_navigation_drawer.xml, fragment_main.xml und activity_main sind "naturbelassen".

Vielen, vielen Dank für Hilfe!!

Problem mit TabHost

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