My application is working fine when I use getChildFragmentManager() but unfortunately, it will only work with API 17 and above. Now when I switch it over to getFragmentManager(), everything works fine except for one thing. Whenever I load my tablayout in horizontal view, both pages are empty and swiping is sluggish. Vertically it is fine and they won't be empty if I first load them vertically and then switch to horizontally, because I'm using a saved instance. I have no idea what is causing this. All I know is that as soon as I switch the code above around, it happens. Let me know what is required to find the issue and I will gladly post it. I am using the support-v13 library's FragmentPagerAdapter. I am doing this so I don't have to use support-v4's way of creating fragments. I do import the ViewPager from v4 in my tablayout fragment.
Edit:
Okay when the tablayout is created for the first time, it works fine. When called again it will be blank and sluggish. It had nothing to do with orientation.
Edit:
Tablayout code Keep in mind that this code is functional. But when I change getChildFragmentManager() to getFragmentManager() it gets sluggish and only works on first oncreate:
import android.app.Fragment;
import android.app.FragmentManager;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.design.widget.TabLayout;
import android.support.v13.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class TabFragment extends Fragment {
public static TabLayout tabLayout;
public static ViewPager viewPager;
public static int int_items = 2;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View x = inflater.inflate(R.layout.tab_layout, null);
tabLayout = (TabLayout) x.findViewById(R.id.tabs);
viewPager = (ViewPager) x.findViewById(R.id.viewpager);
viewPager.setAdapter(new MyAdapter(getChildFragmentManager()));
tabLayout.post(new Runnable() {
#Override
public void run() {
tabLayout.setupWithViewPager(viewPager);
}
});
return x;
}
class MyAdapter extends FragmentPagerAdapter {
public MyAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
return new FragmentOne();
case 1:
return new FragmentTwo();
}
return null;
}
#Override
public int getCount() {
return int_items;
}
#Override
public CharSequence getPageTitle(int position) {
switch (position) {
case 0:
return "TAB1";
case 1:
return "TAB2";
}
return null;
}
}
}
Related
I tried to create a ViewPager in Android Studio.
I get the error:
PagerAdapter() cannot be applied to android.app FragmentManager
at the line super(fm);
Here is my code for the adapter. Do I need to change anything?
package com.example.admin.usthweather;
import android.app.Fragment;
import android.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.app.FragmentStatePagerAdapter;
import android.support.v4.view.PagerAdapter;
import android.view.View;
/**
* Created by Admin on 11/15/2017.
*/
public class HomeFragmentAdapter extends PagerAdapter {
private final int PAGE_COUNT = 3;
private String titles[] = new String[] {"Hanoi","Paris", "Saigon"};
public HomeFragmentAdapter(FragmentManager fm){
super(fm);
}
#Override
public int getCount() {
return PAGE_COUNT;
}
// Override
public Fragment getItem(int page) {
// returns an instance of Fragment corresponding to the specified page
Fragment frag=null;
switch (page){
case 0:
frag=new Hanoi();
break;
case 1:
frag=new Paris();
break;
case 2:
frag=new Saigon();
break;
}
return frag;
}
#Override
public boolean isViewFromObject(View view, Object object) {
return false;
}
}
There is no constructor in PagerAdapter with FragmentManager as parameter. You're code is similar for FragmentPagerAdapter or FragmentStatePagerAdapter so you can use one of them. It will be something like this:
public class HomeFragmentAdapter extends FragmentStatePagerAdapter {
private final int PAGE_COUNT = 3;
private String titles[] = new String[] {"Hanoi","Paris", "Saigon"};
public HomeFragmentAdapter(FragmentManager fm){
super(fm);
}
#Override
public int getCount() {
return PAGE_COUNT;
}
#Override
public Fragment getItem(int page) {
Fragment frag=null;
switch (page){
case 0:
frag=new Hanoi();
break;
case 1:
frag=new Paris();
break;
case 2:
frag=new Saigon();
break;
}
return frag;
}
}
Please remember to use the correct import file for Fragment and FragmentManager from Support library:
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
fm in super(fm); is wrong. Therefore none of this is necessary:
public HomeFragmentAdapter(FragmentManager fm){
super(fm);
}
However, I suspect that you did not want to subclass PagerAdapter, but either or FragmentStatePagerAdapter. As the docs say:
Base class providing the adapter to populate pages inside of a ViewPager. You will most likely want to use a more specific implementation of this, such as FragmentPagerAdapter or FragmentStatePagerAdapter.
Instead of providing a View recycling mechanism directly ViewPager uses callbacks to indicate the steps taken during an update.
I am not sure how to ask this. I tried in here, but I guess I was not clear enough. So, I thought I just write a small App to describe the situation. Please note, the App uses Googles SlidingTabLayout.
Long story short, at any point if I click Button1, the FrameLayout should contain Fragment1, removing Fragment2 (if exists). Therefore, FragmentViewPager should also be destroyed as Fragment2. However, even then if I change the orientation of my device, I get the Toast which is defined in the onCreate() method of FragmentViewPager.
Why FragmentViewPager's onCreate is called even if Fragment2 is paused/destroyed? Is it possible that, the Toast of FragmentViewPager will not be shown when Fragment2 is destroyed?
MainActivity:
package com.abdfahim.testproject;
import android.app.Fragment;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button button1 = (Button) findViewById(R.id.button1);
button1.setOnClickListener(onClickListener);
Button button2 = (Button) findViewById(R.id.button2);
button2.setOnClickListener(onClickListener);
}
private View.OnClickListener onClickListener = new View.OnClickListener() {
#Override
public void onClick(View v) {
Fragment fragment;
switch (v.getId()){
case R.id.button1:
fragment = new Fragment1();
break;
case R.id.button2:
fragment = new Fragment2();
break;
default:
return;
}
getFragmentManager().beginTransaction().replace(R.id.frame_container, fragment, v.getTag().toString()).addToBackStack(null).commit();
}
};
}
Fragment1
package com.abdfahim.testproject;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class Fragment1 extends Fragment {
public Fragment1(){}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment1,container,false);
setHasOptionsMenu(true);
return rootView;
}
}
Fragment2
package com.abdfahim.testproject;
import android.app.Fragment;
import android.app.FragmentManager;
import android.os.Bundle;
import android.support.v13.app.FragmentStatePagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class Fragment2 extends Fragment {
public Fragment2(){}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment2,container,false);
setHasOptionsMenu(true);
CharSequence titles[]= {"Tab A", "Tab B"};
// Creating The ViewPagerAdapter
ViewPagerAdapter adapter = new ViewPagerAdapter(getActivity().getFragmentManager(), titles, titles.length);
ViewPager pager = (ViewPager) rootView.findViewById(R.id.pager);
pager.setAdapter(adapter);
// Assigning the Sliding Tab Layout View
SlidingTabLayout tabs = (SlidingTabLayout) rootView.findViewById(R.id.tabs);
// Setting the ViewPager For the SlidingTabsLayout
tabs.setViewPager(pager);
return rootView;
}
static class ViewPagerAdapter extends FragmentStatePagerAdapter {
private CharSequence titles[];
private int numbOfTabs;
public ViewPagerAdapter(FragmentManager fm, CharSequence mTitles[], int mNumbOfTabs) {
super(fm);
this.titles = mTitles;
this.numbOfTabs = mNumbOfTabs;
}
#Override
public int getItemPosition(Object object) {
return POSITION_NONE;
}
#Override
public Fragment getItem(int position) {
Bundle bundle = new Bundle();
bundle.putString("displayText", "Inside Fragment 2, " + titles[position]);
FragmentViewPager fragment = new FragmentViewPager();
fragment.setArguments(bundle);
return fragment;
}
// This method return the titles for the Tabs in the Tab Strip
#Override
public CharSequence getPageTitle(int position) {
return titles[position];
}
// This method return the Number of tabs for the tabs Strip
#Override
public int getCount() {
return numbOfTabs;
}
}
}
FragmentViewPager
package com.abdfahim.testproject;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import android.widget.Toast;
public class FragmentViewPager extends Fragment {
public FragmentViewPager(){}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_view_pager,container,false);
setHasOptionsMenu(true);
Bundle bundle = this.getArguments();
TextView textView = (TextView) rootView.findViewById(R.id.tabText);
textView.setText(bundle.getString("displayText"));
return rootView;
}
#Override
public void onStart() {
super.onStart();
Toast.makeText(getActivity(), "This is View Pager Fragment", Toast.LENGTH_SHORT).show();
}
}
when you use fragment inside another fragment. you use getChildFragmentManager() instead of getFragmentManager. You can call setAdapter() for the ViewPager from onCreateView() or onActivityCreated()
for more detail. have a look at it
Why it is not possible to use ViewPager within a Fragment? It actually is
For every click your OnClickListener creates the instance of Fragment2 and does not create Fragment1. That is due to the misuse of View#getTag.
In MainActivity#onCreate, change the if in the definition of onClickListener to this(using this answer):
switch (v.getId()){
case R.id.button1:
fragment = new Fragment1();
break;
case R.id.button2:
fragment = new Fragment2();
break;
default:
return;
}
In your code, in the if that is checked upon a click (for example after clicking button1) android asks v (the clicked View) for its tag - but as none was set using View#setTag - it returns null which is of course not equal to the String object created for "button1", thus the if reverts to the else every time.
i followed this article http://www.truiton.com/2015/06/android-tabs-example-fragments-viewpager/ to implement swipe view and it work nice. So now i want to add button on Tab1 and when clicked has to send data to Tab2.
I know there is the issue of using interface but honestly i don't know how to add it on these codes and work provide am completely new to the android.
so far i have tried my best on these links Communication between SlidingTabLayout tabs, How to pass data from one swipe tab to another? and How can I communicate/pass data through different Fragments with Swipe Tab? but i fail.
Any one help please to make it work on every stage , i mean from Tab1 ->Mainactivity->Tab2
thanks alot
Here are the codes after i edit the question
Fragment1
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class TabFragment1 extends Fragment implements AdapterView.OnItemSelectedListener{
Button send;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View v= inflater.inflate(R.layout.tab_fragment_1, container, false);
send=(Button)v.findViewById(R.id.send);
send.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// value to be sent to the TabFragment2 on button click
String value=" My Data";
}
});
return v;
}
}
Fragment2
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class TabFragment2 extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.tab_fragment_2, container, false);
//Display value from TabFragment1
textview.setText(value);
}
}
Interface class
public Interface FragmentCommunication
{
public void printMessage(String message);
}
MainActivity
import android.os.Bundle;
import android.support.design.widget.TabLayout;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
public class MainActivity extends AppCompatActivity implements FragmentCommunication{
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
TabLayout tabLayout = (TabLayout) findViewById(R.id.tab_layout);
tabLayout.addTab(tabLayout.newTab().setText("Tab 1"));
tabLayout.addTab(tabLayout.newTab().setText("Tab 2"));
tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
final ViewPager viewPager = (ViewPager) findViewById(R.id.pager);
final PagerAdapter adapter = new PagerAdapter
(getSupportFragmentManager(), tabLayout.getTabCount());
viewPager.setAdapter(adapter);
viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
#Override
public void onTabSelected(TabLayout.Tab tab) {
viewPager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
}
public void printMessage(String message)
{
Toast.makeText(MainActivity.this,message,Toast.LENGTH_LONG).show();
}
}
Adapter Class
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentStatePagerAdapter;
public class PagerAdapter extends FragmentStatePagerAdapter {
int mNumOfTabs;
public PagerAdapter(FragmentManager fm, int NumOfTabs) {
super(fm);
this.mNumOfTabs = NumOfTabs;
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
TabFragment1 tab1 = new TabFragment1();
return tab1;
case 1:
TabFragment2 tab2 = new TabFragment2();
return tab2;
default:
return null;
}
}
#Override
public int getCount() {
return mNumOfTabs;
}
}
so after posting more code I'm answering:
Implement some FragmentCommunication for both your Fragments:
//public class TabFragment1 extends Fragment implements FragmentCommunication{
public class TabFragment2 extends Fragment implements FragmentCommunication{
//public static final String TAG="TabFragment1";
public static final String TAG="TabFragment2";
...
#Override
public void onActivityCreated (Bundle savedInstanceState){
super.onActivityCreated(savedInstanceState);
if(getActivity() instanceOf MainActivity)
((MainActivity) getActivity()).registerFragmentCommunication(
TAG, this);
}
#Override
public void printMessage(String message){
Toast.makeText(getActivity(), TAG+" says: "+message,
Toast.LENGTH_SHORT).show();
}
}
note this line inside onActivityCreated:
((MainActivity) getActivity()).registerFragmentCommunication(TAG, this);
this means implemented FragmentCommunication, TAG will be unique key/name of Fragment and whole method is registration of your interface in Activity. so now you have to add registerFragmentCommunication method to your MainActivity and keep reference to passed interfaces, e.g. in HashMap:
HashMap<String, FragmentCommunication> fragmentCommunications =
new HashMap<String, FragmentCommunication>();
...
public void registerFragmentCommunication(String key, FragmentCommunication fc){
fragmentCommunications.put(key, fc);
}
so now you can access each FragmentCommunication of both fragments from your MainActivity, e.g by using method like this:
public void callFragmentCommunication(String key, String msg){
if(fragmentCommunications.get(key)!=null)
fragmentCommunications.get(key).printMessage();
}
callFragmentCommunication(TabFragment1.TAG, "hi!");
callFragmentCommunication(TabFragment2.TAG, "hi!");
method is public, so Fragments can call it simply like this:
//inside TabFragment1
if(isAdded() && getActivity()!=null &&
getActivity() instanceOf MainActivity &&
!getActivity().isFinishing())
((MainActivity) getActivity()).callFragmentCommunication(
TabFragment2.TAG, "hi!");
this will show Toast with text: "TabFragment2 says: hi!", which was called inside TabFragment1. now you may pass another kind of data as well :)
there is much more methods like communicating through FragmentStatePagerAdapter like here, passing Bundle arguments where fragments are initialized, additional feedback interfaces (e.g. returning true/false when message was passed) etc. Above is just very simplified way, good luck with improving it! :)
I've done some research on this already, and I seem to understand the solutions suggested out there. This is not a repeat question, I'm just having trouble implementing these solutions to my viewpager/fragment code.
So here is my "FirstFragment.java" that sets up my view pager, and the fragment it calls is "UserFragment.java". Basically what I'm doing is providing a user defined number of forms created as pages in my view pager.
I of course, am experiencing the orientation change issue, where fragment gets created a couple times, and eventually lost. I would like to fix it.
My code for FirstFragment.java is:
import java.util.ArrayList;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.view.ViewPager;
import android.util.SparseArray;
public class FirstFragment extends FragmentActivity
{
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.layout_viewpager);
// Check whether the activity is using the layout version with
// the fragment_container FrameLayout. If so, we must add the first fragment
int size = getIntent().getExtras().getInt("numass1");
ViewPager vp = (ViewPager) findViewById(R.id.viewPager);
if (savedInstanceState != null) {
return;
}
ArrayList<Fragment> lf = new ArrayList<Fragment>();
for(int count=0; count<size; count ++){
Fragment f = new UserFragment();
lf.add(f);
}
FragmentAdapter hello = new FragmentAdapter(getSupportFragmentManager() , lf);
vp.setAdapter(hello);
}
SparseArray<Question> questions = new SparseArray<Question>();
public void saveData(Question quest){
ViewPager vp = (ViewPager) findViewById(R.id.viewPager);
questions.put(vp.getCurrentItem(), quest);
}
public ViewPager getPager() {
ViewPager vp = (ViewPager) findViewById(R.id.viewPager);
return vp;
}
}
Just incase, my FragmentAdapter.java code is:
import java.util.ArrayList;
import java.util.List;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.view.ViewGroup;
public class FragmentAdapter extends FragmentPagerAdapter{
private List<Fragment> fragments;
public FragmentAdapter(FragmentManager fragmentManager, ArrayList<Fragment> fragments) {
super(fragmentManager);
this.fragments = fragments;
}
#Override
public Fragment getItem(int position) {
Fragment fragment = fragments.get(position);
Bundle args = new Bundle();
args.putInt("page_position", position + 1);
args.putInt("size", fragments.size());
fragment.setArguments(args);
return fragment;
}
#Override
public void destroyItem (ViewGroup container, int position, Object object)
{
super.destroyItem(container, position, object);
}
#Override
public int getCount() {
return this.fragments.size();
}
}
Please keep in mind, I am clearly a noob, and I'm trying to learn. So code snippets, and explanations would be awesome!
Thank you very much for your time and help.
EDIT: Please help ...
If you add
android:configChanges="orientation|keyboardHidden"
in <activity> node of your file AndroidManifest.xml your activity will not reset when the orientation changed.
Is it what you wanted?
In my MainActivity i have this code:
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
public class MainActivity extends FragmentActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
myViewPager.setCurrentItem(1);
ViewPager pager = (ViewPager) findViewById(R.id.viewPager);
pager.setAdapter(new MyPagerAdapter(getSupportFragmentManager()));
}
private class MyPagerAdapter extends FragmentPagerAdapter {
public MyPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int pos) {
switch(pos) {
case 2: return FirstFragment.newInstance("FirstFragment, Instance 1");
case 1: return SecondFragment.newInstance("SecondFragment, Instance 1");
case 0: return ThirdFragment.newInstance("ThirdFragment, Instance 1");
default: return ThirdFragment.newInstance("ThirdFragment, Default");
}
}
#Override
public int getCount() {
return 3;
}
}
}
The fragments are working fine and when i run MainActivity i want to open the SecondFragment first, so i tried using:
myViewPager.setCurrentItem(1);
But then i get the error "myViewPager cannot be resolved", i have tried updating SDK and adding support library, but nothing seems to help, any idea how to fix it?
You have not declared myViewPager and you also need to initialize it before myViewPager.setCurrentItem(1);.
You probably meant pager.setCurrentItem(1);