Develop Reference

Android fragment replacement

I have a fragment called ProjectsFragment, that has a constraintLayout, recyclerView and a FloatingActionButton.
I'm trying to make it when I click the button to go to another fragment.
The new fragment is called NewProjectFragment.
The code that I've got so far is below but it's not being replaced. I know the code is being ran as the log is printed
FloatingActionButton fab = view.findViewById(R.id.floatingActionButton);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
NewProjectFragment npf = new NewProjectFragment();
FragmentTransaction transaction = getActivity().getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.constraintLayout, npf);
transaction.addToBackStack(null);
transaction.commit();
Log.d("swap", "swap");
}
});
The tabs are setup using the below on the MainActivity
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ViewPager viewPager = (ViewPager) findViewById(R.id.viewpager);
SimpleFragmentPagerAdapter adapter = new SimpleFragmentPagerAdapter(this, getSupportFragmentManager());
viewPager.setAdapter(adapter);
TabLayout tabLayout = (TabLayout) findViewById(R.id.sliding_tabs);
tabLayout.setupWithViewPager(viewPager);
}
The SimpleFragmentPageAdapter is below
public class SimpleFragmentPagerAdapter extends FragmentPagerAdapter {
private Context mContext;
public SimpleFragmentPagerAdapter(Context context, FragmentManager fm) {
super(fm);
mContext = context;
}
// This determines the fragment for each tab
#Override
public Fragment getItem(int position) {
if (position == 0) {
return new ProjectsFragment();
} else if (position == 1) {
return new ColoursFragment();
} else if (position == 2) {
return new WishListFragment();
} else if (position == 3) {
return new AboutFragment();
} else {
return new ProjectsFragment();
}
}
// This determines the number of tabs
#Override
public int getCount() {
return 4;
}
// This determines the title for each tab
#Override
public CharSequence getPageTitle(int position) {
// Generate title based on item position
switch (position) {
case 0:
return mContext.getString(R.string.project_tab);
case 1:
return mContext.getString(R.string.colours_tab);
case 2:
return mContext.getString(R.string.wish_list_tab);
case 3:
return mContext.getString(R.string.about_tab);
default:
return null;
}
}
}
The ActivityMain.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<android.support.design.widget.TabLayout
android:id="#+id/sliding_tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:tabMode="fixed" />
<android.support.v4.view.ViewPager
android:id="#+id/viewpager"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#android:color/white" />
</LinearLayout>
And the fragment_projects.xml
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".ui.main.ProjectsFragment"
android:id="#+id/constraintLayout" >
<android.support.design.widget.FloatingActionButton
android:id="#+id/floatingActionButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="16dp"
android:layout_marginRight="16dp"
android:layout_marginBottom="16dp"
android:clickable="true"
android:src="#drawable/ic_add_black_24dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent" />
<android.support.v7.widget.RecyclerView
android:id="#+id/recyclerView"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="1.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="1.0">
</android.support.v7.widget.RecyclerView>
</android.support.constraint.ConstraintLayout>

transaction.replace(R.id.constraintLayout, npf);
Looks like you're trying to replace into a constraint layout, which smells funny to me. Usually you have a FrameLayout that is a simple container for the fragments. Thus, my guess would be that you are moving the new fragment into the existing fragment's layout, without constraints, so it's not showing up and the first one remains in place.
Make sure you're using the ID of the view in the layout that contains the first fragment (again, usually a FrameLayout in the owning Actvity layout).
If that is not your issue, post your XML file.
Update.
Yeah, as I guessed, you're replacing into a ConstraintLayout and that's not a good idea, as you've seen. Your setup is a bit weird because you have a ViewPager that is managing one set of fragments and you want to push a new one over everything?
I'd suggest you just launch a new Activity instead.

View Pager is calling other fragments on startup and on swiping too

List of components in my app is following :
TabLayout - Tab1, Tab2, Tab3.
Fragments for Tabs - Tab1.xml & class, Tab2.xml & class, Tab3.xml & class.
ViewPager to show Fragments on tabs.
So, when app starts as i debugged the startup process, it works like following :
it calls 'Tab1.class',
then it calls 'Tab2.class',
and when swipe from 'Tab1' to 'Tab2', it calls 'Tab3.class'.
and when swipe from 'Tab2' to 'Tab3', it calls nothing.
on reverse swiping :
when swipe from 'Tab3' to 'Tab2', it calls 'Tab1.class'.
then when swipe from 'Tab2' to 'Tab1', it calls nothing.
Questions :
So, why does it do that?
How can i call ONLY 'tab1.class' when app starts on 'tab1'?
How can i call ONLY 'tab2.class' when i swipe from 'tab1' to 'tab2'?
MainActivity.java
public class MainActivity extends AppCompatActivity {
private TabLayout tabLayout;
private ViewPager viewPager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
viewPager = (ViewPager) findViewById(R.id.viewPager);
PagerAdapter pagerAdapter = new FixedTabsPagerAdapter(getSupportFragmentManager());
viewPager.setAdapter(pagerAdapter);
tabLayout = (TabLayout) findViewById(R.id.tabLayout);
tabLayout.setupWithViewPager(viewPager);
}
class FixedTabsPagerAdapter extends FragmentPagerAdapter {
public FixedTabsPagerAdapter(FragmentManager manager) {
super(manager);
}
#Override
public Fragment getItem(int position) {
switch (position)
{
case 0:
return new Tab1();
case 1:
return new Tab2();
case 2:
return new Tab3();
default:
return null;
}
}
#Override
public int getCount() {
return 3;
}
#Override
public CharSequence getPageTitle(int position) {
switch (position)
{
case 0:
return getString(R.string.tab1);
case 1:
return getString(R.string.tab2);
case 2:
return getString(R.string.tab3);
default:
return null;
}
}
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="vwc.com.newconcept.MainActivity">
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v7.widget.Toolbar
android:id="#+id/main_toolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<android.support.v4.view.ViewPager
android:id="#+id/viewPager"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.widget.TabLayout
android:id="#+id/tabLayout"
app:tabMode="scrollable"
app:tabGravity="center"
android:layout_gravity="top"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</android.support.v4.view.ViewPager>
</android.support.design.widget.AppBarLayout>
</android.support.v4.widget.DrawerLayout>
Please Do Tell Solution For This Problem.

setOffscreenPageLimit
Set the number of pages that should be retained to either side of the current page in the view hierarchy in an idle state. Pages beyond this limit will be recreated from the adapter when needed.
Hope this helps.
ViewPager mViewpager = (ViewPager)findView....
mViewPager.setOffscreenPageLimit(3);

ViewPager is intented to work in that way to avoid lag in animations while switching from one fragment to other fragment, it will load atleast one extra fragment alongside your Visible Fragment by which it makes sure there is scope to swipe.
because, while swiping view pager has capability to show two fragments simultaneously hence loads the one extra always, without two pages view pager is useless.

For Refresh Fragment When Fragment Visible
#Override
public void setUserVisibleHint(boolean isVisibleToUser) {
super.setUserVisibleHint(isVisibleToUser);
if (getFragmentManager() != null) {
getFragmentManager()
.beginTransaction()
.detach(this)
.attach(this)
.commit();
}
}

Android fragment transaction with SlidingTabLayout not working in API level < 21

in my app I have an ActionBarActivity (I'm using support library with AppCompat) that uses the SlidingTabLayout class from Google (taken from here). So this is the XML code of the activity's layout:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/activity_series_details"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".SeriesDetailsActivity">
<com.my.package.SlidingTabLayout
android:id="#+id/series_details_tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:elevation="2dp"
android:background="#color/primary_material_dark" />
<android.support.v4.view.ViewPager
android:id="#+id/series_details_pager"
android:layout_height="0dp"
android:layout_width="match_parent"
android:layout_weight="1" />
</LinearLayout>
In this activty, when user press an option in the action bar, I want to add a Fragment with a custom animation. This is the code that handle menu click:
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
/* ... OTHER CASES ... */
case R.id.menu_voption:
newFragment = MyNewFragment.newInstance();
getSupportFragmentManager().beginTransaction()
.setCustomAnimations(
R.anim.slide_up,
R.anim.slide_down
)
.add(R.id.activity_series_details, newFragment)
.commit();
editing = true;
break;
default:
return super.onOptionsItemSelected(item);
}
return true;
Doing this, my new fragment is correctly added to the activty and replace the currente fragment but not tab layout, tha remains visible. So I've tryed to add this line before start transaction:
tabsHost.setVisibility(View.GONE);
where tabsHost is the SlidingTabLayout. With this modification, the tabs layout disappear and the new fragment is correctly shown, but only in the API Level >= 21. In my Samsung Galaxy S4 (that runs API 19) and in all other emulators with lesser API level than 21 (my target is 11+), the tabs layout disappear but new fragment is not visible. I'm pretty sure is my fault, but I can't figure why. Thanks all for attention.

Since the SlidingTabLayout is not a fragment, it cannot be managed by the FragmentManager. You would have to make it part of a fragment and add it to your Activity. This is possible with getChildFragmentManager.
Move your activity layout to a fragment:
activity_main.xml
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/activity_series_details"
android:layout_width="match_parent"
android:layout_height="match_parent">
</FrameLayout>
fragment_sliding_tab.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/activity_series_details"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<com.my.package.SlidingTabLayout
android:id="#+id/series_details_tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:elevation="2dp"
android:background="#color/primary_material_dark" />
<android.support.v4.view.ViewPager
android:id="#+id/series_details_pager"
android:layout_height="0dp"
android:layout_width="match_parent"
android:layout_weight="1" />
</LinearLayout>
SlidingTabFragment.java
public class SlidingTabFragment extends Fragment {
private PagerAdapter mPagerAdapter;
private ViewPager mViewPager;
public static SlidingTabFragment newInstance() {
SlidingTabFragment fragment = new SlidingTabFragment();
return fragment;
}
public SlidingTabFragment() {
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
}
#Override
public void onViewCreated(View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
mPagerAdapter = new PagerAdapter(getChildFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) view.findViewById(R.id.series_details_pager);
mViewPager.setAdapter(mSectionsPagerAdapter);
SlidingTabLayout tabs = (SlidingTabLayout) view.findViewById(R.id.series_details_tabs);
tabs.setViewPager(mViewPager);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_sliding_tab, container, false);
}
}
Add your fragment in your Activity's onCreate:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Fragment slidingTabFragment = SlidingTabFragment.newInstance();
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.activity_series_details, slidingTabFragment).commit();
}

java.lang.IllegalArgumentException: No view found for id for fragment NewLogFragment

In my project I have a navigation drawer that's in the MainActivity.java. Each item in that drawer starts a different fragment that takes up the entire screen space. One of these fragments has buttons that need to launch an Activity (this activity extends MainActivity.java - the rationale behind this was to keep the navigation drawer available). When I press any of the buttons in that one fragment to launch another activity, I get this error
java.lang.RuntimeException: Unable to start activity ComponentInfo{.AddWorkoutActivity}: java.lang.IllegalArgumentException:
No view found for id 0x7f0a0041 (id/contentFrame) for fragment NewLogFragment{529f3328 #0 id=0x7f0a0041}
Here, NewLogFragment is the fragment that tries to launch a new activity.
Basically, the structure of my project goes like this:
MainActivity:java -> contains the NavDrawer and launches a fragment -> This fragment then launches another activity, which results in an error.
Here's my some of my code:
public class MainActivity extends ActionBarActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// rest of the code. Note, DrawerList is the list of items in the drawer.
DrawerList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
int editedPosition = position + 1;
Toast.makeText(MainActivity.this, "You selected item " + editedPosition, Toast.LENGTH_SHORT).show();
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction ft = fragmentManager.beginTransaction();
switch(position){
case 0:
ft.replace(R.id.contentFrame, new NewLogFragment()).commit();
break;
}
mDrawerLayout.closeDrawer(mDrawerList);
}
}); // ... rest of the code
activity_main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="#color/primary"
app:popupTheme="#style/Theme.AppCompat"
app:theme="#style/ToolbarTheme" />
<!-- Main layout -->
<android.support.v4.widget.DrawerLayout
android:id="#+id/drawer"
android:layout_width="match_parent"
android:layout_height="match_parent">
<FrameLayout
android:id="#+id/contentFrame"
android:layout_width="match_parent"
android:layout_height="match_parent"></FrameLayout>
<!-- Nav drawer -->
<ListView
android:id="#android:id/list"
android:layout_width="305dp"
android:layout_height="match_parent"
android:layout_gravity="start"
android:background="#android:color/white" />
</android.support.v4.widget.DrawerLayout>
</LinearLayout>
NewLogFragment.java
public class NewLogFragment extends Fragment {
private Button bt_button;
#Override
public View onCreateView(LayoutInflater inflater,
ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.newlog_layout, container, false);
bt_button = (Button) rootView.findViewById(R.id.bt_button);
bt_button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(getActivity(), AddWorkoutActivity.class);
intent.putExtra("type", 1);
startActivity(intent);
}
});
return rootView;
}
#Override
public void onDestroyView() {
super.onDestroyView();
}
newlog_layout.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/fragmentOne">
<LinearLayout
android:id="#+id/ll_buttons"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<Button
android:id="#+id/bt_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="#string/bt_button" />
</LinearLayout>
</RelativeLayout>
Perhaps I didn't structure my project correctly... but I've looked online and this should work nonetheless. No clue what's wrong. Any suggestions on the best way to structure my project are appreciated as well (in terms of whether to keep it this way or make everything a fragment or an activity). But I'd like to get this problem solved first.
EDIT adding AddWorkoutActivity.java
public class AddWorkoutActivity extends MainActivity implements View.OnClickListener {
TextView tv_warmupex, tv_mainex, tv_workout_type, tv_cycle, tv_week, tv_one_rm;
EditText ev_datepicker;
// more layout stuff
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.addworkout_layout);
dateFormatter = new SimpleDateFormat("MM-dd-yyyy", Locale.US);
Intent logFragmentIntent = getIntent();
workout_type = logFragmentIntent.getStringExtra("workout_type");
setUpLayout(workout_type);
}
// and a bunch of helper methods that do all the calculations
public void completeWorkout(MenuItem item) {
if (cb_wu_1.isChecked() && cb_wu_2.isChecked() && cb_wu_3.isChecked() &&
cb_me_1.isChecked() && cb_me_2.isChecked() && cb_me_3.isChecked()) {
// add workout to database
HashMap<String, String> queryValuesMap = new HashMap<String, String>();
queryValuesMap.put("table", MAIN_E);
queryValuesMap.put(WEEK, String.valueOf(e_info[1])); // get latest cycle/week for this exercise and +1 to add to the table
queryValuesMap.put(CYCLE, String.valueOf(e_info[0]));
queryValuesMap.put(WEIGHT, getWeightString());
queryValuesMap.put(DATE_CREATED, changeDateFormat(ev_datepicker.getText().toString()));
queryValuesMap.put(NOTES, "notes");
queryValuesMap.put(MAIN_EXERCISE, workout_type);
dbTools.insertExercise(queryValuesMap);
// Update 1RM table if a new rep max is achieved during current workout
if (Double.parseDouble(getWeightString())>oneRepMax){
HashMap<String, String> queryValuesMapOneRM = new HashMap<String, String>();
queryValuesMapOneRM.put(MAIN_EXERCISE, workout_type); // get latest cycle/week for this exercise and +1 to add to the table
queryValuesMapOneRM.put(WEIGHT, getWeightString());
queryValuesMapOneRM.put(DATE_CREATED, changeDateFormat(ev_datepicker.getText().toString()));
dbTools.updateExerciseRepMax(queryValuesMapOneRM);
}
Intent intent = new Intent(this, MainActivity.class);
startActivity(intent);
} else {
/*if not all buttons are clicked, show a toast
telling user to click all buttons to complete workout
*/
}
}
}

The crash occuring because of , you are trying to replace fragment with the id that doesn't contain in the current activity. My suggestion is to change the project structure like , Use One Activity for the NavDrawer and use fragment for each menu.Other wise it will be more complicated . refer the following link, http://www.androidhive.info/2013/11/android-sliding-menu-using-navigation-drawer/

Update A ListView In One Fragment From A Second Fragment

I have a ViewPager that shows the user 2 fragments.
Fragment 1 contains a button with an onClickListener that adds an entry to the ListView contents in fragment 2. The new entry is a number generated by a random number generator.
Fragment 2 contains a ListView with some random numbers in.
I cannot find a way to refresh the list in fragment 2 from the button listener in fragment 1. How do i do this?
I have tried:
initializing and setting the list adapter in an onResume in
fragment 2.
Calling myViewPager.notifyDataSetChanged from fragment 1.
Neither of the above methods have worked. Any ideas?
Edit: Here is my code:
layout_main.xml
<android.support.v4.view.ViewPager
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/mainpager"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
layout_frag_one.xml
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<Button
android:id="#+id/main_button"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:text="Add Number" />
</RelativeLayout>
layout_frag_two
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<ListView
android:id="#+id/list"
android:layout_width="match_parent"
android:layout_height="wrap_content">
</ListView>
</LinearLayout>
MainActivity
public class SlideActivity extends FragmentActivity {
private final static int FRAGMENT_NUMBER = 2;
private ViewPager pager;
protected void onCreate(Bundle savedInstanceState) {
setContentView(R.layout.activity_mainpager);
pager = (ViewPager) findViewById(R.id.mainpager);
pager.setAdapter(new ViewPagerAdapter(getSupportFragmentManager()));
super.onCreate(savedInstanceState);
}
private class ViewPagerAdapter extends FragmentStatePagerAdapter {
public ViewPagerAdapter(FragmentManager fm) {
super(fm);
}
public Fragment getItem(int index) {
switch(index){
case 0:
return new Fragment1();
case 1:
return new Fragment2();
default:
return new Fragment1();
}
}
public int getCount() {
return FRAGMENT_NUMBER;
}
}
}

You may need to implement some of this to get it working right:
http://developer.android.com/training/basics/fragments/communicating.html
And some more reading here:
http://developer.android.com/guide/components/fragments.html#CommunicatingWithActivity