Develop Reference

How to use MVVM with any fragment?

I have a TabLayout on a activity and when user clicks on any tab then a fragment is loaded. One of those fragments contains a NavigationView running inside a DrawerLayout. Now the problem is I have to implement MVVM for the whole app and so for the fragments too, I have done this for Activities but I am having trouble while implementing this for Fragments and how to deal with ItemSelected with MVVM and what to bind and how? I am unable to find a proper working sample of the same. Here's the code:
MoreFragment.java:
package com.abc.Fragments;
import android.arch.lifecycle.ViewModel;
import android.arch.lifecycle.ViewModelProviders;
import android.content.Context;
import android.net.Uri;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.design.widget.NavigationView;
import android.support.v4.app.Fragment;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.view.WindowManager;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;
import com.abc.MainActivity;
import com.abc.MoreFragmentViewModel;
import com.abc.R;
public class MoreFragment extends Fragment {
private DrawerLayout mDrawerLayout;
private ListView mDrawerList;
private ViewModel viewModel;
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
viewModel = ViewModelProviders.of(this).get(MoreFragmentViewModel.class);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View fragView = inflater.inflate(R.layout.fragment_more, container, false);
return fragView;
}
#Override
public void onViewCreated(#NonNull View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
mDrawerLayout = getView().findViewById(R.id.drawer_layout);
mDrawerLayout.openDrawer(Gravity.END);
}
}
fragment_more.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"
android:id="#+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/white">
<android.support.design.widget.NavigationView
android:id="#+id/nav_view"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="end"
android:background="#color/grey"
app:navigationItemSelectedListener="#{()-> viewModel.onMyItemSelected()}"
app:headerLayout="#layout/nav_header_main"
app:menu="#menu/activity_main_drawer" />
</android.support.v4.widget.DrawerLayout>
MoreFragmentViewModel.java:
package com.abc;
import android.arch.lifecycle.ViewModel;
import android.databinding.BaseObservable;
public class MoreFragmentViewModel extends ViewModel {
public void onMyItemSelected(){
System.out.print("Item Clicked");
}
}
Please do any possible help.

Use:
DataBindingUtil.inflate(inflater, layoutId(), container, false)
To inflate your layout.
And don't forget to add:
<data>
<variable
name="model"
type="MoreFragmentViewModel"/>
</data>
To your fragment layout.

Not able to get the LifeCycle ViewModel Class Using ViewModelProvider

I am trying to get the ViewModel Class for the specific fragment. But ViewModelProvider.of(this).get(UserListViewModel.class) does not work for me. Extending my Fragment from "android.support.v4.app.Fragment", but still it does not work.
Here is the code
package mudasir.android.application.upfit.Fragments;
import android.arch.lifecycle.AndroidViewModel;
import android.arch.lifecycle.ViewModelProvider;
import android.databinding.DataBindingUtil;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import mudasir.android.application.upfit.R;
import mudasir.android.application.upfit.ViewModel.UserListViewModel;
import mudasir.android.application.upfit.databinding.FragmentUserListBinding;
/**
* A simple {#link Fragment} subclass.
*/
public class UserListFragment extends Fragment {
UserListViewModel userListViewModel;
FragmentUserListBinding fragmentUserListBinding;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
fragmentUserListBinding = DataBindingUtil.inflate(inflater, R.layout.fragment_user_list, container, false);
View view = fragmentUserListBinding.getRoot();
userListViewModel = ViewModelProvider.of(this).get(UserListViewModel.class);
return view;
}
}

You are using the wrong class. It should be:
userListViewModel = ViewModelProviders.of(this).get(UserListViewModel.class);
Notice that it's ViewModelProviders

Facing Issues when working with fragment

I have to create an application in which I have to work with Fragment.
In the MainActivity, there is a webView. From the SecondActivity I
have starting using Fragment.
Here is the code of SecondActivity:
package com.dev.testapp;
import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.view.View;
public class Second extends Activity {
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.second);
}
public void choosefragment(View view) {
Fragment fg;
if(view == findViewById(R.id.secondbtn2)) {
fg = new SecondFragment();
}
else
{
fg = new FirstFragment();
}
FragmentManager fm = getFragmentManager();
FragmentTransaction fragmentTransaction = fm.beginTransaction();
fragmentTransaction.replace(R.id.frag1, fg);
fragmentTransaction.commit();
}
}
Hhere is its second.xml file:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:background="#ffffff" >
<Button
android:id="#+id/secondbtn1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="first fragment"
android:onClick="chooseFragment" />
<Button
android:id="#+id/secondbtn2"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="second fragment"
android:onClick="chooseFragment"/>
<fragment
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:name="com.dev.testapp.fragment1"
android:id="#+id/frag1"
/>
</LinearLayout>
After that I created two more classes for Fragments as it is required
code of FirstFragment:
package com.dev.testapp;
import android.app.Activity;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class FirstFragment extends Fragment{
public View onCreate(LayoutInflater inflater,
ViewGroup container , Bundle savedInstanceState) {
//Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment1,container, false);
}
}
And here is the SecondFragment:
package com.dev.testapp;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class SecondFragment extends Fragment{
public View onCreate(LayoutInflater inflater,
ViewGroup container , Bundle savedInstanceState) {
//Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment2,container, false);
}
}
When I am done with all this, my SecondActivity is showing an error that I don't know how to handle:

As noted in previous answers, your problem is incorrect Fragment library for FirstFragment.
Change line 5 of FirstFragment.java:
import android.support.v4.app.Fragment;
to:
import android.app.Fragment;

Your second fragment is of the type android.app.Fragment while your first fragment is android.support.v4.app.Fragment.

your activity use this import android.app.Fragment;
your fragment is import android.support.v4.app.Fragment;
So you either have both extending the Fragment in the app package or in the support library

Error: The method add(int, Fragment, String) in the type FragmentTransaction is not applicable for the arguments (int, FragementTest, String)

Im trying to Use Fragements. But in MainActivity.java file the transaction.add(R.id.my_layout, testfrag, "");not Initiated correctly.please find below the code i used.
package com.example.testtabs;
import android.os.Bundle;
import android.app.Activity;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.app.TabActivity;
import android.view.Menu;
import android.widget.TabHost;
import android.support.v4.app.Fragment;
import com.example.testtabs.R;
public class MainActivity extends TabActivity {
TabHost tab;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
FragementTest testfrag=new FragementTest();
FragmentManager manager=getFragmentManager();
FragmentTransaction transaction=manager.beginTransaction();
transaction.add(R.id.my_layout, testfrag, "");//Error is here
}
}
activity_main.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"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context=".MainActivity"
android:id="#+id/my_layout"
>
Error: The method add(int, Fragment, String) in the type FragmentTransaction is not applicable for the arguments (int, FragementTest, String)
Fragement.test
package com.example.testtabs;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
/**
* A simple {#link android.support.v4.app.Fragment} subclass.
*
*/
public class FragementTest extends Fragment {
public FragementTest() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_fragement, container, false);
}
}

change:
import android.app.FragmentManager;
import android.app.FragmentTransaction;
to:
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
or---
change:
import android.support.v4.app.Fragment;
to
import android.app.Fragment;

All the Fragment should be android.app.Fragment. If you want to use android.support.v4.app.Fragment, you should use getSupportFragmentManager() to get the Manager.

Its working for me:
Instead of using getFragmentManager use getSupportFragmentManager();

trying to add title to fragment

Please pardon my ignorance, I'm a total newbie to programming. I'm trying to add a title at the top of the screen to a horizontal view swiping section of my android app. I think I'm supposed to put:
setTitle("title goes here");
somewhere in the code below but I'm not sure how/where?
here is the code for the first fragment:
import com.viewpagerindicator.TitlePageIndicator;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class Fragment1 extends Fragment{
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
return inflater.inflate(R.layout.fragment_1, null);
}
}

As a Fragment has to be 'hosted' by an Activity, try this
getActivity().setTitle("SumTingWong");