Develop Reference

Previous activity visible under the new fragment

When I call fragment from activity then fragment calling successfully but some part of previous activity is on the top of in fragment, anyone help to correct the code
package com.example.newproject;
import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;
import static android.view.View.GONE;
public class ThankYouPageActivity extends AppCompatActivity {
Button thank_continue_btn,thank_track_btn;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_thank_you_page);
getSupportActionBar().setTitle("Confirmation");
thank_continue_btn = findViewById(R.id.thank_continue_btn);
thank_track_btn = findViewById(R.id.thank_track_btn);
findViewById(R.id.thank_continue_btn).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
FragmentManager fm = getSupportFragmentManager();
HomeFragment fragment = new HomeFragment();
fm.beginTransaction().replace(R.id.thanku_container, fragment).addToBackStack(null).commit();

set background to white in the root tag of your fragment's xml
background = "#FFFFFF"

The container of your Fragment must be overlapped by your Activity layouts. Please attach the layouts of your Activity and Fragment so that I can help you find your issue.

I had same issues , i fixed it by removing previous fragment while setting new fragment in oncreateview
container.removeAllViews(); before replacing the fragment

R.id.thanku_container - I think it is FrameLayout?
Make it full match_parent. Or set background color like activity.

Blank fragment after navigation with BottomNav and TabMenu

I am developing an Android app that has a little bit confusing navigation structure which leads me to my problem. There are two ways to navigate through the app. First is the BottomNav and second is a TabMenu. I thought about working with fragments that replace each other, so I came up with the following structure:
1. BottomNav#1
- TabMenu#1
- Tabmenu#2
- TabMenu#3
- ...
2. BottomNav#2
- TabMenu#4
- Tabmenu#5
- TabMenu#6
- ...
... and so on.
The problem I am facing is that when I navigate from BottomNav#1 to BottomNav#2 and back again there is a blank screen that doesn't show the content of the actual fragment:
When I open the app
After clicking on BottomNav#2 and then back to BottomNav#1 the fragment seems to be blank
My guess is that I somehow have a problem with my fragmentTransaction.replace(); as it seems like the fragment doesn't get loaded again? I am kind of new to this and really tried to find an answer online but this is a bit specific why I guess I didn't find anything.
This is my MainActivity:
package com.example.XXXX;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.design.widget.BottomNavigationView;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.ActionBar;
import android.support.v7.app.AppCompatActivity;
import android.view.MenuItem;
import android.widget.FrameLayout;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
private FrameLayout mMainFrame;
private AusweisFragment ausweisFragment;
private SpendenFragment spendenFragment;
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ausweisFragment = new AusweisFragment();
spendenFragment = new SpendenFragment();
BottomNavigationView navigation = (BottomNavigationView) findViewById(R.id.navigation);
navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener);
}
private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
= new BottomNavigationView.OnNavigationItemSelectedListener()
{
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item)
{
switch (item.getItemId())
{
case R.id.navigation_ausweis:
setFragment(ausweisFragment);
return true;
case R.id.navigation_spenden:
setFragment(spendenFragment);
return true;
}
return false;
}
};
private void setFragment(Fragment fragment)
{
FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.main_frame, fragment);
fragmentTransaction.addToBackStack(null);
fragmentTransaction.commit();
}
}
This should lead to e.g. the fragment called "ausweis" by clicking on on BottomNav#1 (switch case):
package com.example.XXXXXXX;
import android.app.Activity;
import android.os.Bundle;
import android.support.design.widget.TabItem;
import android.support.design.widget.TabLayout;
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 AusweisFragment extends Fragment {
private View rootView;
private AusweisPageAdapter ausweisPageAdapter;
private TabLayout tabLayout;
private ViewPager viewPager;
public AusweisFragment() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState)
{
rootView= inflater.inflate(R.layout.fragment_ausweis, container, false);
tabLayout = rootView.findViewById(R.id.tablayoutAusweis);
viewPager = rootView.findViewById(R.id.viewPagerAusweis);
ausweisPageAdapter = new AusweisPageAdapter(getActivity().getSupportFragmentManager(), tabLayout.getTabCount());
viewPager.setAdapter(ausweisPageAdapter);
viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
tabLayout.addOnTabSelectedListener(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) {
}
});
return rootView;
}
}
After that I would like to call another fragment called "spenden" which is exactly the same as the fragment called "ausweis" but with different named tabs, so I think it is not bother you with more code.
edit: I missed about writing where the "content" I wrote about gets from. For a first try and proof that the fragments change, I hardcoded a phrase like "Ausweis" into the XML which is connected to my fragment java class.
Maybe one of you has an idea to that problem. I think it has something to do with my onCreateView in one of the fragments, but I have no close clue.
Hopefuly I didn't miss an important detail. I am very grateful for any kind of help. Thanks a lot in advance.

The answer to my problem was to use a child-parent relation between the different fragments. With the click on BottomNav#1 I am inflating an fragment which inflates a new fragment inside itself. That was the key problem. In my code I handled this as a second "normal" getFragmentManager();.
The answer is to use getChildFragmentManager(); for the nested fragment instead. Like this:
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState)
{
rootView= inflater.inflate(R.layout.fragment_ausweis, container, false);
tabLayout1 = rootView.findViewById(R.id.tablayoutAusweis);
viewPager = rootView.findViewById(R.id.viewPagerAusweis);
ausweisPageAdapter = new AusweisPageAdapter(getChildFragmentManager(), tabLayout1.getTabCount());
viewPager.setAdapter(ausweisPageAdapter);
viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout1));
...
...
Hopefuly this will help some people when they face the same problem with nested fragments.

Cannot Resolve Symbol CrimeFragment Android Studio

I am getting a cannot resolve symbol error on CrimeFragment and I don't know why. I am a beginner so I'm not sure how to fix this. Here is the code for CrimeActivity.java
package com.bignerdranch.android.criminalintent;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
public class CrimeActivity extends FragmentActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_crime);
FragmentManager fm = getSupportFragmentManager();
Fragment fragment = fm.findFragmentById(R.id.fragment_container);
if (fragment == null) {
fragment = new CrimeFragment();
fm.beginTransaction()
.add(R.id.fragment_container, fragment)
.commit();
}
}
}

Seems like you aren't importing your class CrimeFragment

Make sure that CrimeFragment.java and Crime.java are in the right packages. Select "Packages" view in the top-left corner. If these files hang around separately at the bottom, drag and drop them into the "com.(..).criminalintent" package.

OnListItemClick Shift from one ListFragement to Another using fragment Transactions

I have a list fragment from where when any list item is clicked, I want to move to another list fragement.
import java.util.Arrays;
import java.util.List;
import android.os.Bundle;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.app.ListFragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ListView;
public class Schedule extends ListFragment{
....
....
public void onListItemClick(ListView l, View v, int position, long id) {
....
android.support.v4.app.FragmentManager fragmentManager = getFragmentManager();
android.support.v4.app.FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
DailyList fragment = new DailyList();
fragmentTransaction.replace(R.id.list_fragment, fragment);
fragmentTransaction.commit();
}
This is the new class that I am trying to move to.
public class DailyList extends ListFragment {
public View onCreateView(LayoutInflater inflater,
ViewGroup container, Bundle savedInstanceState){
final View theInflatedView = inflater.inflate(R.layout.day, container, false);
return theInflatedView;
}
....
....
....
}
I tried using v4 android support libraries. but the replace call is giving me this error "The method replace(int, Fragment) in the type FragmentTransaction is not applicable for the arguments (int, DailyList)".
I read few other answers that asked to use v4. That is what I am doing. But still getting error. Please help me out here. Thanks!

I think you are mixing newer fragment support types with support classes. Replace these lines:
import android.app.Fragment;
import android.app.FragmentManager;
with:
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
Then extend 
android.support.v4.app.FragmentActivity
 instead of 
Activity
 and change calls like 
getFragmentManager()
 with 
getSupportFragmentManager()
 and similarly for other methods that you might be using.

Adding extended fragment to Activity

I have been trying to build a Master-Detail f low in android but wanted to change one of the detail fragments to a different fragment. As this is one of my first Android applications, I was just trying to make a picture appear on this new fragment. For this, I built the following two classes
1) Fragment class ( displays the picture to be displayed )
package com.userName.miscapp;
import com.userName.miscapp.dummy.DummyContent;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class PictureFragment extends Fragment {
// Default Copy Constructor for the fragment
public PictureFragment() {
}
#Override
public void onCreate ( Bundle savedInstanceState )
{
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView ( LayoutInflater inflater , ViewGroup container , Bundle savedInstanceState )
{
View rootView = inflater.inflate(R.layout.fragment_simple_picture, container, false);
return rootView;
}
}
2) Activity to display the same
package com.userName.miscapp;
import android.os.Bundle;
import android.app.Activity;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.view.Menu;
public class SimplePicture extends FragmentActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getActionBar().setDisplayHomeAsUpEnabled(true);
if (savedInstanceState == null) {
// Create the detail fragment and add it to the activity
// using a fragment transaction.
Bundle arguments = new Bundle();
arguments.putString(ItemDetailFragment.ARG_ITEM_ID,
getIntent().getStringExtra(ItemDetailFragment.ARG_ITEM_ID));
PictureFragment frag = new PictureFragment();
frag.setArguments(arguments);
android.support.v4.app.FragmentManager fragmentManager = getSupportFragmentManager();
android.support.v4.app.FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.add(R.id.simple_picture_container,frag).commit();
//setContentView(R.layout.activity_simple_picture);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.simple_picture, menu);
return true;
}
}
On compilation, it does not recognize the PictureFragment to be an extension of Fragment class. This is inspite of it being clearly written in the first file. Searching for solutions on Stackoverflow said to extend FragmentActivity instead of Activity and trying to use getSupportFragmentManager() neither of which helped.
PS : Using 11 as the base for the current application.
Any help would be appreciated
Thanks

This is because you are using android.app.Fragment from new API in conjunction with android.support.v4.app.FragmentManager from support library, you should replace import in your PictureFragment from android.app.Fragment to android.support.v4.app.Fragment to make it work.