We Keep Coding

Changing Fragments. Why does it not work

I got this Code for changing Fragments with a Navigation drawer in Android Java. Simply followed official Googles Dev Posts and other pages, but it still doesn't work. Just the Header of the page changes but not the layout. Tell me please why, i wouldn't be asking if i havent tried a lot and read other Posts.
So here's my Code:
In MainActivity Java file
#Override
public boolean onNavigationItemSelected(MenuItem item) {
int id = item.getItemId();
Fragment f = null;
Class fClass = null;
// Tasklist
if (id == R.id.nav_drawer_main_tasklist) {
fClass = TaskList.class;
}
try{
f=(Fragment) fClass.newInstance();
}catch (Exception e){
e.printStackTrace();
}
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction().replace(R.id.frame_main,f).commit();
item.setChecked(true);
setTitle(item.getTitle());
// Drawer
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawerlayout_main);
drawer.closeDrawer(GravityCompat.START
);
in TaskList Java
public class TaskList extends Fragment {
View view;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, Bundle savedInstanceState) {
view = inflater.inflate(R.layout.activity_main_tasklist, container, false);
return super.onCreateView(inflater, container, savedInstanceState);
}
in tasklists XML file
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
tools:context="***">
<android.support.design.widget.FloatingActionButton
android:id="#+id/fab_main_createtask"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentEnd="true"
android:layout_alignParentRight="true"
android:layout_gravity="bottom|end"
android:onClick="fab_main_createtask_onClick"
app:srcCompat="#drawable/ic_add_white_24dp"
tools:layout_editor_absoluteX="0dp"
tools:layout_editor_absoluteY="0dp" />
<LinearLayout
android:layout_width="0dp"
android:layout_height="0dp"
android:orientation="horizontal"
tools:layout_editor_absoluteX="8dp"
tools:layout_editor_absoluteY="8dp">
</LinearLayout>
</RelativeLayout>

#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, Bundle savedInstanceState) {
view = inflater.inflate(R.layout.activity_main_tasklist, container, false);
return super.onCreateView(inflater, container, savedInstanceState);
}
the above is wrong, return the inflated layout and remove nullable.
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, Bundle savedInstanceState) {
view = inflater.inflate(R.layout.activity_main_tasklist, container, false);
return view;
}

You have to return your own fragment view. Update your TaskList fragment as below:
public class TaskList extends Fragment {
View view;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, Bundle savedInstanceState) {
view = inflater.inflate(R.layout.activity_main_tasklist, container, false);
return view ;
}
}

How to customize title in DialogFragment

I want to customize my title in my DialogFragment, I know how to How to set the title to my DialogFragment , but I want more not just a title , I need a customized title(color,fontSize ...), So I defined a TextView and customized it
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.height_fragment,container,false);
TextView title = new TextView(getContext());
title.setText("Your Height Information");
title.setGravity(Gravity.CENTER);
title.setTextSize(30);
title.setBackgroundColor(Color.GRAY);
title.setTextColor(Color.WHITE);
getDialog().setCustomTitle(title); //Error Can not resolve method setCustomTitle(android.widget.TextView)
return view;
}
but there is an error on this line
getDialog().setCustomTitle(title);
getDialog().setCustomTitle(title);
I searched a lot before posting this question but I couldn't find how can I customize my title of DialogFragment.
Thank you for taking time to help me

"getDialog" does not have a method "setCustomTitle".This method can only be used for AlertDialog.Builder. Try it like this:
getDialog().setTitle("Your Height Information");
TextView textView=(TextView) getDialog().findViewById(android.R.id.title);
textView.setTextSize(30);

I never could easily customize the Title of my DialogFragment. So, instead, I use to remove the title and add a TextView to Dialog layout (and use it like a Title). This way, you can customize how you want and easily.
Dialog Code:
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
// Remove TITLE
getDialog().getWindow().requestFeature(Window.FEATURE_NO_TITLE);
View dialogView = dialogView = inflater.inflate(R.layout.height_fragment, null);
// Do your stuff
return dialogView;
}
height_fragment.xml
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<TextView
android:id="#+id/dialog_title"
android:layout_width="match_parent"
android:layout_height="56dp"
<!-- THIS VIEW IS YOUR TITLE... CUSTOMIZE LYKE YOU WANT -->
android:textColor="#color/white"
android:textSize="18sp"
android:textStyle="bold"
android:layout_gravity="top"
android:text="#string/TITLE"
android:gravity="center_vertical"
android:paddingLeft="16dp" />
<!-- Real Content goes below the title -->
</FrameLayout>

You need to connect your xml to your class. findViewById tells your class which TextView to use. Notice how it must match the android:id in the xml:
public class DialogFragmentTest extends DialogFragment {
public final static String TITLE = "title";
public final static String MESSAGE = "message";
#Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
// Get the layout inflater
LayoutInflater inflater = getActivity().getLayoutInflater();
View view = inflater.inflate(R.layout.dialog, null);
// Inflate and set the layout for the dialog
// Pass null as the parent view because its going in the dialog layout
builder.setView(view);
Bundle args = getArguments();
String title = args.getString(TITLE, "default title");
String msg = args.getString(MESSAGE, "default message");
TextView tvTitle = (TextView)view.findViewById(R.id.dialog_title);
tvTitle.setText(title);
TextView tvMessage = (TextView)view.findViewById(R.id.dialog_message);
tvMessage.setText(msg);
Button btnDone = (Button)view.findViewById(R.id.dialog_button);
btnDone.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
dismiss();
}
});
return builder.create();
}
}
dialog.xml:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="300dp"
android:layout_height="wrap_content">
<TextView
android:id="#+id/dialog_title"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center_horizontal"
android:text="title"/>
<TextView
android:id="#+id/dialog_message"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="#id/dialog_title"
android:layout_marginTop="10dp"
android:text="message"/>
<Button
android:id="#+id/dialog_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#id/dialog_message"
android:layout_marginTop="20dp"
android:layout_centerHorizontal="true"
android:text="done"/>
</RelativeLayout>
This is then called from your activity with:
DialogFragmentTest bd = new DialogFragmentTest();
Bundle b = new Bundle();
b.putString(DialogFragmentTest.TITLE, "my title");
b.putString(DialogFragmentTest.MESSAGE, "my message");
bd.setArguments(b);
bd.show(getFragmentManager(), "my title");

Please, use custom dialog, based on DialogFragment:
public class MyCustomDialog extends DialogFragment{
private Context context;
#Override
public void onAttach(Context context) {
super.onAttach(context);
this.context = context;
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, Bundle savedInstanceState) {
View dialogView = inflater.inflate(R.layout.custom_dialog, null, false);
TextView tvTitle = (TextView) getDialog().findViewById(android.R.id.title);
tvTitle.setTextSize(25);
tvTitle.setTextColor(Color.GREEN);
return dialogView;
}
#Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
Dialog dialog = new Dialog(this.context, R.style.CustomDialog);
dialog.setTitle("custom dialog title");
dialog.getWindow().setLayout(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
return dialog;
}
public static MyCustomDialog newInstance() {
MyCustomDialog myCustomDialog = new MyCustomDialog();
return myCustomDialog;
}
}

How do I dynamically make this child Fragment's TextView visible/invisible?

I have a main Activity containing a parent Fragment, which in turn contains a child Fragment. I am trying to make a TextView in the child Fragment visible/invisible dynamically.
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="This text belongs to the Activity"
android:id="#+id/textView"/>
<FrameLayout
android:id="#+id/parent_container"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
fragment_parent.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="This text belongs to the parent fragment"
android:id="#+id/textView"/>
<FrameLayout
android:id="#+id/child_container"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
fragment_child.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="This text belongs to the child fragment"
android:id="#+id/textView"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="But make this text visible dynamically!"
android:id="#+id/make_this_text_visible"
android:visibility="invisible"/>
</LinearLayout>
MainActivity.java
public class MainActivity extends AppCompatActivity {
public static final String PARENT_TAG = "parent_tag";
private ParentFragment mParentFragment;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (savedInstanceState == null) {
mParentFragment = ParentFragment.newInstance();
getSupportFragmentManager().beginTransaction().replace(R.id.parent_container, mParentFragment, PARENT_TAG).commit();
}
else {
mParentFragment = (ParentFragment) getSupportFragmentManager().findFragmentByTag(PARENT_TAG);
}
}
}
ParentFragment.java
public class ParentFragment extends Fragment {
public static final String CHILD_TAG = "child_tag";
private ChildFragment mChildFragment;
private List<Integer> mList;
public static ParentFragment newInstance() {
Bundle args = new Bundle();
ParentFragment fragment = new ParentFragment();
fragment.setArguments(args);
return fragment;
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_parent, container, false);
mList = new ArrayList<Integer>();
if (savedInstanceState == null) {
mChildFragment = ChildFragment.newInstance();
getChildFragmentManager().beginTransaction().replace(R.id.child_container, mChildFragment, CHILD_TAG).commit();
}
else {
mChildFragment = (ChildFragment) getChildFragmentManager().findFragmentByTag(CHILD_TAG);
}
getChildFragmentManager().executePendingTransactions(); //doesn't seem to do anything!
doStuff();
return view;
}
void doStuff() {
mList.add(4); //pretend this is actually querying a database.
//for simplicity it just receives a single 4.
if (mList.size() > 0) { //the list is not empty, display the text!
mChildFragment.setTextVisible(); //error! the textivew of the child fragment is null right now
}
else {
mChildFragment.setTextInvisible(); //error! the textivew of the child fragment is null right now
}
}
}
ChildFragment.java
public class ChildFragment extends Fragment {
private TextView mTextView;
public static ChildFragment newInstance() {
Bundle args = new Bundle();
ChildFragment fragment = new ChildFragment();
fragment.setArguments(args);
return fragment;
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_child, container, false);
mTextView = (TextView) view.findViewById(R.id.make_this_text_visible);
return view;
}
public void setTextVisible() {
mTextView.setVisibility(View.VISIBLE);
}
public void setTextInvisible() {
mTextView.setVisibility(View.INVISIBLE);
}
}
How can I ensure that the child fragment is formed by the time I call doStuff() in the ParentFragment?

What I would do is keep the state of the text view visibility so it can be updated properly once the view has been created if it hasn't been already. Instead of separate methods for setTextVisible() and setTextInvisible have a single method setTextVisibile(boolean isVisible) and implement it as follows:
public class ChildFragment extends Fragment {
private TextView mTextView;
private boolean mIsTextVisible;
public static ChildFragment newInstance() {
Bundle args = new Bundle();
ChildFragment fragment = new ChildFragment();
fragment.setArguments(args);
return fragment;
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_child, container, false);
mTextView = (TextView) view.findViewById(R.id.make_this_text_visible);
setTextVisible(mIsTextVisible);
return view;
}
public void setTextVisible(boolean isVisible) {
mIsTextVisible = isVisible;
if(mTextView != null) {
mTextView.setVisibility(isVisible ? View.VISIBLE : View.GONE);
}
}
}
and then in the parent fragment you can call doStuff() without worrying about the current state of the views in the ChildFragment since mIsTextVisible is properly set. If the mTextView is null at the time setTextVisible() is called the visibility will still be properly set in onCreateView().
Just take care to save and restore the mIsTextVisible flag when the fragment is recreated such as when the device is rotated.
Alternative Answer Using A Callback
Using callbacks update the ParentFragment to implement
ChildFragment.OnViewCreatedListener and its method.
public class ParentFragment extends Fragment
implements ChildFragment.OnViewCreatedListener {
#Override
public void onViewCreated() {
doStuff();
}
}
And then in ChildFragment
public class ChildFragment extends Fragment {
public interface OnViewCreatedListener {
void onViewCreated();
}
public View onCreateView(LayoutInflater inflater,
#Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_child, container, false);
mTextView = (TextView) view.findViewById(R.id.make_this_text_visible);
if(getParentFragment() instanceof OnViewCreatedListener) {
((OnViewCreatedListener) getParentFragment()).onViewCreated();
} else if (getActivity() instanceof OnViewCreatedListener) {
((OnViewCreatedListener) getActivity()).onViewCreated();
}
return view;
}
}

Change TextView inside Fragment gives me NullPointerException

I'm trying to change a Textview's text inside a fragment, but it gaves me a NullPointerException at the setName method.
I have already tried 2 ways to do this:
public class MemberFragment extends Fragment {
private TextView tvName;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view;
view = inflater.inflate(R.layout.fragment_member,container, false);
tvName = (TextView) getView().findViewById(R.id.tvProfileName);
return view;
}
public void setName(String name) {
tvName.setText(name);
}
or:
public class MemberFragment extends Fragment {
private static TextView tvName;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view;
view = inflater.inflate(R.layout.fragment_member,container, false);
return view;
}
public void setName(String name) {
tvName = (TextView) getView().findViewById(R.id.tvProfileName);
tvName.setText(name);
}
but none gave me success. Here is where I instantiate the fragment:
MemberFragment fragment = new MemberFragment();
FragmentManager fm = getFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
ft.replace(R.id.content_frame, fragment);
ft.commit();
fragment.setName(map.get(Tags.NAME));
and the fragment_member.xml:
<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
style="#style/ActionBar.Transparent.MyStyle"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="top" >
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="446dp" >
<TextView
android:id="#+id/tvProfileName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:text="Large Text"
android:textAppearance="?android:attr/textAppearanceLarge" />
</RelativeLayout>
</ScrollView>
Can someone help me?
Thanks.

view in your onCreateView method is the rootView of your fragment.
So just add the following code in your onCreateView method to change the text of your TextView:
((TextView)view.findViewById(R.id.tvProfileName)).setText("Your new text");

try this:
tvName = (TextView) view.findViewById(R.id.tvProfileName);
instead of :
tvName = (TextView) getView().findViewById(R.id.tvProfileName);

NullPointer Exception when assigning value to TextView

I just wanted to passing value from one activity to another but not able to find Textview value from the view.. I just passing one message from main activity to this activity through a text box and I'm seeing textbox value here but not able to assign that to textView...
here is my code..
public class DisplayMessageActivity extends Activity {
private TextView textView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_display_message);
if (savedInstanceState == null) {
getFragmentManager().beginTransaction()
.add(R.id.container, new PlaceholderFragment()).commit();
}
textView = (TextView) findViewById(R.id.displayText);
Intent intent = getIntent();
String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);
textView.setText(message);
}
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="com.example.activityapps.DisplayMessageActivity$PlaceholderFragment" >
<TextView
android:id="#+id/displayText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:text="TextView" />
Please help me out..

The TextView does not belong to the Activity layout. Move the initialization of TextView to onCreateView of PlaceholderFragment.
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_display_message, container, false);
TextView textView = (TextView) rootView.findViewById(R.id.displayText);
return rootView;
}
In Activity
if (savedInstanceState == null) {
String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);
Bundle bundle = new Bundle();
bundle.putString("key", message);
PlaceholderFragment fragobj = new PlaceholderFragment();
fragobj.setArguments(bundle);
getFragmentManager().beginTransaction()
.add(R.id.container, fragobj).commit();
}
Then
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_display_message, container, false);
TextView textView = (TextView) rootView.findViewById(R.id.displayText);
String strtext = getArguments().getString("key");
textView.setText(strtext);
return rootView;
}

View view = inflater.inflate(R.layout.fragment_display_message, container, false);
TextView textView = (TextView) view.findViewById(R.id.displayText);
return view; //in onCreate method
you have extended from activity you can use also this
TextView textView = (TextView) findViewById(R.id.displayText);
//in onCreate method