I'm quite new working with Android/Java, so please bear with me.
I moved code from LoginActivity > onCreate into a fragment I created FragmentLogin to method onCreate where many classes no longer resolve, such as findViewById. I'm assuming that somewhere I didn't pass the context of the container Activity properly.
Or some other newbie mistake...
Here is LoginActivity.java [relevant parts copied]
public class LoginActivity extends FragmentActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Initialize Fragments //
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
setContentView(R.layout.fragment_login);
}
}
and FragmentLogin.java:
public class FragmentLogin extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_login, container, false);
final ValidationManager Check = new ValidationManager();
final SessionManager Session = new SessionManager(this);
final EditText textEmail = (EditText) findViewById(R.id.login_email);
final EditText textPassword = (EditText) findViewById(R.id.login_pass);
final Button buttonLogIn = (Button) findViewById(R.id.button_login);
final Button buttonSignup = (Button) findViewById(R.id.button_signup);
// Listen for FORGOTTEN PASSWORD click event, open ForgottenPassword Fragment //
final Button forgottenPassword = (Button) findViewById(R.id.button_lost_pass);
forgottenPassword.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
setContentView(R.layout.fragment_forgotten_password);
}
});
... more code ...
}
}
The variables/methods that were working when the second block of code was residing in the onCreate method of the Activity but no longer resolve after I moved the code to onCreateView of the FragmentLogin fragment class:
findViewById, setContentView
Basically, this is a login form where the default fragment should be login, and a button on that page (Button forgottenPassword) would open another fragment (FragmentForgottenPassword).
Can anyone tell me what I'm doing wrong?
In your activity layout xml file, add something similar to this:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<fragment android:name="your.package.FragmentLogin"
android:id="#+id/fragment_login"
android:layout_weight="1"
android:layout_width="0dp"
android:layout_height="match_parent" />
</LinearLayout>
In your LoginActivity: remove the fragment manager stuff. You don't need it yet.
public class LoginActivity extends FragmentActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.fragment_login);
}
}
In your FragmentLogin, move the return statement to the end and use the inflated view to find your views by id:
public class FragmentLogin extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
final view view = inflater.inflate(R.layout.fragment_login, container, false);
final ValidationManager Check = new ValidationManager();
final SessionManager Session = new SessionManager(this);
final EditText textEmail = (EditText) view.findViewById(R.id.login_email);
final EditText textPassword = (EditText) view.findViewById(R.id.login_pass);
final Button buttonLogIn = (Button) view.findViewById(R.id.button_login);
final Button buttonSignup = (Button) view.findViewById(R.id.button_signup);
// Listen for FORGOTTEN PASSWORD click event, open ForgottenPassword Fragment //
final Button forgottenPassword = (Button) view.findViewById(R.id.button_lost_pass);
forgottenPassword.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
setContentView(R.layout.fragment_forgotten_password);
}
});
... more code ...
return view;
}
}
You should get subviews from layout while it's being inflated. The layout usually inflated in OnCreateView method.
View layout = inflater.inflate( R.layout.fragment_login, null );
final EditText textEmail = (EditText) layout.findViewById(R.id.login_email);
final EditText textPassword = (EditText) layout.findViewById(R.id.login_pass);
...
return layout;
I am guessing you want to the fragment to be shown within the activity. Try this:
public class LoginActivity extends FragmentActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//put the setContentView() before the fragment initialization also, I noticed your activity layout is the same as your fragment layout,this should not be so, hence I changed that
setContentView(R.layout.activity_login);
// Initialize Fragments //
//you did not initialize the fragments completely, it should be like
//this
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction().replace(R.id.fragment_container, new FragmentLogin()).commit();
}}
then in the Login fragment, it should be like this:
public class FragmentLogin extends Fragment {#Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view=inflater.inflate(R.layout.fragment_login, container, false);
final ValidationManager Check = new ValidationManager();
final SessionManager Session = new SessionManager(this);
final EditText textEmail = (EditText) view.findViewById(R.id.login_email);
final EditText textPassword = (EditText) view.findViewById(R.id.login_pass);
final Button buttonLogIn = (Button) view.findViewById(R.id.button_login);
final Button buttonSignup = (Button) view.findViewById(R.id.button_signup);
// Listen for FORGOTTEN PASSWORD click event, open ForgottenPassword Fragment //
final Button forgottenPassword = (Button) view.findViewById(R.id.button_lost_pass);
forgottenPassword.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
//you cant call setContentView in a fragment
}
});
... more code ...
}}
I am not totally sure I caught all your mistakes but I think you should read these: one and two; they are online tutorials on fragments, you can also browse for more. I think it is a good starting point. All the best
Related
I am working on an android application where I have three fragments I want to show the back button on the toolbar of the fragments to go back to the previous fragments now how can I achieve that?? I am new to android please guide me.
public class SecondFragment extends Fragment {
Button button2;
private PageViewModel viewModel;
EditText editTextName, editTextEmail, editTextDesc;
public SecondFragment() {
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_second, container, false);
button2 = view.findViewById(R.id.next2);
editTextName = view.findViewById(R.id.edittextName);
editTextEmail = view.findViewById(R.id.edditextEmail);
editTextDesc = view.findViewById(R.id.edittexDesc);
viewModel = new ViewModelProvider(requireActivity()).get(PageViewModel.class);
button2.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if (editTextName.getText().toString().isEmpty() || editTextEmail.getText().toString().isEmpty() || editTextDesc.getText().toString().isEmpty())
{
editTextName.setError("Enter name");
editTextEmail.setError("Enter Email");
editTextDesc.setError("Enter Description");
}else {
// viewModel.setName(editTextName.getText().toString());
enterName(editTextName.getText().toString());
enterEmail(editTextEmail.getText().toString());
enterDesc(editTextDesc.getText().toString());
// viewModel.setEmail(editTextEmail.getText().toString());
// viewModel.setDescription(editTextDesc.getText().toString());
FragmentTransaction fragmentTransaction = getActivity().getSupportFragmentManager().beginTransaction();
Fragment NAME = new LastFragment();
fragmentTransaction.replace(R.id.container, NAME);
fragmentTransaction.commit();
}
}
});
return view;
}
this is the code of my fragment borther i have three fragments like this i need to add the back button on the toolbar of there three fragemtns
You can add a toolbar to your activity, which is the container for these fragments.
Then in your fragments you can do something like this:
private void setupToolbar() {
YourActivity yourActivity = (YourActivity) getActivity()
if(yourActivity != null) {
yourActivity.toolbar.setSkipVisibility(View.GONE) // Or View.VISIBLE
yourActivity.toolbar.setText() // Set some text
yourActivity.toolbar.setOnBackButtonClickListener{ yourActivity.onBackPressed() }
}
}
Follow the steps down below.
fragmentTransaction.replace(R.id.container, NAME);
fragmentTransaction.addToBackStack(null); //Add this line
fragmentTransaction.commit();
This will solve your issue. Thank you.
public class SlideshowFragment extends Fragment {
private FragmentSlideshowBinding binding;
public Button btn1,btn2;
#Override
public View onCreateView( LayoutInflater inflater,
ViewGroup container, Bundle savedInstanceState) {
btn1=(Button) findViewById (R.id.button); // find view by id is giving error
(Cannot resolve method 'findViewById' in 'SlideshowFragment)
btn2=(Button) findViewById (R.id.button2);
SlideshowViewModel slideshowViewModel =
new ViewModelProvider(this).get(SlideshowViewModel.class);
binding = FragmentSlideshowBinding.inflate(inflater, container, false);
View root = binding.getRoot();
// final TextView textView = binding.button;
//slideshowViewModel.getText().observe(getViewLifecycleOwner(), textView::setText);
return root;
btn1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
}
});
}
If you're using view binding you don't need to access your components with findViewById method. While using view binding, pressing dot (.) after calling your view binding reference will show you all available components in your layout. You can simply use:
btn1 = binding.button;
btn2 = binding.button2;
But if you still want to access your components with findViewById method you should use it with your root view reference:
btn1 = binding.getRoot().findViewById(R.id.button);
btn2 = binding.getRoot().findViewById(R.id.button2);
How to access button id in an activity.
Activity
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.fragment_meter);
if (Build.VERSION.SDK_INT >= 23) {
checkLocationPermission();
}
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
Fragment map = new Map();
fragmentTransaction.add(R.id.fragment_container, map);
fragmentTransaction.commit();
...
}
Fragment
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
if (view == null) {
view = inflater.inflate(R.layout.fragment_map, container, false);
Button button = (Button)getActivity().findViewById(R.id.btnStop);
}
How to implement setOnClickListener method of btnStop in my code fragment?
add this to fragment:
final View.OnClickListener btnClick = new View.OnClickListener() {
public void onClick(View v){
//button clicked
}
}
add this to activity onCreate:
Button button = (Button)getActivity().findViewById(R.id.btnStop);
button.setOnClickListener(map.btnClick );
another way:
add this to fragment:
Button btnStop;
add this to onCreate of Activity:
map.btnStop = (Button)getActivity().findViewById(R.id.btnStop);
Then in any event listener of fragment that is called after onCreate of Activity (for example onActivityCreated and onStart) you have access to the btnStop and you can set onClick listener for it.
You can create a method in the activity, probably like
public void yourMethod() {
button.performClick();// you can access all the components present in your activity
}
Now create an instance of the activity in the fragment and access this method.
YourActivity activityInstance = (YourActivity) getActivity();
And then you can access the method using the isntance of the activity like
activityInstance.yourMethod();
Whenever you want to perform a click function, you just have to call the funciton.
I've just moved my button onCreatView from my activity_main.java file to the correct file - my ConvertFragment.java file.
Now that I've copy and pasted the code, I'm getting a red-x errors on all of my findViewById's... any thoughts?
thanks in advance!
public class ConvertFragment extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_convert, container, false);
final EditText editDecimal = (EditText) findViewById(R.id.editDecimal);
final EditText editBinary = (EditText) findViewById(R.id.editBinary);
Button buttonConvert = (Button) findViewById(R.id.buttonConvert);
buttonConvert.setOnClickListener(new OnClickListener() {
public void onClick(View arg0) {
int decimal = Integer.valueOf(editDecimal.getText().toString());
editBinary.setText(Integer.toBinaryString(decimal));
}
});
return rootView;
}
}
It's because a fragment doesn't have a method findViewById().
You can either call that method on your activity:
getActivity().findViewById()
Or just use the layout that you've just inflated and find view's inside of it:
rootView.findViewById()
The 2nd one is better (IMO) as it doesn't rely on the activity.
I've got a Fragment implementing onClickListener. What I have is a custom dialer which must show on the edittext the introduced number. But it doesn't show anything.
This is the Fragment:
PhoneView.java
public class PhoneView extends Fragment implements OnTabChangeListener, OnClickListener {
...
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
mRoot = inflater.inflate(R.layout.phone_view, null);
mTabHost = (TabHost) mRoot.findViewById(android.R.id.tabhost);
setupTabs();
return mRoot;
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
setRetainInstance(true);
...
ImageButton button1 = (ImageButton) getView().findViewById(R.id.one);
EditText numTxt = (EditText) getView().findViewById(R.id.digits);
...
button1.setOnClickListener(this); //UPDATED - ADDED
...
}
#Override
public void onClick(View v) {
switch (v.getId()){
case R.id.one:
numTxt.setText(numTxt.getText()+"1");
break;
...
you have to call View.setOnClickListener(OnClickListener) of the view you want to react on the click event
In your Activity class, you need to define your Phoneview as you ClickListener to the button or another "view"
Suppose in your activity class, u have a button named deleteButton, and if u want to register a listener for this button... This is how you would do it.
private Button deleteButton= null;
deleteButton.setOnClickListener(PhoneView);