Develop Reference

if (view == null) issues in fragment

I have updated my Sdk Oreo 8.0 When i come my current fragment to my previous fragment its crash because i am using if (view == null)
if i removed this condition it 'll work fine but have to load again view.
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container,
#Nullable Bundle savedInstanceState) {
if (view == null) {
view = inflater.inflate(R.layout.home_fragement_layout, container, false);
ButterKnife.bind(this, view);
bundle=getArguments();
registrationResponse=(RegistrationResponse)bundle.getSerializable("registerresponse");
setadapter();
hitUserFavouriteOutfitsapi();
swipeRefreshLayout.setOnRefreshListener(this);
}
toolBarTopChangeState =((ToolBarTopChangeState)context);
toolBarTopChangeState.stateChangeToolBarIcon(0);
toolBarTopChangeState.stateChangeToolBarText(getString(R.string.app_name));
return view;
}

Use this code:
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container,
#Nullable Bundle savedInstanceState) {
view = inflater.inflate(R.layout.home_fragement_layout, container, false);
ButterKnife.bind(this, view);
bundle=getArguments();
registrationResponse=(RegistrationResponse)bundle.getSerializable("registerresponse");
setadapter();
hitUserFavouriteOutfitsapi();
swipeRefreshLayout.setOnRefreshListener(this);
toolBarTopChangeState =((ToolBarTopChangeState)context);
toolBarTopChangeState.stateChangeToolBarIcon(0);
toolBarTopChangeState.stateChangeToolBarText(getString(R.string.app_name));
return view;
}

On the lists is a good practice to check if the view is already created and if it's to use it further, but on the activities and fragments you should left the OS to decide when should inflate again the view. You can have a look over android lifecycle to understand better how it's works

it 'll happen because i am adding animation when fragment change and return to back.. This problem facing because of Android 8.0(Oreo) rest os working fine so I removed the animation during fragment change it 'll solved.

Get list of all on screen UI elements

It is possible to get a list of all the currently displayed/on-screen android UI elements?
For example, if I have a app that look like this:
I would get a list that would contain:
TextView (Hello World!)
RelativeLayout (Or whatever the parent container is)
Etc if there were more elements
This would be great in the case I don't know the ID's, or even what UI elements will appear on screen, but I still want to hide/show them.

You can achieve this by using the following manager, nice and clean!
Use it anywhere you want and you'll get a list of the view and all its children.
(Needs to be done recursively)
LayoutManager.getViews(getWindow());
public class LayoutManager
{
private static List<View> views;
public static List<View> getViews(Window window) {
return getViews(window.getDecorView().getRootView(), true);
}
public static List<View> getViews(final View view, boolean starting)
{
if (starting) {
views = new ArrayList<>();
}
views.add(view);
/** Search in each ViewGroup children as well */
if (view instanceof ViewGroup) {
ViewGroup viewGroup = (ViewGroup) view;
for (int i = 0; i < viewGroup.getChildCount(); i++) {
getViews(viewGroup.getChildAt(i), false);
}
}
return views;
}
}

How to count amount of views in layout

Is there a way for Android Studio to show how many views that are present within an XML layout? As we all know, layouts should contain <=80 views hence any more than that then this warning appears therefore it would be very helpful to be told the amount.
LayoutName.xml has more than 80 views, bad for performance
public class FragmentApple extends android.support.v4.app.Fragment {
public FragmentApple () {
}
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_apple,container,false);
int num = FragmentApple.getChildCount(); Log.d("Number of views in layout: ", "" + num);
return v;
}
}

Have you tried this?:
layout.getChildCount();
UPDATE
after what we discussed in the comments, this is what you should do within your code:
public class FragmentApple extends android.support.v4.app.Fragment {
public FragmentApple () {
}
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_apple,container,false);
return v;
}
#Override
public void onStart(){
super.onStart()
RelativeLayout (or Linear as in your xml) rl = (RelativeLayout) v.findViewbyId(R.id.your_layout_id)
int num = rl.getChildCount();
Log.d("Number of views in layout: ", "" + num);
}
}

for new comers to this question, you could use the view hierarchy from android studio's android device monitor:
open the app from your device or an emulator, and browse to the view that you want to inspect
1- from the Studio's Menu bar open
tools -> Android -> Android device monitor
2- from Android device monitor Menu bar open
window -> open perspective -> Hierarchy view
it may load for some time.
if you want to learn more: https://developer.android.com/studio/profile/hierarchy-viewer.html

View getting blurred occasionally on a specific Android device

I have come across a problem where the screen of my Android device(Moto G2) gets blurred on click of a specific button in my app. This event happens occasionally and not everytime I click this button.
This scenario is not happening on few other devices (like LG G3) in which I have tested the app for some time.
I couldnot find anything related or useful in the Logs either.
Just to add, the Log in button which is posing this issue is in a view of a fragment attached.
A screenshot of the scenario :
Adding code in the Activity's onCreate() where it adds the Fragments :
if (savedInstanceState == null) {
facebookLoginBtnFragment = new FacebookLoginBtnFragment();
getSupportFragmentManager().beginTransaction()
.add(R.id.container, facebookLoginBtnFragment).commit();
googleLoginBtnFragment = new GoogleLoginBtnFragment();
getSupportFragmentManager().beginTransaction()
.add(R.id.container2, googleLoginBtnFragment).commit();
} else {
facebookLoginBtnFragment = (FacebookLoginBtnFragment)getSupportFragmentManager().findFragmentById(R.id.container);
googleLoginBtnFragment = (GoogleLoginBtnFragment)getSupportFragmentManager().findFragmentById(R.id.container2);
}
Below is the code of onCreateView() of the Google + fragment :
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_gplusloginbtns, container, false);
gplusButton = (SignInButton)rootView.findViewById(R.id.GPlus_Sign_in_button); gplusButton.setOnClickListener(this);
setGooglePlusButtonText(gplusButton, "Log in with Google");
rootView.findViewById(R.id.GPlus_sign_out_button).setOnClickListener(this);
if (mActivity.getClass().toString().contains("ShowProfile_act")) {
rootView.findViewById(R.id.GPlus_Sign_in_button).setVisibility(View.GONE);
} mConnectionProgressDialog = new ProgressDialog(getActivity()); mConnectionProgressDialog.setMessage("Logging in...");
return rootView;
}
Below is the code for setGooglePlusButtonText() method :
private void setGooglePlusButtonText(SignInButton signInButton, String buttonText) {
// Find the TextView that is inside of the SignInButton and set its text
for (int i = 0; i < signInButton.getChildCount(); i++) {
View v = signInButton.getChildAt(i);
if (v instanceof TextView) {
TextView tv = (TextView) v;
tv.setText(buttonText);
return;
}
}
}
-->The others methods of the fragment deal with connection maintenance part with the Google+ API.I assume they might not be relevant
Any suggestions, advices on the cause and how to avoid such scenarios would be helpful.

Android Maps api v2 strange phenomenon

I've integrated a map fragment (Android Maps Api V2) in my app, and this works fine as shown in this pic :
but when soft keybord is shown, map is slided to top and becomes blank as shown in the following pic :
I also must say that this phenomenon accurs on a galaxy S (2.3.3) not in galaxy SIII and even not in galaxy Y, is it a performance problem or bug or am I missing anything ?
Please help if you ever have encountred this problem..
Thanks.

You could try this:
public class MyMapFragment extends SupportMapFragment() {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = super.onCreateView(inflater, container, savedInstanceState);
setMapTransparent((ViewGroup) view);
return view;
};
private void setMapTransparent(ViewGroup group) {
int childCount = group.getChildCount();
for (int i = 0; i < childCount; i++) {
View child = group.getChildAt(i);
if (child instanceof ViewGroup) {
setMapTransparent((ViewGroup) child);
} else if (child instanceof SurfaceView) {
child.setBackgroundColor(0x00000000);
}
}
}
// ...
};
Instead of using the mapFragment provided by google, use this one. It fixed the same issue for me, but it was doing it on a sliding menu.
Credits to: https://github.com/jfeinstein10/SlidingMenu/issues/168#issuecomment-11834105