If I try to inflate a view within a fragment I am getting NULL.. For example:
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Here I will inflate my view using the layout ID & return.
return view;
}
Whenever a button is clicked I need to create a dynamic view e.g.: button & add to the LinearLayout. I would like to perform this operation inside my fragment class like this:
public void addPlaces() {
Button button = new Button(null);
button.setText("button name");
// e.g. like adding button to enter code here linear layout
linearLayout.addView(button);
}
So, if I get inflate LinearLayout inside onCreateView and use it in add class, I'm getting NULL. How to achieve?
Declare the variable as a instance variable and then initialize Linear Layout
LinearLayout linearLayout;
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment1, container, false);
linearLayout = (LinearLayout) rootView.findViewById(R.id.linearlayout);
return rootView;
}
Then
public void addPlaces() {
Button button = new Button(getActivity());
// needs activity context
// fragment hosted by a activity. use getActivity() to get the context of the hosting activity.
button.setText("button name");
linearlayout.addView(button);
}
Example: Modify the below according to your requirement.
fragment1.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:text="Button" />
<LinearLayout
android:layout_width="fill_parent"
android:id="#+id/linearlayout"
android:layout_height="fill_parent"
android:layout_above="#+id/button1"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:orientation="vertical" >
</LinearLayout>
</RelativeLayout>
Myfragment.java
public class Myfragment extends Fragment {
LinearLayout linearLayout;
View rootView;
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
Button b = (Button) rootView.findViewById(R.id.button1);
b.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
addPlaces();
}
});
linearLayout = (LinearLayout) rootView.findViewById(R.id.linearlayout);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
rootView = inflater.inflate(R.layout.fragment1, container, false);
return rootView;
}
public void addPlaces() {
Button button = new Button(getActivity()); // needs activity context
button.setText("button name");
linearLayout.addView(button);
}
}
Snap shot of my emulator
Edit :
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" >
<fragment android:name="com.example.fragments.Myfragment"
android:id="#+id/frag"
android:layout_above="#+id/button1"
android:layout_width="fill_parent"
android:layout_height="fill_parent" />
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:text="Button" />
</RelativeLayout>
MainActivity.java
public class MainActivity extends FragmentActivity {
Button b;
Myfragment fragment;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragment = new Myfragment();
fragmentTransaction.add(R.id.frag, fragment);
fragmentTransaction.commit();
b = (Button) findViewById(R.id.button1);
b.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
fragment.addPlaces();
}
});
}
}
Myfragment.java
public class Myfragment extends Fragment {
LinearLayout linearLayout;
View rootView;
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
linearLayout = (LinearLayout) rootView.findViewById(R.id.linearlayout);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
rootView = inflater.inflate(R.layout.fragment1, container, false);
return rootView;
}
public void addPlaces() {
Button button = new Button(getActivity()); // needs activity context
button.setText("button name");
linearLayout.addView(button);
}
}
Related
I am sending data from one fragment to another, using interface. This works absolutely fine. Now I am trying to use onSaveInstanceState() to save the value in
a Fragment and retrieving in onCreate(). however i'm getting null in Bundle of onCreate(). P.S. everything works fine when i set the Fragment directly into the activity layout in xml. but when i set the fragment through java code into the activity, the onSaveInstanceState is failing. It is not saving the last known value. Please help. Pasting the code below. You can try it out to know the exact issue.
Fragment_A :
public class Fragment_A extends Fragment implements View.OnClickListener {
Button btnAdd;
int counter = 0;
Communicator comm;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if(savedInstanceState != null){
counter = savedInstanceState.getInt("counter", 0);
}
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_a, container, false);
return view;
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
comm = (Communicator) getActivity();
btnAdd = (Button) getActivity().findViewById(R.id.btnAdd);
btnAdd.setOnClickListener(this);
}
#Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putInt("counter", counter);
}
#Override
public void onClick(View v) {
counter++;
comm.sendData(counter);
}
}
interface Communicator{
void sendData(int i);
}
=====
Activity :
public class Activity_InterComm extends Activity implements Communicator{
FragmentManager manager;
FragmentTransaction transaction;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_intercomm);
Fragment_A fragment_1 = new Fragment_A();
Fragment_B fragment_2 = new Fragment_B();
manager = getFragmentManager();
transaction = manager.beginTransaction();
transaction.add(R.id.frag_a, fragment_1, "Frag1");
transaction.add(R.id.frag_b, fragment_2, "Frag2");
transaction.commit();
}
#Override
public void sendData(int i) {
manager = getFragmentManager();
Fragment_B fragment_b = (Fragment_B) manager.findFragmentById(R.id.frag_b);
fragment_b.setData("Button has been clicked " + i + " times");
}
}
=====
Fragment_B :
public class Fragment_B extends Fragment {
TextView txtMessage;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_b, container, false);
return view;
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
txtMessage = (TextView) getActivity().findViewById(R.id.txtMessage);
}
public void setData(String message){
txtMessage.setText(message);
}
}
activity_intercomm.xml :
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<!--<fragment
android:id="#+id/frag_a"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_marginBottom="8dp"
android:layout_weight="1"
android:name="android.learning.com.fragintercomm.Fragment_A"/>
<fragment
android:id="#+id/frag_b"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:name="android.learning.com.fragintercomm.Fragment_B"/>-->
<LinearLayout
android:id="#+id/frag_a"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_marginBottom="8dp"
android:layout_weight="1"
android:background="#color/colorAccent"
android:orientation="vertical"/>
<LinearLayout
android:id="#+id/frag_b"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_marginBottom="8dp"
android:layout_weight="1"
android:background="#color/colorPrimaryDark"
android:orientation="vertical"/>
</LinearLayout>
the soluion I found was using getView() instead of getActivity() while initializing the button in Fragment_A. use btnAdd = (Button) getView().findViewById(R.id.btnAdd); instead of btnAdd = (Button) getActivity().findViewById(R.id.btnAdd);.
However, you can't use getView() in Fragment_B. The Textview freezes and, onSaveInstanceStat() doesn't work. Please suggest a solution.
Im using the following code to create Floating Action button. Its within a relative layout.
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:fab="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/tools"
android:background="#drawable/form_bg">
<android.support.design.widget.FloatingActionButton
android:id="#+id/myFAB"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/fab_bg_mini"
app:elevation="4dp"/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/trans_white"
android:gravity="center"
android:orientation="vertical"
android:padding="10dp">
<WebView
android:id="#+id/chart"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
</RelativeLayout>
Here is how Im setting the onClickListener for the floating action button within onCreateView method.
public class TrendChart extends Fragment {
private View mRootview;
private static final String URL = "file:///android_asset/taskstatus.html";
private WebView chart;
class InnerWebView extends WebViewClient {
InnerWebView() {
}
public void onPageFinished(WebView view, String url) {
view.loadUrl("javascript: loadTrendChart();");
}
}
public static final TrendChart newInstance(String company_name) {
TrendChart f = new TrendChart();
f.setArguments(new Bundle(1));
return f;
}
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
setHasOptionsMenu(true);
mRootview = inflater.inflate(R.layout.trend_chart, null);
this.chart = (WebView) mRootview.findViewById(R.id.chart);
this.chart.getSettings().setJavaScriptEnabled(true);
this.chart.setWebChromeClient(new WebChromeClient());
this.chart.setWebViewClient(new InnerWebView());
refreshWebView();
return mRootview;
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
FloatingActionButton myFab = (FloatingActionButton) getActivity().findViewById(R.id.myFAB);
myFab.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
Log.d("Clicked","Hello");
}
});
}
private void refreshWebView() {
this.chart.loadUrl(URL);
}
}
The problem is that onClickListener is not getting fired. Why is that so? I tried putting listener within onCreateView method too but still the problem persists. Is there any ways through which I can use floating button within a class that extends Fragments?
You have to put your code when the Activity is fully created as follows :
#Override
public void onActivityCreated(Bundle savedInstanceState)
{
// TODO Auto-generated method stub
super.onActivityCreated(savedInstanceState);
FloatingActionButton myFab = (FloatingActionButton) getActivity().findViewById(R.id.myFAB);
myFab.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
Log.d("Check","Clicked");
}
});
}
If you have your code on onCreateView() your code should look like this :
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.YOUR_LAYOUT, container, false);
FloatingActionButton myFab = (FloatingActionButton) view.findViewById(R.id.myFAB);
myFab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
//Do stuff
}
});
return view;
}
EDIT
Change this :
mRootview = inflater.inflate(R.layout.trend_chart, null);
to this :
mRootview = inflater.inflate(R.layout.trend_chart, container, false);
I am new to the android platform so I know I am just missing something by here is what I have
<!-- activity_main -->
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.example_app.MainActivity"
tools:ignore="MergeRootFrame" >
<fragment
android:id="#+id/mainFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
class="com.example.example_app.MainFragment"
/>
</FrameLayout>
Then I created a fragment called MainFragment.java.
public class MainFragment extends Fragment {
public TextView displayTextView;
public MainFragment() { }
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
this.displayTextView = (TextView)rootView.findViewById(R.id.displayTextView);
return rootView;
}
}
I add the fragment in the OnCreate function in the activity and it seems to be adding everything okay but when I click on the button nothing happens, I logged the function to see its being called but setting the textview doesn't do anything. What am I doing wrong?
<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.example_app.MainActivity$PlaceholderFragment" >
<Button
android:id="#+id/button10"
android:textColor="#ffffff"
android:textSize="34dp"
android:text="10%"
android:layout_below="#id/amountEditText"
android:background="#drawable/pct_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="doSomething"
/>
<TextView
android:text="Blah Blah Blah"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/displayTextView"
></TextView>
</RelativeLayout>
And here is the click Event in the MainActivity.java
public void doSomething(View v) {
this.mainFragment.displayTextView.setText("Nothing to set for some reason!");
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (savedInstanceState == null) {
//
this.mainFragment = (MainFragment) getSupportFragmentManager().findFragmentById(R.id.mainFragment);
mainFragment = new MainFragment();
getSupportFragmentManager().beginTransaction().add(mainFragment, "mainFragment").commit();
}
}
Declaring onClick-Listeners via XML is possible if you work with Activities. According to the Google API, however, you need to declare OnClickListeners programmatically if you use Fragments.
[...] You can also declare the click event handler programmatically rather than in an XML layout. This might be necessary if you instantiate the Button at runtime or you need to declare the click behavior in a Fragment subclass.
Source:
http://developer.android.com/guide/topics/ui/controls/button.html
So you may want to use this instead:
public class MainFragment extends Fragment {
public TextView displayTextView;
public Button yourButton;
public MainFragment() { }
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
this.displayTextView = (TextView)rootView.findViewById(R.id.displayTextView);
yourButton = (Button)rootView.findViewById(R.id.button10);
yourButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
displayTextView.setText("Nothing to set for some reason!");
}
});
return rootView;
}
}
The problem is the way you try to execute the button click. From your question i understand that Button and TextView is in Fragment view. So do why are Trying to access it in activity ?? It is wrong, then there is no point of using Fragments. Also this will lead to many serious issues later .
Fragments are Reusable components so all the functionalities of a fragment must stay inside the Fragment Class
Change Fragment code :
public class MainFragment extends Fragment {
public TextView displayTextView;
public Button yourButton;
public MainFragment() { }
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
this.displayTextView = (TextView)rootView.findViewById(R.id.displayTextView);
yourButton = (Button)rootView.findViewById(R.id.button10);
//Setting click listener for button in fragment
yourButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
displayTextView.setText("Nothing to set for some reason!");
}
});
return rootView;
}
}
and remove android:onClick="doSomething" from XML
I want to show a Button and a PieChart below in a tab.
Thats the code I worked with: https://github.com/JakeWharton/ActionBarSherlock/blob/master/samples/fragments/src/com/actionbarsherlock/sample/fragments/FragmentTabs.java
Instead of the CountingFragment etc. I implemented my own.
I'm not sure what to
My xml:
fragment_graph_categories.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/fragment_graph_categories"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<Button
android:id="#+id/button_filter"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/button_filter" />
</LinearLayout>
And that's my "Tab" attached to the TabManger
public class GraphCategories extends SherlockFragmentActivity {
GraphCategoriesFragment mCategoriesFragment;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.fragment_graph_categories);
if (savedInstanceState == null) {
// Do first time initialization -- add initial fragment.
mCategoriesFragment = GraphCategoriesFragment.newInstance(1);
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.add(R.id.fragment_graph_categories, mCategoriesFragment).commit();
} else {
//mStackLevel = savedInstanceState.getInt("level");
}
}
#Override
protected void onResume() {
if(mCategoriesFragment != null) {
//mCategoriesFragment.onResumeRedraw();
}
}
//notice Inner class
public static class GraphCategoriesFragment extends SherlockFragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
//View mChartView = inflater.inflate(R.layout.hello_world, container, false);
View rlayout = inflater.inflate(R.layout.fragment_graph_categories, container, false);
//? rlayout = new LinearLayout(getActivity());
return rlayout;
}
}
}
But im not sure what to inflate at the fragments onCreateView or if I need a FrameLayout in my xml?
I tried some options but don't figured it out.
I want to add a couple buttons to the bottom of my preferences screen for setting defaults and restoring defaults. This answer doesn't cover how to do this using PreferenceFragment. What is the recommended way to accomplish this.
Activity that loads the preferences fragment:
public class SettingsActivity extends Activity {
#Override
public void onCreate( Bundle savedInstanceState) {
super.onCreate( savedInstanceState);
// load up the preferences fragment
getFragmentManager().beginTransaction().replace( android.R.id.content, new PrefsSettingsFragment()).commit();
}
}
PreferenceFragment implementation:
public class PrefsSettingsFragment extends PreferenceFragment {
#Override
public void onCreate( Bundle savedInstanceState) {
super.onCreate( savedInstanceState);
addPreferencesFromResource( R.xml.preferences);
}
}
preferences.xml:
<?xml version="1.0"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
<EditTextPreference android:key="edit_text_preference_server_address" android:title="#string/preference_server_address"/>
<SwitchPreference android:key="switch_preference_bat" android:title="#string/preference_bat"/>
<SwitchPreference android:key="switch_preference_comm" android:title="#string/preference_comm"/>
<SwitchPreference android:key="switch_preference_dev_mode" android:title="#string/preference_dev_mode" android:defaultValue="true"/>
</PreferenceScreen>
I meet the same question, and I found a way to handle this issue.
Overwrite the method onCreateView in PreferenceFragment, using the given the LayoutInfalter by parameters to create your own View, and return this view.
It's my code. I hope this can be helpful
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// TODO Auto-generated method stub
View v = inflater.inflate(R.layout.set_alarm, null);
Button save = (Button)v.findViewById(R.id.save);
Button revert = (Button)v.findViewById(R.id.revert);
Button delete = (Button)v.findViewById(R.id.delete);
save.setOnClickListener(this);
revert.setOnClickListener(this);
delete.setOnClickListener(this);
if(mId == -1){
delete.setEnabled(false);
}
return v;
}
I modified the previous post a little bit, so that the button will get attached at the bottom of the view.
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
LinearLayout v = (LinearLayout) super.onCreateView(inflater, container, savedInstanceState);
Button btn = new Button(getActivity().getApplicationContext());
btn.setText("Button on Bottom");
v.addView(btn);
btn.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
}
});
return v;
}
Just create your own layout for the settings activity which contains list view with id #android:id/list
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/root"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<FrameLayout
android:id="#+id/fragment"
android:layout_weight="1"
android:layout_width="match_parent"
android:layout_height="0dp">
<ListView
android:id="#android:id/list"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</FrameLayout>
<Button
android:id="#+id/button"
android:text="Save"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
And then in the activity class set the content view before adding preference fragment
public class SettingsActivity extends Activity {
#Override
public void onCreate( Bundle savedInstanceState) {
super.onCreate( savedInstanceState);
setContentView(R.layout.settings_activity)
// load up the preferences fragment
getFragmentManager().beginTransaction().replace( android.R.id.content, new PrefsSettingsFragment()).commit();
}
}
you may try this
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
// TODO Auto-generated method stub
LinearLayout v = (LinearLayout) super.onCreateView(inflater, container, savedInstanceState);
Button SendLogbtn = new Button(getActivity().getApplicationContext());
SendLogbtn.setText("send log file");
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT,
LayoutParams.WRAP_CONTENT);
params.setMargins(100, 0, 0, 500);
SendLogbtn.setLayoutParams(params);
v.addView(SendLogbtn);
SendLogbtn.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// do your code
}
});
return v;
}