Develop Reference

Getting error while calling Intent from fragment (User Login)

I have getting error while calling intent from Fragment.
Following are the log error of the same. Below are the pieces of code from the same activities. The application automatically gets off as i click on the Button for Login.
Please help me out.
Thank you in advance.
Log Report
Process: com.example.lenovo.skanda, PID: 7978
java.lang.NullPointerException: Attempt to invoke virtual method 'android.text.Editable android.widget.EditText.getText()' on a null object reference
at com.example.lenovo.skanda.AdminFragment$1.onClick(AdminFragment.java:43)
HomeFragment.java
public class AdminFragment extends Fragment implements View.OnClickListener{
View viewroot;
View v1;
private EditText Name;
private EditText Password;
static Button Login;
public static Button myLog;
private int Counter = 5;
#Nullable
#Override
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
viewroot = inflater.inflate(R.layout.fragment_admin,container,false);
Name = (EditText) getActivity().findViewById(R.id.editText);
Password = (EditText) getActivity().findViewById(R.id.editText2);
Login = (Button) getActivity().findViewById(R.id.button2);
myLog = (Button) viewroot.findViewById(R.id.button2);
myLog.setOnClickListener(this);
myLog.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v)
{
validate(Name.getText().toString(), Password.getText().toString());
}
});
return viewroot;
}
private void validate (String userName, String userPassword){
if((userName.equals("Admin")) && (userPassword.equals("123"))){
Intent intent = new Intent(AdminFragment.this.getActivity(), Login.class);
startActivity(intent); //Login is the second activity
}
else {
Counter --;
Toast.makeText(getActivity(), "No. of Attempts Left for Login" + String.valueOf(Counter), Toast.LENGTH_SHORT).show();
if (Counter == 0){
Login.setEnabled(false);
Toast.makeText(getActivity(), "For Enable the Login Please Contact..!!", Toast.LENGTH_SHORT).show();
}
}
}
#Override
public void onClick(View v) {
validate(Name.getText().toString(),Password.getText().toString());
}
}
fragment_admin.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"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:background="#android:color/background_dark">
<com.airbnb.lottie.LottieAnimationView
android:id="#+id/animation_view"
android:layout_width="185dp"
android:layout_height="155dp"
android:layout_below="#+id/textView"
android:layout_centerHorizontal="true"
android:layout_gravity="center"
app:lottie_autoPlay="true"
app:lottie_colorFilter="#FFBC00"
app:lottie_fileName="user.json"
app:lottie_loop="true" />
<TextView
android:id="#+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="17dp"
android:text="admin login"
android:textAllCaps="true"
android:textColor="#FFBA24"
android:textSize="25dp"
android:textStyle="bold" />
<TextView
android:id="#+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="#+id/editText"
android:layout_alignStart="#+id/editText2"
android:layout_marginBottom="-247dp"
android:text="Enter your username"
android:textAllCaps="true"
android:textColor="#B7BE5D"
android:textSize="15dp" />
<EditText
android:id="#+id/editText2"
android:layout_width="300dp"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:layout_marginBottom="183dp"
android:ems="10"
android:fontFamily="monospace"
android:hint="Password"
android:inputType="textPassword"
android:textColorHint="#FFFFFF" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="#+id/editText2"
android:layout_alignStart="#+id/editText2"
android:text="Enter your password"
android:textAllCaps="true"
android:textColor="#B7BE5D"
android:textSize="15dp" />
<EditText
android:id="#+id/editText"
android:layout_width="300dp"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="247dp"
android:ems="10"
android:fontFamily="monospace"
android:hint="Username"
android:inputType="textPersonName"
android:textColor="#FFFFFF"
android:textColorHint="#FFFFFF" />
<EditText
android:id="#+id/Editinfo"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:layout_marginBottom="62dp"
android:text="No. of attempts left : "
android:textColor="#FFF"
android:textSize="15dp"
android:textStyle="italic" />
<Button
android:id="#+id/button2"
android:layout_width="210dp"
android:layout_height="45dp"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:layout_marginBottom="111dp"
android:background="#drawable/rounded_button"
android:text="login"
android:textAllCaps="true"
android:textColor="#000"
android:visibility="visible" />
<Button
android:id="#+id/button"
style="#style/Widget.AppCompat.Button.Borderless.Colored"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:background="#19193E"
android:text="LOG IN PROBLEM? CONTACT US."
android:textColor="#FFF"
android:onClick="onClick"
android:visibility="visible" />
</RelativeLayout>

You can't use getActivity().findViewById() like that.
Inside onCreateView(), you haven't yet returned the Fragment's View, meaning it isn't attached to the Activity. getActivity().findViewById() returns null because the Activity currently has no View with that ID. It only will after viewroot is returned, which is after you're invoking it.
Instead, you can do one of two things:
Replace getActivity() with viewroot:
Name = (EditText) viewroot.findViewById(R.id.editText);
Password = (EditText) viewroot.findViewById(R.id.editText2);
Login = (Button) viewroot.findViewById(R.id.button2);
Move your code to onViewCreated() and keep using getActivity() (you should be using the passed view variable, however).
In general, you don't want to use getActivity().findViewById(). If you need to find a View in that Fragment, use getView().findViewById(). Neither of these methods will work until onCreateView() returns.
I also notice that both Login and myLog are the same button. You should assign to one variable and call on it when needed. There's no point in a second local variable.
You should also try following Java's syntax guidelines:
Class names use TitleCase
Variable and function names use camelCase

it should be like this
viewroot = inflater.inflate(R.layout.fragment_admin,container,false);
Name = (EditText) viewroot.findViewById(R.id.editText);
Password = (EditText) viewroot.findViewById(R.id.editText2);
Login = (Button) viewroot.findViewById(R.id.button2);
myLog = (Button) viewroot.findViewById(R.id.button2);

You need to use viewroot instead of getActivity() in onCreateView().
Use the following code:
Name = (EditText) viewroot.findViewById(R.id.editText);
Password = (EditText) viewroot.findViewById(R.id.editText2);
Login = (Button) viewroot.findViewById(R.id.button2);

OnClickListener on non-Mainactivity & change first activity

i've a problem. I want to make a app with a loggin activity and a main activity. (To the OnClickListiner later)
fist:
What ive done so far:
i've created a login. java and login.xml
login.java:
public class Login extends Activity implements OnClickListener {
Button btnStartAnotherActivity;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.login);
boolean hasLogedIn = true;
if (hasLogedIn) {
Intent i = new Intent(Login.this, MainActivity.class);
startActivity(i);
finish();
} else {
}
}
public void onClick(View view) {
//calling an activity using <intent-filter> action name
Intent inent = new Intent("android.name.MainActivity ");
startActivity(inent);
}
}
i've created a MainActivity.java and activity_main.xml
moreover i've some other java and xml files to make a materiel designed Tab view for my MainActivity.
i have 3 tabs thats how it looks so far
[![tab1 with buttons][1]][1]
-now i'be added to the first tab 3 buttons.
example of one button: (the others are the same just a other id )
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Kommt"
android:clickable="false"
android:textColor="#190707"
android:id="#+id/kommt"
android:layout_alignParentStart="true"
android:layout_below="#+id/space" />
-So the app is running now without problems. ( All Tabs and there content is showing like i want it )
when i build the project the mainactivity is open first( see that link of the picture )
HOW TO SET: the login interface to be started once, when starting the app for the first time. After login is succesfully, then the mainactivity will always open. Thats my first problem. What should i add to the Login.java ? and how to set that the login.xml starts before the mainactivity ?
Second:
As i told you ive added some buttons. To test the buttons i've tried to implement a code for toast notification when clicking on button. But every time i build the project with the toast notifitcation code, the app doenst start anymore. Here the code for the toast notification i'm using:
public class MainActivity extends ActionBarActivity implements OnClickListener {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main); // but my main_activity doesnt have buttons ... tab1.xml have b
Button kommtbutton;
kommtbutton= (Button) findViewById(R.id.kommt);
kommtbutton.setOnClickListener(this);}
#Override
public void onClick(View v) {
setContentView(R.layout.tab1); // not sure if this is right ive did it cause the buttons are in the tab1 layout and not main_activity
switch(v.getId())
{
case R.id.kommt:
{
Toast toast1 = Toast.makeText(getApplicationContext(),
"Eingestempelt",
Toast.LENGTH_SHORT);
toast1.show();
break;
} ....}
here i have implemented all 3 buttons in a switch case.
It looks right but the onclicklistinier seems to kill my application before it can start. Maybe someone can help me.
i have following files:
Login.java, MainActivity.java, Tab1.java,Tab2.java,Tab3.java, SlidingTabsLayout.java, SlidingTabStrip.java and ViewPagerAdaper.
and i have this layouts.
acitivy_main.xml, login.xml, tab1,tab2,tab3.xml, toolbar.xml.
I'm not allowed to send pictures cause i'm new here.
Where have i do implement the code for the toast notification ?
thats my activity_main:xml
<LinearLayout 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:orientation="vertical"
tools:context=".MainActivity">
<include
android:id="#+id/tool_bar"
layout="#layout/tool_bar"
android:layout_height="wrap_content"
android:layout_width="match_parent"
/>
<android_package.SlidingTabLayout
android:id="#+id/tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:elevation="2dp"
android:background="#color/ColorPrimary"/>
<android.support.v4.view.ViewPager
android:id="#+id/pager"
android:layout_height="match_parent"
android:layout_width="match_parent"
android:layout_weight="1"/>
and this is my tab1.xml
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/Tabs"
android:background="#FDFDFE"
>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:id="#+id/buchungen"
android:textColor="#190707"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Geht"
android:clickable="false"
android:textColor="#190707"
android:id="#+id/geht"
android:layout_alignParentBottom="true"
android:layout_alignEnd="#+id/textClock"
android:layout_marginBottom="36dp" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Name:"
android:paddingBottom="7dp"
android:paddingTop="7dp"
android:textColor="#190707"
android:id="#+id/name"
android:layout_alignParentStart="true"
android:layout_below="#+id/buchungen" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#190707"
android:paddingBottom="7dp"
android:paddingTop="7dp"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Status:"
android:id="#+id/status"
android:layout_below="#+id/name"
android:layout_alignParentStart="true" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#190707"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Letzte Buchung:"
android:paddingBottom="4dp"
android:paddingTop="7dp"
android:id="#+id/letzteBuchung"
android:layout_below="#+id/status"
android:layout_alignParentStart="true" />
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_alignBottom="#+id/buchungen"
android:weightSum="1"
android:id="#+id/linearLayout">
<ImageView
android:layout_width="314dp"
android:layout_height="310dp"
android:id="#+id/profilbild"
android:layout_gravity="center_horizontal"
android:src="#drawable/time" />
</LinearLayout>
<Space
android:layout_width="20dp"
android:layout_height="20dp"
android:layout_above="#+id/geht"
android:id="#+id/space" />
<TextClock
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#190707"
android:id="#+id/textClock"
android:layout_alignTop="#+id/name"
android:layout_alignParentEnd="true" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Kommt"
android:clickable="false"
android:textColor="#190707"
android:id="#+id/kommt"
android:layout_alignParentStart="true"
android:layout_below="#+id/space" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceSmall"
android:text="Pause An/Aus"
android:textColor="#190707"
android:id="#+id/textView"
android:layout_alignTop="#+id/textView3"
android:layout_alignStart="#+id/pause" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceSmall"
android:text="Einstempeln"
android:textColor="#190707"
android:id="#+id/textView2"
android:layout_above="#+id/kommt"
android:layout_alignParentStart="true" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceSmall"
android:text="Ausstempeln"
android:textColor="#190707"
android:id="#+id/textView3"
android:layout_alignBottom="#+id/geht"
android:layout_alignStart="#+id/geht"
android:layout_alignTop="#+id/textView2" />
<ToggleButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Pause"
android:textColor="#190707"
android:id="#+id/pause"
android:layout_alignBottom="#+id/kommt"
android:layout_centerHorizontal="true"
android:checked="false" />
</RelativeLayout>
The buttons are in the tab1.xml. Where have i to acces them to make a Interaction ( show toast when pressing the button ) ? in the MainActivity.java or the Tab1.java or somewhere else ?
When i try to add toast notification my app just kills itself ...

You have to put all the findViewById and setContentView in the onCreate method or they won't do the job.
First point :
public class MainActivity extends ActionBarActivity
{
// Layout elements
private Button kommtbutton = null;
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
// Attach layout
setContentView(R.layout.activity_main); // but my main_activity doesnt have buttons ... tab1.xml have b
// Retrieve layout elements
kommtbutton= (Button) findViewById(R.id.kommt);
// Attach listeners
kommtbutton.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View view)
{
// Do not use getApplicationContext(), this is an activity
Toast.makeText(MainActivity.this, "Eingestempelt", Toast.LENGTH_SHORT).show();
}
});
}
[...]
}
Second point :
public class LoginActivity extends Activity
{
// Layout elements
private EditText edit_login = null;
private EditText edit_password = null;
private Button btn_login = null;
// Class variables
private SharedPreferences prefs = null;
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
// Check if the user is already logged in
prefs = getSharedPreferences(getPackageName(), MODE_PRIVATE);
if (prefs.getBoolean("isLoggedIn", false))
{
Intent intent = new Intent(LoginActivity.this, MainActivity.class);
startActivity(intent);
finish();
return;
}
// Attach layout
setContentView(R.layout.login);
// Retrieve layout elements
edit_login = (EditText) findViewById(R.id.edit_login);
edit_password = (EditText) findViewById(R.id.edit_password);
btn_login = (Button) findViewById(R.id.btn_login);
// Attach listeners
btn_login.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View view)
{
// Retrieve information
String login = edit_login.getText().toString();
String password = edit_password.getText().toString();
// Do job
boolean canConnect = true; // TODO
if (canConnect)
{
// Update prefs
prefs.edit().putBoolean("isLoggedIn", true).commit();
// Move to activity
Intent intent = new Intent(LoginActivity.this, MainActivity.class);
startActivity(intent);
finish();
}
else
{
// Update prefs
prefs.edit().putBoolean("isLoggedIn", false).commit();
// Display error message
Toast.makeText(LoginActivity.this, "Wrong crendentials", Toast.LENGTH_LONG).show();
}
}
});
}
}

TextView onclick event not working

In my android code, I have implemented onclick event on 3 textviews using following code. But nothing happens when they are clicked. What is wrong ?
<TextView
android:id="#+id/tv1"
android:layout_width="40dp"
android:layout_height="40dp"
android:background="#drawable/menucircle"
android:layout_alignParentLeft="true"
android:layout_centerVertical="true"
android:onClick="selectit"
android:textColor="#ffffff"
/>
public void selectit(View v)
{
Log.d("tv0","ok");
if(v.getId()==tv1.getId())
{Log.d("tv1","ok");
selectoption(1);
Log.d("tv1","ok");
}
if(v.getId()==tv2.getId())
{Log.d("tv2","ok");
selectoption(2);
}
if(v.getId()==tv3.getId())
{Log.d("tv3","ok");
selectoption(3);
}
}

Add this into your xml
android:clickable="true"

You probably need to have this code in your xml
android:clickable="true"
Or Set the Clicklistenner to TextView via code by
TextView btn=(TextView) findViewById(R.id.tv1);
btn.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
selectit(v);
}
});
It will automatically make it clickable so no need of android:clickable="true"

You can set the click handler in xml with these attribute:
android:clickable="true"
Don't forget the clickable attribute, without it, the click handler isn't called.
main.xml
<TextView
android:id="#+id/tv1"
android:layout_width="40dp"
android:layout_height="40dp"
android:background="#drawable/menucircle"
android:layout_alignParentLeft="true"
android:layout_centerVertical="true"
android:onClick="selectit"
android:clickable="true"
android:textColor="#ffffff"
/>
i hope it will help u all the best

Try like below:
android:onClick="onClick"
android:clickable="true"
My textview:
<TextView
android:id="#+id/click"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Click Me"
android:textSize="55sp"
android:onClick="onClick"
android:clickable="true"/>
Main Activity:
public class MyActivity extends Activity {
public void onClick(View v) {
...
}
}

Null Pointer Exception - Getting EditText Value

This is my first question on here I will apologize in advance if I didn't ask this question very well. I have looked at my other questions similar to my problem, but I have not found a good solution to satisfy what is going on in my program.
So my problem is I am trying to assign a value to a variable called, num1 from my EditText field called, num1TextField, but I am not having any luck so far.
The segment inside my java file that throws the exception is:
EditText num1Field = (EditText)v.findViewById(R.id.num1TextField);
num1 = num1Field.getText().toString();
I appreciate every contribution to this problem in advance.
Here is my fragment_compute.xml file:
<?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"
android:orientation="vertical" >
<TextView
android:id="#+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="14dp"
android:text="#string/compute_activity"
android:textAppearance="?android:attr/textAppearanceLarge" />
<TextView
android:id="#+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/textView1"
android:layout_centerHorizontal="true"
android:layout_marginTop="44dp"
android:text="#string/num_1"
android:textAppearance="?android:attr/textAppearanceMedium" />
<EditText
android:id="#+id/num1TextField"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/textView2"
android:layout_centerHorizontal="true"
android:ems="10"
android:inputType="number"
android:gravity="center" >
<requestFocus />
</EditText>
<EditText
android:id="#+id/num2TextField"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/num1TextField"
android:layout_below="#+id/textView3"
android:ems="10"
android:inputType="number"
android:layout_centerHorizontal="true"
android:gravity="center" >
</EditText>
<TextView
android:id="#+id/textView4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/num2TextField"
android:layout_centerHorizontal="true"
android:layout_marginTop="22dp"
android:text="#string/result"
android:textAppearance="?android:attr/textAppearanceMedium" />
<TextView
android:id="#+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/num1TextField"
android:layout_centerHorizontal="true"
android:layout_marginTop="22dp"
android:text="#string/num_2"
android:textAppearance="?android:attr/textAppearanceMedium" />
<TextView
android:id="#+id/result"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/textView4"
android:layout_centerHorizontal="true"
android:layout_marginTop="22dp" />
<Button
android:id="#+id/compute_multiply"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignRight="#+id/num2TextField"
android:layout_below="#+id/result"
android:layout_marginTop="40dp"
android:text="#string/multiply" />
<Button
android:id="#+id/compute_add"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="#+id/compute_multiply"
android:layout_alignBottom="#+id/compute_multiply"
android:layout_alignLeft="#+id/num2TextField"
android:text="#string/add" />
</RelativeLayout>
Here is my ComputeFragment.java code:
public class ComputeFragment extends Fragment {
String num1;
String num2;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup parent, Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_compute, parent, false);
// Add Button
Button addButton = (Button)v.findViewById(R.id.compute_add);
addButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// ERROR STARTS HERE!
EditText num1Field = (EditText)v.findViewById(R.id.num1TextField);
num1 = num1Field.getText().toString(); // Null Pointer Exception is thrown here!
EditText num2Field = (EditText)v.findViewById(R.id.num2TextField);
num2 = num2Field.getText().toString();
// ERROR ENDS HERE!
Intent i = new Intent(getActivity(), AddActivity.class);
i.putExtra("x", num1);
i.putExtra("y", num2);
startActivityForResult(i,0);
}
});
return v;
}
}

The parameter v in EditText num1Field = (EditText)v.findViewById(R.id.num1TextField); is your button, not the whole view.
You should declare the variable in onCreateView:
final EditText num1Field = (EditText)v.findViewById(R.id.num1TextField);
And use it to get the value in onClick
num1 = num1Field.getText().toString();

The parameter view is the button. If the button is on the same parent as the editTexts you could also do:
View parentView = (View) view.getParent();
EditText num1TextField = (EditText)parentView.findViewById(R.id.num1TextField);

Try this code -
#Override
public void onClick(View view) {
EditText num1Field = (EditText)v.findViewById(R.id.num1TextField);
if(num1Field.getText().length() > 0) {
num1 = num1Field.getText().toString();
}
}

Getting error while accessing textfield in Android application

I am getting value of EditText e1 in below example as null. So it throws null pointer exception. I wrote below in MainActivity and calling the function calculateSquare upon click on a button. Am i missing something?
public void calculateSquare(View view) {
setContentView( R.layout.activity_main);
EditText e1=(EditText) findViewById(R.id.editText1);
int number = Integer.parseInt(e1.getText().toString());
int square=number * number;
TextView e2=(TextView) findViewById(R.id.textView2);
e2.setText(square);
}
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" >
<TextView
android:id="#+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="25dp"
android:text="#string/hello_world"
tools:context=".MainActivity" />
<EditText
android:id="#+id/editText1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="#+id/textView1"
android:layout_marginLeft="32dp"
android:layout_marginTop="52dp"
android:layout_toLeftOf="#+id/textView1"
android:ems="10"
android:inputType="number" />
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/editText1"
android:layout_centerHorizontal="true"
android:layout_marginTop="29dp"
android:text="CalculateSquare"
android:onClick="calculateSquare"/>
<TextView
android:id="#+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_alignTop="#+id/editText1"
android:layout_marginRight="36dp"
android:text="Square"
android:textAppearance="?android:attr/textAppearanceLarge" />
</RelativeLayout>

You need to pass in a String as a parameter to the setText().
Change your code to:
e2.setText(square+"");
When you call setText(int) the system will look for the String resource by the given id(int), which needs to be supplied from the R class.
e2.setText(R.string.mystring);
About the null pointer, try cleaning your project, and you should move the initiation to the onCreate() method.
#Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView( R.layout.activity_main);
EditText e1=(EditText) findViewById(R.id.editText1);
TextView e2=(TextView) findViewById(R.id.textView2);
}
public void calculateSquare(View view) {
int number;
if (e1.getText().toString().length()>0){
number = Integer.parseInt(e1.getText().toString());
int square=number * number;
e2.setText(square+"");
}
}
You always need to check if you have entered something in the edittext, since an empty string cannot be converted into an int.