java.lang.illegalstateexception could not find a method (view) in the activity class android fragment

Question

In my program, I am using a gridview with some images. I want to show a menu when user tapped on an image in gridview and then select an action to do from the menu showed.

Here is my code:

package Kazemi.Alireza.scada;
import android.annotation.SuppressLint;
import android.app.Dialog;
import android.app.FragmentManager;
import android.content.Context;
import android.graphics.Typeface;
import android.graphics.drawable.AnimationDrawable;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.ContextMenu;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.view.WindowManager;
import android.view.ViewGroup.LayoutParams;
import android.widget.AdapterView;
import android.widget.AdapterView.AdapterContextMenuInfo;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.PopupWindow;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.AdapterView.OnItemClickListener;


@SuppressLint("NewApi")
public class CitiesTab extends Fragment {

AnimationDrawable[] frameAnimation;
ImageAdapter ia;
GridView gridView;
int in;

public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    return (LinearLayout)inflater.inflate(R.layout.citytab, container, false);
}

public void onStart()
{
    super.onStart();
    ia = new ImageAdapter(getActivity());
    gridView = (GridView) getActivity().findViewById(R.id.gridview);
    gridView.setAdapter(ia);
    gridView.post(new Starter());
    gridView.setOnItemClickListener(new OnItemClickListener()
    {
        public void onItemClick(AdapterView<?> parent, View v, int position, long id)
        {
            dialog = new Dialog(getActivity(), android.R.style.Theme_InputMethod);
            dialog.setContentView(R.layout.pump_menu);
        }});
    /*Button btn = (Button) getActivity().findViewById(R.id.Button_pumpInfo);
    btn.setOnClickListener(new View.OnClickListener() {
        
        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            Toast.makeText(getActivity(), "You clicked on Item 1",
                    Toast.LENGTH_LONG).show();
        }
    });*/
}

public void Btn_pumpInfo_Clicked(View v) {
    // TODO Auto-generated method stub
    Toast.makeText(getActivity(), "You clicked on Item 1",
            Toast.LENGTH_LONG).show();
}

}

here is my pump_menu.xml code:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="#a5c5f0"
    android:orientation="vertical" >

<Button 
    android:id="@+id/Button_pumpInfo" 
    android:layout_height="40dp" 
    android:text="@string/menu_pumpinfo_item1"
    android:textSize="11sp" 
    android:layout_width="125dp"
    android:background="#a5c5f0"
    android:onClick="Btn_pumpInfo_Clicked"/>

and citytab.xml :

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

<GridView 
    android:id="@+id/gridview"
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent"
    android:numColumns="auto_fit"
    android:verticalSpacing="10dp"
    android:horizontalSpacing="10dp"
    android:columnWidth="90dp"
    android:stretchMode="columnWidth"
    android:gravity="center" />

<ImageView 
    android:id="@+id/gifViewer"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:scaleType="center"/>

</LinearLayout>

When I use this code an error occured:

java.lang.RuntimeException: Unable to start activity ComponentInfo{Kazemi.Alireza.scada/Kazemi.Alireza.scada.MainMenu}: java.lang.NullPointerException

And when i comment the Btn_pumpInfo_Clicked() method and uncomment the button listener in onStart() the following error occurs:

java.lang.IllegalStateException: Could not find a method Btn_pumpInfo_Clicked(View) in the activity class android.view.ContextThemeWrapper for onClick handler on view class android.widget.Button with id 'Button_pumpInfo'

Where is the problem?

Timbale

you should post the whole stack trace rather than just one line and do point out the line numbers in your code – Earlearla

Answer 1

You can't register the onClick callback(using android:onClick) for the Button(from the layout of the Dialog) in the Fragment class because Android will not find it as it will search only the Activity for a method matching that name(Btn_pumpInfo_Clicked) and it will throw that exception. Instead look for the Button in the Dialog and assign it a normal listener:

//...
dialog.setContentView(R.layout.pump_menu)
Button b = (Button) dialog.findViewById(R.id.Button_pumpInfo);
b.setOnClickListener(new OnClickListener() {

   @Override
   public void onCLick(View v) {
       // profit
   }
});

Or move the method :

public void Btn_pumpInfo_Clicked(View v) {
    // TODO Auto-generated method stub
    Toast.makeText(getActivity(), "You clicked on Item 1",
            Toast.LENGTH_LONG).show();
}

in the Activity class if it fits you.

Modigliani

@Timbale If my answer helped you could mark it as correct(with the check mark) so the question will become answered. I don't know which of the two options you used, if you're going to use the Dialog class then you better make your own dialog extending Dialog and in that class set the content view and set the listeners. – Modigliani

I don't know how i can mark as correct! could you explain me how to do it? I used first option in my case, and it works for me:) thanks for your comment :) – Timbale

@Timbale If it works there is no problem, I wasn't sure when I posted the answer, I waited to see if your code works:) – Modigliani

my line with findViewById(R.id.Button_pumpInfo) compiles but throws a null pointer exception. Any ideas? – Hamer

@advocate That is happening because findViewById will return null if it can't find the view with the id R.id.Button_pumpInfo. Please start your own question related to the problem providing the proper details like code and stacktrace. – Modigliani

@Luksprog so u mean android:onClick attribute not support Fragment layout..!! – Grassy

@Shubh Yes, the onClick assign method is tied to the Activity. – Modigliani

Answer 2

If this bug is happening only on Android 2.x check your Activity class hierarchy for Android 4 specific class members:

public class HomeActivity extends Activity {

  private android.app.ActionBar.LayoutParams customTitleParams;

  ....
}

The class android.app.ActionBar.LayoutParams is not available on Android 2.x and this can cause the problem.

Loleta

I am having this same problem, and I think you might have hit it on the head. I thought I might test my app on gingerbread, but, my onClick(View v) is crashing on the class android.support.v7.widget.AppCompatImageButton, cannot find it. – Hanrahan

Answer 3

This can also happen when the method to call on onClick of the View(Button) isn't accessible or isn't available in the respective activity. Steps to check:

• Check the method name in the value for android:onClick attribute matches the method actually written.
• Check the access modifier of the method is public so as to be available to the execute.

Liquefacient