title: android:onClick = "functionName" did not recognize the function name in Fragment subclass
body: <p><code>android:onClick = "clickFun1"</code> for <code>Button</code> in my layout xml file did not recognize the <code>clickFun1()</code> method mentioned in <code>DipToVol extends Fragment</code> class. Android Studio says that method nowhere used.</p>
  
  <pre><code>public class DipToVol extends Fragment {
          @Override
          public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                   Bundle savedInstanceState) {
              return inflater.inflate(R.layout.fragment_one, container, false);
      }
  
      public double calVol(short rad, short len, int height) {
          double area;
          area = (Math.PI * Math.pow(rad, 2) / 2) - Math.pow(rad, 2) * Math.asin(1 - (height / (double)rad)) - (rad - height) * Math.sqrt(height * (2 * rad - height));
          return area*len*0.000001;
      }
  
      //here android studio says this method never used
      public void clickFun1 (View view)
      {
          int dipHSD = 0, dipMS = 0;
          final short radHSD = 1219;
          final short lenHSD = 6810;
          final short radMS = 999;
          final short lenMS = 6804;
          double volHSD, volMS;
  
          EditText dipH = (EditText) view.findViewById(R.id.dipHSD1);
          EditText dipM = (EditText) view.findViewById(R.id.dipMS1);
  
          TextView volH = (TextView) view.findViewById(R.id.volHSD1);
          TextView volM = (TextView) view.findViewById(R.id.volMS1);
          try {
              dipHSD = Integer.parseInt(dipH.getText().toString());
              volHSD = calVol(radHSD, lenHSD, dipHSD);
              volHSD = Math.round(volHSD);
              volH.setText(volHSD + "");
          }
          catch (NumberFormatException e) {
              volH.setText("");
          }
          try{ dipMS = Integer.parseInt(dipM.getText().toString());
              volMS = calVol(radMS, lenMS, dipMS);
              volMS = Math.round(volMS);
              volM.setText(volMS + "");
          }catch(NumberFormatException e){volM.setText("");}
  
      }
  
      //here android studio says this method never used
      public void clearFun1(View view){
          EditText dipH = (EditText) view.findViewById(R.id.dipHSD1);
          EditText dipM = (EditText) view.findViewById(R.id.dipMS1);
  
          TextView volH = (TextView) view.findViewById(R.id.volHSD1);
          TextView volM = (TextView) view.findViewById(R.id.volMS1);
  
          volH.setText("");
          volM.setText("");
          dipH.setText("");
          dipM.setText("");
     } 
  
  }
  </code></pre>
  
  <p>fragment_one.xml</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:tools="http://schemas.android.com/tools"
      xmlns:app="http://schemas.android.com/apk/res-auto"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:id="@+id/section_label1"
      android:paddingLeft="@dimen/activity_horizontal_margin"
      android:paddingRight="@dimen/activity_horizontal_margin"
      android:paddingTop="@dimen/activity_vertical_margin"
      android:paddingBottom="@dimen/activity_vertical_margin"
      app:layout_behavior="@string/appbar_scrolling_view_behavior"
      tools:context=".MainActivity"
      android:background="#4ab4b2"&gt;
  
  
         &lt;TableLayout
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:id="@+id/contentView"
          android:layout_weight ="1"
          android:layout_alignParentLeft="true"
          android:layout_alignParentStart="true"
             android:layout_alignParentBottom="false"
             android:layout_alignParentRight="false"
             android:layout_alignWithParentIfMissing="false"&gt;
  
          &lt;TableRow
              android:layout_width="wrap_content"
              android:layout_height="match_parent"
              android:layout_marginTop="10dp"&gt;
  
              &lt;TextView
                  android:layout_width="wrap_content"
                  android:layout_height="wrap_content"
                  android:text="HSD Dip"
                  android:id="@+id/lableDipHSD"
                  android:layout_column="0"
                  android:textSize="30sp"
                  android:textStyle="bold"
                  android:textColor="#ffffff"
                  android:layout_marginLeft="5dp" /&gt;
  
              &lt;EditText
                  android:layout_width="wrap_content"
                  android:layout_height="wrap_content"
                  android:inputType="number"
                  android:ems="10"
                  android:id="@+id/dipHSD1"
                  android:textSize="30sp"
                  android:textStyle="bold"
                  android:layout_column="1"
                  android:textColor="#ffffff"
                  /&gt;
          &lt;/TableRow&gt;
  
          &lt;TableRow
              android:layout_width="wrap_content"
              android:layout_height="match_parent"
              android:layout_marginTop="10dp"&gt;
  
              &lt;TextView
                  android:layout_width="wrap_content"
                  android:layout_height="wrap_content"
                  android:text="MS Dip"
                  android:id="@+id/lableDipMS"
                  android:layout_column="0"
                  android:textSize="30sp"
                  android:textStyle="bold"
                  android:textColor="#ffffff"
                  android:layout_marginLeft="5dp" /&gt;
  
              &lt;EditText
                  android:layout_width="wrap_content"
                  android:layout_height="wrap_content"
                  android:inputType="number"
                  android:id="@+id/dipMS1"
                  android:layout_column="1"
                  android:textStyle="bold"
                  android:textSize="30sp"
                  android:textColor="#ffffff"
                  /&gt;
          &lt;/TableRow&gt;
  
          &lt;TableRow
              android:layout_width="wrap_content"
              android:layout_height="match_parent"
              android:layout_marginTop="10dp"&gt;
  
              &lt;TextView
                  android:layout_width="wrap_content"
                  android:layout_height="wrap_content"
                  android:text="HSD Volume"
                  android:id="@+id/lableVolHSD"
                  android:layout_column="0"
                  android:textStyle="bold"
                  android:textSize="30sp"
                  android:paddingTop="15dp"
                  android:textColor="#ffffff"
                  android:layout_marginLeft="5dp" /&gt;
  
              &lt;TextView
                  android:layout_width="wrap_content"
                  android:layout_height="wrap_content"
                  android:id="@+id/volHSD1"
                  android:layout_column="1"
                  android:textStyle="bold"
                  android:textSize="30sp"
                  android:textColor="#ffffff" /&gt;
          &lt;/TableRow&gt;
  
          &lt;TableRow
              android:layout_width="wrap_content"
              android:layout_height="match_parent"
              android:layout_marginTop="10dp"&gt;
  
              &lt;TextView
                  android:layout_width="wrap_content"
                  android:layout_height="wrap_content"
                  android:text="MS Volume"
                  android:id="@+id/lableVolMS"
                  android:layout_column="0"
                  android:textStyle="bold"
                  android:textSize="30sp"
                  android:paddingTop="15dp"
                  android:textColor="#ffffff"
                  android:layout_marginLeft="5dp"
                  android:paddingBottom="10dp" /&gt;
  
              &lt;TextView
                  android:layout_width="wrap_content"
                  android:layout_height="wrap_content"
                  android:id="@+id/volMS1"
                  android:layout_column="1"
                  android:textStyle="bold"
                  android:textSize="30sp"
                  android:textColor="#ffffff"
                  android:paddingBottom="10dp" /&gt;
          &lt;/TableRow&gt;
  
      &lt;/TableLayout&gt;
  
  
  
  
      &lt;Button
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:text="@string/clearBtn"
          android:id="@+id/clearBtn1"
          android:textSize="25sp"
          android:clickable="true"
          android:onClick="clearFun1"
          android:background="#fa0690"
          android:padding="8dp"
          android:paddingLeft="8dp"
          android:paddingTop="2dp"
          android:paddingRight="8dp"
          android:paddingBottom="2dp"
          android:textAlignment="center"
          android:textStyle="bold"
          android:layout_column="0"
          android:layout_below="@+id/contentView"
          android:layout_alignParentLeft="true"
          android:layout_alignParentStart="true"
          android:layout_marginTop="40dp"
          android:layout_toStartOf="@+id/calcBtn1"
          android:layout_toLeftOf="@+id/calcBtn1"
          android:alpha="0.8"
          android:layout_marginRight="10dp" /&gt;
  
      &lt;Button
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:text="@string/calcBtn"
          android:id="@+id/calcBtn1"
          android:textSize="25sp"
          android:clickable="true"
          android:onClick="clickFun1"
          android:background="#fa0690"
          android:padding="8dp"
          android:paddingLeft="8dp"
          android:paddingTop="2dp"
          android:paddingRight="8dp"
          android:paddingBottom="2dp"
          android:textAlignment="center"
          android:textStyle="bold"
          android:layout_column="0"
          android:layout_alignTop="@+id/clearBtn1"
          android:layout_alignRight="@+id/contentView"
          android:layout_alignEnd="@+id/contentView"
          android:alpha="0.8" /&gt;
  
  &lt;/RelativeLayout&gt;
  </code></pre>
  
  <p>Please tell me where I am doing it wrong. When I run the code, App is crashing. Error log says the <code>clickFun1()</code> doesnt found.</p>
  
  <p>//The logcat</p>
  
  <pre><code>09-10 13:49:24.823 2718-2718/com.example.siv.mahalaxmipetroleums E/AndroidRuntime: FATAL EXCEPTION: main
                                                                                     java.lang.IllegalStateException: Could not find method clickFun1(View) in a parent or ancestor Context for android:onClick attribute defined on view class android.support.v7.widget.AppCompatButton with id 'calcBtn'
                                                                                         at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.resolveMethod(AppCompatViewInflater.java:327)
                                                                                         at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:284)
                                                                                         at android.view.View.performClick(View.java:4240)
                                                                                         at android.view.View$PerformClick.run(View.java:17721)
                                                                                         at android.os.Handler.handleCallback(Handler.java:730)
                                                                                         at android.os.Handler.dispatchMessage(Handler.java:92)
                                                                                         at android.os.Looper.loop(Looper.java:137)
                                                                                         at android.app.ActivityThread.main(ActivityThread.java:5103)
                                                                                         at java.lang.reflect.Method.invokeNative(Native Method)
                                                                                         at java.lang.reflect.Method.invoke(Method.java:525)
                                                                                         at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
                                                                                         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
                                                                                         at dalvik.system.NativeStart.main(Native Method)
  </code></pre>
  
  <p>I have changed the <code>mainActivity.java</code> as follows. Moving code from fragment subclass to <code>mainActivity.java</code></p>
  
  <pre><code>package com.example.siv.mahalaxmipetroleums;
  
  import android.support.design.widget.TabLayout;
  import android.support.v7.app.AppCompatActivity;
  import android.support.v7.widget.Toolbar;
  
  import android.support.v4.app.Fragment;
  import android.support.v4.app.FragmentManager;
  import android.support.v4.app.FragmentPagerAdapter;
  import android.support.v4.view.ViewPager;
  import android.os.Bundle;
  import android.view.Menu;
  import android.view.MenuItem;
  import android.view.View;
  import android.widget.Button;
  import android.widget.EditText;
  import android.widget.TextView;
  
  public class MainActivity extends AppCompatActivity {
  
      /**
       * The {@link android.support.v4.view.PagerAdapter} that will provide
       * fragments for each of the sections. We use a
       * {@link FragmentPagerAdapter} derivative, which will keep every
       * loaded fragment in memory. If this becomes too memory intensive, it
       * may be best to switch to a
       * {@link android.support.v4.app.FragmentStatePagerAdapter}.
       */
      private SectionsPagerAdapter mSectionsPagerAdapter;
  
  
      Button clearBtn_f1,calcBtn_f1,clearBtn_f2,calcBtn_f2;
  
  
  
      /**
       * The {@link ViewPager} that will host the section contents.
       */
      private ViewPager mViewPager;
  
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_main);
  
          Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
          setSupportActionBar(toolbar);
          // Create the adapter that will return a fragment for each of the three
          // primary sections of the activity.
          mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
  
          // Set up the ViewPager with the sections adapter.
          mViewPager = (ViewPager) findViewById(R.id.container);
          mViewPager.setAdapter(mSectionsPagerAdapter);
  
          TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
          tabLayout.setupWithViewPager(mViewPager);
  
          clearBtn_f1 = (Button) findViewById(R.id.clearBtn1);
          clearBtn_f2 = (Button) findViewById(R.id.clearBtn2);
          calcBtn_f1 = (Button) findViewById(R.id.calcBtn1);
          calcBtn_f2 = (Button) findViewById(R.id.calcBtn2);
  
          clearBtn_f1.setOnClickListener(new View.OnClickListener() {
              @Override
              public void onClick(View v) {
                  clearFun1(v);
              }
          });
          clearBtn_f2.setOnClickListener(new View.OnClickListener() {
              @Override
              public void onClick(View v) {
                  clearFun2(v);
              }
          });
  
          calcBtn_f1.setOnClickListener(new View.OnClickListener() {
              @Override
              public void onClick(View v) {
                  clickFun1(v);
              }
          });
  
          calcBtn_f2.setOnClickListener(new View.OnClickListener() {
              @Override
              public void onClick(View v) {
                  clickFun2(v);
              }
          });
  
  
           }
  
  
      @Override
      public boolean onCreateOptionsMenu(Menu menu) {
          // Inflate the menu; this adds items to the action bar if it is present.
          getMenuInflater().inflate(R.menu.menu_main, menu);
          return true;
      }
  
      @Override
      public boolean onOptionsItemSelected(MenuItem item) {
          // Handle action bar item clicks here. The action bar will
          // automatically handle clicks on the Home/Up button, so long
          // as you specify a parent activity in AndroidManifest.xml.
          int id = item.getItemId();
  
          //noinspection SimplifiableIfStatement
          if (id == R.id.action_settings) {
              return true;
          }
  
          return super.onOptionsItemSelected(item);
      }
  
      /**
       * A placeholder fragment containing a simple view.
       */
     public static class PlaceholderFragment extends Fragment {
          /**
           * The fragment argument representing the section number for this
           * fragment.
          // */
          private static final String ARG_SECTION_NUMBER = "section_number";
  
          public PlaceholderFragment() {
          }
  
          /**
           * Returns a new instance of this fragment for the given section
           * number.
           */
          public static PlaceholderFragment newInstance(int sectionNumber) {
              PlaceholderFragment fragment = new PlaceholderFragment();
              Bundle args = new Bundle();
              args.putInt(ARG_SECTION_NUMBER, sectionNumber);
              fragment.setArguments(args);
              return fragment;
          }
  
        /*  @Override
          public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                   Bundle savedInstanceState) {
              View rootView = inflater.inflate(R.layout.fragment_one, container, false);
              TextView textView = (TextView) rootView.findViewById(R.id.section_label);
              textView.setText(getString(R.string.section_format, getArguments().getInt(ARG_SECTION_NUMBER)));
              return rootView;
          }*/
      }
  
      /**
       * A {@link FragmentPagerAdapter} that returns a fragment corresponding to
       * one of the sections/tabs/pages.
       */
      public class SectionsPagerAdapter extends FragmentPagerAdapter {
  
          public SectionsPagerAdapter(FragmentManager fm) {
              super(fm);
          }
  
          @Override
          public Fragment getItem(int position) {
  
              // getItem is called to instantiate the fragment for the given page.
              // Return a PlaceholderFragment (defined as a static inner class below).
  
             if (position == 0) {
                  return new Fragment_One();
              } else if (position == 1) {
                  return new Fragment_Two();
              } else
                  return new Fragment_Three();//PlaceholderFragment.newInstance(position + 1);
  
          }
          @Override
          public int getCount() {
              // Show 3 total pages.
              return 3;
          }
  
          @Override
          public CharSequence getPageTitle(int position) {
              switch (position) {
                  case 0:
                      return "Dip-Vol";
                  case 1:
                      return "Vol-Dip";
                  case 2:
                      return "Temp-Dens";
              }
              return null;
          }
      }
  
      public void clickFun1 (View view)
      {
          short dipHSD = 0, dipMS = 0;
          final short radHSD = 1219;
          final short lenHSD = 6810;
          final short radMS = 999;
          final short lenMS = 6804;
          double volHSD, volMS;
  
          EditText dipH = (EditText) view.findViewById(R.id.dipHSD1);
          EditText dipM = (EditText) view.findViewById(R.id.dipMS1);
  
          TextView volH = (TextView) view.findViewById(R.id.volHSD1);
          TextView volM = (TextView) view.findViewById(R.id.volMS1);
          try {
              dipHSD = Short.parseShort(dipH.getText().toString());
              Liquid_Volume dtvh = new Liquid_Volume(radHSD,lenHSD,dipHSD);
              volHSD = dtvh.getVolume();
              volHSD = Math.round(volHSD);
              volH.setText(volHSD + "");
          }
          catch (NumberFormatException e) {
              volH.setText("");
          }
          try{ dipMS = Short.parseShort(dipM.getText().toString());
              Liquid_Volume dtvm = new Liquid_Volume(radMS,lenMS,dipMS);
              volMS = dtvm.getVolume();
              volM.setText(volMS + "");
          }catch(NumberFormatException e){volM.setText("");}
  
      }
  
      public void clearFun1(View view){
          EditText dipH = (EditText) view.findViewById(R.id.dipHSD1);
          EditText dipM = (EditText) view.findViewById(R.id.dipMS1);
  
          TextView volH = (TextView) view.findViewById(R.id.volHSD1);
          TextView volM = (TextView) view.findViewById(R.id.volMS1);
  
          volH.setText("");
          volM.setText("");
          dipH.setText("");
          dipM.setText("");
      }
  
      public void clickFun2 (View view)
      {
          EditText volH = (EditText) view.findViewById(R.id.volHSD2);
          EditText volM = (EditText) view.findViewById(R.id.volMS2);
  
          TextView dipH = (TextView) view.findViewById(R.id.dipHSD2);
          TextView dipM = (TextView) view.findViewById(R.id.dipMS2);
  
          double volHSD = 0, volMS = 0;
          final double radHSD = 121.9;
          final double lenHSD = 681.0;
          final double radMS = 99.9;
          final double lenMS = 680.4;
          double dipHSD, dipMS;
  
          try {
              volHSD = Double.parseDouble(volH.getText().toString());
              Liquid_Height HSD = new Liquid_Height(radHSD,lenHSD,volHSD);
              dipHSD = HSD.getDip();
              //String.format("%f",dipHSD);
              //dipH.setText(Double.toString(dipHSD));
              dipH.setText(dipHSD + "");
          }
          catch (NumberFormatException e) {
              dipH.setText("");
          }
          try{ volMS = Double.parseDouble(volM.getText().toString());
              Liquid_Height MS = new Liquid_Height(radMS,lenMS,volMS);
              dipMS = MS.getDip();
              //String.format("%f",dipHSD);
              //dipM.setText(String.format("%f",dipMS));
              dipM.setText(dipMS + "");
          }
          catch(NumberFormatException e){
              dipM.setText("");
          }
  
      }
  
      public void clearFun2(View view){
          EditText volH = (EditText) view.findViewById(R.id.volHSD2);
          EditText volM = (EditText) view.findViewById(R.id.volMS2);
  
          TextView dipH = (TextView) view.findViewById(R.id.dipHSD2);
          TextView dipM = (TextView) view.findViewById(R.id.dipMS2);
  
          volH.setText("");
          volM.setText("");
          dipH.setText("");
          dipM.setText("");
      }
  
  }
  </code></pre>
  
  <p>Then I have my fragment_one.java and rest other fragments in the same way.</p>
  
  <pre><code>public class Fragment_One extends Fragment {
  
          @Override
          public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                   Bundle savedInstanceState) {
              return inflater.inflate(R.layout.fragment_one, container, false);
  
      }
  
  }
  </code></pre>
  
  <p>Here the app crashes immediately after i try to open it.</p>
  
  <p>Logcat says the following</p>
  
  <pre><code>09-12 07:17:40.600 2283-2291/com.google.android.gms E/StrictMode: A resource was acquired at attached stack trace but never released. See java.io.Closeable for information on avoiding resource leaks.
                                                                    java.lang.Throwable: Explicit termination method 'close' not called
                                                                        at dalvik.system.CloseGuard.open(CloseGuard.java:184)
                                                                        at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:190)
                                                                        at ...
  </code></pre>