Buttons not working after ContentView change

Thanks for taking the time to look into my problem with me. I'm very new to Android Development and this is my first application attempt. Any and all help would be appreciated. All advice is needed advice at this point.

Main issue at hand is the btnBack and btnSubmit are not triggering an onClick event. Please advise.

helloformstuff.java

package com.uDrew.helloformstuff;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.Spinner;
public class helloformstuff extends Activity implements OnClickListener {

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    Log.i("DrewDebug", "Loading: layout.main");

    setContentView(R.layout.main);

    Log.i("DrewDebug", "Loaded: layout.main");

    Log.i("DrewDebug", "Loading: Drunk Spinner");

    //Drunk Spinner
    Spinner spLevel = (Spinner) findViewById(R.id.spLevel);
    ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(
            this, R.array.drunk_array, android.R.layout.simple_spinner_item);
    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    spLevel.setAdapter(adapter);

    Log.i("DrewDebug", "Loaded: Drunk Spinner");

    Log.i("DrewDebug", "Listening for Buttons");
    //Listen for button clicks
    Button btnNext = (Button) this.findViewById(R.id.btnNext);
    Button btnSubmit = (Button) this.findViewById(R.id.btnSubmit);
 开发者_Go百科   Button btnBack = (Button) this.findViewById(R.id.btnBack);

    if (btnNext!= null) {
        //If btnNext was hit
        btnNext.setOnClickListener(new OnClickListener() {

            public void onClick(View v) {

            Log.i("DrewDebug", "Button Hit: Next");
            //Log the beginning of this code 
            Log.i("DrewDebug", "BEGIN Next Code");

            //Change to second Screen
            setContentView(R.layout.second);

            //Initialize State Spinner
            Spinner spState = (Spinner) findViewById(R.id.spState);
            ArrayAdapter<CharSequence> adapter2 = ArrayAdapter.createFromResource(
                    helloformstuff.this, R.array.state_array, android.R.layout.simple_spinner_item);
            adapter2.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
            spState.setAdapter(adapter2);

          //Log the end of the this code
            Log.i("DrewDebug", "END Next Code");
            }
        });
    }

    if (btnBack != null) {
        //If btnBack was hit
        btnBack.setOnClickListener(new OnClickListener() {
            public void onClick(View v){
                Log.i("DrewDebug", "Button Hit: Back");
                //Log the beginning of this code 
                Log.i("DrewDebug", "BEGIN Back Code");
                //Change to first screen
                setContentView(R.layout.main);

                //Drunk Spinner
                Spinner spLevel = (Spinner) findViewById(R.id.spLevel);
                ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(
                        helloformstuff.this, R.array.drunk_array, android.R.layout.simple_spinner_item);
                adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
                spLevel.setAdapter(adapter);

                //Log the end of the this code
                Log.i("DrewDebug", "END Back Code");
            }
        });
    }
}
}

main.xml

<EditText 
    android:id="@+id/txtQuote" 
    android:layout_width="match_parent"
    android:layout_height="wrap_content" 
    android:text="Enter Quote" /> 

<TextView 
    android:id="@+id/lblWho" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content"
    android:layout_below="@id/txtQuote"
    android:text="Who Said It?"/>

<EditText 
    android:id="@+id/txtFirst" 
    android:layout_width="250px"
    android:layout_height="wrap_content" 
    android:layout_below="@id/lblWho"
    android:layout_alignParentLeft="true"
    android:layout_marginRight="10dip"
    android:text="Anonymous" />

<EditText 
    android:id="@+id/txtLast" 
    android:layout_width="50px"
    android:layout_height="wrap_content"
    android:layout_toRightOf="@id/txtFirst"
    android:layout_alignTop="@id/txtFirst"
    android:text="X"/>

<Spinner 
    android:id="@+id/spLevel"
    android:prompt="@string/drunk_prompt" 
    android:layout_width="match_parent"
    android:layout_height="wrap_content" 
    android:layout_below="@id/txtFirst"
    android:layout_alignParentLeft="true"/>

<Button 
    android:id="@+id/btnNext" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content"
    android:layout_below="@id/spLevel"
    android:layout_alignParentRight="true"
    android:text="Next"/>

second.xml

<TextView 
    android:id="@+id/lblShare" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content"
    android:text="Who's Sharing?"/>

<EditText 
    android:id="@+id/txtFirstShare" 
    android:layout_width="250px"
    android:layout_height="wrap_content" 
    android:layout_below="@id/lblShare"
    android:layout_alignParentLeft="true"
    android:layout_marginRight="10dip"
    android:text="Anonymous" />

<EditText 
    android:id="@+id/txtLastShare" 
    android:layout_width="50px"
    android:layout_height="wrap_content"
    android:layout_toRightOf="@id/txtFirstShare"
    android:layout_alignTop="@id/txtFirstShare"
    android:text="X"/>

<EditText 
    android:id="@+id/txtCity" 
    android:layout_width="250px"
    android:layout_height="wrap_content"
    android:layout_below="@id/txtLastShare"
    android:layout_alignParentLeft="true"
    android:layout_marginRight="10dip"
    android:text="NoWhere"/>

<Spinner 
    android:id="@+id/spState"
    android:prompt="@string/state_prompt" 
    android:layout_width="match_parent"
    android:layout_height="wrap_content" 
    android:layout_toRightOf="@id/txtCity"
    android:layout_alignTop="@id/txtCity"/>

<Button 
    android:id="@+id/btnSubmit" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content"
    android:layout_below="@id/spState"
    android:layout_alignParentRight="true"
    android:text="Submit"/>

<Button 
    android:id="@+id/btnBack" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content"
    android:layout_toLeftOf="@id/btnSubmit"
    android:layout_alignParentLeft="true"
    android:layout_alignTop="@id/btnSubmit"
    android:text="Back"/>

string.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="app_name">Random Drunk Quotes</string>
<string name="drunk_prompt">Level of Buzz</string>
<string-array name="drunk_array">
    <item>One Beer Syndrome</item>
    <item>Buzzed</item>
    <item>Drunk</item>
    <item>Trashed</item>
    <item>Retarded</item>
</string-array>

<string name="state_prompt">State</string>
<string-array name="state_array">
                  <item>AL</item> 
                  <item>AK</item> 
                  <item>AS</item> 
                  <item>AZ</item> 
                  <item>AR</item> 
                  <item>CA</item> 
                  <item>CO</item> 
                  <item>CT</item> 
                  <item>DE</item> 
                  <item>DC</item> 
                  <item>FM</item> 
                  <item>FL</item> 
                  <item>GA</item> 
                  <item>GU</item> 
                  <item>HI</item> 
                  <item>ID</item> 
                  <item>IL</item> 
                  <item>IN</item> 
                  <item>IA</item> 
                  <item>KS</item> 
                  <item>KY</item> 
                  <item>LA</item> 
                  <item>ME</item> 
                  <item>MH</item> 
                  <item>MD</item> 
                  <item>MA</item> 
                  <item>MI</item> 
                  <item>MN</item> 
                  <item>MS</item> 
                  <item>MO</item> 
                  <item>MT</item> 
                  <item>NE</item> 
                  <item>NH</item> 
                  <item>NV</item> 
                  <item>NJ</item> 
                  <item>NM</item> 
                  <item>NY</item> 
                  <item>NC</item> 
                  <item>ND</item> 
                  <item>MP</item> 
                  <item>OH</item> 
                  <item>OK</item> 
                  <item>OR</item> 
                  <item>PW</item> 
                  <item>PA</item> 
                  <item>PR</item> 
                  <item>RI</item> 
                  <item>SC</item> 
                  <item>SD</item> 
                  <item>TN</item> 
                  <item>TX</item> 
                  <item>UT</item> 
                  <item>VT</item> 
                  <item>VI</item> 
                  <item>VA</item> 
                  <item>WA</item> 
                  <item>WV</item> 
                  <item>WI</item> 
                  <item>WY</item> 
</string-array>

New source:

    //Listen for btnNext button click
    Button btnNext = (Button) this.findViewById(R.id.btnNext);
    Button btnBack = (Button) this.findViewById(R.id.btnBack);
    Button btnSubmit = (Button) this.findViewById(R.id.btnSubmit);

    if (btnNext!= null) {
        btnNext.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {

                clickNext();
            }
        });
    }
    if (btnBack != null) {
        //If btnBack was hit
        btnBack.setOnClickListener(new OnClickListener() {
            public void onClick(View v){
                clickBack();
            }
        });
    }
    if (btnSubmit != null) {
        //If btnSubmit was hit
        btnSubmit.setOnClickListener(new OnClickListener() {
            public void onClick(View v){
                clickSubmit();
            }
        });
    }
}



public void clickNext(){
    //Change to second Screen
    setContentView(R.layout.second);

    //Initialize State Spinner
    Spinner spState = (Spinner) findViewById(R.id.spState);
    ArrayAdapter<CharSequence> adapter2 = ArrayAdapter.createFromResource(
            RandomDrunkQuotes.this, R.array.state_array, android.R.layout.simple_spinner_item);
    adapter2.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    spState.setAdapter(adapter2);

    Button btnBack = (Button) findViewById(R.id.btnBack);
    btnBack.setOnClickListener(new OnClickListener() {
        public void onClick(View v){
            clickBack();
        }
    });
}
public void clickBack(){
    //Change to first screen
    setContentView(R.layout.main);

    //Drunk Spinner
    Spinner spLevel = (Spinner) findViewById(R.id.spLevel);
    ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(
            RandomDrunkQuotes.this, R.array.drunk_array, android.R.layout.simple_spinner_item);
    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    spLevel.setAdapter(adapter);

    Button btnNext = (Button) findViewById(R.id.btnNext);
    Button btnSubmit = (Button) findViewById(R.id.btnSubmit);
    btnNext.setOnClickListener(new OnClickListener() {
        public void onClick(View v) {

            clickNext();
        }
    });
}
public void clickSubmit(){

}

Your content view (main.xml) doesn't contain definitions of btnBack and btnSubmit. Your code should look like this:

Button btnNext = (Button) this.findViewById(R.id.btnNext);
if (btnNext!= null) {
    btnNext.setOnClickListener(new OnClickListener() {
        public void onClick(View v) {
            ...

            //Change to second Screen
            setContentView(R.layout.second);

            //Initialize State Spinner
            ...
            Button btnBack = (Button) this.findViewById(R.id.btnBack);
            if (btnBack != null) {
                //If btnBack was hit
                btnBack.setOnClickListener(new OnClickListener() {
                    public void onClick(View v){
                        ...
                    }
                });
            }
            Button btnSubmit = (Button) this.findViewById(R.id.btnSubmit);
            if (btnSubmit != null) {
                //If btnSubmit was hit
                btnSubmit.setOnClickListener(new OnClickListener() {
                    public void onClick(View v){
                        ...
                    }
                });
            }
        }
    });
}

The problem is, since your onClick listeners change the layout, they themselves will also need to set up handlers for the new layout. You'd be best off creating new private methods in your Activity that set up the handler, then call that method in your onCreate and handlers.

The Views are only created when the layout xml is inflated. You are inflating R.layout.main: this only creates the btnNext button, so a listener is set on that, but no listener is set on the btnBack and btnSubmit buttons since they are null in the onCreate method (because they don't exist yet).

One quick fix is to move the btnBack setOnClickListener to immediately after your call to setContentView(R.layout.second);.