title: Android Studio - App Crashes
body: <p>How can I change or add more code to make this app to stop crashing? This activity is called "WhatBin", I simply wanted to make a button listen to when a person would click and change a text view. (VIEW PICTURES BELOW FOR MORE DETAILS.)    </p>
  
  <p>PICTURES: <a href="http://imgur.com/a/ODvHb" rel="nofollow">http://imgur.com/a/ODvHb</a></p>
  
  <pre><code>package com.example.tiffany.whatbin;
  
  import android.os.Bundle;
  import android.support.design.widget.FloatingActionButton;
  import android.support.design.widget.Snackbar;
  import android.support.v7.app.AppCompatActivity;
  import android.support.v7.widget.Toolbar;
  import android.view.View;
  import android.view.Menu;
  import android.view.MenuItem;
  import android.widget.Button;
  import android.widget.EditText;
  import android.widget.TextView;
  
  import org.w3c.dom.Text;
  
  public class WhatBin extends AppCompatActivity {
  
  @Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_what_bin);
      Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
      setSupportActionBar(toolbar);
  
   final TextView txt_answer = (TextView) findViewById(R.id.txt_answer);
  
   Button btn_go = (Button) findViewById(R.id.btn_go);
  
      btn_go.setOnClickListener(new View.OnClickListener() {
          @Override
          public void onClick(View v) {
  
              txt_answer.setText("Marker - Recycle Bin");
  
          }
      });
  
  
  
      };
  }
  </code></pre>
  
  <p>HERE IS THE XML FILE:</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:layout_padddingLeft="@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:showIn="@layout/activity_what_bin" tools:context=".WhatBin"&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Go"
      android:id="@+id/btn.go"
      android:layout_marginBottom="113dp"
      android:textColor="@drawable/abc_dialog_material_background_dark"
      android:layout_alignParentBottom="true"
      android:layout_alignParentRight="true"
      android:layout_alignParentEnd="true" /&gt;
  
  &lt;EditText
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:id="@+id/textEdit"
      android:layout_alignBottom="@+id/btn.go"
      android:layout_alignParentLeft="true"
      android:layout_alignParentStart="true"
      android:layout_toLeftOf="@+id/btn.go"
      android:layout_toStartOf="@+id/btn.go" /&gt;
  
  &lt;TextView
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:textAppearance="?android:attr/textAppearanceSmall"
      android:text="@string/instructiontext"
      android:id="@+id/textinstruc"
      android:layout_below="@+id/textEdit"
      android:layout_alignParentLeft="true"
      android:layout_alignParentStart="true"
      android:layout_toLeftOf="@+id/btn.go"
      android:layout_toStartOf="@+id/btn.go" /&gt;
  
  &lt;TextView
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:textAppearance="?android:attr/textAppearanceLarge"
      android:text="@string/txt.1"
      android:id="@+id/txt.answer"
      android:layout_alignParentTop="true"
      android:layout_alignParentLeft="true"
      android:layout_alignParentStart="true" /&gt;
  
  &lt;/RelativeLayout&gt;
  </code></pre>