title: Android - FATAL EXCEPTION: main - Unable to start activity ComponentInfo
body: <p>My problem is that when I run my app on the android emulator the app starts up but quickly crashes and displays the popup: "Unfortunately, TipCalculator has stopped."  I have looked through the code and have searched the internet thoroughly for an answer. Yes I am a newby at android development. I have looked at the errors that have been generated by LogCat but do not know the problem and where to find it based on the errors I received.</p>
  
  <p>Here is my code:</p>
  
  <p>TipCalc.java</p>
  
  <p>package com.troysantry.tipcalculator;</p>
  
  <pre><code>import android.os.Bundle;
  import android.app.Activity;
  import android.text.Editable;
  import android.text.TextWatcher;
  import android.view.Menu;
  import android.widget.EditText;
  
  public class TipCalc extends Activity {
  
      public static final String TOTAL_BILL = "TOTAL_BILL";
      public static final String CURRENT_TIP = "CURRENT_TIP";
      public static final String BILL_WITHOUT_TIP = "BILL_WITHOUT_TIP";
  
      public double billBeforeTip;
      public double tipAmount;
      public double finalBill;
  
      EditText txtBillBeforeTip;
      EditText txtTipAmount;
      EditText txtFinalBill;
  
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_tip_calc);
  
          if(savedInstanceState==null){
  
              billBeforeTip=0.0;
              tipAmount=0.15;
              finalBill=0.0;
          }
          else{
  
              billBeforeTip=savedInstanceState.getDouble(BILL_WITHOUT_TIP);
              tipAmount=savedInstanceState.getDouble(CURRENT_TIP);
              finalBill=savedInstanceState.getDouble(TOTAL_BILL);
  
          }
              txtBillBeforeTip = (EditText) findViewById(R.id.txtBill);
              txtTipAmount=(EditText) findViewById(R.id.txtTip);
              txtFinalBill=(EditText) findViewById(R.id.txtFinal);
  
              txtBillBeforeTip.addTextChangedListener(billBeforeTipListener);     
      }
  
      private TextWatcher billBeforeTipListener = new TextWatcher(){
  
          @Override
          public void afterTextChanged(Editable arg0) {
              // TODO Auto-generated method stub
  
          }
  
          @Override
          public void beforeTextChanged(CharSequence s, int start, int count,
                  int after) {
              // TODO Auto-generated method stub
  
          }
  
          @Override
          public void onTextChanged(CharSequence s, int start, int before,
                  int count) {
  
              try{
                  billBeforeTip = Double.parseDouble(s.toString());
  
              }
              catch(NumberFormatException e){
                  billBeforeTip=0.0;
              }
  
              UpdateTipAndFinalBill();    
          }
      };
  
      protected void onSaveInstanceState(Bundle outState){
  
          super.onSaveInstanceState(outState);
  
          outState.putDouble(TOTAL_BILL, finalBill);
          outState.putDouble(CURRENT_TIP, tipAmount);
          outState.putDouble(BILL_WITHOUT_TIP, billBeforeTip);
  
      }
  
      private void UpdateTipAndFinalBill(){
          double tipAmount = Double.parseDouble(txtTipAmount.getText().toString());
  
          double finalBill = billBeforeTip + (billBeforeTip*tipAmount);
  
          txtFinalBill.setText(String.format("%.02f",finalBill));
  
      }
      @Override
      public boolean onCreateOptionsMenu(Menu menu) {
          // Inflate the menu; this adds items to the action bar if it is present.
          getMenuInflater().inflate(R.menu.tip_calc, menu);
          return true;
      }
  
  }
  </code></pre>
  
  <p>activity_tip_calc.xml</p>
  
  <pre><code>&lt;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"
      android:paddingBottom="@dimen/activity_vertical_margin"
      android:paddingLeft="@dimen/activity_horizontal_margin"
      android:paddingRight="@dimen/activity_horizontal_margin"
      android:paddingTop="@dimen/activity_vertical_margin"
      tools:context=".TipCalc" &gt;
  
      &lt;TextView
          android:id="@+id/tvBill"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_alignParentLeft="true"
          android:layout_alignParentTop="true"
          android:layout_marginLeft="19dp"
          android:layout_marginTop="14dp"
          android:text="@string/bill_text_view" /&gt;
  
      &lt;TextView
          android:id="@+id/tvFinal"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_alignRight="@+id/txtBill"
          android:layout_below="@+id/txtBill"
          android:layout_marginRight="24dp"
          android:layout_marginTop="18dp"
          android:text="@string/final_text_view" /&gt;
  
      &lt;EditText
          android:id="@+id/txtFinal"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_alignBaseline="@+id/tvFinal"
          android:layout_alignBottom="@+id/tvFinal"
          android:layout_alignRight="@+id/txtTip"
          android:layout_marginRight="25dp"
          android:ems="6"
          android:inputType="numberDecimal"
          android:text="@string/final_bill_edit_text" /&gt;
  
      &lt;TextView
          android:id="@+id/tvTip"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_above="@+id/tvFinal"
          android:layout_centerHorizontal="true"
          android:text="@string/tip_text_view" /&gt;
  
      &lt;EditText
          android:id="@+id/txtTip"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_alignBaseline="@+id/tvTip"
          android:layout_alignBottom="@+id/tvTip"
          android:layout_toRightOf="@+id/tvTip"
          android:ems="5"
          android:inputType="numberDecimal"
          android:text="@string/tip_edit_text"
          android:textSize="16sp" /&gt;
  
      &lt;EditText
          android:id="@+id/txtBill"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_alignBaseline="@+id/tvBill"
          android:layout_alignBottom="@+id/tvBill"
          android:layout_toRightOf="@+id/tvBill"
          android:ems="5"
          android:inputType="numberDecimal"
          android:text="@string/bill_edit_text"
          android:textSize="16sp" /&gt;
  
  &lt;/RelativeLayout&gt;
  </code></pre>
  
  <p>LogCat</p>
  
  <pre><code>11-04 01:24:10.403: D/AndroidRuntime(1050): Shutting down VM
  11-04 01:24:10.403: W/dalvikvm(1050): threadid=1: thread exiting with uncaught exception (group=0x41465700)
  11-04 01:24:10.543: E/AndroidRuntime(1050): FATAL EXCEPTION: main
  11-04 01:24:10.543: E/AndroidRuntime(1050): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.troysantry.tipcalculator/com.troysantry.tipcalculator.TipCalc}: java.lang.ClassCastException: android.widget.TextView cannot be cast to android.widget.EditText
  11-04 01:24:10.543: E/AndroidRuntime(1050):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
  11-04 01:24:10.543: E/AndroidRuntime(1050):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
  11-04 01:24:10.543: E/AndroidRuntime(1050):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
  11-04 01:24:10.543: E/AndroidRuntime(1050):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
  11-04 01:24:10.543: E/AndroidRuntime(1050):     at android.os.Handler.dispatchMessage(Handler.java:99)
  11-04 01:24:10.543: E/AndroidRuntime(1050):     at android.os.Looper.loop(Looper.java:137)
  11-04 01:24:10.543: E/AndroidRuntime(1050):     at android.app.ActivityThread.main(ActivityThread.java:5103)
  11-04 01:24:10.543: E/AndroidRuntime(1050):     at java.lang.reflect.Method.invokeNative(Native Method)
  11-04 01:24:10.543: E/AndroidRuntime(1050):     at java.lang.reflect.Method.invoke(Method.java:525)
  11-04 01:24:10.543: E/AndroidRuntime(1050):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
  11-04 01:24:10.543: E/AndroidRuntime(1050):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
  11-04 01:24:10.543: E/AndroidRuntime(1050):     at dalvik.system.NativeStart.main(Native Method)
  11-04 01:24:10.543: E/AndroidRuntime(1050): Caused by: java.lang.ClassCastException: android.widget.TextView cannot be cast to android.widget.EditText
  11-04 01:24:10.543: E/AndroidRuntime(1050):     at com.troysantry.tipcalculator.TipCalc.onCreate(TipCalc.java:45)
  11-04 01:24:10.543: E/AndroidRuntime(1050):     at android.app.Activity.performCreate(Activity.java:5133)
  11-04 01:24:10.543: E/AndroidRuntime(1050):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
  11-04 01:24:10.543: E/AndroidRuntime(1050):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
  11-04 01:24:10.543: E/AndroidRuntime(1050):     ... 11 more
  11-04 01:29:11.177: I/Process(1050): Sending signal. PID: 1050 SIG: 9
  11-04 01:31:32.080: D/AndroidRuntime(1109): Shutting down VM
  11-04 01:31:32.080: W/dalvikvm(1109): threadid=1: thread exiting with uncaught exception (group=0x41465700)
  11-04 01:31:32.194: E/AndroidRuntime(1109): FATAL EXCEPTION: main
  11-04 01:31:32.194: E/AndroidRuntime(1109): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.troysantry.tipcalculator/com.troysantry.tipcalculator.TipCalc}: java.lang.ClassCastException: android.widget.TextView cannot be cast to android.widget.EditText
  11-04 01:31:32.194: E/AndroidRuntime(1109):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
  11-04 01:31:32.194: E/AndroidRuntime(1109):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
  11-04 01:31:32.194: E/AndroidRuntime(1109):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
  11-04 01:31:32.194: E/AndroidRuntime(1109):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
  11-04 01:31:32.194: E/AndroidRuntime(1109):     at android.os.Handler.dispatchMessage(Handler.java:99)
  11-04 01:31:32.194: E/AndroidRuntime(1109):     at android.os.Looper.loop(Looper.java:137)
  11-04 01:31:32.194: E/AndroidRuntime(1109):     at android.app.ActivityThread.main(ActivityThread.java:5103)
  11-04 01:31:32.194: E/AndroidRuntime(1109):     at java.lang.reflect.Method.invokeNative(Native Method)
  11-04 01:31:32.194: E/AndroidRuntime(1109):     at java.lang.reflect.Method.invoke(Method.java:525)
  11-04 01:31:32.194: E/AndroidRuntime(1109):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
  11-04 01:31:32.194: E/AndroidRuntime(1109):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
  11-04 01:31:32.194: E/AndroidRuntime(1109):     at dalvik.system.NativeStart.main(Native Method)
  11-04 01:31:32.194: E/AndroidRuntime(1109): Caused by: java.lang.ClassCastException: android.widget.TextView cannot be cast to android.widget.EditText
  11-04 01:31:32.194: E/AndroidRuntime(1109):     at com.troysantry.tipcalculator.TipCalc.onCreate(TipCalc.java:44)
  11-04 01:31:32.194: E/AndroidRuntime(1109):     at android.app.Activity.performCreate(Activity.java:5133)
  11-04 01:31:32.194: E/AndroidRuntime(1109):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
  11-04 01:31:32.194: E/AndroidRuntime(1109):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
  11-04 01:31:32.194: E/AndroidRuntime(1109):     ... 11 more
  11-04 01:36:33.195: I/Process(1109): Sending signal. PID: 1109 SIG: 9
  11-04 02:11:09.684: D/AndroidRuntime(1167): Shutting down VM
  11-04 02:11:09.684: W/dalvikvm(1167): threadid=1: thread exiting with uncaught exception (group=0x41465700)
  11-04 02:11:09.855: E/AndroidRuntime(1167): FATAL EXCEPTION: main
  11-04 02:11:09.855: E/AndroidRuntime(1167): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.troysantry.tipcalculator/com.troysantry.tipcalculator.TipCalc}: java.lang.ClassCastException: android.widget.TextView cannot be cast to android.widget.EditText
  11-04 02:11:09.855: E/AndroidRuntime(1167):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
  11-04 02:11:09.855: E/AndroidRuntime(1167):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
  11-04 02:11:09.855: E/AndroidRuntime(1167):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
  11-04 02:11:09.855: E/AndroidRuntime(1167):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
  11-04 02:11:09.855: E/AndroidRuntime(1167):     at android.os.Handler.dispatchMessage(Handler.java:99)
  11-04 02:11:09.855: E/AndroidRuntime(1167):     at android.os.Looper.loop(Looper.java:137)
  11-04 02:11:09.855: E/AndroidRuntime(1167):     at android.app.ActivityThread.main(ActivityThread.java:5103)
  11-04 02:11:09.855: E/AndroidRuntime(1167):     at java.lang.reflect.Method.invokeNative(Native Method)
  11-04 02:11:09.855: E/AndroidRuntime(1167):     at java.lang.reflect.Method.invoke(Method.java:525)
  11-04 02:11:09.855: E/AndroidRuntime(1167):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
  11-04 02:11:09.855: E/AndroidRuntime(1167):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
  11-04 02:11:09.855: E/AndroidRuntime(1167):     at dalvik.system.NativeStart.main(Native Method)
  11-04 02:11:09.855: E/AndroidRuntime(1167): Caused by: java.lang.ClassCastException: android.widget.TextView cannot be cast to android.widget.EditText
  11-04 02:11:09.855: E/AndroidRuntime(1167):     at com.troysantry.tipcalculator.TipCalc.onCreate(TipCalc.java:44)
  11-04 02:11:09.855: E/AndroidRuntime(1167):     at android.app.Activity.performCreate(Activity.java:5133)
  11-04 02:11:09.855: E/AndroidRuntime(1167):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
  11-04 02:11:09.855: E/AndroidRuntime(1167):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
  11-04 02:11:09.855: E/AndroidRuntime(1167):     ... 11 more
  </code></pre>