Unfortunately appName stopped the error

Question

When I run my application after an error message, it gives:

Unfortunately appName stopped the error

I have a MainActivity.java file:

package com.example.hello_world; import android.os.Bundle; import android.app.Activity; import android.app.Dialog; import android.view.Menu; import android.view.View; import android.widget.Button; import android.widget.CompoundButton; import android.widget.CompoundButton.OnCheckedChangeListener; import android.widget.EditText; import android.widget.RadioButton; import android.widget.TextView; import android.widget.Toast; import android.view.View.OnClickListener; public class MainActivity extends Activity implements OnCheckedChangeListener { Button btnSubmit,b2; RadioButton rb1,rb2; EditText etFirstName,etLastName; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); btnSubmit=(Button)findViewById(R.id.btnSubmit); rb1.setOnCheckedChangeListener(new OnCheckedChangeListener() { btnSubmit.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub switch(v.getId()) { case R.id.btnSubmit: boolean didWork=true; try { String fName=((EditText) findViewById(R.id.etFirstName)).getText().toString(); String LName=((EditText) findViewById(R.id.etLastNam)).getText().toString(); Toast msg1 = Toast.makeText(getBaseContext(), fName, Toast.LENGTH_LONG); msg1.show(); HNT entry=new HNT(MainActivity.this); entry.open(); Toast msg2 = Toast.makeText(getBaseContext(), fName, Toast.LENGTH_LONG); msg2.show(); entry.createEntry(fName,LName); entry.close(); break; } catch(Exception e) { didWork=false; Toast msg1 = Toast.makeText(getBaseContext(), "Catch Failed"+e.getMessage(), Toast.LENGTH_LONG); msg1.show(); } finally { if(didWork) { Toast msg1 = Toast.makeText(getBaseContext(), "Sucess", Toast.LENGTH_LONG); msg1.show(); } else { Toast msg1 = Toast.makeText(getBaseContext(), "Failed", Toast.LENGTH_LONG); msg1.show(); } } } } }); } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.main, menu); return true; } @Override public void onCheckedChanged(CompoundButton arg0, boolean arg1) { // TODO Auto-generated method stub } } 

xml file:

 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" style="@style/AppTheme" 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=".MainActivity" > <TextView android:id="@+id/tvFName" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentLeft="true" android:layout_alignParentTop="true" android:layout_marginTop="34dp" android:text="First Name" android:textAppearance="?android:attr/textAppearanceLarge" /> <EditText android:id="@+id/etFirstName" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignBaseline="@+id/tvFName" android:layout_alignBottom="@+id/tvFName" android:layout_alignParentRight="true" android:layout_toRightOf="@+id/tvFName" android:inputType="textPersonName" /> <EditText android:id="@+id/etLastNam" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignLeft="@+id/etFirstName" android:layout_below="@+id/etFirstName" android:layout_marginLeft="13dp" android:layout_marginTop="43dp" android:ems="10" android:inputType="textPersonName" /> <TextView android:id="@+id/TextView01" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignBottom="@+id/etLastNam" android:layout_alignLeft="@+id/tvFName" android:text="Last Name" android:textAppearance="?android:attr/textAppearanceLarge" /> <Button android:id="@+id/btnSubmit" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignLeft="@+id/etLastNam" android:layout_alignParentBottom="true" android:layout_marginBottom="74dp" android:text="Submit" /> </RelativeLayout> 

Manifest file:

 <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.hello_world" android:versionCode="1" android:versionName="1.0" > <uses-sdk android:minSdkVersion="17" android:targetSdkVersion="17" /> <application android:allowBackup="true" android:icon="@drawable/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme" > <activity android:name="com.example.hello_world.MainActivity" android:label="@string/app_name" > <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> </manifest> 

Answer 1

In the posted xml message there is no Radio button

But you have it

  rb1.setOnCheckedChangeListener(new OnCheckedChangeListener() { 

You are probably getting a NullPointerException . If you do not want to remove the above.

Also remove

  implements OnCheckedChangeListener 

and this one

 @Override public void onCheckedChanged(CompoundButton arg0, boolean arg1) { // TODO Auto-generated method stub }