title: java null pointer exception in android
body: <p>in my mainactivity:</p>
  
  <pre><code>count=count+1;
  //the problem seems to be in this line of code below
  String fileName=f.getFileName(count).toString();
  // the method below invokes a method from another class. it works fine so please ignore
  helloTxt.setText(readText.readTxt(fileName));
  </code></pre>
  
  <p>f is an object of class FileName from which i get back the filename:</p>
  
  <pre><code>public class FileName {
  
      String file;
      public String getFileName(int count) {
          // TODO Auto-generated method stub
  
          if (count==1)
          {
              file.equals("textone");
          }
  
          if(count==2)
          {
              file.equals("texttwo");
          }
          return file;
  
      }
  
  
  
      }
  </code></pre>
  
  <p>Log Cat:</p>
  
  <pre><code>03-19 12:02:00.554: D/AndroidRuntime(5550): Shutting down VM
  03-19 12:02:00.554: W/dalvikvm(5550): threadid=1: thread exiting with uncaught exception (group=0x418342a0)
  03-19 12:02:00.562: E/AndroidRuntime(5550): FATAL EXCEPTION: main
  03-19 12:02:00.562: E/AndroidRuntime(5550): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.testflashfile/com.example.testflashfile.MainActivity}: java.lang.NullPointerException
  03-19 12:02:00.562: E/AndroidRuntime(5550):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2097)
  03-19 12:02:00.562: E/AndroidRuntime(5550):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2122)
  03-19 12:02:00.562: E/AndroidRuntime(5550):     at android.app.ActivityThread.access$600(ActivityThread.java:140)
  03-19 12:02:00.562: E/AndroidRuntime(5550):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1228)
  03-19 12:02:00.562: E/AndroidRuntime(5550):     at android.os.Handler.dispatchMessage(Handler.java:99)
  03-19 12:02:00.562: E/AndroidRuntime(5550):     at android.os.Looper.loop(Looper.java:137)
  03-19 12:02:00.562: E/AndroidRuntime(5550):     at android.app.ActivityThread.main(ActivityThread.java:4895)
  03-19 12:02:00.562: E/AndroidRuntime(5550):     at java.lang.reflect.Method.invokeNative(Native Method)
  03-19 12:02:00.562: E/AndroidRuntime(5550):     at java.lang.reflect.Method.invoke(Method.java:511)
  03-19 12:02:00.562: E/AndroidRuntime(5550):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:994)
  03-19 12:02:00.562: E/AndroidRuntime(5550):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:761)
  03-19 12:02:00.562: E/AndroidRuntime(5550):     at dalvik.system.NativeStart.main(Native Method)
  03-19 12:02:00.562: E/AndroidRuntime(5550): Caused by: java.lang.NullPointerException
  03-19 12:02:00.562: E/AndroidRuntime(5550):     at com.example.testflashfile.FileName.getFileName(FileName.java:11)
  03-19 12:02:00.562: E/AndroidRuntime(5550):     at com.example.testflashfile.MainActivity.onCreate(MainActivity.java:48)
  03-19 12:02:00.562: E/AndroidRuntime(5550):     at android.app.Activity.performCreate(Activity.java:5163)
  03-19 12:02:00.562: E/AndroidRuntime(5550):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
  03-19 12:02:00.562: E/AndroidRuntime(5550):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2061)
  03-19 12:02:00.562: E/AndroidRuntime(5550):     ... 11 more
  03-19 12:02:11.164: I/Process(5550): Sending signal. PID: 5550 SIG: 9
  </code></pre>
  
  <p>All the activities are listed in the manifest. So any help which would fix this problem is highly appreciated.</p>
  
  <p>Thanks in advance.</p>