title: Loop to fill an array for use in listview (fill array from txt file strings)
body: <p>I am trying to fill an array for use in a listview in android.  I want the array to be filled with data stored in several .txt files on the sdcard.  I have an Int names Mx that tells the loop how many times to run (well thats what i would like it to do).  The value Mx is also the number of entries required in the array.</p>
  
  <p>I am currently using this code but it doesnt work:</p>
  
  <pre><code> public void arrayload() {
          ///////////////////////////////////working here///////////////////////////////// 
           //new looping code
           for (int i=1; i&lt;=Mx; i++){
                  try{
                       String fileName = String.valueOf(i) +".txt";   
                       File myFile = new File("/sdcard/mx/" +fileName);
                       FileInputStream fIn = new FileInputStream(myFile);
                          BufferedReader myReader = new BufferedReader(
                                  new InputStreamReader(fIn));
                          String aDataRow = "";
                          String aBuffer = "";
                          while ((aDataRow = myReader.readLine()) != null) {
                              aBuffer += aDataRow + "\n";
                          }
                  String[] lvdata = new String[Mx];
                  lvdata[i] = aBuffer;
                  ArrayAdapter&lt;String&gt; adapter = new ArrayAdapter&lt;String&gt;(this, R.layout.logbooklayout, lvdata);
                     lv1.setAdapter(adapter);
                     lv1.scrollTo(0, mxlv); // set the listview at a sensible point
                  }
                   catch (Exception e) {
                          Toast.makeText(getBaseContext(), e.getMessage(),
                                  Toast.LENGTH_SHORT).show();
                      }
           }
  </code></pre>
  
  <p>I have previously been hardcoding each entry into the array but am trying to tidy the code up so it loops based on the value Mx.  I know the array and listview work fine if i manually fill them, wheni use the code below the app crashes.</p>
  
  <p>Logcat output is</p>
  
  <pre><code>03-02 16:41:23.888: E/AndroidRuntime(31497): FATAL EXCEPTION: main
  03-02 16:41:23.888: E/AndroidRuntime(31497): java.lang.NullPointerException
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:394)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.widget.ArrayAdapter.getView(ArrayAdapter.java:362)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.widget.AbsListView.obtainView(AbsListView.java:2159)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.widget.ListView.measureHeightOfChildren(ListView.java:1246)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.widget.ListView.onMeasure(ListView.java:1158)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.view.View.measure(View.java:15513)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:645)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:425)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.view.View.measure(View.java:15513)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4827)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.view.View.measure(View.java:15513)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.widget.LinearLayout.measureVertical(LinearLayout.java:847)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.view.View.measure(View.java:15513)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4827)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2176)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.view.View.measure(View.java:15513)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1874)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1089)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1265)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:989)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4351)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.view.Choreographer.doCallbacks(Choreographer.java:562)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.view.Choreographer.doFrame(Choreographer.java:532)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.os.Handler.handleCallback(Handler.java:725)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.os.Handler.dispatchMessage(Handler.java:92)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.os.Looper.loop(Looper.java:137)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at android.app.ActivityThread.main(ActivityThread.java:5191)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at java.lang.reflect.Method.invokeNative(Native Method)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at java.lang.reflect.Method.invoke(Method.java:511)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:795)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:562)
  03-02 16:41:23.888: E/AndroidRuntime(31497):    at dalvik.system.NativeStart.main(Native Method)
  </code></pre>
  
  <p>Any help with this is really welcome.  I am just cutting my teeth with Java so my code is in need of improving lots! </p>
  
  <p>Thanks</p>