java.lang.NullPointerException in android application.

Question

I am trying to fill an array of an "Runners" with an information in an ArrayList but I get a null pointer exception. I've printed out the size of both the arraylist and the array of Runners and they are what they should be.

--I only included code that I thought was necessary to solve the problem, please comment if you need more

 private Runner r[];
 private EditText runnerName,trackLength,raceDistance;
 private ArrayList<String> runners = new ArrayList<String>();

 public void onClickSetRunner(View v){
    runners.add(runnerName.getText().toString());
    runnerName.setText("");
}

 public void onClickFinish(View v){         
    r = new Runner[runners.size()];     
    int i =0;       
    for(String name : runners){             
        r[i].setFirst(name);
        i++;
    }


}

Logcat (sorry I couldnt get it formatted)

04-15 09:09:45.009: E/AndroidRuntime(28225): FATAL EXCEPTION: main
04-15 09:09:45.009: E/AndroidRuntime(28225): Process: com.example.runtracker, PID: 28225
04-15 09:09:45.009: E/AndroidRuntime(28225): java.lang.IllegalStateException: Could not execute method of the activity
04-15 09:09:45.009: E/AndroidRuntime(28225):    at android.view.View$1.onClick(View.java:3865)
04-15 09:09:45.009: E/AndroidRuntime(28225):    at android.view.View.performClick(View.java:4480)
04-15 09:09:45.009: E/AndroidRuntime(28225):    at android.view.View$PerformClick.run(View.java:18673)
04-15 09:09:45.009: E/AndroidRuntime(28225):    at android.os.Handler.handleCallback(Handler.java:733)
04-15 09:09:45.009: E/AndroidRuntime(28225):    at android.os.Handler.dispatchMessage(Handler.java:95)
04-15 09:09:45.009: E/AndroidRuntime(28225):    at android.os.Looper.loop(Looper.java:157)
04-15 09:09:45.009: E/AndroidRuntime(28225):    at android.app.ActivityThread.main(ActivityThread.java:5872)
04-15 09:09:45.009: E/AndroidRuntime(28225):    at java.lang.reflect.Method.invokeNative(Native Method)
04-15 09:09:45.009: E/AndroidRuntime(28225):    at java.lang.reflect.Method.invoke(Method.java:515)
04-15 09:09:45.009: E/AndroidRuntime(28225):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1069)
04-15 09:09:45.009: E/AndroidRuntime(28225):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:885)
04-15 09:09:45.009: E/AndroidRuntime(28225):    at dalvik.system.NativeStart.main(Native Method)
04-15 09:09:45.009: E/AndroidRuntime(28225): Caused by: java.lang.reflect.InvocationTargetException
04-15 09:09:45.009: E/AndroidRuntime(28225):    at java.lang.reflect.Method.invokeNative(Native Method)
04-15 09:09:45.009: E/AndroidRuntime(28225):    at java.lang.reflect.Method.invoke(Method.java:515)
04-15 09:09:45.009: E/AndroidRuntime(28225):    at android.view.View$1.onClick(View.java:3860)
04-15 09:09:45.009: E/AndroidRuntime(28225):    ... 11 more
04-15 09:09:45.009: E/AndroidRuntime(28225): Caused by: java.lang.NullPointerException
04-15 09:09:45.009: E/AndroidRuntime(28225):    at com.example.runtracker.MainActivity.onClickFinish(MainActivity.java:99)
04-15 09:09:45.009: E/AndroidRuntime(28225):    ... 14 more

If that's all of the code we need, then you haven't initialised your runnerName EditText. — Ken Wolf
– Ken Wolf, Commented Apr 15, 2014 at 13:21
After the initialisation of array r all elements are null. If you try to call a method of a object that is null, that causes the exception. — fabian
– fabian, Commented Apr 15, 2014 at 13:24

laalto · Accepted Answer · 2014-04-15 13:24:35Z

4

You haven't actually initialized r[i]:

r = new Runner[runners.size()];     
int i =0;       
for(String name : runners){             
    r[i].setFirst(name);

you have an array or Runners but each entry in the array is null by default. Add

r[i] = new Runner();

to initialize an entry there.

answered Apr 15, 2014 at 13:24

laalto

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Comments

Dan Harms · Accepted Answer · 2014-04-15 13:26:00Z

0

You created a new array of runners in onClickFinish. However, you don't create new Runner objects in the array so r[i] is null.

answered Apr 15, 2014 at 13:26

Dan Harms

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Comments

Sanjay Rabari · Accepted Answer · 2014-04-15 13:23:58Z

-1

initialize runnerName before u use it.

 runnerName.setText("");
    runners.add(runnerName.getText().toString());

answered Apr 15, 2014 at 13:23

Sanjay Rabari

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