Fatal Exception Main (unable to start activity) Caused by: java.lang.NullPointerException

Question

i'm noob at android and i face a strange exception when i try to settext or setcolor or anything that was working before

protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        pageNoSeek = (SeekBar)findViewById(R.id.pageNoSeekBar);
        pageNotv = (TextView)findViewById(R.id.pageNotv);
        nextButton=(ImageButton)findViewById(R.id.leftButton);
        backButton=(ImageButton)findViewById(R.id.rightButton);
        mainText = (TextView)findViewById(R.id.mainText);
        mainText.setTextColor(Color.RED);
}

as shown in code above there's nothing unusual .. acutally i've used this same code before at another machine .. it gives error at setTextColor or setTextSize if i added it..

> 03-20 07:55:17.552: E/AndroidRuntime(1718): FATAL EXCEPTION: main
03-20 07:55:17.552: E/AndroidRuntime(1718): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.thedarkdimension.keyboardShortcut/com.thedarkdimension.keyboardShortcut.StoryViewController}: java.lang.NullPointerException
03-20 07:55:17.552: E/AndroidRuntime(1718):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
03-20 07:55:17.552: E/AndroidRuntime(1718):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
03-20 07:55:17.552: E/AndroidRuntime(1718):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
03-20 07:55:17.552: E/AndroidRuntime(1718):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
03-20 07:55:17.552: E/AndroidRuntime(1718):     at android.os.Handler.dispatchMessage(Handler.java:99)
03-20 07:55:17.552: E/AndroidRuntime(1718):     at android.os.Looper.loop(Looper.java:137)
03-20 07:55:17.552: E/AndroidRuntime(1718):     at android.app.ActivityThread.main(ActivityThread.java:5041)
03-20 07:55:17.552: E/AndroidRuntime(1718):     at java.lang.reflect.Method.invokeNative(Native Method)
03-20 07:55:17.552: E/AndroidRuntime(1718):     at java.lang.reflect.Method.invoke(Method.java:511)
03-20 07:55:17.552: E/AndroidRuntime(1718):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
03-20 07:55:17.552: E/AndroidRuntime(1718):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
03-20 07:55:17.552: E/AndroidRuntime(1718):     at dalvik.system.NativeStart.main(Native Method)
03-20 07:55:17.552: E/AndroidRuntime(1718): Caused by: java.lang.NullPointerException
03-20 07:55:17.552: E/AndroidRuntime(1718):     at com.thedarkdimension.keyboardShortcut.StoryViewController.getNextPage(StoryViewController.java:95)
03-20 07:55:17.552: E/AndroidRuntime(1718):     at com.thedarkdimension.keyboardShortcut.StoryViewController.connectToDB(StoryViewController.java:84)
03-20 07:55:17.552: E/AndroidRuntime(1718):     at com.thedarkdimension.keyboardShortcut.StoryViewController.onCreate(StoryViewController.java:47)
03-20 07:55:17.552: E/AndroidRuntime(1718):     at android.app.Activity.performCreate(Activity.java:5104)
03-20 07:55:17.552: E/AndroidRuntime(1718):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
03-20 07:55:17.552: E/AndroidRuntime(1718):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
03-20 07:55:17.552: E/AndroidRuntime(1718):     ... 11 more

and i can't get it .. can anyone help :)

Answer 1

From you code snippet for onCreate it seems that you have not called setContentView. For this reason all calls for (X)findViewById(R.id.x); returns null and thus you are getting a Null Pointer Exception when you try to operate on the variables. [mainText is null since the view was not found].

Solution: Call setContentView first and then initialize your variables and do the remaining stuff