wait( ) function not running properly

Question

I am new to using the wait( ); feature. I thought I had it right, but it will not run. I cannot figure out where I went wrong by looking at the examples. Can anyone help me out, please? Thanks in advance!

public class MainActivity
    extends Activity
{
    private ImageView splash;


    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.splash);
        initialize();
    }


    private void initialize()
    {
        splash.setVisibility(View.VISIBLE);
        try
        {
            wait(5000);
        }
        catch (InterruptedException e)
        {
            e.printStackTrace();
        }
        mainMenu();

    }


    private void mainMenu()
    {
        setContentView(R.layout.mainmenu);

    }

LOGCAT:

04-04 23:08:40.075: E/Trace(2555): error opening trace file: No such file or directory (2)
04-04 23:08:48.345: E/AndroidRuntime(2555): FATAL EXCEPTION: main
04-04 23:08:48.345: E/AndroidRuntime(2555): java.lang.RuntimeException: Unable to start activity ComponentInfo{edu.virginia.hotncolduva/edu.virginia.hotncolduva.MainActivity}: java.lang.NullPointerException
04-04 23:08:48.345: E/AndroidRuntime(2555):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
04-04 23:08:48.345: E/AndroidRuntime(2555):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
04-04 23:08:48.345: E/AndroidRuntime(2555):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
04-04 23:08:48.345: E/AndroidRuntime(2555):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
04-04 23:08:48.345: E/AndroidRuntime(2555):     at android.os.Handler.dispatchMessage(Handler.java:99)
04-04 23:08:48.345: E/AndroidRuntime(2555):     at android.os.Looper.loop(Looper.java:137)
04-04 23:08:48.345: E/AndroidRuntime(2555):     at android.app.ActivityThread.main(ActivityThread.java:5041)
04-04 23:08:48.345: E/AndroidRuntime(2555):     at java.lang.reflect.Method.invokeNative(Native Method)
04-04 23:08:48.345: E/AndroidRuntime(2555):     at java.lang.reflect.Method.invoke(Method.java:511)
04-04 23:08:48.345: E/AndroidRuntime(2555):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
04-04 23:08:48.345: E/AndroidRuntime(2555):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
04-04 23:08:48.345: E/AndroidRuntime(2555):     at dalvik.system.NativeStart.main(Native Method)
04-04 23:08:48.345: E/AndroidRuntime(2555): Caused by: java.lang.NullPointerException
04-04 23:08:48.345: E/AndroidRuntime(2555):     at edu.virginia.hotncolduva.MainActivity.initialize(MainActivity.java:24)
04-04 23:08:48.345: E/AndroidRuntime(2555):     at edu.virginia.hotncolduva.MainActivity.onCreate(MainActivity.java:19)
04-04 23:08:48.345: E/AndroidRuntime(2555):     at android.app.Activity.performCreate(Activity.java:5104)
04-04 23:08:48.345: E/AndroidRuntime(2555):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
04-04 23:08:48.345: E/AndroidRuntime(2555):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
04-04 23:08:48.345: E/AndroidRuntime(2555):     ... 11 more
04-04 23:12:09.646: E/AndroidRuntime(2639): FATAL EXCEPTION: main
04-04 23:12:09.646: E/AndroidRuntime(2639): java.lang.RuntimeException: Unable to start activity ComponentInfo{edu.virginia.hotncolduva/edu.virginia.hotncolduva.MainActivity}: java.lang.NullPointerException
04-04 23:12:09.646: E/AndroidRuntime(2639):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
04-04 23:12:09.646: E/AndroidRuntime(2639):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
04-04 23:12:09.646: E/AndroidRuntime(2639):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
04-04 23:12:09.646: E/AndroidRuntime(2639):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
04-04 23:12:09.646: E/AndroidRuntime(2639):     at android.os.Handler.dispatchMessage(Handler.java:99)
04-04 23:12:09.646: E/AndroidRuntime(2639):     at android.os.Looper.loop(Looper.java:137)
04-04 23:12:09.646: E/AndroidRuntime(2639):     at android.app.ActivityThread.main(ActivityThread.java:5041)
04-04 23:12:09.646: E/AndroidRuntime(2639):     at java.lang.reflect.Method.invokeNative(Native Method)
04-04 23:12:09.646: E/AndroidRuntime(2639):     at java.lang.reflect.Method.invoke(Method.java:511)
04-04 23:12:09.646: E/AndroidRuntime(2639):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
04-04 23:12:09.646: E/AndroidRuntime(2639):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
04-04 23:12:09.646: E/AndroidRuntime(2639):     at dalvik.system.NativeStart.main(Native Method)
04-04 23:12:09.646: E/AndroidRuntime(2639): Caused by: java.lang.NullPointerException
04-04 23:12:09.646: E/AndroidRuntime(2639):     at edu.virginia.hotncolduva.MainActivity.initialize(MainActivity.java:24)
04-04 23:12:09.646: E/AndroidRuntime(2639):     at edu.virginia.hotncolduva.MainActivity.onCreate(MainActivity.java:19)
04-04 23:12:09.646: E/AndroidRuntime(2639):     at android.app.Activity.performCreate(Activity.java:5104)
04-04 23:12:09.646: E/AndroidRuntime(2639):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
04-04 23:12:09.646: E/AndroidRuntime(2639):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
04-04 23:12:09.646: E/AndroidRuntime(2639):     ... 11 more
04-04 23:16:21.095: E/AndroidRuntime(2737): FATAL EXCEPTION: main
04-04 23:16:21.095: E/AndroidRuntime(2737): java.lang.RuntimeException: Unable to start activity ComponentInfo{edu.virginia.hotncolduva/edu.virginia.hotncolduva.MainActivity}: java.lang.NullPointerException
04-04 23:16:21.095: E/AndroidRuntime(2737):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
04-04 23:16:21.095: E/AndroidRuntime(2737):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
04-04 23:16:21.095: E/AndroidRuntime(2737):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
04-04 23:16:21.095: E/AndroidRuntime(2737):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
04-04 23:16:21.095: E/AndroidRuntime(2737):     at android.os.Handler.dispatchMessage(Handler.java:99)
04-04 23:16:21.095: E/AndroidRuntime(2737):     at android.os.Looper.loop(Looper.java:137)
04-04 23:16:21.095: E/AndroidRuntime(2737):     at android.app.ActivityThread.main(ActivityThread.java:5041)
04-04 23:16:21.095: E/AndroidRuntime(2737):     at java.lang.reflect.Method.invokeNative(Native Method)
04-04 23:16:21.095: E/AndroidRuntime(2737):     at java.lang.reflect.Method.invoke(Method.java:511)
04-04 23:16:21.095: E/AndroidRuntime(2737):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
04-04 23:16:21.095: E/AndroidRuntime(2737):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
04-04 23:16:21.095: E/AndroidRuntime(2737):     at dalvik.system.NativeStart.main(Native Method)
04-04 23:16:21.095: E/AndroidRuntime(2737): Caused by: java.lang.NullPointerException
04-04 23:16:21.095: E/AndroidRuntime(2737):     at edu.virginia.hotncolduva.MainActivity.initialize(MainActivity.java:27)
04-04 23:16:21.095: E/AndroidRuntime(2737):     at edu.virginia.hotncolduva.MainActivity.onCreate(MainActivity.java:20)
04-04 23:16:21.095: E/AndroidRuntime(2737):     at android.app.Activity.performCreate(Activity.java:5104)
04-04 23:16:21.095: E/AndroidRuntime(2737):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
04-04 23:16:21.095: E/AndroidRuntime(2737):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
04-04 23:16:21.095: E/AndroidRuntime(2737):     ... 11 more
04-04 23:20:05.727: E/AndroidRuntime(2833): FATAL EXCEPTION: main
04-04 23:20:05.727: E/AndroidRuntime(2833): java.lang.RuntimeException: Unable to start activity ComponentInfo{edu.virginia.hotncolduva/edu.virginia.hotncolduva.MainActivity}: java.lang.NullPointerException
04-04 23:20:05.727: E/AndroidRuntime(2833):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
04-04 23:20:05.727: E/AndroidRuntime(2833):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
04-04 23:20:05.727: E/AndroidRuntime(2833):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
04-04 23:20:05.727: E/AndroidRuntime(2833):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
04-04 23:20:05.727: E/AndroidRuntime(2833):     at android.os.Handler.dispatchMessage(Handler.java:99)
04-04 23:20:05.727: E/AndroidRuntime(2833):     at android.os.Looper.loop(Looper.java:137)
04-04 23:20:05.727: E/AndroidRuntime(2833):     at android.app.ActivityThread.main(ActivityThread.java:5041)
04-04 23:20:05.727: E/AndroidRuntime(2833):     at java.lang.reflect.Method.invokeNative(Native Method)
04-04 23:20:05.727: E/AndroidRuntime(2833):     at java.lang.reflect.Method.invoke(Method.java:511)
04-04 23:20:05.727: E/AndroidRuntime(2833):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
04-04 23:20:05.727: E/AndroidRuntime(2833):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
04-04 23:20:05.727: E/AndroidRuntime(2833):     at dalvik.system.NativeStart.main(Native Method)
04-04 23:20:05.727: E/AndroidRuntime(2833): Caused by: java.lang.NullPointerException
04-04 23:20:05.727: E/AndroidRuntime(2833):     at edu.virginia.hotncolduva.MainActivity.initialize(MainActivity.java:27)
04-04 23:20:05.727: E/AndroidRuntime(2833):     at edu.virginia.hotncolduva.MainActivity.onCreate(MainActivity.java:20)
04-04 23:20:05.727: E/AndroidRuntime(2833):     at android.app.Activity.performCreate(Activity.java:5104)
04-04 23:20:05.727: E/AndroidRuntime(2833):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
04-04 23:20:05.727: E/AndroidRuntime(2833):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
04-04 23:20:05.727: E/AndroidRuntime(2833):     ... 11 more

What do you expect `wait` to do? You seem to misunderstand what it is used for (i.e. it is used to wait for a notification, not just wait). Also looking at the stack trace, that is not what is causing the problem (but once you fix that other problem, wait will become your new problem if you follow me)! — assylias, Apr 04 '13 at 23:32
Wait is a Thread thing. You [need to have a syncronized thread in order to call .wait(5000) on the syncronized object][1]. [1]: http://stackoverflow.com/questions/1036754/difference-between-wait-and-sleep — djangofan, Apr 04 '13 at 23:33
just checked link thanks dj and thanks assyl and thanks everyone else :) — Evorlor, Apr 04 '13 at 23:39

score 0 · Accepted Answer · answered Apr 04 '13 at 23:32

You should consider a different approach instead of sleeping in the main thread. Why not just use a handler that is based on a 1s timer and then send a message to the UI thread to change your splash screen (alpha or something) and and once the time has elapsed send the message to load the next content view using a fade in animation.

As for your NPE, ensure that your view is actually linked to something from your layout file R.layout.splash.

After looking at your code, you're not assigning the splash object to an actual view from your layout. Assign this like so:

splash = (ImageView)findViewById(R.id.youridhere);

wait( ) function not running properly

1 Answers1