Android Studios App Development

Question

I am developing an app on android and I'm trying to run the app through the emulator but every time it tells me that it has stopped working and I get these lines:

02-22 23:22:21.977    2170-2170/com.example.sarvagyagupta1.myapp E/AndroidRuntime﹕ FATAL EXCEPTION: main
    Process: com.example.sarvagyagupta1.myapp, PID: 2170
    java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.sarvagyagupta1.myapp/com.example.sarvagyagupta1.myapp.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.Context android.content.Context.getApplicationContext()' on a null object reference
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2209)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
            at android.app.ActivityThread.access$800(ActivityThread.java:144)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.Context android.content.Context.getApplicationContext()' on a null object reference
            at android.content.ContextWrapper.getApplicationContext(ContextWrapper.java:105)
            at com.example.sarvagyagupta1.myapp.MainActivity.<init>(MainActivity.java:61)
            at java.lang.reflect.Constructor.newInstance(Native Method)
            at java.lang.Class.newInstance(Class.java:1572)
            at android.app.Instrumentation.newActivity(Instrumentation.java:1065)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2199)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
            at android.app.ActivityThread.access$800(ActivityThread.java:144)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
device not found

Please, someone help me with this.

getApplicationContext()' on a null object reference at android.content.ContextWrapper.getApplicationContext(ContextWrapper.java:105) — Don Chakkappan, Feb 23 '15 at 04:30
where do I find the source code? Is it the .java code or which one? — Sarvagya Gupta, Feb 23 '15 at 04:59

score 0 · Answer 1 · answered Feb 23 '15 at 04:41

0

YOu can't call getApplicationContext() until after onCreate is called. The Activity isn't fully initialized until then.

answered Feb 23 '15 at 04:41

Gabe Sechan

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don't initialize whatever it is you're calling it for until onCreate. – Gabe Sechan Feb 23 '15 at 05:00
Where do I find this getApplicationContext()? – Sarvagya Gupta Feb 23 '15 at 05:12
line 61 of your MainActivity.java class is where you're incorrectly calling it. – Gabe Sechan Feb 23 '15 at 06:01

Android Studios App Development

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