CODEWITHSUNDEEP
androidandroid-intentextras
NWall
NWall

Reputation: 13

How to use put and get extra in intents

I have two classes, the first one within the onclick i have ;

Intent myIntent = new Intent(getApplicationContext(), PlayGame.class);
        myIntent.putExtra("gameWord", Word.getRandomWord().toUpperCase());
        startActivity(myIntent);
        finish();

then within the receiving class's onCreate i have ; 

    Bundle extras = getIntent().getExtras();

    String secretWord = extras.getString("gameWord");

when i try and run the android application i get an error on "startActivity(myIntent);". Any ideas?

here is my logCat;

Shutting down VM
FATAL EXCEPTION: main
Process: com.example.hunglikeanandroid, PID: 3431
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.hunglikeanandroid/com.example.hunglikeanandroid.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.String.length()' 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 'int java.lang.String.length()' on a null object reference
at com.example.hunglikeanandroid.MainActivity.<init>(MainActivity.java:35)
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)

Upvotes: 0

Views: 867

Answers (3)

howerknea
howerknea

Reputation: 375

ApplicationContext is different from Activity Context.You should use getgetActivity() instead of getApplicationContext。

Upvotes: 1

Fahim
Fahim

Reputation: 12378

Instead of using getApplicationContext() use MainActivity.this, your current activity

Intent myIntent = new Intent(MainActivity.this, PlayGame.class);
 myIntent.putExtra("gameWord", Word.getRandomWord().toUpperCase());
 startActivity(myIntent);

Upvotes: 2

songchenwen
songchenwen

Reputation: 1362

Line 1:

Intent myIntent = new Intent(FirstActivity.this, PlayGame.class);

Upvotes: 1

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