Attempt to invoke interface method 'java.lang.Object java.util.List.get(int)

Question

I am developing new and I am reading JSON file from asset folder but I am getting the following exception

java.lang.NullPointerException: Attempt to invoke interface method 'java.lang.Object java.util.List.get(int)' on a null object reference
    at yodgorbek.komilov.runtastictask1.CustomAdapter.getView(CustomAdapter.kt:45)
    at android.widget.AbsListView.obtainView(AbsListView.java:2365)
    at android.widget.ListView.makeAndAddView(ListView.java:2052)
    at android.widget.ListView.fillDown(ListView.java:786)
    at android.widget.ListView.fillFromTop(ListView.java:847)
    at android.widget.ListView.layoutChildren(ListView.java:1826)
    at android.widget.AbsListView.onLayout(AbsListView.java:2164)
    at android.view.View.layout(View.java:19828)
    at android.view.ViewGroup.layout(ViewGroup.java:6154)
    at androidx.constraintlayout.widget.ConstraintLayout.onLayout(ConstraintLayout.java:1915)
    at android.view.View.layout(View.java:19828)
    at android.view.ViewGroup.layout(ViewGroup.java:6154)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
    at android.view.View.layout(View.java:19828)
    at android.view.ViewGroup.layout(ViewGroup.java:6154)
    at androidx.appcompat.widget.ActionBarOverlayLayout.onLayout(ActionBarOverlayLayout.java:446)
    at android.view.View.layout(View.java:19828)
    at android.view.ViewGroup.layout(ViewGroup.java:6154)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
    at android.view.View.layout(View.java:19828)
    at android.view.ViewGroup.layout(ViewGroup.java:6154)
    at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1791)
    at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1635)
    at android.widget.LinearLayout.onLayout(LinearLayout.java:1544)
    at android.view.View.layout(View.java:19828)
    at android.view.ViewGroup.layout(ViewGroup.java:6154)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
    at com.android.internal.policy.DecorView.onLayout(DecorView.java:765)
    at android.view.View.layout(View.java:19828)
    at android.view.ViewGroup.layout(ViewGroup.java:6154)
    at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2643)
    at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2348)
    at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1482)
    at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:7124)
    at android.view.Choreographer$CallbackRecord.run(Choreographer.java:1008)
    at android.view.Choreographer.doCallbacks(Choreographer.java:804)
    at android.view.Choreographer.doFrame(Choreographer.java:732)
    at android.view.Choreographer$FrameHandler.handleMessage(Choreographer.java:907)
    at android.os.Handler.dispatchMessage(Handler.java:106)
    at android.os.Looper.loop(Looper.java:176)
    at android.app.ActivityThread.main(ActivityThread.java:6662)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:547)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:873)

below my code to gist

Possible duplicate of What is a NullPointerException, and how do I fix it? — Ashish
– Ashish, Commented Oct 21, 2019 at 12:50
@FurqanKhan My code very long thats why I have posted gistlist please check it stackoverflow did not allowed to post all thats why I shared as gist — Edgar
– Edgar, Commented Oct 21, 2019 at 12:53
@sashabeliy check model value is it null? val model = gson.fromJson(loadJSONFromAssets(), NetworkResponse::class.java) — Basi
– Basi, Commented Oct 21, 2019 at 12:55

Furqan Khan · Accepted Answer · 2019-10-21 12:56:37Z

1

You are using a wrong key for members in your Group data class, it is data while in your json it shows the key is members use the following class and it will work

data class Group(
    @SerializedName("group_id")
    val group_id: Int,

    @SerializedName("group_name")
    val group_name: String,

    @SerializedName("members")
    val members: List<Member>

)

answered Oct 21, 2019 at 12:56

Furqan Khan

5684 silver badges14 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

Edgar Over a year ago

it is showing empty white screen what is your suggestion

Furqan Khan Over a year ago

because in your main activity xml you have not assinged the constraints to list view, i would recommend to change constraint layout to linear layout

Edgar Over a year ago

it is still the same i have changed to linearlayout vertical

Edgar Over a year ago

what do you think main problem

Amit Tiwary · Accepted Answer · 2019-10-21 12:58:50Z

0

You are not using correct key

data class Group(
@SerializedName("group_id")
val group_id: Int,

@SerializedName("group_name")
val group_name: String,

@SerializedName("data")
val members: List<Member>)

According to your json schema it should be

data class Group(
@SerializedName("group_id")
val group_id: Int,

@SerializedName("group_name")
val group_name: String,

@SerializedName("members")
val members: List<Member>)

answered Oct 21, 2019 at 12:58

Amit Tiwary

7971 gold badge8 silver badges16 bronze badges

2 Comments

Edgar Over a year ago

it did not help

Amit Tiwary Over a year ago

App is still crashing or some other error is coming?

Collectives™ on Stack Overflow

Attempt to invoke interface method 'java.lang.Object java.util.List.get(int)

2 Answers 2

4 Comments

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

4 Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related