Add OnClickListener to elements inside headerLayout

Question

I am trying to make an app where you can toggle the drawer using by clicking onto an imageview, however it seems I get a nasty error everytime I set an onClickListener in the OnCreate of the main activity

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.myapplication, PID: 7921
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.myapplication/com.example.myapplication.activities.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ImageView.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3356)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3500)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2049)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:223)
        at android.app.ActivityThread.main(ActivityThread.java:7523)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:941)
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ImageView.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
        at com.example.myapplication.activities.MainActivity.onCreate(MainActivity.kt:43)
        at android.app.Activity.performCreate(Activity.java:7984)
        at android.app.Activity.performCreate(Activity.java:7973)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1309)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3329)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3500) 
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83) 
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) 
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2049) 
        at android.os.Handler.dispatchMessage(Handler.java:106) 
        at android.os.Looper.loop(Looper.java:223) 
        at android.app.ActivityThread.main(ActivityThread.java:7523) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:941)

Been digging around for half an hour with no results, any tips on how to do this?

Everything else works except this. Just in case your wondering, here are the important bits of code:

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        setUpActionBar()

        showProgressDialog(resources.getString(R.string.please_wait))
        FirestoreClass().loadUserData(this)

       
        nav_view_main.setNavigationItemSelectedListener(this)

        iv_cancel_icon.setOnClickListener {
            toggleDrawer()
        }
    }

    private fun toggleDrawer(){
        if(drawer_layout_main.isDrawerOpen(GravityCompat.START)){
            drawer_layout_main.closeDrawer(GravityCompat.START)
        } else {
            drawer_layout_main.openDrawer(GravityCompat.START)
        }
    }

    private fun setUpActionBar(){

        setSupportActionBar(toolbar_main_activity)

        toolbar_main_activity.setNavigationIcon(R.drawable.ic_action_navigation_menu)

        toolbar_main_activity.setNavigationOnClickListener {
            toggleDrawer()
        }

        getSupportActionBar()!!.setDisplayShowTitleEnabled(false)

    }

The answer to your question is already answered here : [https://stackoverflow.com/a/34327715/7027154](https://stackoverflow.com/a/34327715/7027154) — Ankit Gupta, Jul 14 '20 at 00:04
Yeah, I already saw that, and I totally skipped over it because it was java. Looked over it and tried to implement it as best as I could in kotlin, and it doesn't work for me. — Brady Gho, Jul 15 '20 at 14:54

score 1 · Accepted Answer · answered Jul 16 '20 at 09:33

Code in Kotlin from the shared link above :

//Getting navigation view child and modifying its data
val navigationView = findViewById(your_navigation_view_id_in_drawer_layout)
val headerview = navigationView.getHeaderView(0)
val profilename = headerview.findViewById(your_view_id)
profilename.text = "text"

//Setting on click listener on header child
val child = headView.findViewById(child_id)
child.setOnClickListener{ view ->
    //Code to execute on click
}

If this still doesn't resolve your issue, then kindly share the XML code in the comments and then will give you a solution based on that.

Alright, thanks, it worked. I modified the code a bit though. — Brady Gho, Jul 17 '20 at 14:58

Add OnClickListener to elements inside headerLayout

1 Answers1