Crashing Alert Dialog with Button OnClick of ImageView Android

I'm trying to launch an AlertDialog from onClick of ImageView, with 2 buttons. AlertDialog is crashing whenever I place buttons with OnCLickListener, but does not if none.

Here's the code:

public void onClickPTap(View view) {
    final AlertDialog.Builder alertDialog = new AlertDialog.Builder(PlumberActivity.this);

    LayoutInflater inflater = this.getLayoutInflater();
    final View sub_options = inflater.inflate(R.layout.sub_options, null);

    alertDialog.setView(sub_options);

    Button btInstallation = (Button) findViewById(R.id.button_installation);
    Button btRepair = (Button) findViewById(R.id.button_repair);

    btInstallation.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            if(!isWorkerFound) {
                requestService(FirebaseAuth.getInstance().getCurrentUser().getUid());
            } else {
                sendRequestToWorker(workerId);
            }
        }
    });

    btRepair.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            //none
        }
    });

    alertDialog.show();
}

Here's the error:

E/UncaughtException: java.lang.IllegalStateException: Could not execute method for android:onClick
                     at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:293)
                     at android.view.View.performClick(View.java:4781)
                     at android.view.View$PerformClick.run(View.java:19900)
                     at android.os.Handler.handleCallback(Handler.java:739)
                     at android.os.Handler.dispatchMessage(Handler.java:95)
                     at android.os.Looper.loop(Looper.java:159)
                     at android.app.ActivityThread.main(ActivityThread.java:5541)
                     at java.lang.reflect.Method.invoke(Native Method)
                     at java.lang.reflect.Method.invoke(Method.java:372)
                     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:975)
                     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:770)
                  Caused by: java.lang.reflect.InvocationTargetException
                     at java.lang.reflect.Method.invoke(Native Method)
                     at java.lang.reflect.Method.invoke(Method.java:372)
                     at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
                     at android.view.View.performClick(View.java:4781) 
                     at android.view.View$PerformClick.run(View.java:19900) 
                     at android.os.Handler.handleCallback(Handler.java:739) 
                     at android.os.Handler.dispatchMessage(Handler.java:95) 
                     at android.os.Looper.loop(Looper.java:159) 
                     at android.app.ActivityThread.main(ActivityThread.java:5541) 
                     at java.lang.reflect.Method.invoke(Native Method) 
                     at java.lang.reflect.Method.invoke(Method.java:372) 
                     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:975) 
                     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:770) 
                  Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
                     at com.fixitph.client.PlumberActivity.onClickPTap(PlumberActivity.java:86)

PlumberActivity.java:86 is the line btInstallation.setOnClickListener..

onClickTap(View view) is the onClick of the ImageView

I have a the same pattern of code on a different function and it's working fine, don't know what is wrong. Please help. Thank you.