Exception in Scrollview

Question

In my android application, I'm facing a IllegalStateException. I can't reproduce this exception later. This is the stacktrace

Non-fatal Exception: java.lang.IllegalStateException: ScrollView can host only one direct child
       at android.widget.ScrollView.addView(ScrollView.java:397)
       at android.support.design.widget.BaseTransientBottomBar.showView(BaseTransientBottomBar.java:436)
       at android.support.design.widget.BaseTransientBottomBar$1.handleMessage(BaseTransientBottomBar.java:178)
       at android.os.Handler.dispatchMessage(Handler.java:98)
       at android.os.Looper.loop(Looper.java:146)
       at android.app.ActivityThread.main(ActivityThread.java:5679)
       at java.lang.reflect.Method.invokeNative(Method.java)
       at java.lang.reflect.Method.invoke(Method.java:515)
       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1291)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1107)
       at dalvik.system.NativeStart.main(NativeStart.java)  

Anyone please help me!

Answer 1

I examined the question carefully, and I logically found that it is related to showing Snackbar on a fragment or activity, taken as a reference in another class as global object, when it is invalidated in onStop(), onDestroy() life cycle callback stage respectively:

https://stackoverflow.com/a/52019719/787399

Answer 2

Inside your ScrollView you have to host a child (e.g. a Linear Layout) which at it's time will host all the UI elements from that scrollview. You can't have, for example, 2 textviews added directly to a ScrollView. You need to have something to hold those UI elements inside the scrollview.

Answer 3

In ScrollView you can have only one View (in View I mean TextView, Button and cetera, but ViewGroup is child of View too) or ViewGroup. So if you have multiple Views put them in a proper ViewGroup and it will work fine.

Answer 4

Scrollview can only have one direct child

example: This is valid-->

ScrollView
    LinearLayout
        Other Views
        ....
        ....
    LinearLayout
ScrollView

This is not-->

ScrollView
    LinearLayout
        Other Views
        ....
        ....
    LinearLayout
    LinearLayout
        Other Views
        ....
        ....
    LinearLayout

ScrollView

Answer 5

I got the same issue. and I have reproduced using the below steps.

Step 1: make you Fragment Or Activity Layout with a parent of Scrollview.

Step 2: show Snackbar in onPause(), onStop(), onDestroy() like belove.

@Override
    public void onPause() {
        super.onPause();
        Snackbar.make(button, "onPause", Snackbar.LENGTH_LONG).show();
    }

    @Override
    public void onStop() {
        super.onPause();
        Snackbar.make(button, "onStop", Snackbar.LENGTH_LONG).show();
    }

    @Override
    public void onDestroy() {
        super.onDestroy();

        Snackbar.make(button, "onDestroy", Snackbar.LENGTH_LONG).show();
    }

Now run an app and check in logcat. when you click on back button you will get same error mention in question.

Solution:

make a common Snackbar like below.

@Override
        public void onPause() {
            super.onPause();
            showSnackbar("onPause");
        }

        @Override
        public void onStop() {
            super.onPause();
            showSnackbar("onStop");
        }

        @Override
        public void onDestroy() {
            super.onDestroy();
            showSnackbar("onDestroy");
        }

    private void showSnackbar(String message) {
            if (isValidContext(getActivity())) {
                Snackbar.make(btnConsume, message, Snackbar.LENGTH_LONG).show();
            } 
        }

    public static boolean isValidContext(final Context context) {

            if (context == null) {
                return false;
            }
            if (context instanceof Activity) {
                final Activity activity = (Activity) context;
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
                    return !activity.isDestroyed() && !activity.isFinishing();
                } else {
                    return !activity.isFinishing();
                }
            }
            return true;

        }

Answer 6

ScrollView will not accept many child's, Use only one Layout inside ScrollView like LinearLayout, RelativeLayout,FrameLayout or ConstraintLayout(Based on your needs)and then add all your child's.

See this for your reference

 <?xml version="1.0" encoding="utf-8"?>
    <ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
            xmlns:app="http://schemas.android.com/apk/res-auto"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

          //Add your Views here
        </android.support.constraint.ConstraintLayout>
    </ScrollView>

Answer 7

Scroll view allow only one child directly like below :

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:orientation="vertical">
     <ScrollView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content">
       <!--Here scroll view allow only one direct child-->
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical">
           <!--Here your other xml code-->
        </LinearLayout>
    </ScrollView>
 </LinearLayout>