CODEWITHSUNDEEP
androidlistviewnullpointerexceptionimageview
daydr3am3r
daydr3am3r

Reputation: 956

Change expandable listview group image onCreate and from child

I have created a custom expandable list view and a custom adapter. The list view consists in 3 XML layouts (please ignore the dumb use of table layout!):

One that defines the ExpandableListView

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

    <ExpandableListView
        android:id="@+id/expandable_list"
        android:groupIndicator="@null"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:cacheColorHint="#00000000" >
        <!-- android:listSelector="@android:color/transparent" -->
    </ExpandableListView>
</LinearLayout>

Another that defines the parent (group):

<?xml version="1.0" encoding="utf-8"?>
<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content"
    android:stretchColumns="1" 
    android:paddingTop="0dip" 
    android:layout_gravity="center_vertical" 
    android:gravity="center_vertical">
    
    <TableRow android:layout_gravity="center_vertical"> 
        <ImageView
            android:id="@+id/image"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"  
            android:layout_marginLeft="10dip"
            android:layout_gravity="center_vertical"
            android:gravity="center_vertical"/>
  
            <TableLayout 
                android:layout_width="wrap_content" 
                android:layout_height="100dip"
                android:stretchColumns="1" 
                android:paddingTop="0dip" 
                android:layout_gravity="center_vertical"
                android:gravity="center_vertical">
        
                <TableRow android:layout_gravity="center_vertical">        
                    <TextView
                        android:id="@+id/list_item_text_view"
                        android:textColor="@color/tab_sel"
                        android:layout_height="wrap_content"
                        android:layout_width="wrap_content"
                        android:layout_weight="1" 
                        android:layout_gravity="left|center_vertical"
                        android:gravity="center_vertical"
                        android:fillViewport="true" 
                        android:textSize="17sp" 
                        android:layout_marginLeft="10dip"
                        android:textStyle="bold"/>
                </TableRow>
            </TableLayout> 
            <ImageView
                android:layout_width="25dip"
                android:id="@+id/rightcheck"
                android:layout_height="25dip"
                android:layout_gravity="left|center_vertical"  
                android:scaleType="centerCrop"
                android:background="@drawable/sectionuncheck"
                android:layout_marginRight="8sp"
                android:layout_marginTop="0dip"/>
    </TableRow>   
</TableLayout>

And the last one defines the children:

<?xml version="1.0" encoding="utf-8"?>
<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:stretchColumns="1" 
    android:paddingTop="0dip" 
    android:layout_gravity="top">
    <!--   android:background="@drawable/bar_bg" -->
    <TableRow> 
        <ImageView
            android:id="@+id/image"
            android:layout_width="30dip"
            android:layout_height="30dip"  
            android:layout_marginLeft="20dip"
            android:src="@drawable/arrow"
            android:layout_gravity="center_vertical"  
            android:scaleType="centerCrop"/>
    
            <TableLayout 
                android:layout_width="wrap_content" 
                android:layout_height="65dp" 
                android:stretchColumns="1" 
                android:paddingTop="0dip" 
                android:layout_gravity="top"
                android:gravity="center_vertical" >
        
                <TableRow>        
                    <TextView
                        android:id="@+id/list_item_text_child"
                        android:layout_height="wrap_content"
                        android:layout_width="0dp"
                        android:layout_weight="1" 
                        android:layout_gravity="left|center_vertical" 
                        android:textSize="15sp" 
                        android:layout_marginLeft="20dip"
                        android:layout_marginRight="35dip"
                        android:text=""
                        android:textColor="#003479"/>
                </TableRow>
                <TableRow >
                    <TextView
                        android:id="@+id/text"          
                        android:layout_height="wrap_content"
                        android:layout_width="0dp"
                        android:layout_weight="1" 
                        android:layout_gravity="left|center_vertical" 
                        android:textSize="15sp" 
                        android:layout_marginLeft="20dip"
                        android:layout_marginRight="35dip"
                        android:text=""
                        android:textColor="#44B5E7"/>
                </TableRow>
            </TableLayout> 
            <ImageView
                android:id="@+id/ivProdCheck"
                android:layout_width="25dip"
                        android:layout_height="25dip"
                        android:layout_gravity="left|center_vertical"  
                        android:scaleType="centerCrop"
                        android:layout_marginRight="8dp"
                android:background="@drawable/check"
                android:visibility="gone"/>
    </TableRow>   
</TableLayout>

Every time I click on a child, it gets selected or unselected, meaning that the ivProdCheck gets visible or not

if(is_preffered == 0)
{
    Glob.getPreferred().add(prod_curent);
image.setVisibility(View.VISIBLE);
}
else
{
image.setVisibility(View.GONE);
}

Same thing happens in the adapter, to display the checked/uncheck items on activity start:

@Override
    //in this method you must set the text to see the children on the list
    public View getChildView(int i, int i1, boolean b, View view, ViewGroup viewGroup) 
    {
        /*........*/
        
        if(Glob.getPreferred() != null)
        {
            for (Product to_compare : Glob.getPreferred())
            {
                if(to_compare.id_produs == id_produs_curent)
                {
                    image.setVisibility(View.VISIBLE);
                    break;
                }
            }
        }   
                
        view.setTag(holder);
 
        //return the entire view
        return view;
    }

When I click on the group/parent, I select/deselect all children and change the image according to that

if(counter != prod_in_cat)
{
    for(Product p : cat_curent.getProd())
    {
    Glob.getPreferred().add(p);
    }
                                                                           
    imageParent.setImageResource(R.drawable.sectioncheck);
}
else
{
    imageParent.setImageResource(R.drawable.sectionuncheck);
}

Problem statement

Every time a group is selected (meaning all children are selected), if I then deselect one child, I also want to change the parent image. Also, if I manually select/deselect all children in one group, I want to change the group image too. Same thing goes for onCreate().

I tried this on child click (the logs show what it's supposed to, so no error on that side):

if(counter != cat_curent.getProduse().size())
{
    //  Log.e("!=  -> ","counter " + counter);
    //  Log.e("!=  -> ","cat_curent" + cat_curent.getProduse().size());
                        
        imageParent.setImageResource(R.drawable.sectioncheck);  
}
else
{
    //  Log.e("!=  -> ","counter " + counter);
    //  Log.e("!=  -> ","cat_curent" + cat_curent.getProduse().size());
                        
        imageParent.setImageResource(R.drawable.sectionuncheck);
}

and this on onCreate()

if((prod_pref > 0) && (prod_pref < prod_cat_glob))
{
    Log.e("Log 4", "Categoria " + i + " Produse " + prod_pref);
    imageParent.setImageResource(R.drawable.sectionuncheck); //NullPointerException here
}
else if(prod_pref == prod_cat_glob)
{
    imageParent.setImageResource(R.drawable.sectioncheck); //NullPointerException here
}

and every time I get NullPointerException when I use setImageResource()

What's the catch here?

Upvotes: 0

Views: 604

Answers (1)

daydr3am3r
daydr3am3r

Reputation: 956

Nevermind, I got it working. The data source for my list view was always updated when I clicked a parent or child. The problem is the list wasn't refreshing. I had something similar to fix a few days ago and trying .notifyDataSetChanged() didn't work so I didn't use it for this. It turns out however, that this works. Thanks anyway @m0skit0. Still not sure however, why the NPE. I'll try to figure it out.

Upvotes: 0

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