Android ListView NullPointerException when inflating View

Question

i have a ListView with a custom row: detail_row1.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:orientation="horizontal" 
    android:layout_height="wrap_content"
    android:padding="6dip"
    **android:background="@drawable/item_background_selector"**  ---> line 7
    android:id="@+id/detail_linearLayout"
  >

<TextView 
    android:id="@+id/propName"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"   
    android:layout_weight="1"    
    android:textSize="16sp"
    android:textStyle="bold" 
    android:textColor="#000000"
    android:gravity="center_vertical|left"
    android:paddingTop="10sp"
    android:paddingBottom="10sp"
    android:paddingLeft="4sp"

/>

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_weight="2"
    android:id="@+id/propValue"       
    android:textColor="#000000"
    android:textSize="16sp"
    android:textStyle="bold"
    android:paddingTop="10sp"
    android:paddingBottom="10sp"
    android:paddingRight="4sp"
    android:gravity="center_vertical|right"
    />  

</LinearLayout>

my /drawable/item_background_selector.xml (SAME if i put it under /color/item_background_selector.xml and properly reference it in detail_row1.xml)

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_selected="false" android:color="#ACD52B">
    </item>
    <item android:state_selected="true" android:color="#0094CE">
    </item>
</selector>

when I try to inflate this view in my ListAdapter:

public View getView(int position, View convertView, ViewGroup parent) {
    View v=convertView;
    if(v==null) {
    LayoutInflater vi = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        v=vi.inflate(R.layout.detail_row1, null); **--> NullPointerException**
   }
    .
    .

It throws a NullPointerException.

This is not the case if i simply remove line 7 (android/background) from detail_row1.xml

Any clue / help on why this is happening (fairly new to android)

Thanks in advance!

(edit) Logcat:

**08-24 00:27:53.637: E/AndroidRuntime(15295): FATAL EXCEPTION: main**
08-24 00:27:53.637: E/AndroidRuntime(15295): android.view.InflateException: Binary XML file line #2: Error inflating class <unknown>
08-24 00:27:53.637: E/AndroidRuntime(15295):    at android.view.LayoutInflater.createView(LayoutInflater.java:613)
08-24 00:27:53.637: E/AndroidRuntime(15295):    at com.android.internal.policy.impl.PhoneLayoutInflater.onCreateView(PhoneLayoutInflater.java:56)
08-24 00:27:53.637: E/AndroidRuntime(15295):    at android.view.LayoutInflater.onCreateView(LayoutInflater.java:660)
08-24 00:27:53.637: E/AndroidRuntime(15295):    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:685)
08-24 00:27:53.637: E/AndroidRuntime(15295):    at android.view.LayoutInflater.inflate(LayoutInflater.java:466)
08-24 00:27:53.637: E/AndroidRuntime(15295):    at android.view.LayoutInflater.inflate(LayoutInflater.java:396)
08-24 00:27:53.637: E/AndroidRuntime(15295):    at android.view.LayoutInflater.inflate(LayoutInflater.java:352)
08-24 00:27:53.637: E/AndroidRuntime(15295):    at **com.dhomes.steel.DetailActivity$1.getView(DetailActivity.java:101)**

(2nd edit)

My listAdapter:

lvProperties.setAdapter(new ListAdapter() {
//Section section=new Section();

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    View v=convertView;

   if(v==null) {
   //LayoutInflater vi = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
   LayoutInflater vi =(LayoutInflater)DetailActivity.this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
   v=vi.inflate(R.layout.detail_row1, null);
   }

   TextView name=(TextView)v.findViewById(R.id.propName);
   TextView value=(TextView)v.findViewById(R.id.propValue);

   if(name!=null) {
       name.setText(section.propNames.get(position));
   }
   if(value!=null) {
       value.setText(section.propValues.get(position));
   }        
   return v;
}
.
.
.
}

Try putting Line 7 back in and do a Project -> Clean, then reload the app — James Fazio, Aug 23 '12 at 05:09
@JamesFazio +1 yes you were right.That is what i'm typing now. But, you'd put. — Praveenkumar, Aug 23 '12 at 05:10
just did, same results. I didn't clean before btw but did manually delete my gen/R.java file. Could it have anything to do with the SDK version? I'm using 16 for target but 8 for minSdk — David Homes, Aug 23 '12 at 05:14
The selector, unfortunately, cannot be used for colors. See this: http://stackoverflow.com/questions/3592780/selector-on-background-color-of-textview — Sameer, Aug 23 '12 at 05:49

score 1 · Answer 1 · answered Aug 23 '12 at 05:13

LayoutInflater vi = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
v=vi.inflate(R.layout.detail_row1, null);

From, above lines. You're inflating this in your customadapter class only it seems. So, you've the context object from Constructor so better use that like below -

...
LayoutInflater vi = (LayoutInflater)context.getSystemService(context.LAYOUT_INFLATER_SERVICE);
v=vi.inflate(R.layout.detail_row1, null);
...

And, Don't remove the background from your xml file. Just try to clean your project and run after done this changes.

it's an anonymous inner ListAdapter: lvProperties.setAdapter(new ListAdapter() {....... getting the same problem. Trying to use the activity's context gives the same problem. — David Homes, Aug 23 '12 at 05:26

score 0 · Accepted Answer · edited May 23 '17 at 10:24

0

My comment seems to be getting hidden. So posting as an answer.

The selector, unfortunately, cannot be used for colors. See this: Selector on background color of TextView

edited May 23 '17 at 10:24

Community

1
1

answered Aug 23 '12 at 09:42

Sameer

4,379
1
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hi sameer, I'm going to try that answer right now and mark the answer as correct if it works. thanks for the help – David Homes Aug 23 '12 at 13:55
Samir, the app is not crashing now using that answer, I still can't get the results I want though (forcing/faking a default selection on my listview with setSelection + selectors) but I'm going to mark this as correct as it was the source of the problem. If you do know though why my item doesn't change with listView setSelection that would be great (already made the list CHOICE_MODE_SINGLE, request focus, used both android:state_selected, state_checked, state_pressed to no avail) – David Homes Aug 23 '12 at 15:05
Works for me. How are you "selecting" the item? You have to use the up-down keys or trackball to select item in the listview. You cannot select by touching (or clicking in the emulator). You can get a "Click" event when you touch an item. Refer to this : http://stackoverflow.com/questions/2433952/android-list-view-selected-item-1 – Sameer Aug 24 '12 at 08:57

score 0 · Answer 3 · answered Aug 23 '12 at 10:17

I am not sure but you can try this. Instead of calling inflater in getview call it in constructor of your adapter class as:

LayoutInflater vi =(LayoutInflater)DetailActivity.this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

and then call layout id in getView as:

if (convertView == null) {

            convertView = inflater.inflate(R.layout.cat_content, null);

            holder.name = (TextView) convertView.findViewById(R.id.name);
            convertView.setTag(holder);
        } else {
            holder = (ViewHolder) convertView.getTag();
        }

Android ListView NullPointerException when inflating View

3 Answers3