CODEWITHSUNDEEP
androidlistviewbaseadapter
user3344591
user3344591

Reputation: 567

Blank screen: ListView and BaseAdapter

I'm trying to display information from User class in a ListView. When I run the application, I get only an empty screen. I'm using a ListView in activity_main.xml which looks like this:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<ListView 
android:id="@+id/listview"
android:layout_width="match_parent"
android:layout_height="match_parent" />

</LinearLayout>

I have a data model xml which will be inflated as each item in the list. This xml looks like this:

<TextView xmlns:android="http://schemas.android.com/apk/res/android"

    android:id="@+id/textline"
    android:layout_width="fill_parent"
    android:layout_height="26dip"
    android:text="Description"
    android:textSize="12sp"
    android:textColor="@android:color/black" 

/>

I wrote ListAdapter which extends BaseAdapter. I declared an ArrayList. I populated the ArrayList in the constructor of ListAdapater. The override methods of ListAdapter looks like this:

@Override
public int getCount() {
    return userList.size();
}

@Override
public Object getItem(int position) {
    return userList.get(position);
}

@Override
public long getItemId(int position) {
    return position;
}

@Override
public View getView(int position, View view, ViewGroup parent) {

    if(view==null){
        Log.e("Info","Inflating view");
        inflater=LayoutInflater.from(parent.getContext());
        view=inflater.inflate(R.layout.data_model, parent,false);
    }
    User user=userList.get(position);
    TextView tv=(TextView)view.findViewById(R.id.textline);
    tv.setText(user.getName());

    return null;
}

The onCreate() of MainActivity looks like this:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    ListView lv=(ListView)findViewById(R.id.listview);
    ListAdapter adapter=new ListAdapter();
    lv.setAdapter(adapter);

}

I have no idea why am I getting the empty white screen. Also, when I placed Log() statements as first statement of each method of ListAdapter, I saw the Log() statements being printed twice in LogCat.

Any pointers towards the solution will be helpful.

Upvotes: 0

Views: 962

Answers (3)

wael
wael

Reputation: 454

 @Override
 public View getView(int position, View view, ViewGroup parent) {

if(view==null){
    Log.e("Info","Inflating view");
    inflater=LayoutInflater.from(parent.getContext());
    view=inflater.inflate(R.layout.data_model, parent,false);
}
User user=userList.get(position);
TextView tv=(TextView)view.findViewById(R.id.textline);
tv.setText(user.getName());

return view;
}

Upvotes: 0

Steel
Steel

Reputation: 255

The getView method is returning null for each position. You need to return your view.

Upvotes: 0

adneal
adneal

Reputation: 30804

In Adapter.getView you're returning null when you should be returning view, in your case.

Upvotes: 1

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