CODEWITHSUNDEEP
android
problemgenerator
problemgenerator

Reputation: 69

findViewById() returns null in TabActivity class

I have NewTransferActivity class, which extends TabActivity. The code: 

public class NewTransferActivity extends TabActivity {

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.account_transfer);

    TabHost tabHost = getTabHost();
    TabHost.TabSpec spec;

    spec = tabHost.newTabSpec("receiver").setIndicator("Rec").setContent(getReceiverTab());
    tabHost.addTab(spec);

    spec = tabHost.newTabSpec("transfer").setIndicator("Trans").setContent(getTransferTab());
    tabHost.addTab(spec);

}

private TabContentFactory getReceiverTab(){
    TabContentFactory factory = new TabContentFactory() {
        @Override
        public View createTabContent(String tag) {

            ...

            return layout;
        }
    };
    return factory;
}

private TabContentFactory getTransferTab(){
    TabContentFactory factory = new TabContentFactory() {

        @Override
        public View createTabContent(String tag) {
            LinearLayout layout = (LinearLayout) findViewById(R.id.mytrans);

            if (layout == null){
                //layout = new LinearLayout(NewTransferActivity.this);
                System.out.println("NULL>>>>>>");
                return new LinearLayout(NewTransferActivity.this);
            }
            return layout;
        }
    };
    return factory;
} ...

my xml file, which contains layout is:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/mytrans"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >


<TextView
    android:id="@+id/textView1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="Medium Text"
    android:textAppearance="?android:attr/textAppearanceMedium" />

<EditText
    android:id="@+id/editText1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" >

    <requestFocus />
</EditText>


<TextView
    android:id="@+id/textView2"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="Medium Text"
    android:textAppearance="?android:attr/textAppearanceMedium" />

<EditText
    android:id="@+id/editText2"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" />


<TextView
    android:id="@+id/textView3"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="Medium Text"
    android:textAppearance="?android:attr/textAppearanceMedium" />

<EditText
    android:id="@+id/editText3"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" />


<TextView
    android:id="@+id/textView4"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="Medium Text"
    android:textAppearance="?android:attr/textAppearanceMedium" />

<EditText
    android:id="@+id/editText4"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" />

</LinearLayout>

I want to load layout for a single tab from xml file which I definded. Unfortunatelly I am getting NullPointerException because layout is null in method getTransferTab(). 'LinearLayout layout = (LinearLayout) findViewById(R.id.mytrans)' returns null. What I am doing wrong? Thanks in advance.

Upvotes: 0

Views: 669

Answers (2)

Lalit Poptani
Lalit Poptani

Reputation: 67296

You should rather try to use LayoutInflater to get the view hierarchy from the xml,

    TabContentFactory factory = new TabContentFactory() {
        @Override
        public View createTabContent(String tag) {

             LayoutInflater inflater = LayoutInflater.from(Activity_Name.this);
             View linearLayout = inflater.inflate(R.layout.mytrans, null);

            return linearLayout;
        }
    };

Upvotes: 1

Kuffs
Kuffs

Reputation: 35661

My first thoughts are that, in this line:

 LinearLayout layout = (LinearLayout) findViewById(R.id.mytrans);

you are calling the findViewById method of your TabContentFactory

You need to call the version of that command that is located in the Activity.

Upvotes: 1

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