Question

I have a custom control which is supposed to work like the Segmenttab controller in iOS.

It has 3 textviews and the layout is as follows:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/groupofthree"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:background="@color/background"
    android:orientation="horizontal" >

    <TextView
        android:id="@+id/tv_1"
        android:layout_width="0dp"
        android:layout_height="fill_parent"
        android:layout_weight="1"
        android:background="@color/black"
        android:gravity="center"
        android:text="Retiree"
        android:textColor="@color/whitetext"
        android:textSize="15dp"
        android:textStyle="normal" />

    <TextView
        android:id="@+id/tv_2"
        android:layout_width="0dp"
        android:layout_height="fill_parent"
        android:layout_weight="1"
        android:background="@color/lightGrey"
        android:gravity="center"
        android:padding="3dp"
        android:text="Under18/fulltime"
        android:textColor="@color/whitetext"
        android:textSize="15dp"
        android:textStyle="normal" />

    <TextView
        android:id="@+id/tv_3"
        android:layout_width="0dp"
        android:layout_height="fill_parent"
        android:layout_weight="1"
        android:background="@color/black"
        android:gravity="center"
        android:text="Others"
        android:textColor="@color/whitetext"
        android:textSize="15dp"
        android:textStyle="normal" />

</LinearLayout>

The control looks like this:

    public class SegmentedRadioGroup extends View{

        private Context m_Context;

        public TextView tv1;
        public TextView tv2;
        public TextView tv3;
        int selectedIndex = 0;

        public SegmentedRadioGroup(Context context, AttributeSet attrs) {

            super(context, attrs);
            m_Context = context;

        }

        public SegmentedRadioGroup(Context context, AttributeSet attrs, int defStyle) {

            super(context, attrs, defStyle);
        }

        public SegmentedRadioGroup(Context context) {
            super(context);
            // TODO Auto-generated constructor stub

            m_Context = context;
            LayoutInflater inflater = (LayoutInflater) m_Context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            View v = inflater.inflate(R.layout.threeradiobutton, null);


            v.isInEditMode();
            tv1 = (TextView) v.findViewById(R.id.tv_1);
            tv2 = (TextView) v.findViewById(R.id.tv_2);
            tv3 = (TextView) v.findViewById(R.id.tv_3);

            tv1.setOnClickListener(new OnClickListener() {

                @Override
                public void onClick(View v) {
                    // TODO Auto-generated method stub

                    selectedIndex = 0;
                    tv1.setBackgroundColor(R.color.darkgrey);
                    tv2.setBackgroundColor(R.color.lightGrey);
                    tv3.setBackgroundColor(R.color.lightGrey);
                }
            });

            tv2.setOnClickListener(new OnClickListener() {

                @Override
                public void onClick(View v) {
                    // TODO Auto-generated method stub
                    selectedIndex = 1;
                    tv1.setBackgroundColor(R.color.lightGrey);
                    tv2.setBackgroundColor(R.color.darkgrey);
                    tv3.setBackgroundColor(R.color.lightGrey);

                }
            });

            tv3.setOnClickListener(new OnClickListener() {

                @Override
                public void onClick(View v) {
                    // TODO Auto-generated method stub
                    selectedIndex = 2;

                    tv1.setBackgroundColor(R.color.lightGrey);
                    tv2.setBackgroundColor(R.color.lightGrey);
                    tv3.setBackgroundColor(R.color.darkgrey);
                }
            });
        }

        @Override
        protected void onDraw(Canvas canvas) {
            // TODO Auto-generated method stub
            super.onDraw(canvas);


        }


    }

The activity in which i add this custom view to the layout is as follows:

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

        <RelativeLayout
            android:id="@+id/widget1216"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:background="@drawable/appspecific_menubar" >

            <TextView
                android:id="@+id/widget1222"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerHorizontal="true"
                android:layout_centerVertical="true"
                android:text="@string/transaction_accounts_topbar"
                android:textColor="@color/whitetext"
                android:textSize="18sp"
                android:textStyle="bold" >
            </TextView>

            <ImageButton
                android:id="@+id/home_button"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_alignParentLeft="true"
                android:layout_alignParentTop="true"
                android:background="@null"
                android:paddingBottom="5dip"
                android:paddingLeft="10dip"
                android:paddingTop="5dip"
                android:src="@drawable/home" >
            </ImageButton>
        </RelativeLayout>
    <LinearLayout 
        android:id="@+id/testLayout"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical" />.
     </LinearLayout>

And the activity looks like this. I have added the view into the layout using addview.

    public class TransactionAccount extends Activity {
        LinearLayout selector;
        SegmentedRadioGroup sg_test;
        LayoutInflater inflater;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            // TODO Auto-generated method stub
            super.onCreate(savedInstanceState);
            setContentView(R.layout.transactionaccount_main);
            selector = (LinearLayout)findViewById(R.id.testLayout);




            sg_test = new SegmentedRadioGroup(this);
            selector.addView(sg_test);



    //      inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    //      selector = inflater.inflate(R.id., null);

    //      sg_test = new SegmentedRadioGroup(this);

    //      sg_test.tv1.setText("1");
    //      sg_test.tv2.setText("2");
    //      sg_test.tv3.setText("3");
    //      sg_test.tv1.setBackgroundColor(R.color.blacktext);
    //      sg_test.setVisibility(View.VISIBLE);
    //      
    //      Log.d("TransactionAccount", "onCreate++++++" + sg_test.tv1.getText());
    //      Log.d("TransactionAccount", "onCreate++++++" + sg_test.tv2.getText());
    //      Log.d("TransactionAccount", "onCreate++++++" + sg_test.tv3.getText());
        }
    }

But what i see on the screen is a blank screen.. and not the custom control which should show up. Kindly tell me where am i going wrong.

Thanks in advance.

Answer 1

First of all, you can’t add child Views to a subclass of View because it doesn’t have the addView method. Instead, you should extend ViewGroup or one of its subclasses(like LinearLayout, RelativeLayout etc).

After you do the above thing you can simple add the Views with:

View v = inflater.inflate(R.layout.threeradiobutton, this, true);

to actually add the inflated layout to the custom View.

Right now you don’t see something on the screen because there isn’t something to see, your custom View is empty.