IllegalStateException when adding a view to a TableRow on Android

Question

I'm currently creating an application that adds rows to an existing table. The code looks like this:

TextView exampleTextView = (TextView) messageView.findViewById(R.id.exampleLabel);
exampleTextView.setText(locationMsg.getMessageContent());

TableRow tr = (TableRow) messageView.findViewById(R.id.tableRow);
tr.addView(exampleTextView);
table.addView(tr);

In the XML I've got a table layout that's inside a linearLayout thats inside a frameLayout thats inside a tabwidget and it looks like this:

<TableLayout
 android:id="@+id/distanceTable" 
 android:layout_height="wrap_content"
 android:layout_width="wrap_content"
 android:layout_gravity="center"
 android:background="#DDDDDD"
 android:stretchColumns="1" >
 <TableRow>
  <TextView
  android:textColor="#000000"
  android:text="@string/label_device"
  android:layout_gravity="center"
  android:padding="3dip"
  android:textSize="18sp" />

  <TextView
  android:textColor="#000000"
  android:text="@string/label_distance"
  android:layout_gravity="center"
  android:padding="3dip"
  android:textSize="18sp" />
  <TextView
  android:textColor="#000000"
  android:text="@string/label_time"
  android:layout_gravity="center"
  android:padding="3dip"
  android:textSize="18sp" />
 </TableRow>
 <TableRow android:id="@+id/tableRow" >
  <TextView
  android:id="@+id/exampleLabel"
  android:textColor="#000000"
  android:layout_gravity="center"
  android:padding="3dip"
  android:textSize="18sp" />
  <TextView
  android:id="@+id/anotherExampleLabel"
  android:textColor="#000000"
  android:layout_gravity="center"
  android:padding="3dip"
  android:textSize="18sp" />
  <TextView
  android:id="@+id/someOtherLabel"
  android:textColor="#000000"
  android:layout_gravity="center"
  android:padding="3dip"
  android:textSize="18sp" />
 </TableRow>
</TableLayout>

Creating those labels works fine, but when I want to add the text to a row, the application crashes and I get an "IllegalStateException", the detailed message is:

The specified child already has a parent. You must call removeView() on the child's parent first.

I don't quite get it. When I look at a tutorial like this there isn't anything that has to be removed first. So what exactly am I doing wrong?

Answer 1

The exampleLabel that you add in your code to the tableRow you added already in the XML file to the same table.

Since a UI element can only have one parent, this isn't possible.

I also don't know why you want to add it again, since it is already added to the exactly same view.

In your tutorial I can0t find a textview that is already added to the table in the xml file?

Answer 2

Your textview is already a child of another view. You cannot simply change the parent - you must remove the view from one parent and add it to another.

Looking closer, you simply don't have to manually add the particular text view to the table row - it is already there according to your xml.

addView() method usually invoked for newly created views, not for the ones you define in xml.