Thursday, May 17, 2012

ScrollView inside ScrollView Scrolling problem in Android


While designing rich layouts you might need to use two scrollview in your app.
Well ideally its not advised to use two scrollview in a view. So try to avoid it.
*Why this problem occurs ? : *
When you put two scrollview android just get confused which scroll view is touched. So sometimes it gets unable to deliver touch event.
But even if the requirement forces you to make such layouts. Try this...
Say case is somewhat like this....
<ScrollView android:id="@+id/parent_scroll"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:background="@drawable/dotted_bg"
            android:focusableInTouchMode="false">
                        <LinearLayout   />
                        <LinearLayout   />
                        <LinearLayout  >
                        <ScrollView android:id="@+id/child_scroll" 
                        android:layout_width="fill_parent"
                        android:layout_height="fill_parent"
                        android:background="@drawable/text_box_bg">
                    <TextView android:id="@+id/text_description"
                        android:layout_width="fill_parent"
                        android:layout_height="fill_parent"
                        android:textColor="@color/gray"
                        android:textSize="12dip"
                        android:padding="5dip"
                        android:scrollbars="vertical"/>
                    </ScrollView>
                          </LinearLayout>
</ScrollView>
Step 1 : Provide unique id to both the scrollview.
Step 2 : get reference of that two scrollview in your activity.
     parentScroll=(ScrollView)findViewById(R.id.parent_scroll);
     childScroll=(ScrollView)findViewById(R.id.child_scroll);
Step 3: Now set touch listeners for both.
                      parentScroll.setOnTouchListener(new View.OnTouchListener() {

                public boolean onTouch(View v, MotionEvent event) {
                    Log.v(TAG,"PARENT TOUCH");
                    findViewById(R.id.child_scroll).getParent().requestDisallowInterceptTouchEvent(false);
                    return false;
                }
            });
            childScroll.setOnTouchListener(new View.OnTouchListener() {

                public boolean onTouch(View v, MotionEvent event)
                {
                    Log.v(TAG,"CHILD TOUCH");
                                        // Disallow the touch request for parent scroll on touch of child view
                    v.getParent().requestDisallowInterceptTouchEvent(true);
                    return false;
                }
            });
Done ...








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