I am using one textfield in the detail band and set stretch with overflow true ,my requirement is to increase the detail band height dynamically when the text field has more data , i set split Type to Stretch but there is no change the band doesn't show all the data
I found this answer for you from a duplicate question:
Assuming you have dynamic text in text fields, you can set the isStretchWithOverflow attribute of the <textField> element to true. This will cause the text field to expand to accomodate the text.
Make sure that any elements below the text field have a positionType of "Float", otherwise the text from the text field will be displayed "on top" of the other elements.