Set Uitextfield on keyboard return key is not clickable

Today in the search bar, found that the system soft keyboard has the bottom corner of the "Search" button in the input box, whether there is no text can be clicked on the state, remember other software in the state without text is not clickable state, at first thought to textfield content to make a judgment,  Later found that the system itself with the judgment, you can make the button is gray non-clickable _textfield.enablesreturnkeyautomatically = YES; Send as non-point status when no text is available

Set Uitextfield on keyboard return key is not clickable