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copied!<h3><code>-[UITextField selectedText]</code></h3> <p>Although <a href="http://developer.apple.com/library/ios/#DOCUMENTATION/UIKit/Reference/UITextField_Class/Reference/UITextField.html"><code>UITextField</code></a> doesn't have a <code>selectedText</code> method, it conforms to the <a href="http://developer.apple.com/library/ios/DOCUMENTATION/UIKit/Reference/UITextInput_Protocol/Reference/Reference.html#//apple_ref/occ/intf/UITextInput"><code>UITextInput</code> protocol</a>. So, you can use the required properties & methods of the <code>UITextInput</code> protocol to determine the <code>selectedText</code> of a <code>UITextField *textField</code> (or any object that conforms to the <code>UITextInput</code> protocol, such as a <a href="http://developer.apple.com/library/ios/#DOCUMENTATION/UIKit/Reference/UITextView_Class/Reference/UITextView.html"><code>UITextView</code></a>).</p> <pre><code>NSString *selectedText = [textField textInRange:textField.selectedTextRange]; NSLog(@"selectedText: %@", selectedText); </code></pre> <p>As an aside, you can also use the required properties & methods of the <code>UITextInput</code> to calculate the <code>selectedRange</code> of a <code>UITextField *textField</code>.</p> <pre><code>UITextRange *selectedTextRange = textField.selectedTextRange; NSUInteger location = [textField offsetFromPosition:textField.beginningOfDocument toPosition:selectedTextRange.start]; NSUInteger length = [textField offsetFromPosition:selectedTextRange.start toPosition:selectedTextRange.end]; NSRange selectedRange = NSMakeRange(location, length); NSLog(@"selectedRange: %@", NSStringFromRange(selectedRange)); </code></pre> <h3><code>-[UITextFieldDelegate textFieldDidChangeSelection:]</code></h3> <p>Although, <code>UITextFieldDelegate</code> doesn't declare a <code>textFieldDidChangeSelection:</code> delegate method like <a href="http://developer.apple.com/library/ios/DOCUMENTATION/UIKit/Reference/UITextViewDelegate_Protocol/Reference/UITextViewDelegate.html#//apple_ref/occ/intfm/UITextViewDelegate/textViewDidChangeSelection%3a"><code>-[UITextViewDelegate textViewDidChangeSelection:]</code></a>, you can still hook into when the selection of a <code>UITextField</code> has changed. To do so, subclass <code>UITextField</code> and use method swizzling to add your own code to the <code>textField.inputDelegate</code>'s native implementation of <a href="http://developer.apple.com/library/ios/DOCUMENTATION/UIKit/Reference/UITextInputDelegate_Protocol/Reference/Reference.html#//apple_ref/occ/intfm/UITextInputDelegate/selectionDidChange%3a"><code>-[UITextInputDelegate selectionDidChange:]</code></a>.</p> <pre><code>// MyTextField.h #import <UIKit/UIKit.h> @interface MyTextField : UITextField @end // MyTextField.m #import <objc/runtime.h> #import "MyTextField.h" UIKIT_STATIC_INLINE void mySelectionDidChange(id self, SEL _cmd, id<UITextInput> textInput); @implementation MyTextField { BOOL swizzled; } #pragma mark - UIResponder // Swizzle here because self.inputDelegate is set after becomeFirstResponder gets called. - (BOOL)becomeFirstResponder { if ([super becomeFirstResponder]) { [self swizzleSelectionDidChange:YES]; return YES; } else { return NO; } } // Unswizzle here because self.inputDelegate may become the inputDelegate for another UITextField. - (BOOL)resignFirstResponder { if ([super resignFirstResponder]) { [self swizzleSelectionDidChange:NO]; return YES; } else { return NO; } } #pragma mark - Swizzle -[UITextInput selectionDidChange:] // Swizzle selectionDidChange: to "do whatever you want" when the text field's selection has changed. // Only call this method on the main (UI) thread because it may not be thread safe. - (void)swizzleSelectionDidChange:(BOOL)swizzle { if (swizzle == swizzled || ![self respondsToSelector:@selector(inputDelegate)]) return; // 4.3 Class inputDelegateClass = object_getClass(self.inputDelegate); SEL mySelector = @selector(mySelectionDidChange:); class_addMethod(inputDelegateClass, mySelector, (IMP)mySelectionDidChange, "v@:@"); Method myMethod = class_getInstanceMethod(inputDelegateClass, mySelector); Method uiKitMethod = class_getInstanceMethod(inputDelegateClass, @selector(selectionDidChange:)); method_exchangeImplementations(uiKitMethod, myMethod); swizzled = swizzle; // NSLog(@"swizzled? %i", method_getImplementation(uiKitMethod) == (IMP)venmo_selectionDidChange); } @end UIKIT_STATIC_INLINE void mySelectionDidChange(id self, SEL _cmd, id<UITextInput> textInput) { // Call the native implementation of selectionDidChange:. [self performSelector:@selector(mySelectionDidChange:) withObject:textInput]; // "Do whatever you want" with the selectedText below. NSString *selectedText = [textInput textInRange:textInput.selectedTextRange]; NSLog(@"selectedText: %@", selectedText); } </code></pre>

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