如何在iphone中从uitextfield获取选定的文本?

I am working on Text to speech application in iPhone,

我正在研究iPhone的文本到语音应用，

in which have a text field that takes input, i want user to select some portion of text from text field and my application will convert that selected text into speech.

在文本字段接受输入的情况下，我希望用户从文本字段中选择文本的某些部分，我的应用程序将选择的文本转换为语音。

my problem is how would i get the text that user has selected from text field?

我的问题是如何从文本字段中获取用户选择的文本?

5 个解决方案

#1

-[UITextField selectedText]

Although UITextField doesn't have a selectedText method, it conforms to the UITextInput protocol. So, you can use the required properties & methods of the UITextInput protocol to determine the selectedText of a UITextField *textField (or any object that conforms to the UITextInput protocol, such as a UITextView).

虽然UITextField没有selectedText方法，但它符合UITextInput协议。因此，您可以使用UITextInput协议所需的属性和方法来确定UITextField *textField的selectedText(或任何符合UITextInput协议的对象，如UITextView)。

NSString *selectedText = [textField textInRange:textField.selectedTextRange];
NSLog(@"selectedText: %@", selectedText);

As an aside, you can also use the required properties & methods of the UITextInput to calculate the selectedRange of a UITextField *textField.

顺便说一下，您还可以使用UITextInput所需的属性和方法来计算UITextField *textField的selectedRange。

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));

-[UITextFieldDelegate textFieldDidChangeSelection:]

Although, UITextFieldDelegate doesn't declare a textFieldDidChangeSelection: delegate method like -[UITextViewDelegate textViewDidChangeSelection:], you can still hook into when the selection of a UITextField has changed. To do so, subclass UITextField and use method swizzling to add your own code to the textField.inputDelegate's native implementation of -[UITextInputDelegate selectionDidChange:].

尽管UITextFieldDelegate没有声明textFieldDidChangeSelection:委托方法，比如-[UITextViewDelegate textViewDidChangeSelection:]，但是当UITextField的选择发生变化时，您仍然可以继续使用它。为此，子类UITextField和使用方法swizzle将您自己的代码添加到textField。inputDelegate的本机实现-[UITextInputDelegate selectionDidChange:]。

// 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);        
}

#2

I did solve my query as follow :

我确实解决了以下问题:

I implement UITextView's delegate and implement following method

我实现了UITextView的委托并实现了以下方法

- (void)textViewDidChangeSelection:(UITextView *)textView {
    NSRange r = textView.selectedRange;
    NSLog(@"Start from : %d",r.location); //starting selection in text selection
    NSLog(@"To : %d",r.length); // end position in text selection
    NSLog([tv.text substringWithRange:NSMakeRange(r.location, r.length)]); //tv is my text view
}

That's it!

就是这样!

#3

Swift

In Swift, getting the selected text from a UITextField is done like this:

在Swift中，从UITextField获取所选文本的操作如下:

if let textRange = myTextField.selectedTextRange {

    let selectedText = myTextField.textInRange(textRange)

}

where textRange is a UITextRange that is used to get the actual selected text.

其中textRange是用于获取实际选定文本的uitoutange。

#4

A similar topic is discussed here: Can I select a specific block of text in a UITextField?

这里讨论了一个类似的主题:我可以在UITextField中选择一个特定的文本块吗?

AFAIK there is no event if text is selected. However, you could setup an NSTimer to watch your textfield and check the _selectedRange. If it changes, go fire up your text-to-speech code.

如果选择了文本，则没有事件发生。但是，您可以设置一个NSTimer来监视文本字段并检查_selectedRange。如果它改变了，启动你的文本到语音代码。

EDIT: I was wrong about the selection. UITextField cannot do what you want to achieve. But if you use UITextView instead, you can implement its UITextViewDelegate and override

编辑:我选错了。UITextField不能做您想要实现的事情。但是如果您使用UITextView，您可以实现它的UITextViewDelegate并覆盖它

- (void)textViewDidChangeSelection:(UITextView *)textView

In there, you can use the selectedRange poperty to get the selection. See this reference for details:

在那里，您可以使用selectedRange poperty来获取选择。详见此参考资料:

https://developer.apple.com/library/ios/documentation/UIKit/Reference/UITextView_Class/Reference/UITextView.html#//apple_ref/doc/uid/TP40006898-CH3-SW13

https://developer.apple.com/library/ios/documentation/UIKit/Reference/UITextView_Class/Reference/UITextView.html / / apple_ref / doc / uid / TP40006898-CH3-SW13

#5

Swift 4

斯威夫特4

for getting the selected UITextField:

获取选定的UITextField:

import UIKit


extension UIView {
func getSelectedTextField() -> UITextField? {

    let totalTextFields = getTextFieldsInView(view: self)

    for textField in totalTextFields{
        if textField.isFirstResponder{
            return textField
        }
    }

    return nil

}

func getTextFieldsInView(view: UIView) -> [UITextField] {

    var totalTextFields = [UITextField]()

    for subview in view.subviews as [UIView] {
        if let textField = subview as? UITextField {
            totalTextFields += [textField]
        } else {
            totalTextFields += getTextFieldsInView(view: subview)
        }
    }

    return totalTextFields
}
}