//
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// YYTextView.swift
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// OKProject
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//
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// Created by alvin_y on 2020/5/28.
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// Copyright © 2020 yangwang. All rights reserved.
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//
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import Foundation
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@IBDesignable class YYTextView: UITextView {
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/// 占位字符串
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@IBInspectable var placeholder: String = ""
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/// 最大可输入字数
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@IBInspectable var maximumLength: Int = 0
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deinit {
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NotificationCenter.default.removeObserver(self)
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}
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required init?(coder aDecoder: NSCoder) {
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super.init(coder: aDecoder)
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initialization()
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}
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override init(frame: CGRect, textContainer: NSTextContainer?) {
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super.init(frame: frame, textContainer: textContainer)
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initialization()
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}
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override func layoutSubviews() {
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super.layoutSubviews()
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setNeedsDisplay()
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}
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private func initialization() {
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NotificationCenter.default.addObserver(self, selector: #selector(textViewTextDidChange(sender:)), name: UITextView.textDidChangeNotification, object: nil)
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}
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@objc private func textViewTextDidChange(sender: Notification) {
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let string = text
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let inputMode = textInputMode?.primaryLanguage; // 键盘输入模式
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if (maximumLength > 0) {
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if (inputMode == "zh-Hans") {
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let selectedRange: UITextRange? = markedTextRange
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if selectedRange == nil {
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let substring = string!.prefix(maximumLength)
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text = String(substring)
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}
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} else {
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if string!.count > maximumLength {
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let substring = string!.prefix(maximumLength)
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text = String(substring)
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}
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}
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}
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setNeedsDisplay()
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}
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override func draw(_ rect: CGRect) {
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guard !hasText else { return }
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// 属性
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let attributes: [NSAttributedString.Key : Any] = [.font: font!, .foregroundColor: UIColor.lightGray]
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// 画文字
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var aRect = CGRect.zero
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aRect.origin.x = 5
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aRect.origin.y = 8
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aRect.size.width = rect.size.width - (2 * aRect.origin.x)
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aRect.size.height = rect.size.height
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let string = placeholder as NSString
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string.draw(in: aRect, withAttributes: attributes)
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}
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}
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