[英]React: How to maintain caret position when editing contentEditable div?
目前
<div>
时存储一个newValue
,并在用户输入时更新newValue
。 注意:我以这种方式设置此行为有两个主要原因:(1)我不想发送要在每次击键时保存的数据,以及(2)我计划使用此 div 的变体,其中检查每个输入以验证输入是否为数字。<div>
失去焦点时发送newValue
保存,然后重置 prop 的状态。问题
onChangeHandler
正在将可编辑 div 中插入符号的位置移动到左侧。 这导致击键123456
显示为654321
代码:
class Input extends Component {
constructor(props) {
super(props);
this.state = {
//newValue input by user
newValue : undefined
}
}
//handler during key press / input
onChangeHandler = event => {
let targetValue = event.currentTarget.textContent;
this.setState({"newValue": targetValue})
}
//handler when user opens input form
onBlurHandler = event => {
//some code that sends the "newValue" to be saved, and resets state
}
render() {
//determine which value to show in the div
let showValue;
//if there is a new value being input by user, show this value
if (this.state.newValue !== undefined) {
showValue = this.state.newValue;
} else {
//if prop has no value e.g. null or undefined, use "" placeholder
if (this.props.value) {
showValue = this.props.value;
} else {
showValue = "";
}
}
return (
<table>
<tbody>
<td>
<div
contentEditable="true"
suppressContentEditableWarning="true"
onInput={this.onChangeHandler.bind(this)}
onBlur={this.onBlurHandler}
>{showValue}
</div>
</td>
</tbody>
</table>
)
}
}
export default Input;
笔记
<textarea>
来做这个,但切换到<div>
以更好地控制自动调整 div 高度行为(参考CSS:删除滚动条并用可变高度替换文本区域中的表 <td> )我能够在https://stackoverflow.com/a/13950376/1730260 中使用以下解决方案来解决此问题
主要变化:
EditCaretPositioning.js
:(1) saveSelection 以保存插入符位置,以及 (2) restoreSelection 以恢复插入符位置。Input
组件的状态下保存插入符号位置saveSelection()
restoreSelection()
作为设置状态后的回调id
添加到<div>
以便可以在restoreSelection()
函数中引用编辑CaretPositioning.js
const EditCaretPositioning = {}
export default EditCaretPositioning;
if (window.getSelection && document.createRange) {
//saves caret position(s)
EditCaretPositioning.saveSelection = function(containerEl) {
var range = window.getSelection().getRangeAt(0);
var preSelectionRange = range.cloneRange();
preSelectionRange.selectNodeContents(containerEl);
preSelectionRange.setEnd(range.startContainer, range.startOffset);
var start = preSelectionRange.toString().length;
return {
start: start,
end: start + range.toString().length
}
};
//restores caret position(s)
EditCaretPositioning.restoreSelection = function(containerEl, savedSel) {
var charIndex = 0, range = document.createRange();
range.setStart(containerEl, 0);
range.collapse(true);
var nodeStack = [containerEl], node, foundStart = false, stop = false;
while (!stop && (node = nodeStack.pop())) {
if (node.nodeType === 3) {
var nextCharIndex = charIndex + node.length;
if (!foundStart && savedSel.start >= charIndex && savedSel.start <= nextCharIndex) {
range.setStart(node, savedSel.start - charIndex);
foundStart = true;
}
if (foundStart && savedSel.end >= charIndex && savedSel.end <= nextCharIndex) {
range.setEnd(node, savedSel.end - charIndex);
stop = true;
}
charIndex = nextCharIndex;
} else {
var i = node.childNodes.length;
while (i--) {
nodeStack.push(node.childNodes[i]);
}
}
}
var sel = window.getSelection();
sel.removeAllRanges();
sel.addRange(range);
}
} else if (document.selection && document.body.createTextRange) {
//saves caret position(s)
EditCaretPositioning.saveSelection = function(containerEl) {
var selectedTextRange = document.selection.createRange();
var preSelectionTextRange = document.body.createTextRange();
preSelectionTextRange.moveToElementText(containerEl);
preSelectionTextRange.setEndPoint("EndToStart", selectedTextRange);
var start = preSelectionTextRange.text.length;
return {
start: start,
end: start + selectedTextRange.text.length
}
};
//restores caret position(s)
EditCaretPositioning.restoreSelection = function(containerEl, savedSel) {
var textRange = document.body.createTextRange();
textRange.moveToElementText(containerEl);
textRange.collapse(true);
textRange.moveEnd("character", savedSel.end);
textRange.moveStart("character", savedSel.start);
textRange.select();
};
}
更新了 contentEditable div 组件:
import CaretPositioning from 'EditCaretPositioning'
class Input extends Component {
constructor(props) {
super(props);
this.state = {
//newValue input by user
newValue : undefined,
//stores positions(s) of caret to handle reload after onChange end
caretPosition : {
start : 0,
end : 0
}
}
}
//handler during key press / input
onChangeHandler = event => {
let targetValue = event.currentTarget.textContent;
//save caret position(s), so can restore when component reloads
let savedCaretPosition = CaretPositioning.saveSelection(event.currentTarget);
this.setState({
"newValue": targetValue,
"caretPosition" : savedCaretPosition
}, () => {
//restore caret position(s)
CaretPositioning.restoreSelection(document.getElementById("editable"), this.state.caretPosition);
})
}
//handler when user opens input form
onBlurHandler = event => {
//some code that sends the "newValue" to be saved, and resets state
}
render() {
//determine which value to show in the div
let showValue;
//if there is a new value being input by user, show this value
if (this.state.newValue !== undefined) {
showValue = this.state.newValue;
} else {
//if prop has no value e.g. null or undefined, use "" placeholder
if (this.props.value) {
showValue = this.props.value;
} else {
showValue = "";
}
}
return (
<table>
<tbody>
<td>
<div
id="editable"
contentEditable="true"
suppressContentEditableWarning="true"
onInput={this.onChangeHandler.bind(this)}
onBlur={this.onBlurHandler}
>{showValue}
</div>
</td>
</tbody>
</table>
)
}
}
export default Input;
ContentEditable 是一个棘手的问题,尤其是对于 react,因为您必须考虑许多不同类型的行为。 我建议你看看 Facebook 的 DraftJS。
他们采用了 contentEditable 并阻止了所有默认行为,并构建了一个很好的框架来使标签可编辑,他们将其用于富文本编辑器,但您可以使用相同的框架而无需所有花里胡哨的东西来控制可编辑的内容。
我也遇到过这个问题,同时尝试在<td>
上编辑内容。 编辑时光标转到开始,我尝试了多种方法但没有任何帮助!
后来,我最终使用了这个“contenteditable”的 React 包。
https://github.com/lovasoa/react-contenteditable
以前,我使用的代码是这样的
<td
onInput={(e) =>this.handleInput(e, user, "name", index)}
contentEditable={user.isEditable}
className={
user.isEditable ? "border border-success" : ""
}
>
{user.name}
</td>
包含包后,我使用以下代码对其进行了更改。 现在它可以正常工作了。
<td className={user.isEditable ? "border border-success" : ""}>
<ContentEditable
html={user.name}
disabled={!user.isEditable}
onChange={(e) =>
this.handleInput(e, user, "name", index)
}
style={{ "text-decoration": "none" }}
/>
</td>
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.