如何格式化EditText以遵循“dd/mm/yyyy”格式，就像我们可以使用TextWatcher格式化来屏蔽用户输入看起来像“0.05€”一样。我不是在谈论限制字符，或者验证日期，只是掩盖了以前的格式。
我为一个项目写了这个TextWatcher，希望它对某人有帮助。请注意，它不会验证用户输入的日期，并且您应该在焦点更改时处理该日期，因为用户可能尚未完成输入日期。
更新25/06制作一个wiki，看看我们是否达到了更好的最终代码。
更新07/06我终于为观察者本身添加了某种验证。它将执行以下无效日期：
1900-2100范围内，请将其更改为在范围内这个验证符合我的需要，但是你们中的一些人可能想稍微改变一下，范围很容易改变，你可以将这些验证挂钩到例如Toast消息，以通知用户我们已经修改了他/她的日期，因为它无效。
在这段代码中，我将假设我们有一个名为EditText的date的引用，它附加了这个TextWatcher，这可以这样做：
EditText date;
date = (EditText)findViewById(R.id.whichdate);
date.addTextChangedListener(tw);
TextWatcher tw = new TextWatcher() {
private String current = "";
private String ddmmyyyy = "DDMMYYYY";
private Calendar cal = Calendar.getInstance();
当用户更改EditText的文本时
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
if (!s.toString().equals(current)) {
String clean = s.toString().replaceAll("[^\\d.]|\\.", "");
String cleanC = current.replaceAll("[^\\d.]|\\.", "");
int cl = clean.length();
int sel = cl;
for (int i = 2; i <= cl && i < 6; i += 2) {
sel++;
}
//Fix for pressing delete next to a forward slash
if (clean.equals(cleanC)) sel--;
if (clean.length() < 8){
clean = clean + ddmmyyyy.substring(clean.length());
}else{
//This part makes sure that when we finish entering numbers
//the date is correct, fixing it otherwise
int day = Integer.parseInt(clean.substring(0,2));
int mon = Integer.parseInt(clean.substring(2,4));
int year = Integer.parseInt(clean.substring(4,8));
mon = mon < 1 ? 1 : mon > 12 ? 12 : mon;
cal.set(Calendar.MONTH, mon-1);
year = (year<1900)?1900:(year>2100)?2100:year;
cal.set(Calendar.YEAR, year);
// ^ first set year for the line below to work correctly
//with leap years - otherwise, date e.g. 29/02/2012
//would be automatically corrected to 28/02/2012
day = (day > cal.getActualMaximum(Calendar.DATE))? cal.getActualMaximum(Calendar.DATE):day;
clean = String.format("%02d%02d%02d",day, mon, year);
}
clean = String.format("%s/%s/%s", clean.substring(0, 2),
clean.substring(2, 4),
clean.substring(4, 8));
sel = sel < 0 ? 0 : sel;
current = clean;
date.setText(current);
date.setSelection(sel < current.length() ? sel : current.length());
}
}
我们还实现了其他两个功能，因为我们必须这样做
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {}
@Override
public void afterTextChanged(Editable s) {}
};
这会产生以下效果，删除或插入字符将显示或隐藏dd/mm/yyyy蒙版。应该很容易修改以适应其他格式的掩码，因为我试图让代码尽可能简单。
目前的答案非常好，并帮助指导我自己的解决方案。我决定发布自己的解决方案有几个原因，即使这个问题已经有一个有效的答案：
要使用它，只需执行以下操作：
解决方案如下所示：
class DateInputMask(val input : EditText) {
fun listen() {
input.addTextChangedListener(mDateEntryWatcher)
}
private val mDateEntryWatcher = object : TextWatcher {
var edited = false
val dividerCharacter = "/"
override fun onTextChanged(s: CharSequence, start: Int, before: Int, count: Int) {
if (edited) {
edited = false
return
}
var working = getEditText()
working = manageDateDivider(working, 2, start, before)
working = manageDateDivider(working, 5, start, before)
edited = true
input.setText(working)
input.setSelection(input.text.length)
}
private fun manageDateDivider(working: String, position : Int, start: Int, before: Int) : String{
if (working.length == position) {
return if (before <= position && start < position)
working + dividerCharacter
else
working.dropLast(1)
}
return working
}
private fun getEditText() : String {
return if (input.text.length >= 10)
input.text.toString().substring(0,10)
else
input.text.toString()
}
override fun afterTextChanged(s: Editable) {}
override fun beforeTextChanged(s: CharSequence, start: Int, count: Int, after: Int) {}
}
}
使用JuanCortés代码的一种更简洁的方法是将它放在一个类中：
public class DateInputMask implements TextWatcher {
private String current = "";
private String ddmmyyyy = "DDMMYYYY";
private Calendar cal = Calendar.getInstance();
private EditText input;
public DateInputMask(EditText input) {
this.input = input;
this.input.addTextChangedListener(this);
}
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
}
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
if (s.toString().equals(current)) {
return;
}
String clean = s.toString().replaceAll("[^\\d.]|\\.", "");
String cleanC = current.replaceAll("[^\\d.]|\\.", "");
int cl = clean.length();
int sel = cl;
for (int i = 2; i <= cl && i < 6; i += 2) {
sel++;
}
//Fix for pressing delete next to a forward slash
if (clean.equals(cleanC)) sel--;
if (clean.length() < 8){
clean = clean + ddmmyyyy.substring(clean.length());
}else{
//This part makes sure that when we finish entering numbers
//the date is correct, fixing it otherwise
int day = Integer.parseInt(clean.substring(0,2));
int mon = Integer.parseInt(clean.substring(2,4));
int year = Integer.parseInt(clean.substring(4,8));
mon = mon < 1 ? 1 : mon > 12 ? 12 : mon;
cal.set(Calendar.MONTH, mon-1);
year = (year<1900)?1900:(year>2100)?2100:year;
cal.set(Calendar.YEAR, year);
// ^ first set year for the line below to work correctly
//with leap years - otherwise, date e.g. 29/02/2012
//would be automatically corrected to 28/02/2012
day = (day > cal.getActualMaximum(Calendar.DATE))? cal.getActualMaximum(Calendar.DATE):day;
clean = String.format("%02d%02d%02d",day, mon, year);
}
clean = String.format("%s/%s/%s", clean.substring(0, 2),
clean.substring(2, 4),
clean.substring(4, 8));
sel = sel < 0 ? 0 : sel;
current = clean;
input.setText(current);
input.setSelection(sel < current.length() ? sel : current.length());
}
@Override
public void afterTextChanged(Editable s) {
}
}
然后你可以重复使用它
new DateInputMask(myEditTextInstance);
尝试使用一个解决此问题的库，因为屏蔽它不是开箱即用的。有很多极端情况（比如在已经屏蔽的文本中添加/删除字符）并正确处理这个问题，你最终会得到很多代码（和bug）。
以下是一些可用的库： https://github.com/egslava/edittext-mask https://github.com/dimitar-zabaznoski/MaskedEditText https://github.com/pinball83/Masked-Edittext https://github.com/RedMadRobot/input-mask-android https://github.com/santalu/mask-edittext
**请注意，在编写这些库时并非没有问题，因此您有责任选择最适合您的库并测试代码。
JuanCortés的维基像魅力https://stackoverflow.com/a/16889503/3480740
这是我的Kotlin版本
fun setBirthdayEditText() {
birthdayEditText.addTextChangedListener(object : TextWatcher {
private var current = ""
private val ddmmyyyy = "DDMMYYYY"
private val cal = Calendar.getInstance()
override fun onTextChanged(p0: CharSequence?, p1: Int, p2: Int, p3: Int) {
if (p0.toString() != current) {
var clean = p0.toString().replace("[^\\d.]|\\.".toRegex(), "")
val cleanC = current.replace("[^\\d.]|\\.", "")
val cl = clean.length
var sel = cl
var i = 2
while (i <= cl && i < 6) {
sel++
i += 2
}
//Fix for pressing delete next to a forward slash
if (clean == cleanC) sel--
if (clean.length < 8) {
clean = clean + ddmmyyyy.substring(clean.length)
} else {
//This part makes sure that when we finish entering numbers
//the date is correct, fixing it otherwise
var day = Integer.parseInt(clean.substring(0, 2))
var mon = Integer.parseInt(clean.substring(2, 4))
var year = Integer.parseInt(clean.substring(4, 8))
mon = if (mon < 1) 1 else if (mon > 12) 12 else mon
cal.set(Calendar.MONTH, mon - 1)
year = if (year < 1900) 1900 else if (year > 2100) 2100 else year
cal.set(Calendar.YEAR, year)
// ^ first set year for the line below to work correctly
//with leap years - otherwise, date e.g. 29/02/2012
//would be automatically corrected to 28/02/2012
day = if (day > cal.getActualMaximum(Calendar.DATE)) cal.getActualMaximum(Calendar.DATE) else day
clean = String.format("%02d%02d%02d", day, mon, year)
}
clean = String.format("%s/%s/%s", clean.substring(0, 2),
clean.substring(2, 4),
clean.substring(4, 8))
sel = if (sel < 0) 0 else sel
current = clean
birthdayEditText.setText(current)
birthdayEditText.setSelection(if (sel < current.count()) sel else current.count())
}
}
override fun beforeTextChanged(p0: CharSequence?, p1: Int, p2: Int, p3: Int) {
}
override fun afterTextChanged(p0: Editable) {
}
})
}
此答案不会对剩余的无类型数字应用完整掩码。但是，它是相关的，是我需要的解决方案。它的工作方式类似于PhoneNumberFormattingTextWatcher的工作原理。
在您键入时，它会添加斜杠以分隔格式为mm/dd/yyyy的日期。它没有做任何验证 - 只是格式化。
不需要EditText参考。只需设置监听器即可。 myEditText.addTextChangedListener(new DateTextWatcher());
import android.text.Editable;
import android.text.TextWatcher;
import java.util.Locale;
/**
* Adds slashes to a date so that it matches mm/dd/yyyy.
*
* Created by Mark Miller on 12/4/17.
*/
public class DateTextWatcher implements TextWatcher {
public static final int MAX_FORMAT_LENGTH = 8;
public static final int MIN_FORMAT_LENGTH = 3;
private String updatedText;
private boolean editing;
@Override
public void beforeTextChanged(CharSequence charSequence, int start, int before, int count) {
}
@Override
public void onTextChanged(CharSequence text, int start, int before, int count) {
if (text.toString().equals(updatedText) || editing) return;
String digitsOnly = text.toString().replaceAll("\\D", "");
int digitLen = digitsOnly.length();
if (digitLen < MIN_FORMAT_LENGTH || digitLen > MAX_FORMAT_LENGTH) {
updatedText = digitsOnly;
return;
}
if (digitLen <= 4) {
String month = digitsOnly.substring(0, 2);
String day = digitsOnly.substring(2);
updatedText = String.format(Locale.US, "%s/%s", month, day);
}
else {
String month = digitsOnly.substring(0, 2);
String day = digitsOnly.substring(2, 4);
String year = digitsOnly.substring(4);
updatedText = String.format(Locale.US, "%s/%s/%s", month, day, year);
}
}
@Override
public void afterTextChanged(Editable editable) {
if (editing) return;
editing = true;
editable.clear();
editable.insert(0, updatedText);
editing = false;
}
}
Kotlin版本没有验证
editText.addTextChangedListener(object : TextWatcher{
var sb : StringBuilder = StringBuilder("")
var _ignore = false
override fun afterTextChanged(s: Editable?) {}
override fun beforeTextChanged(s: CharSequence?, start: Int, count: Int, after: Int) {}
override fun onTextChanged(s: CharSequence?, start: Int, before: Int, count: Int) {
if(_ignore){
_ignore = false
return
}
sb.clear()
sb.append(if(s!!.length > 10){ s.subSequence(0,10) }else{ s })
if(sb.lastIndex == 2){
if(sb[2] != '/'){
sb.insert(2,"/")
}
} else if(sb.lastIndex == 5){
if(sb[5] != '/'){
sb.insert(5,"/")
}
}
_ignore = true
editText.setText(sb.toString())
editText.setSelection(sb.length)
}
})
将android:inputType="date"添加到你的EditText