如何使用 InputFilter 限制 Android 中 EditText 中的字符？
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How do I use InputFilter to limit characters in an EditText in Android?
提问by Tim Wayne
I want to restrict the chars to 0-9, a-z, A-Z and spacebar only. Setting inputtype I can limit to digits but I cannot figure out the ways of Inputfilter looking through the docs.
我想将字符限制为 0-9、az、AZ 和空格键。设置 inputtype 我可以限制为数字，但我无法弄清楚 Inputfilter 查看文档的方式。
回答by moonlightcheese
I found this on another forum. Works like a champ.
我在另一个论坛上找到了这个。像冠军一样工作。
InputFilter filter = new InputFilter() {
public CharSequence filter(CharSequence source, int start, int end,
Spanned dest, int dstart, int dend) {
for (int i = start; i < end; i++) {
if (!Character.isLetterOrDigit(source.charAt(i))) {
return "";
}
}
return null;
}
};
edit.setFilters(new InputFilter[] { filter });
回答by ?ukasz Sromek
InputFilters are a little complicated in Android versions that display dictionary suggestions. You sometimes get a SpannableStringBuilder, sometimes a plain Stringin the sourceparameter.
InputFilters 在显示字典建议的 Android 版本中有点复杂。你有时会在参数中得到一个SpannableStringBuilder，有时是一个普通String的source。
The following InputFiltershould work. Feel free to improve this code!
以下InputFilter应该工作。随意改进此代码！
new InputFilter() {
@Override
public CharSequence filter(CharSequence source, int start, int end,
Spanned dest, int dstart, int dend) {
if (source instanceof SpannableStringBuilder) {
SpannableStringBuilder sourceAsSpannableBuilder = (SpannableStringBuilder)source;
for (int i = end - 1; i >= start; i--) {
char currentChar = source.charAt(i);
if (!Character.isLetterOrDigit(currentChar) && !Character.isSpaceChar(currentChar)) {
sourceAsSpannableBuilder.delete(i, i+1);
}
}
return source;
} else {
StringBuilder filteredStringBuilder = new StringBuilder();
for (int i = start; i < end; i++) {
char currentChar = source.charAt(i);
if (Character.isLetterOrDigit(currentChar) || Character.isSpaceChar(currentChar)) {
filteredStringBuilder.append(currentChar);
}
}
return filteredStringBuilder.toString();
}
}
}
回答by Florian Fr?hlich
much easier:
容易得多：
<EditText
android:inputType="text"
android:digits="0,1,2,3,4,5,6,7,8,9,*,qwertzuiopasdfghjklyxcvbnm" />
回答by Kamil Seweryn
None of posted answers did work for me. I came with my own solution:
没有一个已发布的答案对我有用。我带来了自己的解决方案：
InputFilter filter = new InputFilter() {
@Override
public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {
boolean keepOriginal = true;
StringBuilder sb = new StringBuilder(end - start);
for (int i = start; i < end; i++) {
char c = source.charAt(i);
if (isCharAllowed(c)) // put your condition here
sb.append(c);
else
keepOriginal = false;
}
if (keepOriginal)
return null;
else {
if (source instanceof Spanned) {
SpannableString sp = new SpannableString(sb);
TextUtils.copySpansFrom((Spanned) source, start, sb.length(), null, sp, 0);
return sp;
} else {
return sb;
}
}
}
private boolean isCharAllowed(char c) {
return Character.isLetterOrDigit(c) || Character.isSpaceChar(c);
}
}
editText.setFilters(new InputFilter[] { filter });
回答by Mohamed Ibrahim
Use this its work 100% your need and very simple.
使用它的工作 100% 您的需要并且非常简单。
<EditText
android:inputType="textFilter"
android:digits="@string/myAlphaNumeric" />
In strings.xml
在strings.xml中
<string name="myAlphaNumeric">abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789</string>
回答by Mohamed Ibrahim
To avoid Special Characters in input type
避免输入类型中的特殊字符
public static InputFilter filter = new InputFilter() {
@Override
public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {
String blockCharacterSet = "~#^|$%*!@/()-'\":;,?{}=!$^';,?×÷<>{}￡￥?%~`¤??_|《》??°?○●□■◇◆??▲▼??↑↓←→☆★?:-);-):-D:-(:'(:O 1234567890";
if (source != null && blockCharacterSet.contains(("" + source))) {
return "";
}
return null;
}
};
You can set filter to your edit text like below
您可以将过滤器设置为您的编辑文本，如下所示
edtText.setFilters(new InputFilter[] { filter });
回答by mblenton
In addition to the accepted answer, it is also possible to use e.g.: android:inputType="textCapCharacters"as an attribute of <EditText>in order to only accept upper case characters (and numbers).
除了接受的答案外，还可以使用 eg:android:inputType="textCapCharacters"作为属性，<EditText>以便只接受大写字符（和数字）。
回答by Groxx
For some reason the android.text.LoginFilter class's constructor is package-scoped, so you can't directly extend it (even though it would be identical to this code). But you can extend LoginFilter.UsernameFilterGeneric! Then you just have this:
出于某种原因， android.text.LoginFilter 类的构造函数是包范围的，因此您不能直接扩展它（即使它与此代码相同）。但是你可以扩展 LoginFilter.UsernameFilterGeneric！然后你只有这个：
class ABCFilter extends LoginFilter.UsernameFilterGeneric {
public UsernameFilter() {
super(false); // false prevents not-allowed characters from being appended
}
@Override
public boolean isAllowed(char c) {
if ('A' <= c && c <= 'C')
return true;
if ('a' <= c && c <= 'c')
return true;
return false;
}
}
This isn't really documented, but it's part of the core lib, and the source is straightforward. I've been using it for a while now, so far no problems, though I admit I haven't tried doing anything complex involving spannables.
这并没有真正记录在案，但它是核心库的一部分，源代码很简单。我已经使用它一段时间了，到目前为止没有问题，尽管我承认我还没有尝试过做任何涉及可跨度的复杂事情。
回答by Kailas
It's Right, the best way to go about it to fix it in the XML Layout itself using:
是的，最好的方法是使用以下方法在 XML 布局本身中修复它：
<EditText
android:inputType="text"
android:digits="0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ" />
as rightly pointed by Florian Fr?hlich, it works well for text views even.
正如 Florian Fr?hlich 正确指出的那样，它甚至适用于文本视图。
<TextView
android:inputType="text"
android:digits="0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ" />
Just a word of caution, the characters mentioned in the android:digitswill only be displayed, so just be careful not to miss any set of characters out :)
请注意， 中提到的字符android:digits只会显示出来，所以请注意不要错过任何一组字符:)
回答by Swifty McSwifterton
This simple solution worked for me when I needed to prevent the user from entering empty strings into an EditText. You can of course add more characters:
当我需要防止用户在 EditText 中输入空字符串时，这个简单的解决方案对我有用。您当然可以添加更多字符：
InputFilter textFilter = new InputFilter() {
@Override
public CharSequence filter(CharSequence c, int arg1, int arg2,
Spanned arg3, int arg4, int arg5) {
StringBuilder sbText = new StringBuilder(c);
String text = sbText.toString();
if (text.contains(" ")) {
return "";
}
return c;
}
};
private void setTextFilter(EditText editText) {
editText.setFilters(new InputFilter[]{textFilter});
}
