如何在Android中使用InputFilter限制EditText中的字符？

我只想将字符限制为0-9、a-z、a-z和空格键。设置inputtype我可以限制为数字，但我无法找出Inputfilter查看文档的方式。

如果您将Inputfilter子类化，则可以创建自己的Inputfilter，以过滤掉任何非字母数字字符

InputFilter接口有一个方法，

filter（CharSequence source、int start、int end、Spand dest、int dstart、int dend）

，它为您提供了所需的所有信息，让您知道在EditText中输入了哪些字符

创建自己的InputFilter后，可以通过调用setFilters（…）将其分配给EditText

---

，int，int，android.text.span，int，int）

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 });

InputFilter过滤器=新的InputFilter（）{
公共CharSequence筛选器（CharSequence源、int开始、int结束、，
跨越目的地、内部数据起点、内部数据起点）{
for（int i=start；i

除了可接受的答案外，还可以使用例如：

android:inputType=“textCapCharacters”

作为

的属性，以便只接受大写字符（和数字）。

可以使用

setonkeylister

。在这个方法中，我们可以自定义输入

edittext

在显示字典建议的Android版本中，InputFilter有点复杂。有时在

源

参数中会出现

SpannableStringBuilder

，有时会出现一个普通的

字符串

以下

InputFilter

应该可以工作。请随意改进此代码

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();
        }
    }
}

newInputFilter（）{
@凌驾
公共CharSequence筛选器（CharSequence源、int开始、int结束、，
跨越目的地、内部数据起点、内部数据起点）{
if（SpannableStringBuilder的源实例）{
SpannableStringBuilder sourceAsSpannableBuilder=（SpannableStringBuilder）源；
对于（inti=end-1；i>=start；i--）{
char currentChar=源字符（i）；
如果（！Character.isleterOrdGit（currentChar）和&！Character.isSpaceChar（currentChar））{
sourceAsSpannableBuilder.delete（i，i+1）；
}     
}
返回源；
}否则{
StringBuilder filteredStringBuilder=新建StringBuilder（）；
对于（inti=start；i

简单得多：

<EditText
    android:inputType="text"
    android:digits="0,1,2,3,4,5,6,7,8,9,*,qwertzuiopasdfghjklyxcvbnm" />

---

由于某些原因，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）。但是您可以扩展LoginFilter.UsernameFilterGeneric！那么你就有这个：

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;
    }
}

类ABCFilter扩展了LoginFilter.UsernameFilterGeneric{ 公共UsernameFilter（）{ super（false）；//false防止追加不允许的字符 } @凌驾 允许使用公共布尔值（字符c）{

---

如果（'A'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效。当然，您可以添加更多字符：

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});

}

---

所有张贴的答案都不适用于我。我有自己的解决方案：

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 });

InputFilter过滤器=新的InputFilter（）{
@凌驾
公共CharSequence筛选器（CharSequence源、int开始、int结束、跨区目标、int开始、int结束）{
布尔值keepOriginal=true；
StringBuilder sb=新的StringBuilder（结束-开始）；
for（int i=start；i

这是正确的，最好的解决方法是在XML布局本身中使用以下方法修复它：

<EditText
android:inputType="text"
android:digits="0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ" />

正如Florian Fröhlich正确指出的那样，它甚至适用于文本视图

<TextView
android:inputType="text"
android:digits="0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ" />

---

请注意，

android:digits

中提到的字符只会显示出来，所以请注意不要漏掉任何字符集：）

忽略其他人处理过的span内容，为了正确处理字典建议，我发现以下代码是有效的

源代码随着建议的增长而增长，因此在返回任何内容之前，我们必须查看它实际希望我们替换多少字符

如果没有任何无效字符，则返回null，以便进行默认替换

否则，我们需要从实际要放入EditText的子字符串中提取有效字符

InputFilter filter = new InputFilter() { 
    public CharSequence filter(CharSequence source, int start, int end, 
    Spanned dest, int dstart, int dend) { 

        boolean includesInvalidCharacter = false;
        StringBuilder stringBuilder = new StringBuilder();

        int destLength = dend - dstart + 1;
        int adjustStart = source.length() - destLength;
        for(int i=start ; i<end ; i++) {
            char sourceChar = source.charAt(i);
            if(Character.isLetterOrDigit(sourceChar)) {
                if(i >= adjustStart)
                     stringBuilder.append(sourceChar);
            } else
                includesInvalidCharacter = true;
        }
        return includesInvalidCharacter ? stringBuilder : null;
    } 
}; 

InputFilter过滤器=新的InputFilter（）{
公共CharSequence筛选器（CharSequence源、int开始、int结束、，
public class Wordfilter implements InputFilter
{
    @Override
    public CharSequence filter(CharSequence source, int start, int end,Spanned dest, int dstart, int dend) {
        // TODO Auto-generated method stub
        boolean append = false;
        String text = source.toString().substring(start, end);
        StringBuilder str = new StringBuilder(dest.toString());
        if(dstart == str.length())
        {
            append = true;
            str.append(text);
        }
        else
            str.replace(dstart, dend, text);
        if(str.toString().contains("aaaaaaaaaaaa/*the word here*/aaaaaaaa"))
        {
            if(append==true)
                return "";
            else
                return dest.subSequence(dstart, dend);
        }
        return null;
    }
}

<EditText
android:inputType="textFilter"
android:digits="@string/myAlphaNumeric" />

<string name="myAlphaNumeric">abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789</string>

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;
    }
};

edtText.setFilters(new InputFilter[] { filter });

editText.addTextChangedListener(new TextWatcher() {

    @Override
    public void afterTextChanged(Editable editable) {
        super.afterTextChanged(editable);

        String originalText = editable.toString();
        int originalTextLength = originalText.length();
        int currentSelection = editText.getSelectionStart();

        // Create the filtered text
        StringBuilder sb = new StringBuilder();
        boolean hasChanged = false;
        for (int i = 0; i < originalTextLength; i++) {
            char currentChar = originalText.charAt(i);
            if (isAllowed(currentChar)) {
                sb.append(currentChar);
            } else {
                hasChanged = true;
                if (currentSelection >= i) {
                    currentSelection--;
                }
            }
        }

        // If we filtered something, update the text and the cursor location
        if (hasChanged) {
            String newText = sb.toString();
            editText.setText(newText);
            editText.setSelection(currentSelection);
        }
    }

    private boolean isAllowed(char c) {
        // TODO: Add the filter logic here
        return Character.isLetter(c) || Character.isSpaceChar(c);
    }
    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {
        // Do Nothing
    }

    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {
        // Do Nothing
    }
});

public void setNameFilter() {
    InputFilter filter = new InputFilter() {
        @RequiresApi(api = Build.VERSION_CODES.KITKAT)
        public CharSequence filter(CharSequence source, int start, int end,
                                   Spanned dest, int dstart, int dend) {
            for (int i = start; i < end; i++) {
                if (dend == 0) {
                    if (Character.isSpaceChar(source.charAt(i)) ||
                            !Character.isAlphabetic(source.charAt(i))) {
                        return Constants.Delimiter.BLANK;
                    } else {
                        return String.valueOf(source.charAt(i)).toUpperCase();
                    }
                } else if (Character.isSpaceChar(source.charAt(i)) &&
                        String.valueOf(dest).endsWith(Constants.Delimiter.ONE_SPACE)) {
                    return Constants.Delimiter.BLANK;
                } else if ((!Character.isSpaceChar(source.charAt(i)) &&
                        !Character.isAlphabetic(source.charAt(i)))) {
                    return Constants.Delimiter.BLANK;
                }
            }
            return null;
        }
    };
    editText.setFilters(new InputFilter[]{filter, new InputFilter.LengthFilter(Constants.Length.NAME_LENGTH)});
}

<string name="vin_code_mask">0123456789abcdefghjklmnprstuvwxyz</string>

android:digits="@string/vin_code_mask"

edit_text.filters += InputFilter { source, start, end, _, _, _ ->
    val mask = getString(R.string.vin_code_mask)
    for (i in start until end) {
        if (!mask.contains(source[i])) {
            return@InputFilter ""
        }
    }
    null
}

edit_text.keyListener = DigitsKeyListener.getInstance(context.getString(R.string.vin_code_mask))

/**
 * Returns the filter of the editText'es CharSequence value when [filterType] is:
 * 1 -> letters; 2 -> letters and digits; 3 -> digits;
 * 4 -> digits and dots
 */
class InputFilterAlphanumeric(private val filterType: Int): InputFilter {
    override fun filter(source: CharSequence?, start: Int, end: Int, dest: Spanned?, dstart: Int, dend: Int): CharSequence {
        (source as? SpannableStringBuilder)?.let {sourceAsSpannableBuilder  ->
            for (i in (end - 1) downTo start) {
                val currentChar = source[i]
                when(filterType) {
                    1 -> {
                        if (!currentChar.isLetter() && !currentChar.isWhitespace()) {
                            sourceAsSpannableBuilder.delete(i, i + 1)
                        }
                    }
                    2 -> {
                        if (!currentChar.isLetterOrDigit() && !currentChar.isWhitespace()) {
                            sourceAsSpannableBuilder.delete(i, i + 1)
                        }
                    }
                    3 -> {
                        if (!currentChar.isDigit()) {
                            sourceAsSpannableBuilder.delete(i, i + 1)
                        }
                    }
                    4 -> {
                        if (!currentChar.isDigit() || !currentChar.toString().contains(".")) {
                            sourceAsSpannableBuilder.delete(i, i + 1)
                        }
                    }
                }
            }
            return source
        } ?: run {
            val filteredStringBuilder = StringBuilder()
            for (i in start until end) {
                val currentChar = source?.get(i)
                when(filterType) {
                    1 -> {
                        if (currentChar?.isLetter()!! || currentChar.isWhitespace()) {
                            filteredStringBuilder.append(currentChar)
                        }
                    }
                    2 -> {
                        if (currentChar?.isLetterOrDigit()!! || currentChar.isWhitespace()) {
                            filteredStringBuilder.append(currentChar)
                        }
                    }
                    3 -> {
                        if (currentChar?.isDigit()!!) {
                            filteredStringBuilder.append(currentChar)
                        }
                    }
                    4 -> {
                        if (currentChar?.isDigit()!! || currentChar.toString().contains(".")) {
                            filteredStringBuilder.append(currentChar)
                        }
                    }
                }
            }
            return filteredStringBuilder
        }
    }
}

fun EditText.filterByDataType(filterType: Int) {
    this.filters = arrayOf<InputFilter>(InputFilterAlphanumeric(filterType))
}

edit_text.filters = arrayOf(object : InputFilter {
    override fun filter(
        source: CharSequence?,
        start: Int,
        end: Int,
        dest: Spanned?,
        dstart: Int,
        dend: Int
    ): CharSequence? {
        return source?.subSequence(start, end)
            ?.replace(Regex("[^A-Za-z0-9 ]"), "")
    }
})

val regex = Regex("[a-zA-Z\\d ]")
    
editText.filters = arrayOf(InputFilter { source, _, _, _, _, _ ->
    source.filter { regex.matches(it.toString()) }
})