如何防止在Android中的EditText中刪除特殊字符？

Question

如何防止在EditText中刪除某些字符？

例如，防止 「」 從刪除字符的光標在下面的文字：

"Amir,Mahdy"

Answer 1

我的猜測是檢查字符在TextWatcher如下：

EditText editText = (EditText)findViewById(R.id.editText); 
editText.addTextChangedListener(new TextWatcher() { 

    @Override 
    public void afterTextChanged(Editable s) { 
     // TODO Auto-generated method stub 

    } 

    @Override 
    public void beforeTextChanged(CharSequence s, int start, int count, int after) { 
     // TODO Auto-generated method stub 
     // Get cursor position 
     int cursorPosition = editText.getSelectionStart(); 

     // Check if the previous character is "," and move your cursor 
     if (s.charAt(cursorPosition - 1) == ',') 
      editText.setSelection(cursorPosition - 2); 
     } 

    @Override 
    public void onTextChanged(CharSequence s, int start, int before, int count) { 
    } 

}); 

Answer 2

東西像這樣應該可以工作：

全局變量：

private String lastText  = ""; 
private int  countOfCommas= 0; 
private EditText editText; 

代碼：

editText = ((EditText) findViewById(R.id.editText)); 
updateText("Amir,Mahdy"); 

editText.addTextChangedListener(new TextWatcher() { 
    @Override 
    public void onTextChanged(CharSequence s, int start, int before, int count) { 
    } 

    @Override 
    public void beforeTextChanged(CharSequence s, int start, int count, int after) { 
    } 

    @Override 
    public void afterTextChanged(Editable s) { 
     int new_countOfCommas = s.toString().length() - s.toString().replace(",", "").length(); 
     if(new_countOfCommas < countOfCommas) { 
      int cursor_pos = editText.getSelectionStart(); 
      editText.setText(lastText); 
      if(cursor_pos <= lastText.length()) { 
       editText.setSelection(cursor_pos); 
      } 
     } else { 
      countOfCommas = s.toString().length() - s.toString().replace(",", "").length(); 
      lastText = s.toString(); 
     } 
    } 
}); 

功能以編程方式設置文本：

void updateText(String str) { 
    countOfCommas = str.length() - str.replace(",", "").length(); 
    lastText = str; 
    editText.setText(str); 
} 

Answer 3

嗨，我面臨着同樣的問題，防止用戶刪除特殊字符，在我的情況十進制字符。這是我如何做到的。 在strings.xml補充一點：

<item type="id" name="SEPARATOR" />

比EditTextaddTextChangedListener和方法beforeTextChanged補充一點：

int position = editText.getText().toString().indexOf(your_special_character); 
editTrxt.setTag(R.id.SEPARATOR, position); 

比afterTextChanged只返回後面那個字是這樣的：

String text = editText.getText().toString(); 
try { 
    if (!text.contains(your_special_character +"")){ 
    int position = (int)editText.getTag(R.id.SEPARATOR); 
    text = new StringBuilder(text).insert(position, separator).toString(); 
    } 
}catch (Exception ignored){ 
}