在Android中限制EditText文本长度的最佳方法是什么?
有没有通过xml实现这一点的方法?
在Android中限制EditText文本长度的最佳方法是什么?
有没有通过xml实现这一点的方法?
当前回答
TextView tv = new TextView(this);
tv.setFilters(new InputFilter[]{ new InputFilter.LengthFilter(250) });
其他回答
由于goto10的观察,我将以下代码组合在一起,通过设置最大长度来防止丢失其他过滤器:
/**
* This sets the maximum length in characters of an EditText view. Since the
* max length must be done with a filter, this method gets the current
* filters. If there is already a length filter in the view, it will replace
* it, otherwise, it will add the max length filter preserving the other
*
* @param view
* @param length
*/
public static void setMaxLength(EditText view, int length) {
InputFilter curFilters[];
InputFilter.LengthFilter lengthFilter;
int idx;
lengthFilter = new InputFilter.LengthFilter(length);
curFilters = view.getFilters();
if (curFilters != null) {
for (idx = 0; idx < curFilters.length; idx++) {
if (curFilters[idx] instanceof InputFilter.LengthFilter) {
curFilters[idx] = lengthFilter;
return;
}
}
// since the length filter was not part of the list, but
// there are filters, then add the length filter
InputFilter newFilters[] = new InputFilter[curFilters.length + 1];
System.arraycopy(curFilters, 0, newFilters, 0, curFilters.length);
newFilters[curFilters.length] = lengthFilter;
view.setFilters(newFilters);
} else {
view.setFilters(new InputFilter[] { lengthFilter });
}
}
EditText editText = new EditText(this);
int maxLength = 3;
editText.setFilters(new InputFilter[] {new InputFilter.LengthFilter(maxLength)});
xml中的简单方式:
android:maxLength="4"
如果您需要在xml编辑文本中设置4个字符,请使用
<EditText
android:id="@+id/edtUserCode"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:maxLength="4"
android:hint="Enter user code" />
科特林:
edit_text.filters += InputFilter.LengthFilter(10)
中兴刀片A520具有奇怪的效果。当您键入超过10个符号(例如15个)时,EditText将显示前10个符号,但其他5个符号不可见且不可访问。但当您使用Backspace删除符号时,它会先删除右边的5个符号,然后删除剩下的10个符号。要克服这种行为,请使用以下解决方案:
android:inputType="textNoSuggestions|textVisiblePassword"
android:maxLength="10"
或者:
android:inputType="textNoSuggestions"
或者,如果您想获得建议:
private class EditTextWatcher(private val view: EditText) : TextWatcher {
private var position = 0
private var oldText = ""
override fun afterTextChanged(s: Editable?) = Unit
override fun beforeTextChanged(s: CharSequence?, start: Int, count: Int, after: Int) {
oldText = s?.toString() ?: ""
position = view.selectionStart
}
override fun onTextChanged(s: CharSequence?, start: Int, before: Int, count: Int) {
val newText = s?.toString() ?: ""
if (newText.length > 10) {
with(view) {
setText(oldText)
position = if (start > 0 && count > 2) {
// Text paste in nonempty field.
start
} else {
if (position in 1..10 + 1) {
// Symbol paste in the beginning or middle of the field.
position - 1
} else {
if (start > 0) {
// Adding symbol to the end of the field.
start - 1
} else {
// Text paste in the empty field.
0
}
}
}
setSelection(position)
}
}
}
}
// Usage:
editTextWatcher = EditTextWatcher(view.edit_text)
view.edit_text.addTextChangedListener(editTextWatcher)
以编程方式为Java尝试以下操作:
myEditText(new InputFilter[] {new InputFilter.LengthFilter(CUSTOM_MAX_LEN)});