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
//Set Length filter. Restricting to 10 characters only
editText.setFilters(new InputFilter[]{new InputFilter.LengthFilter(MAX_LENGTH)});
//Allowing only upper case characters
editText.setFilters(new InputFilter[]{new InputFilter.AllCaps()});
//Attaching multiple filters
editText.setFilters(new InputFilter[]{new InputFilter.LengthFilter(MAX_LENGTH), new InputFilter.AllCaps()});
其他回答
对于其他想知道如何实现这一点的人,这里是我的扩展EditText类EditTextNumeric。
.setMaxLength(int)-设置最大位数
.setMaxValue(int)-限制最大整数值
.setMin(int)-限制最小整数值
.getValue()-获取整数值
import android.content.Context;
import android.text.InputFilter;
import android.text.InputType;
import android.widget.EditText;
public class EditTextNumeric extends EditText {
protected int max_value = Integer.MAX_VALUE;
protected int min_value = Integer.MIN_VALUE;
// constructor
public EditTextNumeric(Context context) {
super(context);
this.setInputType(InputType.TYPE_CLASS_NUMBER);
}
// checks whether the limits are set and corrects them if not within limits
@Override
protected void onTextChanged(CharSequence text, int start, int before, int after) {
if (max_value != Integer.MAX_VALUE) {
try {
if (Integer.parseInt(this.getText().toString()) > max_value) {
// change value and keep cursor position
int selection = this.getSelectionStart();
this.setText(String.valueOf(max_value));
if (selection >= this.getText().toString().length()) {
selection = this.getText().toString().length();
}
this.setSelection(selection);
}
} catch (NumberFormatException exception) {
super.onTextChanged(text, start, before, after);
}
}
if (min_value != Integer.MIN_VALUE) {
try {
if (Integer.parseInt(this.getText().toString()) < min_value) {
// change value and keep cursor position
int selection = this.getSelectionStart();
this.setText(String.valueOf(min_value));
if (selection >= this.getText().toString().length()) {
selection = this.getText().toString().length();
}
this.setSelection(selection);
}
} catch (NumberFormatException exception) {
super.onTextChanged(text, start, before, after);
}
}
super.onTextChanged(text, start, before, after);
}
// set the max number of digits the user can enter
public void setMaxLength(int length) {
InputFilter[] FilterArray = new InputFilter[1];
FilterArray[0] = new InputFilter.LengthFilter(length);
this.setFilters(FilterArray);
}
// set the maximum integer value the user can enter.
// if exeeded, input value will become equal to the set limit
public void setMaxValue(int value) {
max_value = value;
}
// set the minimum integer value the user can enter.
// if entered value is inferior, input value will become equal to the set limit
public void setMinValue(int value) {
min_value = value;
}
// returns integer value or 0 if errorous value
public int getValue() {
try {
return Integer.parseInt(this.getText().toString());
} catch (NumberFormatException exception) {
return 0;
}
}
}
示例用法:
final EditTextNumeric input = new EditTextNumeric(this);
input.setMaxLength(5);
input.setMaxValue(total_pages);
input.setMinValue(1);
当然,适用于EditText的所有其他方法和属性也都有效。
这很好。。。
android:maxLength=“10”
这将只接受10个字符。
文档
实例
android:maxLength="10"
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 });
}
}
XML
android:maxLength=“10”
编程方式:
int maxLength = 10;
InputFilter[] filters = new InputFilter[1];
filters[0] = new InputFilter.LengthFilter(maxLength);
yourEditText.setFilters(filters);
注意:在内部,EditText和TextView解析XML中android:maxLength的值,并使用InputFilter.LengthFilter()应用它。
参见:TextView.java#L1564