很遗憾，答案中的代码无法正常工作。
它有两个问题：
- 如果手机语言配置使用“，”作为小数分隔符，则无法正常工作。
- 如果数字在小数部分有尾随零，则无法正常工作。例如1.01。
我疯狂地尝试修复它。
最终，我得到了以下代码，在我的手机上运行良好:
NumberTextWatcher.java
import android.text.Editable;
import android.text.TextWatcher;
import android.text.method.DigitsKeyListener;
import android.util.Log;
import android.widget.EditText;
import java.math.RoundingMode;
import java.text.DecimalFormat;
import java.text.DecimalFormatSymbols;
import java.text.ParseException;
import java.util.Locale;
public class NumberTextWatcher
implements TextWatcher {
private static final String TAG = "NumberTextWatcher";
private final int numDecimals;
private String groupingSep;
private String decimalSep;
private boolean nonUsFormat;
private DecimalFormat df;
private DecimalFormat dfnd;
private boolean hasFractionalPart;
private EditText et;
private String value;
private String replicate(char ch, int n) {
return new String(new char[n]).replace("\0", "" + ch);
}
public NumberTextWatcher(EditText et, Locale locale, int numDecimals) {
et.setKeyListener(DigitsKeyListener.getInstance("0123456789.,"));
this.numDecimals = numDecimals;
DecimalFormatSymbols symbols = new DecimalFormatSymbols(locale);
char gs = symbols.getGroupingSeparator();
char ds = symbols.getDecimalSeparator();
groupingSep = String.valueOf(gs);
decimalSep = String.valueOf(ds);
String patternInt = "#,###";
dfnd = new DecimalFormat(patternInt, symbols);
String patternDec = patternInt + "." + replicate('#', numDecimals);
df = new DecimalFormat(patternDec, symbols);
df.setDecimalSeparatorAlwaysShown(true);
df.setRoundingMode(RoundingMode.DOWN);
this.et = et;
hasFractionalPart = false;
nonUsFormat = !decimalSep.equals(".");
value = null;
}
@Override
public void afterTextChanged(Editable s) {
Log.d(TAG, "afterTextChanged");
et.removeTextChangedListener(this);
try {
int inilen, endlen;
inilen = et.getText().length();
String v = value.replace(groupingSep, "");
Number n = df.parse(v);
int cp = et.getSelectionStart();
if (hasFractionalPart) {
int decPos = v.indexOf(decimalSep) + 1;
int decLen = v.length() - decPos;
if (decLen > numDecimals) {
v = v.substring(0, decPos + numDecimals);
}
int trz = countTrailingZeros(v);
StringBuilder fmt = new StringBuilder(df.format(n));
while (trz-- > 0) {
fmt.append("0");
}
et.setText(fmt.toString());
} else {
et.setText(dfnd.format(n));
}
endlen = et.getText().length();
int sel = (cp + (endlen - inilen));
if (sel > 0 && sel <= et.getText().length()) {
et.setSelection(sel);
} else {
et.setSelection(et.getText().length() - 1);
}
} catch (NumberFormatException | ParseException nfe) {
}
et.addTextChangedListener(this);
}
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
Log.d(TAG, "beforeTextChanged");
value = et.getText().toString();
}
private int countTrailingZeros(String str) {
int count = 0;
for (int i = str.length() - 1; i >= 0; i--) {
char ch = str.charAt(i);
if ('0' == ch) {
count++;
} else {
break;
}
}
return count;
}
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
Log.d(TAG, "onTextChanged");
String newValue = s.toString();
String change = newValue.substring(start, start + count);
String prefix = value.substring(0, start);
String suffix = value.substring(start + before);
if (".".equals(change) && nonUsFormat) {
change = decimalSep;
}
value = prefix + change + suffix;
hasFractionalPart = value.contains(decimalSep);
Log.d(TAG, "VALUE: " + value);
}
}
然后只需简单地使用它执行以下操作：
Locale locale = new Locale("es", "AR"); // For example Argentina
int numDecs = 2; // Let's use 2 decimals
TextWatcher tw = new NumberTextWatcher(myEditText, locale, numDecs);
myEditText.addTextChangedListener(tw);
