EditTextをプログラムでインスタンス化している場合、Martinsの回答は機能しません。私は先に進みDigitsKeyListener、カンマとピリオドの両方を小数点区切り文字として使用できるように、API 14のインクルードクラスを変更しました。
これを使用するには、呼び出しsetKeyListener()にEditText、例えば
// Don't allow for signed input (minus), but allow for decimal points
editText.setKeyListener( new MyDigitsKeyListener( false, true ) );
ただし、TextChangedListenerコンマをピリオドに置き換える場合は、マーティンのトリックを使用する必要があります。
import android.text.InputType;
import android.text.SpannableStringBuilder;
import android.text.Spanned;
import android.text.method.NumberKeyListener;
import android.view.KeyEvent;
class MyDigitsKeyListener extends NumberKeyListener {
/**
* The characters that are used.
*
* @see KeyEvent#getMatch
* @see #getAcceptedChars
*/
private static final char[][] CHARACTERS = new char[][] {
new char[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' },
new char[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '-' },
new char[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '.', ',' },
new char[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '-', '.', ',' },
};
private char[] mAccepted;
private boolean mSign;
private boolean mDecimal;
private static final int SIGN = 1;
private static final int DECIMAL = 2;
private static MyDigitsKeyListener[] sInstance = new MyDigitsKeyListener[4];
@Override
protected char[] getAcceptedChars() {
return mAccepted;
}
/**
* Allocates a DigitsKeyListener that accepts the digits 0 through 9.
*/
public MyDigitsKeyListener() {
this(false, false);
}
/**
* Allocates a DigitsKeyListener that accepts the digits 0 through 9,
* plus the minus sign (only at the beginning) and/or decimal point
* (only one per field) if specified.
*/
public MyDigitsKeyListener(boolean sign, boolean decimal) {
mSign = sign;
mDecimal = decimal;
int kind = (sign ? SIGN : 0) | (decimal ? DECIMAL : 0);
mAccepted = CHARACTERS[kind];
}
/**
* Returns a DigitsKeyListener that accepts the digits 0 through 9.
*/
public static MyDigitsKeyListener getInstance() {
return getInstance(false, false);
}
/**
* Returns a DigitsKeyListener that accepts the digits 0 through 9,
* plus the minus sign (only at the beginning) and/or decimal point
* (only one per field) if specified.
*/
public static MyDigitsKeyListener getInstance(boolean sign, boolean decimal) {
int kind = (sign ? SIGN : 0) | (decimal ? DECIMAL : 0);
if (sInstance[kind] != null)
return sInstance[kind];
sInstance[kind] = new MyDigitsKeyListener(sign, decimal);
return sInstance[kind];
}
/**
* Returns a DigitsKeyListener that accepts only the characters
* that appear in the specified String. Note that not all characters
* may be available on every keyboard.
*/
public static MyDigitsKeyListener getInstance(String accepted) {
// TODO: do we need a cache of these to avoid allocating?
MyDigitsKeyListener dim = new MyDigitsKeyListener();
dim.mAccepted = new char[accepted.length()];
accepted.getChars(0, accepted.length(), dim.mAccepted, 0);
return dim;
}
public int getInputType() {
int contentType = InputType.TYPE_CLASS_NUMBER;
if (mSign) {
contentType |= InputType.TYPE_NUMBER_FLAG_SIGNED;
}
if (mDecimal) {
contentType |= InputType.TYPE_NUMBER_FLAG_DECIMAL;
}
return contentType;
}
@Override
public CharSequence filter(CharSequence source, int start, int end,
Spanned dest, int dstart, int dend) {
CharSequence out = super.filter(source, start, end, dest, dstart, dend);
if (mSign == false && mDecimal == false) {
return out;
}
if (out != null) {
source = out;
start = 0;
end = out.length();
}
int sign = -1;
int decimal = -1;
int dlen = dest.length();
/*
* Find out if the existing text has '-' or '.' characters.
*/
for (int i = 0; i < dstart; i++) {
char c = dest.charAt(i);
if (c == '-') {
sign = i;
} else if (c == '.' || c == ',') {
decimal = i;
}
}
for (int i = dend; i < dlen; i++) {
char c = dest.charAt(i);
if (c == '-') {
return ""; // Nothing can be inserted in front of a '-'.
} else if (c == '.' || c == ',') {
decimal = i;
}
}
/*
* If it does, we must strip them out from the source.
* In addition, '-' must be the very first character,
* and nothing can be inserted before an existing '-'.
* Go in reverse order so the offsets are stable.
*/
SpannableStringBuilder stripped = null;
for (int i = end - 1; i >= start; i--) {
char c = source.charAt(i);
boolean strip = false;
if (c == '-') {
if (i != start || dstart != 0) {
strip = true;
} else if (sign >= 0) {
strip = true;
} else {
sign = i;
}
} else if (c == '.' || c == ',') {
if (decimal >= 0) {
strip = true;
} else {
decimal = i;
}
}
if (strip) {
if (end == start + 1) {
return ""; // Only one character, and it was stripped.
}
if (stripped == null) {
stripped = new SpannableStringBuilder(source, start, end);
}
stripped.delete(i - start, i + 1 - start);
}
}
if (stripped != null) {
return stripped;
} else if (out != null) {
return out;
} else {
return null;
}
}
}
