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using System.Collections.Generic;
using Android.Text;
using Android.Text.Method;
using Java.Lang;
using Java.Text;
namespace Xamarin.Forms.Platform.Android
{
internal class LocalizedDigitsKeyListener : NumberKeyListener
{
readonly char _decimalSeparator;
// I'm not aware of a situation/locale where this would need to be something different,
// but we'll make it easy to localize the sign in the future just in case
const char SignCharacter = '-';
static Dictionary<char, LocalizedDigitsKeyListener> s_unsignedCache;
static Dictionary<char, LocalizedDigitsKeyListener> s_signedCache;
static char GetDecimalSeparator()
{
var format = NumberFormat.Instance as DecimalFormat;
if (format == null)
{
return '.';
}
DecimalFormatSymbols sym = format.DecimalFormatSymbols;
return sym.DecimalSeparator;
}
public static NumberKeyListener Create(InputTypes inputTypes)
{
if ((inputTypes & InputTypes.NumberFlagDecimal) == 0)
{
// If decimal isn't allowed, we can just use the Android version
#pragma warning disable 0618
return DigitsKeyListener.GetInstance(inputTypes.HasFlag(InputTypes.NumberFlagSigned), false);
#pragma warning restore 0618
}
// Figure out what the decimal separator is for the current locale
char decimalSeparator = GetDecimalSeparator();
if (decimalSeparator == '.')
{
// If it's '.', then we can just use the default Android version
#pragma warning disable 0618
return DigitsKeyListener.GetInstance(inputTypes.HasFlag(InputTypes.NumberFlagSigned), true);
#pragma warning restore 0618
}
// If decimals are enabled and the locale's decimal separator is not '.'
// (which is hard-coded in the Android DigitKeyListener), then use
// our custom one with a configurable decimal separator
return GetInstance(inputTypes, decimalSeparator);
}
public static LocalizedDigitsKeyListener GetInstance(InputTypes inputTypes, char decimalSeparator)
{
if ((inputTypes & InputTypes.NumberFlagSigned) != 0)
{
return GetInstance(inputTypes, decimalSeparator, ref s_signedCache);
}
return GetInstance(inputTypes, decimalSeparator, ref s_unsignedCache);
}
static LocalizedDigitsKeyListener GetInstance(InputTypes inputTypes, char decimalSeparator, ref Dictionary<char, LocalizedDigitsKeyListener> cache)
{
if (cache == null)
{
cache = new Dictionary<char, LocalizedDigitsKeyListener>(1);
}
if (!cache.ContainsKey(decimalSeparator))
{
cache.Add(decimalSeparator, new LocalizedDigitsKeyListener(inputTypes, decimalSeparator));
}
return cache[decimalSeparator];
}
protected LocalizedDigitsKeyListener(InputTypes inputTypes, char decimalSeparator)
{
_decimalSeparator = decimalSeparator;
InputType = inputTypes;
}
public override InputTypes InputType { get; }
char[] _acceptedChars;
protected override char[] GetAcceptedChars()
{
if ((InputType & InputTypes.NumberFlagSigned) == 0)
{
return _acceptedChars ??
(_acceptedChars = new[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', _decimalSeparator });
}
return _acceptedChars ??
(_acceptedChars = new[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', SignCharacter, _decimalSeparator });
}
static bool IsSignChar(char c)
{
return c == SignCharacter;
}
bool IsDecimalPointChar(char c)
{
return c == _decimalSeparator;
}
public override ICharSequence FilterFormatted(ICharSequence source, int start, int end, ISpanned dest, int dstart,
int dend)
{
// Borrowed heavily from the Android source
ICharSequence filterFormatted = base.FilterFormatted(source, start, end, dest, dstart, dend);
if (filterFormatted != null)
{
source = filterFormatted;
start = 0;
end = filterFormatted.Length();
}
int sign = -1;
int dec = -1;
int dlen = dest.Length();
// Find out if the existing text has a sign or decimal point characters.
for (var i = 0; i < dstart; i++)
{
char c = dest.CharAt(i);
if (IsSignChar(c))
{
sign = i;
}
else if (IsDecimalPointChar(c))
{
dec = i;
}
}
for (int i = dend; i < dlen; i++)
{
char c = dest.CharAt(i);
if (IsSignChar(c))
{
return new String(""); // Nothing can be inserted in front of a sign character.
}
if (IsDecimalPointChar(c))
{
dec = i;
}
}
// If it does, we must strip them out from the source.
// In addition, a sign character must be the very first character,
// and nothing can be inserted before an existing sign character.
// 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);
var strip = false;
if (IsSignChar(c))
{
if (i != start || dstart != 0)
{
strip = true;
}
else if (sign >= 0)
{
strip = true;
}
else
{
sign = i;
}
}
else if (IsDecimalPointChar(c))
{
if (dec >= 0)
{
strip = true;
}
else
{
dec = i;
}
}
if (strip)
{
if (end == start + 1)
{
return new String(""); // Only one character, and it was stripped.
}
if (stripped == null)
{
stripped = new SpannableStringBuilder(source, start, end);
}
stripped.Delete(i - start, i + 1 - start);
}
}
return stripped ?? filterFormatted;
}
}
}
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