興味のある方のために、これが私が元の質問をどのように解決したかです。これは、複数のロケールを処理できる通貨編集テキストの完全な実装です。それでも問題が発生する可能性があります（日本の通貨記号が正しく表示されないようで、必要なキーボード（12_KEY）を取得できません）が、そうでない場合は、これが役立つ場合があります。
public class CurrencytestActivity extends Activity
{
private static final Integer MAX_VALUE_DIGITS = 9;
EditText et1;
NumberFormat mCurrencyFormatter;
CurrencyTextWatcher tw;
@Override public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// Get info about local currency
mCurrencyFormatter = NumberFormat.getCurrencyInstance();
int fractionDigits = mCurrencyFormatter.getCurrency().getDefaultFractionDigits();
et1 = (EditText)findViewById(R.id.et1); // Get a handle to the TextEdit control
// Add local currency symbol to digits allowed for EditText display and use
// DigitsKeyListener to tell the control. Unfortunately, this also resets the inputType
// that is specified in the XML layout file. Don't know how to fix that yet.
// Also, this doesn't seem to work for Japanese (probably due to UNICODE or something).
// The symbol gets added to displayCharacters, but the EditText doesn't use it.
String displayCharacters = "0123456789.," + mCurrencyFormatter.getCurrency().getSymbol();
et1.setKeyListener(DigitsKeyListener.getInstance( displayCharacters ));
// Add a text watcher to the EditText to manage currency digit entry. The TextWatcher
// won't allow the symbol or decimal or comma to be entered by the user, but they are
// still displayed when the result is formatted in afterTextChanged().
tw = new CurrencyTextWatcher( MAX_VALUE_DIGITS, fractionDigits );
et1.addTextChangedListener( tw );
et1.setCursorVisible( false );
((Button)findViewById(R.id.button1)).setOnClickListener(onButtonClick);
}
public class CurrencyTextWatcher implements TextWatcher
{
boolean mEditing; // Used to prevent recursion
Double mAmount;
int mDigitCount, mMaxDigits, mFractionDivisor;
public CurrencyTextWatcher( int maxDigits, int fractionDigits )
{
mEditing = false;
mFractionDivisor = (fractionDigits == 0) ? 1 : ((fractionDigits == 1) ? 10 : 100);
mAmount = 0.0;
mDigitCount = 0;
mMaxDigits = maxDigits;
}
public synchronized void afterTextChanged(Editable s)
{
// Don't update EditText display if we are editing
if ( !mEditing )
{
// Under cover of mEditing, update the EditText display with
// the newly formatted value
mEditing = true;
s.replace( 0, s.length(), mCurrencyFormatter.format( mAmount ));
mEditing = false;
}
}
public void beforeTextChanged(CharSequence s, int start, int count, int after) { }
public double GetAmount() { return( mAmount ); }
public void onTextChanged(CharSequence s, int start, int before, int count)
{
if ( !mEditing )
{
// Added a digit to the value
if (( count == 1 ) && ( mDigitCount < mMaxDigits ))
{
// Obtain the added character
CharSequence x = s.subSequence( start, start + count );
// Ignore any characters other than number digits for addition to value
if (( x.charAt( 0 ) >= '0') && ( x.charAt( 0 ) <= '9'))
{
// Multiply by ten to shift existing digits to the left and
// add in the new digit as the decimal place appropriate to this currency
mAmount = (mAmount * 10) + (Double.parseDouble( x.toString() ) / mFractionDivisor);
mDigitCount += 1;
}
}
// Delete last digit from the value
else if (( count == 0 ) && ( mDigitCount > 0))
{
// Subtract the amount of the last digit and divide by ten to
// effectively delete the last character entered
mAmount -= (mAmount % (0.001 * mFractionDivisor) );
mAmount /= 10;
mDigitCount -= 1;
}
}
}
}
private View.OnClickListener onButtonClick = new View.OnClickListener()
{
@Override public void onClick(View v)
{
if (v.getId() == R.id.button1 )
{
// Get the value from the textwatcher and display it.
double mAmountTest = tw.GetAmount();
((TextView)findViewById(R.id.tv1)).setText(mCurrencyFormatter.format( mAmountTest ));
}
}
};
}
そして付随するXMLレイアウト：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="center|top"
android:orientation="vertical" >
<EditText
android:id="@+id/et1"
android:layout_width="210dp"
android:layout_height="wrap_content"
android:imeOptions= "actionNext"
android:inputType="phone" >
<requestFocus />
</EditText>
<TextView
android:id="@+id/tv1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Large Text"
android:textAppearance="?android:attr/textAppearanceLarge" />
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Extract from TextWatcher" />
</LinearLayout>