public void insert(String delta) {
String currentText = getText().toString();
int selectionHandle = getSelectionStart();
String textBeforeInsertionHandle = currentText.substring(0, selectionHandle);
String textAfterInsertionHandle = currentText.substring(selectionHandle, currentText.length());
// Add extra rules for decimal points and operators
if (delta.length() == 1) {
char text = delta.charAt(0);
// don't allow two dots in the same number
if (text == Constants.DECIMAL_POINT) {
int p = selectionHandle - 1;
while (p >= 0 && Solver.isDigit(getText().charAt(p))) {
if (getText().charAt(p) == Constants.DECIMAL_POINT) {
return;
}
--p;
}
p = selectionHandle;
while (p < getText().length() && Solver.isDigit(getText().charAt(p))) {
if (getText().charAt(p) == Constants.DECIMAL_POINT) {
return;
}
++p;
}
}
char prevChar = selectionHandle > 0 ? getText().charAt(selectionHandle - 1) : '\0';
// don't allow 2 successive minuses
if (text == Constants.MINUS && prevChar == Constants.MINUS) {
return;
}
// don't allow multiple successive operators
if (Solver.isOperator(text) && text != Constants.MINUS) {
while (Solver.isOperator(prevChar)) {
if (selectionHandle == 1) {
return;
}
--selectionHandle;
prevChar = selectionHandle > 0 ? getText().charAt(selectionHandle - 1) : '\0';
textBeforeInsertionHandle = textBeforeInsertionHandle.substring(0, selectionHandle);
}
}
}
mIsInserting = true;
setText(
textBeforeInsertionHandle + delta + BaseModule.SELECTION_HANDLE + textAfterInsertionHandle);
mIsInserting = false;
}
