protected void setState(CalculatorState state) {
if (mCurrentState != state) {
mCurrentState = state;
invalidateEqualsButton();
if (state == CalculatorState.RESULT || state == CalculatorState.ERROR) {
mDeleteButton.setVisibility(View.GONE);
mClearButton.setVisibility(View.VISIBLE);
} else {
mDeleteButton.setVisibility(View.VISIBLE);
mClearButton.setVisibility(View.GONE);
}
if (state == CalculatorState.ERROR) {
final int errorColor = getResources().getColor(R.color.calculator_error_color);
mFormulaEditText.setTextColor(errorColor);
mResultEditText.setTextColor(errorColor);
if (android.os.Build.VERSION.SDK_INT >= 21) {
getWindow().setStatusBarColor(errorColor);
}
} else {
mFormulaEditText.setTextColor(getResources().getColor(R.color.display_formula_text_color));
mResultEditText.setTextColor(getResources().getColor(R.color.display_result_text_color));
if (android.os.Build.VERSION.SDK_INT >= 21) {
getWindow().setStatusBarColor(getResources().getColor(R.color.calculator_accent_color));
}
}
}
}
@Override
public void onEvaluate(String expr, String result, int errorResourceId) {
if (mCurrentState == CalculatorState.INPUT || mCurrentState == CalculatorState.GRAPHING) {
if (result == null || Solver.equal(result, expr)) {
mResultEditText.setText(null);
} else {
mResultEditText.setText(result);
}
} else if (errorResourceId != INVALID_RES_ID) {
onError(errorResourceId);
} else if (saveHistory(expr, result, true)) {
mDisplayView.scrollToMostRecent();
onResult(result);
} else if (mCurrentState == CalculatorState.EVALUATE) {
// The current expression cannot be evaluated -> return to the input state.
setState(CalculatorState.INPUT);
}
invalidateEqualsButton();
}