Question

您好我是Java新手并学习如何构建Android应用程序。我有这个计算器，我一直在努力，我需要帮助找出如何设置EditText的值。当用户在EditText中键入CA，OR或FL时，如何为其分配值？ CA = 7％，OR = 8％，FL = 10％，谢谢

public void calculate(View view) {

    EditText billET = findViewById(R.id.edit_bill_amount);
    EditText tipPercentET = findViewById(R.id.edit_tip_percent);
    EditText taxPercentET = findViewById(R.id.edit_tax_percent);


    String billString = billET.getText().toString();
    String tipPercentString = tipPercentET.getText().toString();
    String taxPercentString = taxPercentET.getText().toString();



    float bill = Float.parseFloat(billString);
    int tipPercent = Integer.parseInt(tipPercentString);
    int taxPercent = Integer.parseInt(taxPercentString);

    TipCalculator tc = new TipCalculator(tipPercent / 100.0F, bill, taxPercent / 100.0F);
    float taxAmount = tc.taxAmount();
    float tipAmount = tc.tipAmount();
    float total = tc.totalAmount();

    TextView taxAmountTV = findViewById(R.id.label_tax_amount_value);

    TextView tipAmountTV = findViewById(R.id.label_tip_amount_value);
    TextView totalAmountTV = findViewById(R.id.label_total_amount_value);

    taxAmountTV.setText(taxAmount + "");
    tipAmountTV.setText(tipAmount + "");
    totalAmountTV.setText(total + "");

}

Answer 1

您可以使用 TextWatcher 。

TextWatcher watcher;
watcher=new TextWatcher() {
    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) { }

    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {}

    @Override
    public void afterTextChanged(Editable s) {
         edittext.removeTextChangedListener(watcher); 
         switch(s.toString){

            case "CA" : 
               edittext.setText("7%");
            case "OR" :
               edittext.setText("8%");
            case "FL" :
               edittext.setText("10%");
        }
        edittext.addTextChangedListener(watcher);
    }
};
edittext.addTextChangedListener(watcher);

Answer 2

实施将是这样的

EditText editText = findViewById(R.id.editText);

if (editText.getText().toString().equals("CA")) {
    textView.setText("CA=7%");
}

Answer 3

您可以将这些百分比存储到静态变量中，然后分配它们。如果我正确地解决了您的问题，可能的解决方案如下：

//outside of the calculate method

protected static String CA_PERCENTAGE = "CA = 7%";
protected static String OR_PERCENTAGE = "OR = 8%";
protected static String FL_PERCENTAGE = "FL = 10%";

//inside your calculate method
switch(area){

    case "CA" : 
        tipAmountTV.setText(CA_PERCENTAGE);
    case "OR" :
        tipAmountTV.setText(OR_PERCENTAGE);
    case "FL" :
        tipAmountTV.setText(FL_PERCENTAGE);
}

当然这不是“最漂亮”的事情，但是因为你是Java的新手，你可以玩switch statement。

Android提示，税，总计算器

3 个答案: