DatePicker - EditText 只返回当前日期 - 怎么了？答案

【问题标题】：DatePicker - EditText only returning current date - what's wrong?DatePicker - EditText 只返回当前日期 - 怎么了？
【发布时间】：2020-11-18 09:15:36
【问题描述】：

主要活动

 {
        date = findViewById(R.id.add_date);
        dueDate = findViewById(R.id.add_dueDate);
        final Calendar calendar = Calendar.getInstance();
        date.setOnClickListener(v -> {
            year = calendar.get(Calendar.YEAR);
            month = calendar.get(Calendar.MONTH);
            day = calendar.get(Calendar.DAY_OF_MONTH);
            DatePickerDialog datePickerDialog = new DatePickerDialog(addScreen.this, (view, year, month, dayOfMonth) -> date.setText(SimpleDateFormat.getDateInstance().format(calendar.getTime())), year, month, day);
            datePickerDialog.show();
        });
        dueDate.setOnClickListener(v -> {
            year = calendar.get(Calendar.YEAR);
            month = calendar.get(Calendar.MONTH);
            day = calendar.get(Calendar.DAY_OF_MONTH);
            DatePickerDialog datePickerDialog = new DatePickerDialog(addScreen.this, (view, year, month, dayOfMonth) -> dueDate.setText(SimpleDateFormat.getDateInstance().format(calendar.getTime())), year, month, day);
            datePickerDialog.show();
        });
    }

此代码有问题，我无法选择。我让日历（onClick 提示）选择日期，但即使我选择过去、现在或未来的日期，它总是在编辑文本中返回当前（今天的）日期。

【问题讨论】：

标签： java android android-studio date kotlin

【解决方案1】：

您在使用日历实例时未使用所选日期对其进行更新，因此它包含当前日期。您需要在使用之前将所选日期设置为日历实例。

date.setOnClickListener(v -> {
            year = calendar.get(Calendar.YEAR);
            month = calendar.get(Calendar.MONTH);
            day = calendar.get(Calendar.DAY_OF_MONTH);
            DatePickerDialog datePickerDialog = new DatePickerDialog(addScreen.this, { view, year, monthOfYear, dayOfMonth -> 
                calendar.set(Calendar.YEAR, year)
                calendar.set(Calendar.MONTH, monthOfYear)
                calendar.set(Calendar.DAY_OF_MONTH, dayOfMonth)

                date.setText(SimpleDateFormat.getDateInstance().format(calendar.getTime()))

                }, year, month, day);
            datePickerDialog.show();
        });