String currentDateandTime = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date());
Toast.makeText(getApplicationContext(), currentDateandTime, Toast.LENGTH_SHORT).show();

我自己的工作解决方案:

Calendar c = Calendar.getInstance();

String sDate = c.get(Calendar.YEAR) + "-" 
+ c.get(Calendar.MONTH)
+ "-" + c.get(Calendar.DAY_OF_MONTH) 
+ " at " + c.get(Calendar.HOUR_OF_DAY) 
+ ":" + c.get(Calendar.MINUTE);

希望这能有所帮助!

简单地复制此代码，并希望这为您工作良好。

Calendar c = Calendar.getInstance();
SimpleDateFormat sdf = new SimpleDateFormat("dd:MMMM:yyyy HH:mm:ss a");
String strDate = sdf.format(c.getTime());

如果您想以特定的模式获取日期和时间，可以使用

Date d = new Date();
CharSequence s = DateFormat.format("yyyy-MM-dd hh:mm:ss", d.getTime());

实际上，最好使用TextClock小部件。它为您处理所有的复杂性，并将尊重用户的12/24小时的偏好。 http://developer.android.com/reference/android/widget/TextClock.html

为显示当前日期和时间的Textview

    /// For Show Date
    String currentDateString = DateFormat.getDateInstance().format(new Date());
    // textView is the TextView view that should display it
    textViewdate.setText(currentDateString);
    /// For Show Time
    String currentTimeString = DateFormat.getTimeInstance().format(new Date());
    // textView is the TextView view that should display it
    textViewtime.setText(currentTimeString);

检查完整的代码Android -显示当前日期和时间在一个Android Studio示例的源代码