Use:

Calendar c = Calendar.getInstance();

int seconds = c.get(Calendar.SECOND);
int minutes = c.get(Calendar.MINUTE);
int hour = c.get(Calendar.HOUR);
String time = hour + ":" + minutes + ":" + seconds;


int day = c.get(Calendar.DAY_OF_MONTH);
int month = c.get(Calendar.MONTH);
int year = c.get(Calendar.YEAR);
String date = day + "/" + month + "/" + year;

// Assuming that you need date and time in a separate
// textview named txt_date and txt_time.

txt_date.setText(date);
txt_time.setText(time);

public class XYZ extends Activity {

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //setContentView(R.layout.main);

        Calendar c = Calendar.getInstance();
        System.out.println("Current time => "+c.getTime());

        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        String formattedDate = df.format(c.getTime());
        // formattedDate have current date/time
        Toast.makeText(this, formattedDate, Toast.LENGTH_SHORT).show();


      // Now we display formattedDate value in TextView
        TextView txtView = new TextView(this);
        txtView.setText("Current Date and Time : "+formattedDate);
        txtView.setGravity(Gravity.CENTER);
        txtView.setTextSize(20);
        setContentView(txtView);
    }

}

如果你想要一行代码:

String date = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(Calendar.getInstance().getTime());

结果是“2016-09-25 16:50:34”

这并不难，因为有几种方法可以做到这一点。我假设你想把当前的日期和时间放入TextView。

String currentDateTimeString = java.text.DateFormat.getDateTimeInstance().format(new Date());

// textView is the TextView view that should display it
textView.setText(currentDateTimeString);

文档中有更多内容，可以在这里轻松找到 ． 在那里，您将找到关于如何更改用于转换的格式的更多信息。

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

Use:

Calendar c = Calendar.getInstance();

int seconds = c.get(Calendar.SECOND);
int minutes = c.get(Calendar.MINUTE);
int hour = c.get(Calendar.HOUR);
String time = hour + ":" + minutes + ":" + seconds;


int day = c.get(Calendar.DAY_OF_MONTH);
int month = c.get(Calendar.MONTH);
int year = c.get(Calendar.YEAR);
String date = day + "/" + month + "/" + year;

// Assuming that you need date and time in a separate
// textview named txt_date and txt_time.

txt_date.setText(date);
txt_time.setText(time);