我试图创建一个EditText，当我单击它时，会显示一个DatePickerDialog/code>，这样我就可以选择我的生日，然后我选择的日期会写在EditText中。 我在网上找到了这段代码，但我有问题，因为它的行是这样说的:
new DatePickerDialog(TheClassName.this, datePickerListener, myCalendar..
DatePickerListener是红色的，我不明白为什么？ 如果有人能帮助我，我将非常感激。
//some of the needed imports
import android.widget.DatePicker;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Locale;
//private field variables in the Activity class
private Calendar myCalendar = Calendar.getInstance();
private EditText etDate;
//onCreate method of the Activity class
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
etDate = (EditText) findViewById(R.id.et_date);
etDate.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
new DatePickerDialog(TheClassName.this, datePickerListener, myCalendar
.get(Calendar.YEAR), myCalendar.get(Calendar.MONTH),
myCalendar.get(Calendar.DAY_OF_MONTH)).show();
}
});
DatePickerDialog.OnDateSetListener datePickerListener = new DatePickerDialog.OnDateSetListener() {
@Override
public void onDateSet(DatePicker view, int year, int monthOfYear,
int dayOfMonth) {
myCalendar.set(Calendar.YEAR, year);
myCalendar.set(Calendar.MONTH, monthOfYear);
myCalendar.set(Calendar.DAY_OF_MONTH, dayOfMonth);
String myFormat = "MM/dd/yy";
SimpleDateFormat sdf = new SimpleDateFormat(myFormat, Locale.US);
etDate.setText(sdf.format(myCalendar.getTime()));
}
};
}
您需要做一些更改，如下所示
>
初始化MyCalendal以避免NullPointerException
MyCalendar=新GregorianCalendar（）；
在使用DatePickerListener之前声明它以避免未解析的变量
将TheClassName.this更改为您的activity类名以获取上下文； 我在下面假设为mainactivity.this
使edittext& DatePickerDialog.OnDateSetListener作为Final，以便从EditTextOnClickListener回调访问它们
因此，在完成这些更改后，您可以使用以下代码替换代码:
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final EditText etDate = (EditText) findViewById(R.id.et_date);
myCalendar = new GregorianCalendar();
final DatePickerDialog.OnDateSetListener datePickerListener = new DatePickerDialog.OnDateSetListener() {
@Override
public void onDateSet(DatePicker view, int year, int monthOfYear,
int dayOfMonth) {
myCalendar.set(Calendar.YEAR, year);
myCalendar.set(Calendar.MONTH, monthOfYear);
myCalendar.set(Calendar.DAY_OF_MONTH, dayOfMonth);
String myFormat = "MM/dd/yy";
SimpleDateFormat sdf = new SimpleDateFormat(myFormat, Locale.US);
etDate.setText(sdf.format(myCalendar.getTime()));
}
};
etDate.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
new DatePickerDialog(MainActivity.this, datePickerListener, myCalendar
.get(Calendar.YEAR), myCalendar.get(Calendar.MONTH),
myCalendar.get(Calendar.DAY_OF_MONTH)).show();
}
});
}
