我有一个Fragment带有多个参数的构造函数.我的应用程序在开发期间工作正常,但在生产中我的用户有时会看到此崩溃:
android.support.v4.app.Fragment$InstantiationException: Unable to instantiate fragment
make sure class name exists, is public, and has an empty constructor that is public
我可以创建一个空的构造函数,因为这个错误消息建议,但这对我没有意义,因为那时我将不得不调用一个单独的方法来完成设置Fragment.
我很好奇为什么这种崩溃偶尔会发生.也许我使用ViewPager不正确？我Fragment自己实例化所有s并将它们保存在一个列表中Activity.我不使用FragmentManager事务,因为ViewPager我看到的例子并不需要它,并且一切似乎都在开发期间工作.
我在尝试生成已签名的APK时遇到此错误.问题是,我的应用程序能够在我的设备上正常运行和调试.我不知道为什么当我尝试生成APK时,出现了这个错误.如何忽略此错误并生成签名的APK？我正在使用Android Studio 1.2.1.1 for Mac.
我的课程扩展DialogFragment如下:
public class DatePickerFragment extends DialogFragment implements DatePickerDialog.OnDateSetListener {
EditText editDate;
private Calendar dateTime = Calendar.getInstance();
private SimpleDateFormat dateFormatter = new SimpleDateFormat("dd MMMM yyyy");
public DatePickerFragment(EditText editText) {
editDate = editText;
}
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
// Use the current date as the default date in the picker
final Calendar c = Calendar.getInstance();
int year = c.get(Calendar.YEAR);
int month = c.get(Calendar.MONTH);
int day = c.get(Calendar.DAY_OF_MONTH);
// Create a new instance of DatePickerDialog and return it
return …我继承了这个Android应用程序.当我尝试构建已签名的APK时,我收到一条错误消息Error:(31) Error: Avoid non-default constructors in fragments: use a default constructor plus Fragment#setArguments(Bundle) instead [ValidFragment]
它指向这段代码:
public class BasicInfoFragment extends BasePassportFragment implements LocationEditText.LocationEditTextListener {
private User user;
private Templates templates;
public BasicInfoFragment() {
super(false);
}
public BasicInfoFragment(User user) {
super(false);
this.user = user;
}
public BasicInfoFragment(User user, Templates templates) {
super(false);
this.user = user;
this.templates = templates;
}
...
}
错误指向第二和第三的方法,public BasicInfoFragment(User user)并public BasicInfoFragment(User user, Templates templates)让我困惑,为什么public BasicInfoFragment()是好的,但其他两个都没有？