我有一个简单的DatePickerFragment，它将今天的日期作为默认日期加载到向用户显示的DatePickerDialog中。然后，用户从DatePicker中选择一个日期，然后代码在EditText行上设置该日期。如果用户稍后再次单击EditText行来编辑他们选择的日期，我希望对话框显示所选日期，而不是今天的日期。
我在EditText行上使用了空白测试。如果为空，请在对话框中设置今天的日期。如果不为空，则从用户先前选择的EditText行设置Dialog中的现有日期。到目前为止，我已经尝试将Bundle中先前选择的日期从onDateSet传递回onCreateDialog。我得到一个致命异常：“片段已经处于活动状态”所以我的逻辑必须设置在与片段不正确的循环中。我在这里缺少什么？
partial Fragment file:
import android.content.DialogInterface;
import android.support.v4.app.DialogFragment;
import android.app.Dialog;
import android.app.DatePickerDialog;
import android.view.inputmethod.InputMethodManager;
import android.os.Bundle;
import android.widget.DatePicker;
import android.widget.EditText;
import java.util.Calendar;
public class DatePickerFragment extends DialogFragment implements DatePickerDialog.OnDateSetListener {
private EditText txtDate;
private int currentyear;
private int currentmonth;
private int currentday;
private int prvselectedyear;
private int prvselectedmonth;
private int prvselectedday;
private String stringDueDateFrag;
public DatePickerFragment() {
}
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
txtDate = (EditText) getActivity().getWindow().getDecorView().getRootView().findViewById(R.id.FEditText);
// If the FEditText line is empty (no "Due Date") entered then add current date to a new DatePickerDialog.
if (txtDate.getText().length() == 0) {
// DatePickerDialog is a simple dialog containing a DatePicker.
// Set up a Calendar object that will capture the current date for the DatePickerDialog to use.
// Use the current date as the default date in the DatePicker.
final Calendar cal = Calendar.getInstance();
currentyear = cal.get(Calendar.YEAR);
currentmonth = cal.get(Calendar.MONTH);
currentday = cal.get(Calendar.DAY_OF_MONTH);
// Create a new instance of DatePickerDialog by passing 5 parameters/arguments to the constructor and return it.
DatePickerDialog dialog = new DatePickerDialog(getActivity(), this, currentyear, currentmonth, currentday);
dialog.getDatePicker().setCalendarViewShown(true);
dialog.getDatePicker().setSpinnersShown(false);
dialog.setTitle("Select a Due Date");
return dialog;
}
// If the FEditText line already has a due date then put the user's previously selected date in
// the DatePickerDialog to edit.
else {
final Calendar prvcalendar = Calendar.getInstance();
prvselectedyear = prvcalendar.get(Calendar.YEAR);
prvselectedmonth = prvcalendar.get(Calendar.MONTH);
prvselectedday = prvcalendar.get(Calendar.DAY_OF_MONTH);
// Create a new instance of DatePickerDialog by passing 5 parameters/arguments to the constructor and return it.
DatePickerDialog dialog = new DatePickerDialog(getActivity(), this, prvselectedyear, prvselectedmonth, prvselectedday);
dialog.getDatePicker().setCalendarViewShown(true);
dialog.getDatePicker().setSpinnersShown(false);
dialog.setTitle("Select a Due Date");
return dialog;
}
}
public void onDateSet (DatePicker view,int year, int month, int day) {
txtDate = (EditText) getActivity().getWindow().getDecorView().getRootView().findViewById(R.id.FEditText);
stringDueDateFrag = (month + 1) + "/" + day + "/" + year + " ";
txtDate.setText(stringDueDateFrag);
txtDate.setSelection(txtDate.getText().length());
// Set up a Calendar object to capture the user selected date in case the user wants
// edit the date later. Put the user selected date in a Bundle for onCreateDialog function to use.
Calendar prvcalendar = Calendar.getInstance();
Bundle argsbundle = new Bundle();
argsbundle.putInt("year", prvcalendar.get(Calendar.YEAR));
argsbundle.putInt("month", prvcalendar.get(Calendar.MONTH));
argsbundle.putInt("day", prvcalendar.get(Calendar.DAY_OF_MONTH));
setArguments(argsbundle);
}
部分活动文件：
public class Activity extends AppCompatActivity {
private ListenerEditText fListenerEditText;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.cardviewinput);
fListenerEditText = (ListenerEditText) findViewById(R.id.FEditText);
fListenerEditText.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
DialogFragment newFragment = new DatePickerFragment();
newFragment.show(getSupportFragmentManager(), "datePicker");
}
});
fListenerEditText.setOnFocusChangeListener(new OnFocusChangeListener() {
@Override
public void onFocusChange(View v, boolean hasFocus) {
if (hasFocus && (fListenerEditText.getText().length() == 0)) {
DialogFragment newFragment = new DatePickerFragment();
newFragment.show(getSupportFragmentManager(), "datePicker");
}
}
});
以下是Android Studio的异常输出：
09-19 03:18:43.052 17379-17379/com.example.jdw.fourthscreen W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0xa6310288)
09-19 03:18:43.052 17379-17379/com.example.jdw.fourthscreen E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.IllegalStateException: Fragment already active
at android.support.v4.app.Fragment.setArguments(Fragment.java:551)
at com.example.jdw.fourthscreen.DatePickerFragment.onDateSet(DatePickerFragment.java:100)
at android.app.DatePickerDialog.tryNotifyDateSet(DatePickerDialog.java:148)
at android.app.DatePickerDialog.onClick(DatePickerDialog.java:116)
at com.android.internal.app.AlertController$ButtonHandler.handleMessage(AlertController.java:166)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4745)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
答案 0 :(得分：0)
当您的EditText为空并点击它时，您会显示两次对话框。
onClick()方法中的第一个和onFocusChange()中的第二个。
我建议你在Dialog类中添加一个boolean变量来指示对话框是否已经显示。
您可以覆盖show()和onDismiss()方法：
private boolean mIsShown = false;
@Override
public void show(FragmentManager manager, String tag) {
super.show(manager, tag);
mIsShown = true;
}
@Override
public void onDismiss(DialogInterface dialog) {
mIsShown = false;
super.onDismiss(dialog);
}
public boolean isDialogShown(){
return mIsShown;
}
然后在调用对话框之前，您需要检查它是否已经显示。
DatePickerFragment mPickerFragment;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.cardviewinput);
fListenerEditText = (ListenerEditText) findViewById(R.id.FEditText);
fListenerEditText.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if(mPickerFragment == null || !mPickerFragment.isDialogShown()){
mPickerFragment = new DatePickerFragment();
mPickerFragment.show(getSupportFragmentManager(), "datePicker");
}
}
});
fListenerEditText.setOnFocusChangeListener(new OnFocusChangeListener() {
@Override
public void onFocusChange(View v, boolean hasFocus) {
if (hasFocus && (fListenerEditText.getText().length() == 0) && ((mPickerFragment == null || !mPickerFragment.isDialogShown()))) {
mPickerFragment = new DatePickerFragment();
mPickerFragment.show(getSupportFragmentManager(), "datePicker");
}
}
});
}