android - Activity 被杀死后恢复了多个 DialogFragment

Question

我有 1 个 Activity 显示 1 个 DialogFragment，我使用 setAlwaysFinish 应用强制 Activity 在 onPause 后被杀死。

在暂停和恢复 Activity 后，我有时会显示 2 或 3 相同的 DialogFragment。有人知道如何防止这种情况吗？

注意:我离开了 Activity，但 Dialog 仍然显示。在多次尝试使用 setAlwaysFinish 后，该错误被发现。

代码: Activity

package com.example.testdialog;
import java.util.Calendar;
import android.os.Bundle;
import android.support.v4.app.DialogFragment;
import android.support.v4.app.FragmentActivity;
import android.view.Menu;
import android.view.View;

public class MainActivity extends FragmentActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    public void showDialog(View v) {
        Calendar today = Calendar.getInstance();
        DialogFragment d = DateDialog.newInstance(today.get(Calendar.DAY_OF_MONTH), today.get(Calendar.MONTH), today.get(Calendar.YEAR));
        d.show(getSupportFragmentManager(), "mydialog");
    }
}

代码:DialogFragment

package com.example.testdialog;
import android.app.DatePickerDialog;
import android.app.DatePickerDialog.OnDateSetListener;
import android.app.Dialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.DialogFragment;
import android.widget.DatePicker;

public class DateDialog extends DialogFragment implements OnDateSetListener {
    public static final String TAG = "datepicker";
    public static final int SEARCH_FLIGHT = 0;
    public static final int PASSENGER = 1;

    static DateDialog newInstance(int day, int month, int year) {
        DateDialog d = new DateDialog();
        Bundle bun = new Bundle();
        bun.putInt("day", day);
        bun.putInt("month", month);
        bun.putInt("year", year);
        d.setArguments(bun);
        return d;
    }

    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        Bundle bun = getArguments();
        int year = bun.getInt("year");
        int month = bun.getInt("month");
        int day = bun.getInt("day");

        DatePickerDialog d = new DatePickerDialog(getActivity(), this, year, month, day);
        d.setButton(DialogInterface.BUTTON_POSITIVE, "OK", d);
        d.setTitle("my dialog");
        return d;
    }

    @Override
    public void onDestroyView() {
        Dialog d = getDialog();
        if (d != null && getRetainInstance())
            d.setDismissMessage(null);
        super.onDestroyView();
    }
}

Answer 1

你可以在你的dialogfragment中使用这个来阻止它:

@Override
public void show(FragmentManager manager, String tag) {
    if (tag != null && tag.equals("FRAGMENT_TAG_MAX_ONE_INSTANCE")) {
        // we do not show it twice
        if (manager.findFragmentByTag(tag) == null) {
            super.show(manager, tag);
        }
    } else {
        super.show(manager, tag);
    }
}

和改变:

d.show(getSupportFragmentManager(), "FRAGMENT_TAG_MAX_ONE_INSTANCE");