android - 将字符串从对话框 fragment 返回到 Activity

Question

这个问题在这里已经有了答案:

Receive result from DialogFragment (15 个回答)

关闭 9年前。

我已经阅读了很多关于此的帖子，但我找不到任何适用于此案例的帖子。

我有一个时间选择器对话框，我已将整数值放在一个字符串中，我需要将此字符串返回到主要 Activity 。

这个字符串值将用于设置按钮的文本。

如果有人可以帮助我，将不胜感激。

谢谢

对话框 fragment

public class TimePickerFragment extends DialogFragment implements TimePickerDialog.OnTimeSetListener {
    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        // Use the current time as the default values for the picker
        final Calendar c = Calendar.getInstance();
        int hour = c.get(Calendar.HOUR_OF_DAY);
        int minute = c.get(Calendar.MINUTE);

        // Create a new instance of TimePickerDialog and return it
        return new TimePickerDialog(getActivity(), this, hour, minute, DateFormat.is24HourFormat(getActivity()));
    }

    public void onTimeSet(TimePicker view, int hourOfDay, int minute) {
        // Do something with the time chosen by the user
        String Time =Integer.toString(hourOfDay) + " : " + Integer.toString(minute);
    }
}

代码

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


        Button btn = (Button) findViewById(R.id.start_time_button);
        Button.setText(Time);


    }

Answer 1

首选方法是使用回调从 Fragment 获取信号。此外，这是 Android 在 Communicating with the Activity 提出的推荐方法

对于您的示例，在您的 DialogFragment 中，添加一个接口(interface)并注册它。

public static interface OnCompleteListener {
    public abstract void onComplete(String time);
}

private OnCompleteListener mListener;

// make sure the Activity implemented it
@Override
public void onAttach(Activity activity) {
    super.onAttach(activity); 
    try {
        this.mListener = (OnCompleteListener)activity;
    }
    catch (final ClassCastException e) {
        throw new ClassCastException(activity.toString() + " must implement OnCompleteListener");
    }
}

现在在你的Activity

中实现这个 接口(interface)

public class MyActivity extends Activity implements MyDialogFragment.OnCompleteListener {
    //...

    public void onComplete(String time) {
        // After the dialog fragment completes, it calls this callback.
        // use the string here
    }
}

现在在您的 DialogFragment 中，当用户单击 OK 按钮时，通过您的回调将该值发送回 Activity。

public void onTimeSet(TimePicker view, int hourOfDay, int minute) {
    String time = Integer.toString(hourOfDay) + " : " + Integer.toString(minute);
    this.mListener.onComplete(time);
}