我做对了吗？

Question

我正在学习和记住 Android，我想了解我的错误。 这是我的确认/取消 AlertDialog 类。在单独的类中创建它以拆分代码，而不是将所有内容放在一个 Activity 中：

public class ConversationAlertDialog extends DialogFragment {

    public static Dialog createDialog(Context context) {
        // Use the Builder class for convenient dialog construction
        AlertDialog.Builder builder = new AlertDialog.Builder(context);

        builder.setMessage("Continue?")
               .setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int id) {
                        // User confirms

                    }
                })
                .setNegativeButton("No", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int id) {
                        // User cancelled
                    }
                });
        // Create the AlertDialog object and return it
        return builder.create();
    }
}

这是我显示 AlertDialog 的 Activity：

    buttonConvert.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            ConversationAlertDialog.createDialog(ConversionActivity.this).show();
        }
    });

接下来我想创建回调，这样我就可以在 Activity 中编写对话框取消/确认行为。这样，使用 Activity 中已经编写的代码也会更容易。我还在学习回调所以不确定，但我认为我应该实现接口。

各种提示都会对我有所帮助。

Answer 1

他是我使用的代码。我发现它非常灵活，因为您可以为稍微不同的任务创建几个类似的对话框。您将需要创建一个布局文件 - 这为您在功能和样式方面提供了极大的灵活性。

我的布局文件是fragment_ok_cancel_dialog。

在调用对话框的 Activity 中，您需要实现 Listener。

implements OkCancelDialogFragment.OkCancelDialogListener

另一个优点是使用我的代码，您可以更改标题和消息以适应任何活动的需要。

private void callMyDialog(){ 
    //Customize the title and message as needed
    String title = "This is my dialog title";
    String mess = "This is my dialog message";
    OkCancelDialogFragment dialog = OkCancelDialogFragment.newInstance(title, mess);
    dialog.show(getFragmentManager(), "OkCancelDialogFragment2");
}

现在需要在调用DialogFragment的Activity中实现对话框回调。

@Override
public void onFinishOkCancelDialog(boolean submit) {
    if(submit){
        // Do something positive
    }
    else{
        // Do something negative
    }
}

现在是DialogFragment的代码：

public class OkCancelDialogFragment extends DialogFragment {

    private static final String ARG_TITLE = "title";
    private static final String ARG_MESSAGE = "message";

    Context context = null;

    private String title;
    private String message;
    private boolean submitData = false;

    private OkCancelDialogListener mListener;

    public OkCancelDialogFragment() {
    }

    public static OkCancelDialogFragment newInstance(String title, String message) {
        OkCancelDialogFragment fragment = new OkCancelDialogFragment();
        Bundle args = new Bundle();
        args.putString(ARG_TITLE, title);
        args.putString(ARG_MESSAGE, message);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (getArguments() != null) {
            title = getArguments().getString(ARG_TITLE);
            message = getArguments().getString(ARG_MESSAGE);
        }
    }

    @Override
    public Dialog onCreateDialog(Bundle saveIntsanceState){

        context = getActivity();

        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());

        LayoutInflater inflater = getActivity().getLayoutInflater();

        View rootView = inflater.inflate(R.layout.fragment_ok_cancel_dialog, null, false);
        final TextView titleView = (TextView)rootView.findViewById(R.id.tvTitle);
        final TextView messView = (TextView)rootView.findViewById(R.id.tvMessage);

        titleView.setText(title);
        messView.setText(message);

        builder.setView(rootView)
//                .setTitle(title)
                .setPositiveButton(R.string.ok_button_dialog_title, new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {

                        submitData = true;
                        if(mListener == null) mListener = (OkCancelDialogListener) context;
                        mListener.onFinishOkCancelDialog(submitData);
                    }
                })
                .setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        submitData = false;
                        if(mListener == null) mListener = (OkCancelDialogListener) context;
                        mListener.onFinishOkCancelDialog(submitData);
                    }
                });
        return builder.create();
    }


    @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        try {
            if(mListener == null) mListener = (OkCancelDialogListener) context;
        }
        catch (Exception ex){
            throw new RuntimeException(context.toString()
                    + " must implement OnFragmentInteractionListener");
        }
    }

    @Override
    public void onDetach() {
        super.onDetach();
        mListener = null;
    }


    public interface OkCancelDialogListener {
        void onFinishOkCancelDialog(boolean submit);
    }

}

请注意.setTitle(title) 适用于 API 23 或更高版本（或者 API 21 或更高版本？）。

Answer 2

在ConversationAlertDialog 类中创建一个接口。

public interface onActionSelect{
void onOkSelect();
void onCancelSelect();
}

在 Activity 上实现它并将它的引用传递给 ConversationAlertDialog 类。然后像这样从对话框中调用。

  // For Positive Button Click
  public void onClick(DialogInterface dialog, int id) {
    // User confirms
    if(mCallBack != null) mCallBack.onOkSelect()
 }

  // For Negative  Button Click
  public void onClick(DialogInterface dialog, int id) {
    // User confirms
    if(mCallBack != null) mCallBack.onCancelSelect()
 }

当点击正面或负面按钮时，您将在 MainActivity 中收到通知。

Answer 3

public class ConversationAlertDialog extends DialogFragment {
    private onMyEvent event;
    public void setMyEvent(onMyEvent e)
    {
        this.event=e;
    }
    public static Dialog createDialog(Context context) {
        // Use the Builder class for convenient dialog construction
        AlertDialog.Builder builder = new AlertDialog.Builder(context);

        builder.setMessage("Continue?")
               .setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int id) {
                        // User confirms
                        if(null!=event)
                        {
                            event.ok();
                        }
                    }
                })
                .setNegativeButton("No", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int id) {
                        if(null!=event)
                        {
                            event.cancel();
                        }
                        // User cancelled
                    }
                });
        // Create the AlertDialog object and return it
        return builder.create();
    }
    public interface onMyEvent{
        void ok();
        void cancel();
    }
}

buttonConvert.setOnClickListener(new View.OnClickListener() {
    public void onClick(View v) {
        Dialog  dialog=ConversationAlertDialog.createDialog(ConversionActivity.this);
        dialog.setMyEvent(new onMyEvent{....})
        dialog.show();
    }
});