java - 使用 Mortar + Flow 从对话框中获取用户输入

Question

我正在使用 Mortar 构建我的应用程序+ Flow .我试图找出正确的方法来显示一个弹出窗口，该弹出窗口请求用户提供一些文本。我创建了这个弹出类:

public class SavedPageTitleInputPopup implements Popup<SavedPageTitleInput, Optional<String>> {

private final Context context;

private AlertDialog dialog;

public SavedPageTitleInputPopup(Context context) {
    this.context = context;
}

@Override public Context getContext() {
    return context;
}

@Override
public void show(final SavedPageTitleInput info, boolean withFlourish,
                 final PopupPresenter<SavedPageTitleInput, Optional<String>> presenter) {
    if (dialog != null) throw new IllegalStateException("Already showing, can't show " + info);

    final EditText input = new EditText(context);
    LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT,
                                                                 LinearLayout.LayoutParams.MATCH_PARENT);
    input.setLayoutParams(lp);
    input.setText(info.savedPage.getName());

    dialog = new AlertDialog.Builder(context).setTitle(info.title)
                                             .setView(input)
                                             .setMessage(info.body)
                                             .setPositiveButton(info.confirm, new DialogInterface.OnClickListener() {
                                                 @Override public void onClick(DialogInterface d, int which) {
                                                     dialog = null;
                                                     final String newTitle = Strings.emptyToNull(String.valueOf(input.getText()));
                                                     presenter.onDismissed(Optional.fromNullable(newTitle));
                                                 }
                                             })
                                             .setNegativeButton(info.cancel, new DialogInterface.OnClickListener() {
                                                 @Override public void onClick(DialogInterface d, int which) {
                                                     dialog = null;
                                                     presenter.onDismissed(Optional.<String>absent());
                                                 }
                                             })
                                             .setCancelable(true)
                                             .setOnCancelListener(new DialogInterface.OnCancelListener() {
                                                 @Override public void onCancel(DialogInterface d) {
                                                     dialog = null;
                                                     presenter.onDismissed(Optional.<String>absent());
                                                 }
                                             })
                                             .show();
}

@Override public boolean isShowing() {
    return dialog != null;
}

@Override public void dismiss(boolean withFlourish) {
    dialog.dismiss();
    dialog = null;
}
}

这个类按预期工作。它使用 SavedPage 确定要在对话框中显示的内容，并使用 PopupPresenter#onDismissed 将用户输入返回给 PopupPresenter当按下正确的按钮时。

我的问题是编写用于显示对话框和处理输入的 PopupPresenter 子类。这是我现在拥有的:

new PopupPresenter<SavedPage, Optional<String>>() {
  @Override protected void onPopupResult(Optional<String> result) {
    if (result.isPresent()) {
      // The user entered something, so update the API 
      // Oh wait, I don't have a reference to the SavedPage
      // that was displayed in the dialog!
    }
  }
}

正如评论所说，我没有对对话框中显示的 SavedPage 的引用。它存储在 PopupPresenter 的 whatToShow 字段中，但在调用 onPopupResult 之前该字段被清空。似乎我会不必要地重复自己以保留 SavedPage 的额外副本。

Answer 1

关于 PopupPresenter 的文档还不多和 Popup .我唯一看到的是示例项目中的一个基本示例。他们创建了一个 ConfirmerPopup基于 Confirmation 内的数据目的。 ConfirmerPopup 的目的是根据类声明中提供给 Confirmation 对象的标题/正文来捕获用户的 boolean 决定。

public class ConfirmerPopup implements Popup<Confirmation, Boolean> {

在您的情况下，您希望从用户那里捕获额外的用户输入文本。当调用 PopupPresenter#onPopupResult 时，结果对象应包含 SavedPageTitleInputPopup 所需的所有数据。如下修改您的 SavedPageTitleInputPopup

public class SavedPageTitleInputPopup implements Popup<SavedPage, SavedPageResults> {
  private final Context context;
  private AlertDialog dialog;

  public SavedPageTitleInputPopup(Context context) {
    this.context = context;
  }

  @Override public Context getContext() {
    return context;
  }

  @Override
  public void show(SavedPage info, boolean withFlourish, final PopupPresenter<SavedPage, SavedPageResults> presenter) {
    if (dialog != null) throw new IllegalStateException("Already showing, can't show " + info);
    // Create your Dialog but scrape all user data within OnClickListeners
    final AlertDialog.Builder builder = new AlertDialog.Builder(context);
    //Anything else you need to do... .setView() or .setTitle() for example
    builder.setPositiveButton(info.confirm, new DialogInterface.OnClickListener() {
      @Override
      public void onClick(DialogInterface d, int which) {
        dialog = null;
        //Save data to SavedPageResults
        final SavedPageResults results = new SavedPageResults():
        presenter.onDismissed(results);
      }
    });
    builder.setNegativeButton(info.cancel, new DialogInterface.OnClickListener() {
      @Override
      public void onClick(DialogInterface d, int which) {
        dialog = null;
        final SavedPageResults results = new SavedPageResults();
        presenter.onDismissed(results);
      }
    });
    dialog = builder.show();
  }

  @Override public boolean isShowing() {
    return dialog != null;
  }

  @Override public void dismiss(boolean withFlourish) {
    dialog.dismiss();
    dialog = null;
  }
}  

您的 PopupPresenter 现在不需要了解有关 Dialog 实现的任何信息。

new PopupPresenter<SavedPage, SavedPageResults>() {
  @Override protected void onPopupResult(SavedPageResults result) {
    if (result.isPresent()) {
      updateUi(result.getSavedText());  
    }
  }
}