java如何将方法名设置为新类中的参数？

Question

我创建了一个AlertDialog类，该类有一个名为OnYesClicked()的方法，当单击肯定按钮时将调用该方法。但是，我需要在同一个活动中多次使用此AlertDialog类，因此我想将名称OnYesClicked()设置为参数，以便为不同的对话框调用正确的方法，否则可能会调用错误的方法或两个方法。在搜索了包括一个here在内的其他类似问题后，我不太确定如何解决这个问题 完整代码如下：

import 安卓.app.AlertDialog;
import 安卓.app.Dialog;
import 安卓.content.Context;
import 安卓.content.DialogInterface;
import 安卓.os.Bundle;
import 安卓.widget.Toast;
import 安卓x.annotation.NonNull;
import 安卓x.annotation.Nullable;
import 安卓x.appcompat.app.AppCompatDialogFragment;

public class ExampleDialog extends AppCompatDialogFragment {

    private static final String ARGUMENT_TITLE = "title";
    private static final String ARGUMENT_POSITIVE = "positive";
    private static final String ARGUMENT_MESSAGE = "message";
    private static final String ARGUMENT_POSITIVE_TEXT = "positive_text";
    private static final String ARGUMENT_NEGATIVE = "negative";
    private static final String ARGUMENT_NEGATIVE_TEXT = "negative_text";

    private ExampleDialogListener listener;

    private String title;
    private String message;
    private String positive;
    private String positivetext;
    private String negative;
    private  String negativetext;

    public static ExampleDialog newInstance(String title, String message, String positive,//request input from user when call, save as string
                                            String positivetext, String negative, String negativetext) {
        Bundle args = new Bundle();
        // Store all arguments into bundle.
        args.putString(ARGUMENT_TITLE, title); //save as name ARGUMENT_TITLE, value is the user input title, shove inside a bundle called args
        args.putString(ARGUMENT_POSITIVE, positive);
        args.putString(ARGUMENT_MESSAGE, message);
        args.putString(ARGUMENT_POSITIVE_TEXT, positivetext);
        args.putString(ARGUMENT_NEGATIVE, negative);
        args.putString(ARGUMENT_NEGATIVE_TEXT, negativetext);
        ExampleDialog fragment = new ExampleDialog();
        fragment.setArguments(args); //put whole bundle into fragment
        return fragment; //fragment is given to code that call this newInstance
    }


    @Override
    public Dialog onCreateDialog(@Nullable Bundle savedInstanceState)  {

        title = getArguments().getString(ARGUMENT_TITLE); //using key, retrieve string value (user input), set as "title"
        positive = getArguments().getString(ARGUMENT_POSITIVE);
        message = getArguments().getString(ARGUMENT_MESSAGE);
        positivetext = getArguments().getString(ARGUMENT_POSITIVE_TEXT);
        negative = getArguments().getString(ARGUMENT_NEGATIVE);
        negativetext = getArguments().getString(ARGUMENT_NEGATIVE);

        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        builder.setTitle(title)
                .setMessage(message)
                .setNegativeButton(negative, new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        Toast toast = Toast.makeText(getContext(), negativetext, Toast.LENGTH_SHORT);
                        toast.show();
                    }
                })
                .setPositiveButton(positive, new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        Toast toast = Toast.makeText(getContext(), positivetext, Toast.LENGTH_SHORT);
                        toast.show();
                        listener.onYesClicked(); //listens for method onYesClicked(), need declare in code when call this class
                    }
                });
        return builder.create();
    }

    public interface ExampleDialogListener {
        void onYesClicked();
    }

    @Override
    public void onAttach(@NonNull Context context) {
        super.onAttach(context);

        try {
            listener = (ExampleDialogListener) context;
        } catch (ClassCastException e) {
            throw new ClassCastException(context.toString()
                    + "must implement ExampleDialogListener");
        }
    }
}

使用该类时，我还需要调用以下命令

  public void openDialog() {
          ExampleDialog dialog = ExampleDialog.newInstance("Title", "message",
                                                      "positive","positive text",
                                                      "negative","negative text");
          dialog.show(getSupportFragmentManager(),"example dialog");}
 @Override
 public void onYesClicked() {
    //what happens if yes is clicked
 }

Answer 1

不要在ExampleDialog的onAttach()中设置侦听器，而是从外部传递ExampleDialogListener的实例。在活动中维护ExampleDialogListener的不同侦听器实例，这将使您能够控制单个ExampleDialog的回调

像这样：

步骤1：删除在ExampleDialog的onAttach()中设置ExampleDialogListener的语句

@Override
public void onAttach(@NonNull Context context) {
    super.onAttach(context);

    /*try {
        listener = (ExampleDialogListener) context;
    } catch (ClassCastException e) {
        throw new ClassCastException(context.toString()
                + "must implement ExampleDialogListener");
    }*/
}

第2步：在ExampleFragment中添加一个public方法来初始化ExampleDialogListener

public void setListener(ExampleDialogListener listener) {
    this.listener = listener;
}

步骤3：在方法newInstance()中传递ExampleDialogListener的实例，并在那里设置侦听器

public static ExampleDialog newInstance(
    String title,
    String message,
    String positive,
    String positivetext,
    String negative,
    String negativetext,
    ExampleDialogListener listener /* Pass the Listener from outside */
) {

    Bundle args = new Bundle();

    args.putString(ARGUMENT_TITLE, title);
    args.putString(ARGUMENT_POSITIVE, positive);
    args.putString(ARGUMENT_MESSAGE, message);
    args.putString(ARGUMENT_POSITIVE_TEXT, positivetext);
    args.putString(ARGUMENT_NEGATIVE, negative);
    args.putString(ARGUMENT_NEGATIVE_TEXT, negativetext);

    ExampleDialog fragment = new ExampleDialog();
    fragment.setArguments(args);
    fragment.setListener(listener); // <   SET THE LISTENER HERE

    return fragment;

}

第4步：创建ExampleDialogListener的多个实例

private ExampleDialog.ExampleDialogListener listener1 = new ExampleDialog.ExampleDialogListener() {
    @Override
    public void onYesClicked() {
        // Your Implementation
    }
};

private ExampleDialog.ExampleDialogListener listener2 = new ExampleDialog.ExampleDialogListener() {
    @Override
    public void onYesClicked() {
        // Your Implementation
    }
};

private ExampleDialog.ExampleDialogListener listener3 = new ExampleDialog.ExampleDialogListener() {
    @Override
    public void onYesClicked() {
        // Your Implementation
    }
};

最后，为每个ExampleDialog设置不同的侦听器

public void openDialog() {
    ExampleDialog dialog1 = ExampleDialog.newInstance(
        "Title",
        "message",
        "positive",
        "positive text",
        "negative",
        "negative text",
        listener1
    );

    ExampleDialog dialog2 = ExampleDialog.newInstance(
        "Title",
        "message",
        "positive",
        "positive text",
        "negative",
        "negative text",
        listener2
    );

    ExampleDialog dialog3 = ExampleDialog.newInstance(
        "Title",
        "message",
        "positive",
        "positive text",
        "negative",
        "negative text",
        listener3
    );

    dialog1.show(getSupportFragmentManager(),"example dialog");
    dialog2.show(getSupportFragmentManager(),"example dialog");
    dialog3.show(getSupportFragmentManager(),"example dialog");
}