java - 如何从单独的类中的对话框返回值

Question

我想创建一个函数，在屏幕上显示一个带有 2 个按钮的对话框，如果用户按下“确定”，则返回 1；如果用户按下“取消”，则返回 0。

public class CDlg {

static int ShowConfirm(String caption, String msg, Context context) {
    int rez;
    AlertDialog.Builder delAllDialog = new AlertDialog.Builder(context);
    delAllDialog.setTitle(caption);

    TextView dialogTxt_id = new TextView(context);
    LayoutParams dialogTxt_idLayoutParams = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
    dialogTxt_id.setLayoutParams(dialogTxt_idLayoutParams);
    dialogTxt_id.setText(msg);
    LinearLayout layout = new LinearLayout(context);
    layout.setOrientation(LinearLayout.VERTICAL);
    layout.addView(dialogTxt_id);
    delAllDialog.setView(layout);

    delAllDialog.setPositiveButton("OK", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface arg0, int arg1) {
            rez = 1;
        }
    });

    delAllDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface arg0, int arg1) {
            rez = 0;
        }
    });

    delAllDialog.show();
    return rez;
}

}

我现在确信我做得对，因为我不知道如何将结果从下层传递到外层。有错误消息

Cannot refer to a non-final variable rez inside an inner class defined in a different method

因此，我想使用该函数，如下所示:

if (CDlg.ShowConfirm("User confirmation","Delete?",this)==1){
        ...
}

Answer 1

你不能那样做。 ShowConfirm 只能显示对话框。当用户单击“确定”或“取消”按钮时，您才能执行您想要的操作:

public class CDlg {
    void ShowConfirm(String caption, String msg) {
        AlertDialog.Builder delAllDialog = new AlertDialog.Builder(this);
        delAllDialog.setTitle(caption);

        TextView dialogTxt_id = new TextView(this);
        LayoutParams dialogTxt_idLayoutParams = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
        dialogTxt_id.setLayoutParams(dialogTxt_idLayoutParams);
        dialogTxt_id.setText(msg);
        LinearLayout layout = new LinearLayout(this);
        layout.setOrientation(LinearLayout.VERTICAL);
        layout.addView(dialogTxt_id);
        delAllDialog.setView(layout);

        delAllDialog.setPositiveButton("OK", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface arg0, int arg1) {
                handleButtonClick(1);
            }
        });

        delAllDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface arg0, int arg1) {
                handleButtonClick(2);
            }
        });

        delAllDialog.show();
    }

    void handleButtonClick(int rez) {
        switch(rez) {
            case 1: ..... break;
            case 2: ..... break;
            .....
        }
    }
}

if (CDlg.ShowConfirm("用户确认","删除?",this)==1) 语句在 Android 中没有用处，因为 ShowConfirm 不会等到用户按下一个按钮。

只需调用 ShowConfirm("用户确认","删除?"); 并在 onClick 中实现适当的代码即可。