在android studio中点击回收器视图时如何检索数据库id？

Question

我一直在开发一个Android应用程序，当我单击回收器视图中的特定行时，我需要获取数据库ID。当我之前编写这个应用程序时，我根据记录的名称更新和删除了记录，但是当我回到这个项目时，我很快就了解到删除或/和更改了具有该名称的所有记录。然后我编写了一个简单的 rawQuery 来使用游标从姓名列表中获取 id。了解到，这将拉出所有具有该名称的 id，但我不知道该选择哪一个（因为该查询会拉出我必须选择的 id 的选项）。

 public Cursor getDbId(String studentName) {

        SQLiteDatabase db = this.getWritableDatabase();

        Cursor getDb = (db.rawQuery("SELECT " + ID_COL + " FROM " + TABLE_NAME + " WHERE " + NAME_COL + " = ?", new String[]{studentName}));
        getDb.moveToFirst();
        return getDb;
    }

 updateCourseBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {


                if (cursor != null && cursor.moveToNext()) {
                    String str = cursor.getString(cursor.getColumnIndex("id"));


                    System.out.println(str);
                    dbHandler.updateCourse(str, studentNameUpd.getText().toString(), studentSubjectUpd.getText().toString(), studentHoursUpd.getText().toString(), studentCoreUpd.getText().toString());

                    // displaying a toast message that our course has been updated.
                    Toast.makeText(UpdateCourseActivity.this, "Course Updated..", Toast.LENGTH_SHORT).show();

                    // launching our main activity.
                    Intent i = new Intent(UpdateCourseActivity.this, MainActivity.class);
                    startActivity(i);
                }
                /* inside this method we are calling an update course
                   method and passing all our edit text values. */

            }
        });

@Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {

//        Cursor cursor = dbHandler.getDbId(studentName);
        /* on below line we are setting data
           to our views of recycler view item. */
        CourseModal modal = courseModalArrayList.get(position);

        holder.studentNameRV.setText(modal.getStudentName());
        holder.studentCoreRV.setText(modal.getStudentCore());
        holder.studentSubjectRV.setText(modal.getStudentSubject());
        holder.studentHoursRV.setText(modal.getStudentHours());



        // below line is to add on click listener for our recycler view item.
        holder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                System.out.println();

;
                // on below line we are calling an intent.
                Intent i = new Intent(context, UpdateCourseActivity.class);

                // below we are passing all our values.
                i.putExtra("name", modal.getStudentName());
                i.putExtra("core", modal.getStudentCore());
                i.putExtra("subject", modal.getStudentSubject());
                i.putExtra("hours", modal.getStudentHours());


                // starting our activity.
                context.startActivity(i);
            }
        });
    }

public class CourseModal {

/* variables for our studentName,
   description, tracks and duration, id. */
private String studentName;
private String studentSubject;
private String studentHours;
private String studentCore;

public String getStudentName() {
    return studentName;
}

public void setStudentName(String studentName) {
    this.studentName = studentName;
}

public String getStudentSubject() {
    return studentSubject;
}

public void setStudentSubject(String studentSubject) {
    this.studentSubject = studentSubject;
}

public String getStudentHours() {
    return studentHours;
}

public void setStudentHours(String studentHours) {
    this.studentHours = studentHours;
}

public String getStudentCore() {
    return studentCore;
}

public void setStudentCore(String studentCore) {
    this.studentCore = studentCore;
}

private int id;
int o = 0;
int i = 0;

// creating getter and setter methods



public int getId() {
    return id;
}

public void setId(int id) {
    this.id = id;
}

// constructor
public CourseModal(String studentName, String studentSubject, String studentHours, String studentCore) {
    this.studentName = studentName;
    this.studentSubject = studentSubject;
    this.studentHours = studentHours;
    this.studentCore = studentCore;
}

}

我也尝试使用 onBindViewHolder 位置，因为这会让我知道我单击的项目的位置。我认为这会从数据库中提取。然而，由于 onBindViewHolder 对我来说是拉取数组 id 列表，所以这不起作用。

Answer 1

我使用了 onBindViewHolder 中的数组 id，使用了 CourseModal，并设置了 id。然后我获取了该 id 并将光标切换为使用数组索引来更改每个记录本身。