如何使用Android在sqlite中获取行数? [英] How to get row count in sqlite using Android?

问题描述

我正在创建任务管理器.我有任务列表，我希望当我点击特定的任务列表名称时，如果它为空，那么它会继续添加任务活动，但如果它有 2 或 3 个任务，那么它会以列表形式向我显示这些任务.

I am creating task manager. I have tasklist and I want when I click on particular tasklist name if it empty then it goes on Add Task activity but if it has 2 or 3 tasks then it shows me those tasks into it in list form.

我正在尝试在列表中计数.我的数据库查询就像:

I am trying to get count in list. my database query is like:

public Cursor getTaskCount(long tasklist_Id) {

    SQLiteDatabase db = this.getWritableDatabase();
    Cursor cursor= db.rawQuery("SELECT COUNT (*) FROM " + TABLE_TODOTASK + " WHERE " + KEY_TASK_TASKLISTID + "=?",
             new String[] { String.valueOf(tasklist_Id) });
    if(cursor!=null && cursor.getCount()!=0)
          cursor.moveToNext();
    return cursor;
}    

在我的活动中:

list_tasklistname.setOnItemClickListener(new OnItemClickListener() {
    @Override
    public void onItemClick(AdapterView<?> arg0,
            android.view.View v, int position, long id) {
                db = new TodoTask_Database(getApplicationContext());
                Cursor c = db.getTaskCount(id);
                System.out.println(c.getCount());
                if(c.getCount()>0) {    
                System.out.println(c);
                Intent taskListID = new Intent(getApplicationContext(), AddTask_List.class);
                task = adapter.getItem(position);
                int taskList_id = task.getTaskListId();
                taskListID.putExtra("TaskList_ID", taskList_id);
                startActivity(taskListID);
            }
            else {
                Intent addTask = new Intent(getApplicationContext(), Add_Task.class);
                startActivity(addTask);
            }
        }
    });
    db.close();
}

但是当我点击任务列表名称时，它会返回 1，机器人的任务数.

but when I am clicking on tasklist name it is returning 1, bot number of tasks into it.

推荐答案

Using DatabaseUtils.queryNumEntries():

public long getProfilesCount() {
    SQLiteDatabase db = this.getReadableDatabase();
    long count = DatabaseUtils.queryNumEntries(db, TABLE_NAME);
    db.close();
    return count;
}

或(效率低下)

public int getProfilesCount() {
    String countQuery = "SELECT  * FROM " + TABLE_NAME;
    SQLiteDatabase db = this.getReadableDatabase();
    Cursor cursor = db.rawQuery(countQuery, null);
    int count = cursor.getCount();
    cursor.close();
    return count;
}

活动中:

int profile_counts = db.getProfilesCount();
    db.close();

这篇关于如何使用Android在sqlite中获取行数?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！