几天前我问过如何在活动之间共享数据,一个用户告诉我使用SQLite,所以我做了.我想让用户点击MainLayout中的按钮,它会将他重定向到AddTaskLayout,在那里他可以添加任务名称,按下Save按钮应用程序会将他重定向回MainLayout,他的任务将在ListView中列出.

到目前为止,我创建了数据库,表格和我需要的一切.我的问题是：如何将存储在数据库表中的数据添加到ListView？我发现的每个答案都是用Java编写的,所以搜索旧的StackOverflow问题并没有那么有用：/

这是代码：

我的DBRepository是表示创建数据库,创建表,向表插入数据以及获取相同数据的类：

public class DBRepository

{

public void CreateDatabase()

{

string dbPath = Path.Combine(System.Environment.GetFolderPath

(System.Environment.SpecialFolder.Personal), "database.db3");

var db = new SQLiteConnection(dbPath);

}

public void CreateTable()

{

string dbPath = Path.Combine(System.Environment.GetFolderPath

(System.Environment.SpecialFolder.Personal), "database.db3");

var db = new SQLiteConnection(dbPath);

db.CreateTable();

}

public string InsertRecord(string task)

{

string dbPath = Path.Combine(System.Environment.GetFolderPath

(System.Environment.SpecialFolder.Personal), "database.db3");

var db = new SQLiteConnection(dbPath);

ToDoTasks item = new ToDoTasks();

item.Task = task;

db.Insert(item);

return task;

}

public string GetData()

{

string dbPath = Path.Combine(System.Environment.GetFolderPath

(System.Environment.SpecialFolder.Personal), "database.db3");

var db = new SQLiteConnection(dbPath);

string output = "";

var table = db.Table();

foreach(var item in table)

{

output += item;

}

return output;

}

}

我创建表的ToDoTasks类：

[Table("ToDo")]

public class ToDoTasks

{

[PrimaryKey, AutoIncrement, Column("_Id")]

public int Id { get; set; }

[MaxLength(100)]

public string Task { get; set; }

}

我的AddTaskActivity表示用户输入任务名称的第二个布局：

protected override void OnCreate(Bundle bundle)

{

base.OnCreate(bundle);

SetContentView(Resource.Layout.AddTask);

//define buttons

Button save, cancel;

save = FindViewById(Resource.Id.save);

cancel = FindViewById(Resource.Id.cancel);

save.Click += save_click;

cancel.Click += cancel_click;

}

private void save_click(object sender, EventArgs e)

{

DBRepository dbr = new DBRepository();

EditText name = FindViewById(Resource.Id.taskName);

//enter user's input(task name) to table

var result = dbr.InsertRecord(name.Text);

StartActivity(typeof(MainActivity));

}

private void cancel_click(object sender, EventArgs e)

{

StartActivity(typeof(MainActivity));

}

我想要填充listView的MainActivity：

protected override void OnCreate(Bundle bundle)

{

base.OnCreate(bundle);

// Set view

SetContentView(Resource.Layout.Main);

//create database if it doesn't exist

DBRepository dbr = new DBRepository();

dbr.CreateDatabase();

//create table (if it doesn't exist)

dbr.CreateTable();

//Define buttons

Button addTask;

ListView list;

addTask = FindViewById(Resource.Id.addTask);

addTask.Click += addTask_click;

}

private void addTask_click(object sender, EventArgs e)

{

StartActivity(typeof(AddTaskActivity));

}

我非常感谢你的帮助.我知道这些都是非常基本的问题,但有人必须要求他们为自己和许多其他(未来)C#android开发人员.谢谢！

//

更新：我检查了Johan的答案是否正确,但这是(在我的情况下)正确的代码：

我需要更改GetData()方法以返回List(不像以前那样对象),然后在ListView中显示List.这是代码：

You helped me a lot, but I had to make few changes, so here they are for the record:

在DBRepository中需要将GetData()方法更改为：

public List GetData()

{

string dbPath = Path.Combine(System.Environment.GetFolderPath

(System.Environment.SpecialFolder.Personal), "database.db3");

var db = new SQLiteConnection(dbPath);

List data = new List();

foreach (var item in db.Table())

{

var zad = item.Task.ToString();

data.Add(zad);

}

return data;

}

然后,在MainActivity中,ListView的代码只添加：

var items = dbr.GetData();

var listView = FindViewById(Resource.Id.listView);

listView.Adapter = new ArrayAdapter(this, Android.Resource.Layout.SimpleListItem1, items);

我希望将来可以帮助别人.再次感谢大家.

最佳答案 根据我的评论,您需要进行以下更改.

public List GetData()

{

string dbPath = Path.Combine(System.Environment.GetFolderPath(System.Environment.SpecialFolder.Personal), "database.db3");

var db = new SQLiteConnection(dbPath);

return db.Table().ToList();

}

然后在您的Activity中,您可以在其中执行以下操作

protected override void OnCreate(Bundle bundle)

{

base.OnCreate(bundle);

// Set view

SetContentView(Resource.Layout.Main);

//create database if it doesn't exist

DBRepository dbr = new DBRepository();

dbr.CreateDatabase();

//create table (if it doesn't exist)

dbr.CreateTable();

var items = dbr.GetData();

var listView = FindViewById(Android.Resource.Id.ListView);

listView.Adapter = new ArrayAdapter(this, Android.Resource.Layout.SimpleListItem1, items);

}

如果您的活动继承自ListActivity,您可以执行以下操作

protected override void OnCreate(Bundle bundle)

{

base.OnCreate(bundle);

// Set view

SetContentView(Resource.Layout.Main);

//create database if it doesn't exist

DBRepository dbr = new DBRepository();

dbr.CreateDatabase();

//create table (if it doesn't exist)

dbr.CreateTable();

var items = dbr.GetData();

ListAdapter = new ArrayAdapter(this, Android.Resource.Layout.SimpleListItem1, items);

}