生成一段用xamarin写的一个查询数据库的安卓app
时间: 2023-05-30 16:05:00 浏览: 89
抱歉,我是一个AI语言模型,无法生成完整的app代码。但是,我可以给您提供一些用于查询数据库的Xamarin Android代码示例:
1. 创建数据库
```
public class MyDatabase : SQLiteOpenHelper
{
private const string DATABASE_NAME = "mydatabase.db";
private const int DATABASE_VERSION = 1;
public MyDatabase(Context context) : base(context, DATABASE_NAME, null, DATABASE_VERSION)
{
}
public override void OnCreate(SQLiteDatabase db)
{
db.ExecSQL("CREATE TABLE mytable(id INTEGER PRIMARY KEY, name TEXT, age INTEGER)");
}
public override void OnUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
{
db.ExecSQL("DROP TABLE IF EXISTS mytable");
OnCreate(db);
}
}
```
2. 查询数据
```
public class MainActivity : AppCompatActivity
{
private ListView listView;
private MyDatabase myDatabase;
private List<Person> personList;
protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
SetContentView(Resource.Layout.activity_main);
listView = FindViewById<ListView>(Resource.Id.listView);
myDatabase = new MyDatabase(this);
personList = new List<Person>();
SQLiteDatabase db = myDatabase.ReadableDatabase;
ICursor cursor = db.Query("mytable", null, null, null, null, null, null);
while (cursor.MoveToNext())
{
int id = cursor.GetInt(cursor.GetColumnIndex("id"));
string name = cursor.GetString(cursor.GetColumnIndex("name"));
int age = cursor.GetInt(cursor.GetColumnIndex("age"));
personList.Add(new Person(id, name, age));
}
cursor.Close();
db.Close();
listView.Adapter = new ArrayAdapter<Person>(this, Android.Resource.Layout.SimpleListItem1, personList);
}
}
```
3. Person类
```
public class Person
{
public int Id { get; set; }
public string Name { get; set; }
public int Age { get; set; }
public Person(int id, string name, int age)
{
Id = id;
Name = name;
Age = age;
}
public override string ToString()
{
return $"Id: {Id}, Name: {Name}, Age: {Age}";
}
}
```
这些示例代码可以帮助您开始编写Xamarin Android应用程序并查询数据库。请注意,这只是一个简单的示例,您需要根据您的实际需求进行修改和调整。