Android orm 框架xUtils简介
数据库操作建议用ORM框架，简单高效。这里推荐xUtils，里面包含DBUtils。github地址：https://github.com/wyouflf/xUtils
获得数据库实例建议用单例模式。
static DbUtils db = null; public static DbUtils getDb(Context context) { if (context == null) { context = DoctorApplication.getInstance(); } if (db == null) { db = DbUtils.create(context, "xUtils.db"); }); db.configAllowTransaction(true); return db; } db.configAllowTransaction(true); return db; }
创建一个实体类，对应数据库中的表。
@Table(name = "User") public class User { private int id; //主键ID，必须 private String uid; private String type; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getType() { return type; } public void setType(String type) { this.type = type; } public String getUid() { return uid; } public void setUid(String uid) { this.uid = uid; } }
查找：
// 查找,根据主键ID查找 User userTemp = db.findById(User.class, user.getId()); List<User> list = db.findAll(User.class);//通过类型查找，查找所有 User user = db.findFirst(Selector.from(User.class).where("type","=","0")); // IS NULL User user = db.findFirst(Selector.from(User.class).where("type","=", null)); // IS NOT NULL User user = db.findFirst(Selector.from(User.class).where("type","!=", null));
List<User> list = db.findAll(Selector.from(User) .where("id" ,"<", 54) .and(WhereBuilder.b("id", ">", 20).or("id", " < ", 30)) .orderBy("id") .limit(pageSize) .offset(pageSize * pageIndex)); // op为"in"时，最后一个参数必须是数组或Iterable的实现类(例如List等) User test = db.findFirst(Selector.from(User.class).where("id", "in", new int[]{1, 2, 3})); // op为"between"时，最后一个参数必须是数组或Iterable的实现类(例如List等) User test = db.findFirst(Selector.from(User.class).where("uid", "between", new String[]{"1", "5"})); DbModel dbModel = db.findDbModelAll(Selector.from(User.class).select("uid"));//select("name")只取出name列 List<DbModel> dbModels = db.findDbModelAll(Selector.from(User.class).groupBy("type").select("uid", "count(uid)")); ... List<DbModel> dbModels = db.findDbModelAll(sql); // 自定义sql查询 db.execNonQuery(sql) // 执行自定义sql
//多条件混合查询
List<User> userEnts = TCommUtil.getDb(this).findAll(Selector.from(User.class).where(WhereBuilder.b("id", ">", 5).or("id", "<", 3)).and("uid", "=", "0"));
//模糊查询like
String str = "select id,nickname,age,gender,zhenduan,avatar,pid,type from User where uid = "
+ uid
+ " and type like '%"
+ value + "%'";
Cursor cursor = TCommUtil.getDb( this ).execQuery(str);
cursor.moveToFirst();
for (int i = 0; i < cursor.getCount(); i++) {
User userEnt = new User();
userEnt.setId(cursor.getInt(0));
...
cursor.moveToNext();
}
cursor.close();
保存
User userEnt = new User(); TCommUtil.getDb(this).save(user); List<User> userEnts = new ArrayList<User>(); TCommUtil.getDb(this).saveAll(userEnts);
删除
TCommUtil.getDb(this).deleteAll(User.class); TCommUtil.getDb(this).delete(User.class, WhereBuilder.b("id", "=", 3));
修改
userEnt.setType("3"); TCommUtil.getDb(this).update(userEnt, WhereBuilder.b("id", "=", 0), "type"); 正文到此结束
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文章和留言都翻到11页了 没有OOM
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朋友，翻页到11页，及以后，会出现OOM，无法访问
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搞个gitee的项目
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版本号是多少，你可以下载哪个代码仓库，jdk选1.8 直接跑就行
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