详解Android中一些SQLite的增删改查操作

import android.content.ContentValues; 
import android.database.Cursor; 
import android.database.sqlite.SQLiteDatabase; 
 
/** 
 * 对表的增删改查的操作。这里的表里只有uid一列作为举例。 
 */ 
public class DemoDBUtil { 
 
 //要操作的表名 
 public static final String DEMO_DB_NAME = "demo_db_name"; 
 //SQLiteDatabase对象 
 private SQLiteDatabase sqLiteDatabase; 
  
 /** 
  * 带参构造方法，初始化SQLiteDatabase。 
  * @param sqLiteDatabase SQLiteDatabase实例 
  */ 
 public DemoDBUtil(SQLiteDatabase sqLiteDatabase){ 
  this.sqLiteDatabase = sqLiteDatabase; 
 } 
  
 /** 
  * 增加数据。 
  * @param uid 要新增的uid 
  */ 
 public void add(String uid){ 
  ContentValues values = new ContentValues(); 
  values.put("uid", uid); 
  sqLiteDatabase.insert(DEMO_DB_NAME, null, values); 
 } 
  
 /** 
  * 删除表里所有数据。 
  */ 
 public void delete(){ 
  sqLiteDatabase.delete(DEMO_DB_NAME, null, null); 
 } 
  
 /** 
  * 删除表里与uid对应的数据。 
  * @param uid 某个uid 
  */ 
 public void delete(String uid){ 
  sqLiteDatabase.delete(DEMO_DB_NAME, "uid = ? ", new String[]{uid}); 
 } 
  
 /** 
  * 更新表，将表所有uid替换为newUid。 
  */ 
 public void update(){ 
  ContentValues values = new ContentValues(); 
  values.put("uid", "newUid"); 
  sqLiteDatabase.update(DEMO_DB_NAME, values, null, null); 
 } 
  
 /** 
  * 将表里对应的uid替换为newUid。 
  * @param uid 表里的某个uid 
  */ 
 public void update(String uid){ 
  ContentValues values = new ContentValues(); 
  values.put("uid", "newUid"); 
  sqLiteDatabase.update(DEMO_DB_NAME, values, "uid = ? ", new String[]{uid}); 
 } 
  
 /** 
  * 查询表里所有数据，取得uid对应的值。 
  */ 
 public void query(){ 
  Cursor cursor = sqLiteDatabase.query(DEMO_DB_NAME, null, null, null, null, null, null); 
  while (cursor.moveToNext()) { 
   String uid = cursor.getString(cursor.getColumnIndex("uid")); 
  } 
  if (null != cursor) { 
   cursor.close(); 
  } 
 } 
  
 /** 
  * 取得对应uid的值。 
  * @param uid 表里的某个uid 
  */ 
 public void query(String uid){ 
  Cursor cursor = sqLiteDatabase.query(DEMO_DB_NAME, null, "uid = ? ", new String[]{uid}, null, null, null); 
  while (cursor.moveToNext()) { 
   String queryUid = cursor.getString(cursor.getColumnIndex("uid")); 
  } 
  if (null != cursor) { 
   cursor.close(); 
  } 
 } 
  
 /** 
  * 取得最后一条记录。 
  */ 
 public void queryLastRecord(){ 
  String lastTimeSql = "select * from demo_db_name order by id desc LIMIT 1"; 
  Cursor cursor = sqLiteDatabase.rawQuery(lastTimeSql, null); 
  while (cursor.moveToNext()) { 
   String queryUid = cursor.getString(cursor.getColumnIndex("uid")); 
  } 
  if (null != cursor) { 
   cursor.close(); 
  } 
 } 
}