demo链接:https://download.csdn.net/download/meixi_android/10710400
创建数据库版本v.1
/**
* 作者:created by meixi
* 邮箱:[email protected]
* 日期:2018/10/9 11
*/
public class DBHelper extends SQLiteOpenHelper {
private static final String DATABASE_NAME = "mall.db";
private static final int DATABASE_VERSION = 1000;
private static DBHelper instance = null;
public DBHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
public synchronized static DBHelper getInstance(Context context) {
if (instance == null) {
instance = new DBHelper(context);
}
return instance;
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(SQL.CREATE_TABLE_FAVORITE);
// 若不是第一个版本安装,直接执行数据库升级
// 请不要修改FIRST_DATABASE_VERSION的值,其为第一个数据库版本大小
final int FIRST_DATABASE_VERSION = 1000;
onUpgrade(db, FIRST_DATABASE_VERSION, DATABASE_VERSION);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// 使用for实现跨版本升级数据库
for (int i = oldVersion; i < newVersion; i++) {
switch (i) {
default:
break;
}
}
}
}
创建数据库版本v.2
public class DBHelper2 extends SQLiteOpenHelper {
private static final String DATABASE_NAME = "mall.db";
private static final int DATABASE_VERSION = 1001;
private static DBHelper2 instance = null;
public DBHelper2(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
public synchronized static DBHelper2 getInstance(Context context) {
if (instance == null) {
instance = new DBHelper2(context);
}
return instance;
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(SQL.CREATE_TABLE_FAVORITE);
// 若不是第一个版本安装,直接执行数据库升级
// 请不要修改FIRST_DATABASE_VERSION的值,其为第一个数据库版本大小
final int FIRST_DATABASE_VERSION = 1000;
onUpgrade(db, FIRST_DATABASE_VERSION, DATABASE_VERSION);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// 使用for实现跨版本升级数据库
for (int i = oldVersion; i < newVersion; i++) {
switch (i) {
case 1000:
upgradeToVersion1001(db);
break;
default:
break;
}
}
}
private void upgradeToVersion1001(SQLiteDatabase db){
// favorite表新增1个字段
String sql1 = "ALTER TABLE "+SQL.T_FAVORITE+" ADD COLUMN deleted VARCHAR";
db.execSQL(sql1);
}
}
创建数据库版本v.3
/**
* 作者:created by meixi
* 邮箱:[email protected]
* 日期:2018/10/9 17
*/
public class DBHelper3 extends SQLiteOpenHelper {
private static final String DATABASE_NAME = "mall.db";
private static final int DATABASE_VERSION = 1002;
private static DBHelper3 instance = null;
public DBHelper3(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
public synchronized static DBHelper3 getInstance(Context context) {
if (instance == null) {
instance = new DBHelper3(context);
}
return instance;
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(SQL.CREATE_TABLE_FAVORITE);
// 若不是第一个版本安装,直接执行数据库升级
// 请不要修改FIRST_DATABASE_VERSION的值,其为第一个数据库版本大小
final int FIRST_DATABASE_VERSION = 1000;
onUpgrade(db, FIRST_DATABASE_VERSION, DATABASE_VERSION);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// 使用for实现跨版本升级数据库
for (int i = oldVersion; i < newVersion; i++) {
switch (i) {
case 1000:
upgradeToVersion1001(db);
break;
case 1001:
upgradeToVersion1002(db);
break;
default:
break;
}
}
}
private void upgradeToVersion1001(SQLiteDatabase db){
// favorite表新增1个字段
String sql1 = "ALTER TABLE "+SQL.T_FAVORITE+" ADD COLUMN deleted VARCHAR";
db.execSQL(sql1);
}
private void upgradeToVersion1002(SQLiteDatabase db){
// favorite表新增2个字段,添加新字段只能一个字段一个字段加,sqlite有限制不予许一条语句加多个字段
String sql1 = "ALTER TABLE "+SQL.T_FAVORITE+" ADD COLUMN message VARCHAR";
String sql2 = "ALTER TABLE "+SQL.T_FAVORITE+" ADD COLUMN type VARCHAR";
db.execSQL(sql1);
db.execSQL(sql2);
}
}
创建数据库语句:
public class SQL {
public static final String T_FAVORITE = "favorite";
public static final String CREATE_TABLE_FAVORITE =
"CREATE TABLE IF NOT EXISTS " + T_FAVORITE + "(" +
"_id integer primary key autoincrement, " +
"title VARCHAR, " +
"url VARCHAR, " +
"createDate VARCHAR " +
")";
}
实现增删改查activity:
public class MainActivity extends AppCompatActivity {
private static String CREATE_TABLE ="create table number(_id integer primary key autoincrement ,phone real)";
int ab = 0,cd;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button button1=findViewById(R.id.baocunid);
Button button2=findViewById(R.id.duquid);
Button button3=findViewById(R.id.shanchuid);
Button button4=findViewById(R.id.xiugaiid);
button1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
ab++;
boolean nn = baocun(MainActivity.this, new String[] { "114499title","rullll---htt;s=="+ab,"加入的xxx" });
Log.i("lgq","sbbbb---"+nn);
}
});
button2.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
getBai(MainActivity.this);
}
});
button3.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String ss= Delete(MainActivity.this,"1");
Log.i("lgq","shanchu=g==="+ss);
}
});
button4.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String ss = updata(MainActivity.this,"");
Log.i("lgq","xiugg=g==="+ss);
}
});
}
public static boolean baocun(Context context, String[] values) {
SQLiteDatabase db2=null;
DBHelper2 dbHelper = null;
try {
dbHelper =new DBHelper2(context);
db2 = dbHelper.getWritableDatabase();
db2=dbHelper.getWritableDatabase();
db2.beginTransaction();
db2.execSQL("insert into favorite (title,url,deleted) values (?,?,?)",values);
db2.setTransactionSuccessful();
db2.endTransaction();
return true;
} catch (Exception e) {
e.printStackTrace();
return false;
}finally{
}
}
public List<String> getBai(Context context){
List<String> list = new ArrayList<String>();
SQLiteDatabase db2=null;
DBHelper2 dbHelper = null;
try {
dbHelper= new DBHelper2(context);
db2=dbHelper.getWritableDatabase();
Cursor cursor =db2.rawQuery("select _id,title,deleted from favorite", null);
while(cursor.moveToNext()){
cd++;
// int dbid = cursor.getInt(cursor.getColumnIndex("_id"));
int id=cursor.getInt(cursor.getColumnIndex("_id"));
String haoma = cursor.getString(cursor.getColumnIndex("title"))+"";
String names = cursor.getString(cursor.getColumnIndex("deleted"));
list.add(haoma);
System.out.println("lgqs======"+haoma+"......."+names+" "+cd+" id=== "+id);
}
db2.setTransactionSuccessful();
db2.endTransaction();
} catch (Exception e) {
e.printStackTrace();
}
return list;
}
public static String Delete(Context context,String string){
SQLiteDatabase db2=null;
DBHelper2 dbHelper = null;
try {
dbHelper =new DBHelper2(context);
db2 = dbHelper.getWritableDatabase();
db2=dbHelper.getWritableDatabase();
db2.beginTransaction();
db2.execSQL("delete from favorite where _id=?",new String[] { string });
db2.setTransactionSuccessful();
db2.endTransaction();
return "成功";
} catch (Exception e) {
e.printStackTrace();
return "失败";
}
}
public static String updata(Context context,String string){
SQLiteDatabase db2=null;
DBHelper2 dbHelper = null;
try {
dbHelper =new DBHelper2(context);
db2 = dbHelper.getWritableDatabase();
db2=dbHelper.getWritableDatabase();
db2.beginTransaction();
db2.execSQL("update favorite set title ="+"2222999"+" where url =?",new String[]{"rullll---htt;s==3"});
db2.setTransactionSuccessful();
db2.endTransaction();
return "成功";
} catch (Exception e) {
e.printStackTrace();
return "失败";
}
}
}