不讲GreenDao是什么和怎么用，只讲升级，很简单，按照步骤来就行
一、新建一个类，
public class DBopenHelper extends DaoMaster.DevOpenHelper {
// name 数据库名字
public DBopenHelper(Context context, String name) {
super(context, name);
}
public DBopenHelper(Context context, String name, SQLiteDatabase.CursorFactory factory) {
super(context, name, factory);
}
@Override
public void onUpgrade(Database db, int oldVersion, int newVersion) {
//把需要管理的数据库表DAO作为最后一个参数传入到方法中（只传更改过的表，新增的不用）
MigrationHelper.migrate(db, new MigrationHelper.ReCreateAllTableListener() {
@Override
public void onCreateAllTables(Database db, boolean ifNotExists) {
DaoMaster.createAllTables(db, ifNotExists);
}
@Override
public void onDropAllTables(Database db, boolean ifExists) {
DaoMaster.dropAllTables(db, ifExists);
}
}, HangUpDao.class);//可添加多个改动过的表对象Dao
}
}
注意： HangUpDao.class);//可添加多个改动过的表对象Dao，这里就是你需要修改的表
二、再新建一个类
/*
* 数据库升级帮助类
* **/
public class MigrationHelper {
public static boolean DEBUG = false;
private static String TAG = "MigrationHelper";
private static final String SQLITE_MASTER = "sqlite_master";
private static final String SQLITE_TEMP_MASTER = "sqlite_temp_master";
private static WeakReference
public interface ReCreateAllTableListener{
void onCreateAllTables(Database db, boolean ifNotExists);
void onDropAllTables(Database db, boolean ifExists);
}
public static void migrate(SQLiteDatabase db, Class>... daoClasses) {
printLog("【The Old Database Version】" + db.getVersion());
Database database= new StandardDatabase(db);
migrate(database, daoClasses);
}
public static void migrate(SQLiteDatabase db, ReCreateAllTableListener listener, Class>... daoClasses) {
weakListener = new WeakReference<>(listener);
migrate(db, daoClasses);
}
public static void migrate(Database database, ReCreateAllTableListener listener, Class>... daoClasses) {
weakListener = new WeakReference<>(listener);
migrate(database, daoClasses);
}
public static void migrate(Database database, Class>... daoClasses) {
printLog("【Generate temp table】start");
generateTempTables(database, daoClasses);
printLog("【Generate temp table】complete");
ReCreateAllTableListener listener= null;
if (weakListener != null) {
listener= weakListener.get();
}
if (listener!= null) {
listener.onDropAllTables(database, true);
printLog("【Drop all table by listener】");
listener.onCreateAllTables(database, false);
printLog("【Create all table by listener】");
} else {
dropAllTables(database, true, daoClasses);
createAllTables(database, false, daoClasses);
}
printLog("【Restore data】start");
restoreData(database, daoClasses);
printLog("【Restore data】complete");
}
private static void generateTempTables(Database db, Class>... daoClasses) {
for (int i= 0; i< daoClasses.length; i++) {
String tempTableName= null;
DaoConfig daoConfig= new DaoConfig(db, daoClasses[i]);
String tableName= daoConfig.tablename;
if (!isTableExists(db, false, tableName)) {
printLog("【New Table】" + tableName);
continue;
}
try {
tempTableName= daoConfig.tablename.concat("_TEMP");
StringBuilder dropTableStringBuilder= new StringBuilder();
dropTableStringBuilder.append("DROP TABLE IF EXISTS ").append(tempTableName).append(";");
db.execSQL(dropTableStringBuilder.toString());
StringBuilder insertTableStringBuilder= new StringBuilder();
insertTableStringBuilder.append("CREATE TEMPORARY TABLE ").append(tempTableName);
insertTableStringBuilder.append(" AS SELECT * FROM ").append(tableName).append(";");
db.execSQL(insertTableStringBuilder.toString());
printLog("【Table】" + tableName+"\n ---Columns-->"+getColumnsStr(daoConfig));
printLog("【Generate temp table】" + tempTableName);
} catch (SQLException e) {
Log.e(TAG, "【Failed to generate temp table】" + tempTableName, e);
}
}
}
private static boolean isTableExists(Database db, boolean isTemp, String tableName) {
if (db== null || TextUtils.isEmpty(tableName)) {
return false;
}
String dbName= isTemp? SQLITE_TEMP_MASTER : SQLITE_MASTER;
String sql= "SELECT COUNT(*) FROM " + dbName+ " WHERE type = ? AND name = ?";
Cursor cursor=null;
int count= 0;
try {
cursor= db.rawQuery(sql, new String[]{"table", tableName});
if (cursor== null || !cursor.moveToFirst()) {
return false;
}
count= cursor.getInt(0);
} catch (Exception e) {
e.printStackTrace();
} finally {
if (cursor!= null)
cursor.close();
}
return count> 0;
}
private static String getColumnsStr(DaoConfig daoConfig) {
if (daoConfig== null) {
return "no columns";
}
StringBuilder builder= new StringBuilder();
for (int i= 0; i< daoConfig.allColumns.length; i++) {
builder.append(daoConfig.allColumns[i]);
builder.append(",");
}
if (builder.length() > 0) {
builder.deleteCharAt(builder.length() - 1);
}
return builder.toString();
}
private static void dropAllTables(Database db, boolean ifExists, @NonNull Class>... daoClasses) {
reflectMethod(db, "dropTable", ifExists, daoClasses);
printLog("【Drop all table by reflect】");
}
private static void createAllTables(Database db, boolean ifNotExists, @NonNull Class>... daoClasses) {
reflectMethod(db, "createTable", ifNotExists, daoClasses);
printLog("【Create all table by reflect】");
}
/**
* dao class already define the sql exec method, so just invoke it
*/
private static void reflectMethod(Database db, String methodName, boolean isExists, @NonNull Class>... daoClasses) {
if (daoClasses.length < 1) {
return;
}
try {
for (Class cls: daoClasses) {
Method method= cls.getDeclaredMethod(methodName, Database.class, boolean.class);
method.invoke(null, db, isExists);
}
} catch (NoSuchMethodException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
}
private static void restoreData(Database db, Class>... daoClasses) {
for (int i= 0; i< daoClasses.length; i++) {
DaoConfig daoConfig= new DaoConfig(db, daoClasses[i]);
String tableName= daoConfig.tablename;
String tempTableName= daoConfig.tablename.concat("_TEMP");
if (!isTableExists(db, true, tempTableName)) {
continue;
}
try {
// get all columns from tempTable, take careful to use the columns list
List
List
ArrayList
ArrayList
for (TableInfo tableInfo: tempTableInfos) {
if (newTableInfos.contains(tableInfo)) {
String column= '`' + tableInfo.name + '`';
intoColumns.add(column);
selectColumns.add(column);
}
}
// NOT NULL columns list
for (TableInfo tableInfo: newTableInfos) {
if (tableInfo.notnull && !tempTableInfos.contains(tableInfo)) {
String column= '`' + tableInfo.name + '`';
intoColumns.add(column);
String value;
if (tableInfo.dfltValue != null) {
value= "'" + tableInfo.dfltValue + "' AS ";
} else {
value= "'' AS ";
}
selectColumns.add(value+ column);
}
}
if (intoColumns.size() != 0) {
StringBuilder insertTableStringBuilder= new StringBuilder();
insertTableStringBuilder.append("REPLACE INTO ").append(tableName).append(" (");
insertTableStringBuilder.append(TextUtils.join(",", intoColumns));
insertTableStringBuilder.append(") SELECT ");
insertTableStringBuilder.append(TextUtils.join(",", selectColumns));
insertTableStringBuilder.append(" FROM ").append(tempTableName).append(";");
db.execSQL(insertTableStringBuilder.toString());
printLog("【Restore data】 to " + tableName);
}
StringBuilder dropTableStringBuilder= new StringBuilder();
dropTableStringBuilder.append("DROP TABLE ").append(tempTableName);
db.execSQL(dropTableStringBuilder.toString());
printLog("【Drop temp table】" + tempTableName);
} catch (SQLException e) {
Log.e(TAG, "【Failed to restore data from temp table 】" + tempTableName, e);
}
}
}
private static List
List
Cursor cursor= null;
try {
cursor= db.rawQuery("SELECT * FROM " + tableName+ " limit 0", null);
if (null != cursor&& cursor.getColumnCount() > 0) {
columns= Arrays.asList(cursor.getColumnNames());
}
} catch (Exception e) {
e.printStackTrace();
} finally {
if (cursor!= null)
cursor.close();
if (null == columns)
columns= new ArrayList<>();
}
return columns;
}
private static void printLog(String info){
if(DEBUG){
Log.d(TAG, info);
}
}
private static class TableInfo {
int cid;
String name;
String type;
boolean notnull;
String dfltValue;
boolean pk;
@Override
public boolean equals(Object o) {
return this == o
|| o!= null
&& getClass() == o.getClass()
&& name.equals(((TableInfo) o).name);
}
@Override
public String toString() {
return "TableInfo{" +
"cid=" + cid +
", name='" + name + '\'' +
", type='" + type + '\'' +
", notnull=" + notnull +
", dfltValue='" + dfltValue + '\'' +
", pk=" + pk +
'}';
}
private static List
String sql= "PRAGMA table_info(" + tableName+ ")";
printLog(sql);
Cursor cursor= db.rawQuery(sql, null);
if (cursor== null)
return new ArrayList<>();
TableInfo tableInfo;
List
while (cursor.moveToNext()) {
tableInfo= new TableInfo();
tableInfo.cid = cursor.getInt(0);
tableInfo.name = cursor.getString(1);
tableInfo.type = cursor.getString(2);
tableInfo.notnull = cursor.getInt(3) == 1;
tableInfo.dfltValue = cursor.getString(4);
tableInfo.pk = cursor.getInt(5) == 1;
tableInfos.add(tableInfo);
// printLog(tableName + "：" + tableInfo);
}
cursor.close();
return tableInfos;
}
}
}
三、在 DaoManager 类里面，修改代码，关键
/**
* 判断是否有存在数据库，如果没有则创建
*/
public DaoMaster getDaoMaster() {
if (mDaoMaster == null) {
// mHelper = new DaoMaster.DevOpenHelper(mContext, DB_NAME, null);（原有代码）
mHelper = new DBopenHelper(mContext, DB_NAME);//指向你新建的自定义的类
mDaoMaster = new DaoMaster(mHelper.getWritableDatabase());
}
return mDaoMaster;
}
四、（1）、在你需要升级修改的数据库实体类里面，新增或者删除或者咋地都行，操作做完后，删除原有的 get set 方法，重新 build 一下，懂我意思吧，
（2）、修改数据库版本号，+1 即可，不知道在哪修改先去学习 GreenDao如何配置，再来学升级。
（3）、把你原来已经安装好的程序卸载掉再进行测试。