Logcat报了如下的错误：android.database.sqlite.SQLiteException: near ",": syntax error (code 1): , while compiling: alter table playhistory add src_type INTEGER,total_time long,definition integer,current_time long,web_type integer,total_episodes integer
分析：
由于alter table tablename add 后面加了多个列导致失败。
如果要增加多个列，需要把这句话拆分成一个个单独的alter table语句。
从官方的图例上可以看出，alter table tablename add column 本身不支持Loop循环。
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
if (oldVersion < 2) {
new_column = "alter table " + PlayHistoryTable.TABLE_NAME + " add " + PlayHistoryTable.SRC_TYPE + " integer";
db.execSQL(new_column);
new_column = "alter table " + PlayHistoryTable.TABLE_NAME + " add " + PlayHistoryTable.TIME_TOTAL + " long";
db.execSQL(new_column);
new_column = "alter table " + PlayHistoryTable.TABLE_NAME + " add " + PlayHistoryTable.DEFINITION + " integer";
db.execSQL(new_column);
new_column = "alter table " + PlayHistoryTable.TABLE_NAME + " add " + PlayHistoryTable.CURRENT_TIME + " long";
db.execSQL(new_column);
new_column = "alter table " + PlayHistoryTable.TABLE_NAME + " add " + PlayHistoryTable.WEB_TYPE + " integer";
db.execSQL(new_column);
new_column = "alter table " + PlayHistoryTable.TABLE_NAME + " add " + PlayHistoryTable.TOTAL_EPISODES + " integer";
db.execSQL(new_column);
db.execSQL(SQL_CREATE_DOWNLOAD);
}
}