我正在尝试使用和一些http请求来填充数据库中的几个表和Android应用程序。填充这些表时，表中的部分数据将填充和展开视图。问题是我收到一个错误，告诉我我创建的表没有创建。
错误日志：
01-05 13:33:29.811: E/SQLiteLog(1823): (1) no such table: lvl2List
01-05 13:33:29.831: E/AndroidRuntime(1823): android.database.sqlite.SQLiteException: no such table: lvl2List (code 1): , while compiling: SELECT id, Title, Description FROM lvl2List
这是我的代码：
MainActivity.java
public class MainActivity extends Activity
{
private List<lvItem> myLVItems = new ArrayList<lvItem>();
private List<Parent> myParent = new ArrayList<Parent>();
ExpandableListView exv;
final DBHelper db2 = new DBHelper(this);
@Override
protected void onCreate(Bundle savedInstanceState) {
exv=(ExpandableListView)findViewById(R.id.expandableListView1);
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
db2.open();
lvl3 lvl3Item = new lvl3();
lvl3Item.popDB(db2, myParent);
}
}
DBHelper.java
public class DBHelper
{
private static final String Database_Name = "MyDBs";
private static final int Database_Version = 2;
public static final String Key_ID = "id";
public static final String Key_Title = "Title";
public static final String Key_Summary = "Summary";
public static final String Key_Book = "Book";
public static final String Key_Chapter = "Chapter";
public static final String Key_Description = "Description";
public static final String Key_SourceType = "SourceType";
private static final String Lvl3_Table_Name = "lvl3";
private static final String Lvl2_Table_Name = "lvl2List";
private static final String Lvl1_Table_Name = "lvl1List";
private static final String Lvl3_Create = "CREATE TABLE IF NOT EXISTS lvl3 (id integer primary key autoincrement, "
+"Summary VARCHAR, Book VARCHAR, Chapter VARCHAR, Description VARCHAR, SourceType VARCHAR);";
private static final String Lvl2_Create = "CREATE TABLE IF NOT EXISTS lvl2List (id integer primary key autoincrement, "
+"Title VARCHAR, Description VARCHAR);";
private static final String Lvl1_Create = "CREATE TABLE IF NOT EXISTS lvl1List (id integer primary key autoincrement, "
+"Title VARCHAR, Description VARCHAR);";
public DBHelper(Context ctx) {
this.context = ctx;
DBhelper = new DatabaseHelper(context);
}
private static class DatabaseHelper extends SQLiteOpenHelper
{
DatabaseHelper(Context context)
{
super(context, Database_Name, null, Database_Version);
}
@Override
public void onCreate(SQLiteDatabase db)
{
try
{
db.execSQL(Lvl3_Create);
db.execSQL(Lvl2_Create);
db.execSQL(Lvl1_Create);
}catch(SQLException e){
}
}
public long insertLvl2Record(String Title, String Description)
{
ContentValues initialValues = new ContentValues();
initialValues.put(Key_Title, Title);
initialValues.put(Key_Description, Description);
return db.insert(Lvl2_Table_Name, null, initialValues);
}
public long insertLvl3Record(String Summary, String Book, String Chapter, String Description, String SourceType)
{
ContentValues initialValues = new ContentValues();
initialValues.put(Key_Summary, Summary);
initialValues.put(Key_Book, Book);
initialValues.put(Key_Chapter, Chapter);
initialValues.put(Key_Description, Description);
initialValues.put(Key_SourceType, SourceType);
return db.insert(Lvl3_Table_Name, null, initialValues);
}
public int getLvl2Count()
{
Cursor c = db.query(Lvl2_Table_Name, new String[] {Key_ID, Key_Title,Key_Description},
null, null, null, null, null);
return c.getCount();
}
public int getLvl3Count()
{
Cursor c = db.query(Lvl3_Table_Name, new String[] {Key_ID, Key_Summary,Key_Book,Key_Verse,Key_Scripts,Key_Description,Key_SourceType}, null, null, null, null, null);
return c.getCount();
}
lvl3.java
public class lvl3
{
DBHelper db2;
List<Parent> parent;
public void popDB(DBHelper db, List<Parent> myParent)
{
this.db2 = db;
this.parent = myParent;
Lvl3Thread lvl3theard = new Lvl3Thread();
lvl3theard.execute();
}
public class Lvl3Thread extends AsyncTask<String, Integer, String>{
@Override
protected String doInBackground(String... params)
{
//Httprequest that get the data for the database… this works
}
@Override
protected void onPostExecute(String result)
{
lvl2 lvl2Item = new lvl2();
lvl2Item.popDB(db2, parent);
}
}
}
lvl2.java
public class lvl3
{
DBHelper db2;
List<Parent> parent;
public void popDB(DBHelper db, List<Parent> myParent)
{
this.db2 = db;
this.parent = myParent;
Lvl3Thread lvl3theard = new Lvl3Thread();
lvl3theard.execute();
}
public class Lvl3Thread extends AsyncTask<String, Integer, String>{
@Override
protected String doInBackground(String... params)
{
//Httprequest that get the data for the database… this works
}
@Override
protected void onPostExecute(String result)
{
lvl2 lvl2Item = new lvl2();
lvl2Item.popDB(db2, parent);
}
}
public void popLvl2List(DBHelper db)
{
List<lvItem> childlvItems = new ArrayList<lvItem>();
Cursor cLvl3 = db.getAllLvl3Records();
db.getLvl2Count(); //This is where the error is coming from stating that there is no lvl2List table
}
}
我尝试使用db2.detLvl2Count();，但这不起作用。如果我评论该行out the program will run. I have tried reordering the db.execSQL so that db.execSQL(Lvl2_Create);是第一个，但我仍然得到该表不存在的错误。
答案 0 :(得分：3)
onCreate类的 DBHelper。
您是否有机会稍后添加lvl2List表？
如果是，请尝试重新安装该应用，然后重试。
添加/更改SQL表时，请使用onUpgrade方法。请参阅official documentation
同样在您onCreate的{{1}} DBHelper方法中，您需要＆＃34;进食＆＃34; SQLException - 不要这样做 - 它可能会为您提供有趣的信息; - ）
吃Exception我的意思是，你默默地＆＃34;处理异常并继续前进。
这是onCreate的<{1}}方法：
DatabaseHelper注意@Override
public void onCreate(SQLiteDatabase db) {
try {
db.execSQL(Lvl3_Create);
db.execSQL(Lvl2_Create);
db.execSQL(Lvl1_Create);
} catch (SQLException e) {
// Handle a possible exception here.
}
}
- 子句。在这里，您至少应该catch或e.printStacktrace();。
在您的情况下，您可能没有完成此日志记录，因为Log.e(e);方法仅在您第一次安装和启动应用程序时调用。
关于此问题，请参阅此SO post或仅搜索Google - 这是一个已知问题＆＃34; /＆＃34;行为＆＃34;我们作为程序员倾向于做; - ）
可以找到关于如何处理异常的良好信息here。
答案 1 :(得分：0)
我知道这个话题已经过时并且已经解决了。但是我想把这个提示包含在像我一样的其他人有同样的问题。尝试在文件名中包含.db，如：
Order.where(...).fetch({withRelated: 'items'}).then(...)这解决了我的问题