在2小时之前我从eclipse文件浏览器中提取了我的db文件，那时它已经拥有了所有数据。但现在当我通过拉动db文件检查它只有一个表android_metadata没有别的我感到震惊 为什么会这样？ 可以解释一下吗？
我的完整数据库代码
package com.example.istudy;
import java.text.ParseException;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.graphics.AvoidXfermode;
import android.util.Log;
import com.example.dbtable.ProfileTable;
import com.example.dbtable.Sem5;
public class DBHandler extends SQLiteOpenHelper {
private static final int VERSION = 1;
private static final String DB_NAME = "iStudy";
private static final String TABLE_NAME1 = "sem5";
private static final String TABLE_NAME2 = "profile";
//columns
private static final String KEY_SUBJ = "sub_name";
private static final String KEY_CHAP = "total_chapters";
private static final String KEY_CHAP_COMPLETED = "chap_completed";
private static final String KEY_CHAP_REMAINING = "chap_remaining";
private static final String KEY_NAME = "name";
private static final String KEY_SEM = "sem";
private static final String KEY_COLG_TIMING = "colg_timing";
private static final String KEY_STUDY_HOURS = "study_hours";
private static final String KEY_TERM_START = "term_start";
private static final String KEY_TERM_END = "term_end";
public DBHandler(Context context) {
super(context, DB_NAME, null, VERSION);
// TODO Auto-generated constructor stub
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
Log.d(Profile.getTag(), "oncreate (...) is ececuting ...");
String create_table = "CREATE TABLE " + TABLE_NAME1 + " ( " + KEY_SUBJ + " TEXT PRIMARY KEY , " + KEY_CHAP + " INTEGER , " +
KEY_CHAP_COMPLETED + " INTEGER, " + KEY_CHAP_REMAINING + " INTEGER " + " )";
db.execSQL(create_table);
create_table = null;
create_table = "CREATE TABLE " + TABLE_NAME2 + " ( " + KEY_NAME + " TEXT PRIMARY KEY, " + KEY_SEM + " INTEGER , " + KEY_COLG_TIMING + " TEXT ," +
KEY_STUDY_HOURS + " TEXT , " + KEY_TERM_START + " DATE , " + KEY_TERM_END + " DATE )";
db.execSQL(create_table);
Log.d(Profile.getTag(), "After creating table inserting sem5 table data");
insertInSem5Table(db);
}
private void insertInSem5Table(SQLiteDatabase db ){
String[] subName = {"ADBMS","CN","EVS","MP","TCS"};
for (int i = 0; i < subName.length; i++) {
ContentValues values = new ContentValues();
values.put(KEY_SUBJ, subName[i]);
if( !(subName[i].equals("MP")) ){
values.put(KEY_CHAP, 8);
}
else{
values.put(KEY_CHAP, 7);
}
values.put(KEY_CHAP_COMPLETED, -1);
if( !(subName[i].equals("MP")) ){
values.put(KEY_CHAP_REMAINING, 8);
}
else{
values.put(KEY_CHAP_REMAINING, 7);
}
long insert = db.insert(TABLE_NAME1, null, values);
Log.d(Profile.getTag() , String.valueOf(insert)) ;
}
Log.d(Profile.getTag(), "closing the db after inserting sem5 data");
db.close();
}
public void insertProfileData(String name, int sem, String colgTimingFrom, String colgTimingTo, String studyHourFrom, String studyHourTo,
Date termStart, Date termEnd ){
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_NAME, name);
values.put(KEY_SEM, sem);
values.put(KEY_COLG_TIMING, colgTimingFrom + " " + colgTimingTo );
values.put(KEY_STUDY_HOURS, studyHourFrom + " " + studyHourTo );
values.put(KEY_TERM_START, termStart.toString() );
values.put(KEY_TERM_END, termEnd.toString() );
db.insert(TABLE_NAME2, null, values);
Log.d(Profile.getTag(), "values inserted successfully ....");
db.close();
}
public List<Sem5> getAllRecordsOfSem5Table( ){
List<Sem5> list = new ArrayList<Sem5>();
String query = "SELECT * FROM " + TABLE_NAME1;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(query, null);
if( cursor.moveToFirst() ){
do{
Sem5 sem5 = new Sem5();
// int columnIndex = cursor.getColumnIndex(KEY_SUBJ);
// int columnIndex2 = cursor.getColumnIndex(KEY_CHAP);
// int columnIndex3 = cursor.getColumnIndex(KEY_CHAP_COMPLETED);
// int columnIndex4 = cursor.getColumnIndex(KEY_CHAP_REMAINING);
//
//
//
// Log.d("naved " , cursor.getString(columnIndex));
// Log.d("naved " , cursor.getString(columnIndex2));
// Log.d("naved " , cursor.getString(columnIndex3));
//// Log.d("naved " , cursor.getString(columnIndex4));
// String string = cursor.getString(columnIndex4);
// if( string == null )
// Log.d("naved chap_remaing " , " null " );
// else
// Log.d("naved chap_remainig " , string);
sem5.setKEY_SUBJ(cursor.getString(0));
sem5.setKEY_CHAP(Integer.parseInt(cursor.getString(1)));
sem5.setKEY_CHAP_COMPLETED(Integer.parseInt(cursor.getString(2)));
sem5.setKEY_CHAP_REMAINING(Integer.parseInt(cursor.getString(3)));
list.add(sem5);
}while(cursor.moveToNext());
}
db.close();
return list;
}
public List<ProfileTable> getAllRecordsOfProfileTable( ){
Log.d(Profile.getTag(), "Getting all records of profile table ....");
List<ProfileTable> list = new ArrayList<ProfileTable>();
String query = "SELECT * FROM " + TABLE_NAME2;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(query, null);
if( cursor.moveToFirst() ){
do{
ProfileTable profileTable = new ProfileTable();
profileTable.setKEY_NAME(cursor.getString(0));
profileTable.setKEY_SEM(Integer.parseInt(cursor.getString(1)));
Date colgTiming = null, studyHrs = null, termStart = null, termEnd = null;
try {
colgTiming = java.text.DateFormat.getInstance().parse(cursor.getString(2));
studyHrs = java.text.DateFormat.getInstance().parse(cursor.getString(3));
termStart = java.text.DateFormat.getInstance().parse(cursor.getString(4));
termEnd = java.text.DateFormat.getInstance().parse(cursor.getString(5));
profileTable.setKEY_COLG_TIMING( colgTiming);
profileTable.setKEY_STUDY_HOURS(studyHrs);
profileTable.setKEY_TERM_START(termStart);
profileTable.setKEY_TERM_END(termEnd);
list.add(profileTable);
} catch (Exception e) {
// TODO: handle exception
db.close();
return null;
}
}while(cursor.moveToNext());
}
Log.d(Profile.getTag(), "Closing db ....after getting profile table...");
db.close();
return list;
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
}
}
我的活动代码
public class Profile extends Activity implements OnClickListener {
private static final String TAG = "iStudy";
//private DBHandler dbHandler;
public static String getTag() {
return TAG;
}
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
DBHandler dbHandler = new DBHandler(this);
Log.d(TAG , "Retriving profile data ...");
List<ProfileTable> allRecordsOfProfileTable = dbHandler.getAllRecordsOfProfileTable();
if( allRecordsOfProfileTable == null || allRecordsOfProfileTable.size() == 0 ){
Log.d(TAG , "Retrived profile record ..it was either null or allRecordsOfProfileTable.size() == 0 ... so starting profile_activity");
setContentView( R.layout.profile_screen );
}else{
Log.d(TAG , "Retrived profile record ..it was not null so starting home_activity");
setContentView( R.layout.home_activity ) ;
}
Button nxtBtn = (Button) findViewById(R.id.nxtBtn);
nxtBtn.setOnClickListener(this);
} }
如果您想了解更多信息，我只会向您展示相关代码。
对于任何想要更多日志信息的人，请参阅此
答案 0 :(得分：0)
从我的代码中可以看出，资产文件夹中的数据库与应用程序之间目前没有关联，除了数据库位于资产文件夹中。
我希望在某些时候您的应用程序已卸载，可能是通过调试，然后数据库是新的，没有表，如果您没有找到创建新表的代码，结果是一个空数据库。
如果您想在运行时将资产文件夹中的数据库复制到您的应用程序中，您必须执行Open SQLite database fails Android
中的答案。有几种工具可以使用sqlite数据库，例如sqlitestudio，sqliteadmin，sqlitedatabasebrowser等来访问和维护资产文件夹中的数据库。 希望这会有所帮助。