在下面的 LogCat 中，您可以看到我的数据库表永远不会更新，即使我增加了数据库版本。我在我的数据库中添加了一个表，并将其导入到 assets 文件夹中。在我的 onUpgrade 方法中，我删除了以前的旧版本 db 并复制新版本。至少我在我的代码中做到了。我现实从未调用过该方法。我每次都没有得到这样的表格错误。
04-24 02:08:27.502: D/szipinf(6630): Initializing inflate state
04-24 02:08:27.612: D/szipinf(6630): Initializing inflate state
04-24 02:08:27.612: D/szipinf(6630): Initializing zlib to inflate
04-24 02:08:30.972: I/Database(6630): sqlite returned: error code = 1, msg = no such table: tbl4
04-24 02:08:30.972: E/DataAdapter(6630): getTestData >>android.database.sqlite.SQLiteException: no such table: tbl4: , while compiling: SELECT * FROM tbl4 ORDER BY _ID ASC
04-24 02:08:30.982: D/AndroidRuntime(6630): Shutting down VM
04-24 02:08:30.982: W/dalvikvm(6630): threadid=1: thread exiting with uncaught exception (group=0x40018560)
04-24 02:08:31.202: E/AndroidRuntime(6630): FATAL EXCEPTION: main
04-24 02:08:31.202: E/AndroidRuntime(6630): java.lang.RuntimeException: Unable to start activity ComponentInfo{rs.androidaplikacije.themostcompleteiqtest/rs.androidaplikacije.themostcompleteiqtest.LogicTest}: android.database.sqlite.SQLiteException: no such table: tbl4: , while compiling: SELECT * FROM tbl4 ORDER BY _ID ASC
04-24 02:08:31.202: E/AndroidRuntime(6630): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1768)
04-24 02:08:31.202: E/AndroidRuntime(6630): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1784)
04-24 02:08:31.202: E/AndroidRuntime(6630): at android.app.ActivityThread.access$1500(ActivityThread.java:123)
04-24 02:08:31.202: E/AndroidRuntime(6630): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:939)
04-24 02:08:31.202: E/AndroidRuntime(6630): at android.os.Handler.dispatchMessage(Handler.java:99)
04-24 02:08:31.202: E/AndroidRuntime(6630): at android.os.Looper.loop(Looper.java:130)
04-24 02:08:31.202: E/AndroidRuntime(6630): at android.app.ActivityThread.main(ActivityThread.java:3835)
04-24 02:08:31.202: E/AndroidRuntime(6630): at java.lang.reflect.Method.invokeNative(Native Method)
04-24 02:08:31.202: E/AndroidRuntime(6630): at java.lang.reflect.Method.invoke(Method.java:507)
04-24 02:08:31.202: E/AndroidRuntime(6630): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:864)
04-24 02:08:31.202: E/AndroidRuntime(6630): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:622)
04-24 02:08:31.202: E/AndroidRuntime(6630): at dalvik.system.NativeStart.main(Native Method)
04-24 02:08:31.202: E/AndroidRuntime(6630): Caused by: android.database.sqlite.SQLiteException: no such table: tbl4: , while compiling: SELECT * FROM tbl4 ORDER BY _ID ASC
04-24 02:08:31.202: E/AndroidRuntime(6630): at android.database.sqlite.SQLiteCompiledSql.native_compile(Native Method)
04-24 02:08:31.202: E/AndroidRuntime(6630): at android.database.sqlite.SQLiteCompiledSql.compile(SQLiteCompiledSql.java:92)
04-24 02:08:31.202: E/AndroidRuntime(6630): at android.database.sqlite.SQLiteCompiledSql.<init>(SQLiteCompiledSql.java:65)
04-24 02:08:31.202: E/AndroidRuntime(6630): at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:83)
04-24 02:08:31.202: E/AndroidRuntime(6630): at android.database.sqlite.SQLiteQuery.<init>(SQLiteQuery.java:49)
04-24 02:08:31.202: E/AndroidRuntime(6630): at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:42)
04-24 02:08:31.202: E/AndroidRuntime(6630): at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1356)
04-24 02:08:31.202: E/AndroidRuntime(6630): at android.database.sqlite.SQLiteDatabase.rawQuery(SQLiteDatabase.java:1324)
04-24 02:08:31.202: E/AndroidRuntime(6630): at rs.androidaplikacije.themostcompleteiqtest.TestAdapter.getTestDataLogic(TestAdapter.java:103)
04-24 02:08:31.202: E/AndroidRuntime(6630): at rs.androidaplikacije.themostcompleteiqtest.LogicTest.nextQuestion(LogicTest.java:136)
04-24 02:08:31.202: E/AndroidRuntime(6630): at rs.androidaplikacije.themostcompleteiqtest.LogicTest.onCreate(LogicTest.java:93)
04-24 02:08:31.202: E/AndroidRuntime(6630): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
04-24 02:08:31.202: E/AndroidRuntime(6630): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1722)
04-24 02:08:31.202: E/AndroidRuntime(6630): ... 11 more
04-24 02:08:32.912: I/Process(6630): Sending signal. PID: 6630 SIG: 9
数据库助手：
public class DataBaseHelper extends SQLiteOpenHelper
{
private static String TAG = "DataBaseHelper"; // Tag just for the LogCat window
//destination path (location) of our database on device
private static String DB_PATH = "/data/data/rs.androidaplikacije.themostcompleteiqtest/databases/";
private static String DB_NAME ="pitanja.sqlite";// Database name
private static SQLiteDatabase mDataBase;
private final Context mContext;
private static final int DATABASE_VERSION = 25;
public DataBaseHelper(Context mojContext)
{
super(mojContext, DB_NAME, null, DATABASE_VERSION);// 1 it's Database Version
DB_PATH = mojContext.getApplicationInfo().dataDir + "/databases/";
this.mContext = mojContext;
}
public void createDataBase() throws IOException
{
//If database not exists copy it from the assets
this.getReadableDatabase();
this.close();
try
{
//Copy the database from assests
copyDataBase();
Log.e(TAG, "createDatabase database created");
}
catch (IOException mIOException)
{
throw new Error("ErrorCopyingDataBase");
}
}
/**
* Check if the database already exist to avoid re-copying the file each time you open the application.
* @return true if it exists, false if it doesn't
*/
public boolean checkDataBase(){
SQLiteDatabase checkDB = null;
try{
String myPath = DB_PATH + DB_NAME;
checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
}catch(SQLiteException e){
//database does't exist yet.
}
if(checkDB != null){
checkDB.close();
}
return checkDB != null ? true : false;
}
/*Check that the database exists here: /data/data/your package/databases/Da Name
private boolean checkDataBase()
{
File dbFile = new File(DB_PATH + DB_NAME);
//Log.v("dbFile", dbFile + " "+ dbFile.exists());
return dbFile.exists();
}*/
//Copy the database from assets
private void copyDataBase() throws IOException
{
InputStream mInput = mContext.getAssets().open(DB_NAME);
String outFileName = DB_PATH + DB_NAME;
OutputStream mOutput = new FileOutputStream(outFileName);
byte[] mBuffer = new byte[1024];
int mLength;
while ((mLength = mInput.read(mBuffer))>0)
{
mOutput.write(mBuffer, 0, mLength);
}
mOutput.flush();
mOutput.close();
mInput.close();
}
//Open the database, so we can query it
public boolean openDataBase() throws SQLException
{
String mPath = DB_PATH + DB_NAME;
//Log.v("mPath", mPath);
mDataBase = SQLiteDatabase.openDatabase(mPath, null, SQLiteDatabase.CREATE_IF_NECESSARY);
//mDataBase = SQLiteDatabase.openDatabase(mPath, null, SQLiteDatabase.NO_LOCALIZED_COLLATORS);
return mDataBase != null;
}
@Override
public void close()
{
if(mDataBase != null)
mDataBase.close();
super.close();
}
@Override
public void onCreate(SQLiteDatabase arg0) {
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
mContext.deleteDatabase(DB_NAME);
try {
copyDataBase();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
适配器：
public class TestAdapter
{
protected static final String TAG = "DataAdapter";
private final Context mContext;
private SQLiteDatabase mDb;
private DataBaseHelper mDbHelper;
public TestAdapter(Context context)
{
this.mContext = context;
mDbHelper = new DataBaseHelper(mContext);
}
public TestAdapter createDatabase() throws SQLException
{
try
{
mDbHelper.createDataBase();
}
catch (IOException mIOException)
{
Log.e(TAG, mIOException.toString() + " UnableToCreateDatabase");
throw new Error("UnableToCreateDatabase");
}
return this;
}
public TestAdapter open() throws SQLException
{
try
{
mDbHelper.openDataBase();
mDbHelper.close();
mDb = mDbHelper.getReadableDatabase();
}
catch (SQLException mSQLException)
{
Log.e(TAG, "open >>"+ mSQLException.toString());
throw mSQLException;
}
return this;
}
public void close()
{
mDbHelper.close();
}
public Cursor getTestDataMDPI(String whereClause)
{;
try
{
String sql ="SELECT * FROM tblPitanjaDanskaMDPI WHERE 1 = 1 " + whereClause + " ORDER BY _ID ASC";
Cursor mCur = mDb.rawQuery(sql, null);
if (mCur!=null)
{
mCur.moveToNext();
}
return mCur;
}
catch (SQLException mSQLException)
{
Log.e(TAG, "getTestData >>"+ mSQLException.toString());
throw mSQLException;
}
}
public Cursor getTestDataHDPI(String whereClause)
{;
try
{
String sql ="SELECT * FROM tblPitanjaDanskaHDPI WHERE 1 = 1 " + whereClause + " ORDER BY _ID ASC";
Cursor mCur = mDb.rawQuery(sql, null);
if (mCur!=null)
{
mCur.moveToNext();
}
return mCur;
}
catch (SQLException mSQLException)
{
Log.e(TAG, "getTestData >>"+ mSQLException.toString());
throw mSQLException;
}
}
public Cursor getTestDataLogic(String whereClause)
{;
try
{
String sql ="SELECT * FROM tbl4 " + whereClause + " ORDER BY _ID ASC";
Cursor mCur = mDb.rawQuery(sql, null);
if (mCur!=null)
{
mCur.moveToNext();
}
return mCur;
}
catch (SQLException mSQLException)
{
Log.e(TAG, "getTestData >>"+ mSQLException.toString());
throw mSQLException;
}
}
}
这里只是为了让你们看到这个表存在（它是一个工作表，只是为了尝试这个 onUpgrade 方法）：
