来自资产更新问题Android的Sqlite数据库
我已经使用下面的代码从Assets文件夹复制了sqlite数据库。我的应用程序运行良好,但当我想更新任何专栏时,它不允许我这样做。我也设置了getwritabledatabase(),但仍然存在相同的问题。我应该怎么做才能将其更改为可写模式来自资产更新问题Android的Sqlite数据库,android,sqlite,Android,Sqlite,我已经使用下面的代码从Assets文件夹复制了sqlite数据库。我的应用程序运行良好,但当我想更新任何专栏时,它不允许我这样做。我也设置了getwritabledatabase(),但仍然存在相同的问题。我应该怎么做才能将其更改为可写模式 public class DataBaseHelper extends SQLiteOpenHelper { private static String TAG = "DataBaseHelper"; private static String DB
public class DataBaseHelper extends SQLiteOpenHelper
{
private static String TAG = "DataBaseHelper";
private static String DB_PATH = "";
private static String DB_NAME ="Quotes";
private SQLiteDatabase mDataBase;
private final Context mContext;
public DataBaseHelper(Context context)
{
super(context, DB_NAME, null, 1);
DB_PATH = "/data/data/" + context.getPackageName() + "/databases/";
this.mContext = context;
}
public void createDataBase() throws IOException
{
boolean mDataBaseExist = checkDataBase();
if(!mDataBaseExist)
{
super.getWritableDatabase();
this.close();
try
{
//Copy the database from assests
copyDataBase();
Log.e(TAG, "createDatabase database created");
}
catch (IOException mIOException)
{
throw new Error("ErrorCopyingDataBase");
}
}
}
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.OPEN_READWRITE);
return mDataBase != null;
}
@Override
public synchronized void close()
{
if(mDataBase != null)
mDataBase.close();
super.close();
}
@Override
public void onCreate(SQLiteDatabase arg0) {
// TODO Auto-generated method stub
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
}
}
我能够正确地阅读而不能写入。尝试更改此
SQLiteDatabase。在此SQLiteDatabase中打开\u READWRITE
。打开数据库时没有本地化的\u COLLATORS。看起来您硬编码了一个可能无法写入的路径。似乎更适合在DataBaseHelper()构造函数中设置:
DB_PATH = getWritableDatabase().getPath();
getWritableDatabase().close();
然后将copyDataBase()
方法更改为仅使用DB\u PATH覆盖新创建的数据库:
//Copy the database from assets
private void copyDataBase() throws IOException
{
InputStream mInput = mContext.getAssets().open(DB_NAME);
OutputStream mOutput = new FileOutputStream(DB_PATH); // <- Just DB_PATH
byte[] mBuffer = new byte[1024];
int mLength;
while ((mLength = mInput.read(mBuffer))>0)
{
mOutput.write(mBuffer, 0, mLength);
}
mOutput.flush();
mOutput.close();
mInput.close();
}
//从资产复制数据库
私有void copyDataBase()引发IOException
{
InputStream mInput=mContext.getAssets().open(DB_NAME);
OutputStream mOutput=新文件OutputStream(DB_路径);//0)
{
mOutput.write(mBuffer,0,最大长度);
}
mOutput.flush();
mOutput.close();
mInput.close();
}
不要再使用openDataBase()
方法。只需在DataBaseHelper实例上调用getWriteableDatabase()即可获取数据库。您的代码看起来正常。我所做的工作如下:
public class DataBaseHelper extends SQLiteOpenHelper{
/*
* Global declaration of variables.
*/
private final Context myContext;
private static String DB_PATH = "";
private static final String DATABASE_NAME = "Quotes";
private static final int DATABASE_VERSION = 1;
static SQLiteDatabase sqliteDataBase;
public DataBaseHelper(Context context) {
super(context, DATABASE_NAME, null ,DATABASE_VERSION);
this.myContext = context;
//The Android's default system path of your application database.
DB_PATH = myContext.getDatabasePath(DATABASE_NAME).getPath();
}
public void createDataBase() throws IOException{
boolean databaseExist = checkDataBase();
if(databaseExist){
}else{
this.getWritableDatabase();
copyDataBase();
}
}
public boolean checkDataBase(){
File databaseFile = new File(DB_PATH);
return databaseFile.exists();
}
private void copyDataBase() throws IOException{
InputStream myInput = myContext.getAssets().open(DATABASE_NAME);
String outFileName = DB_PATH;
OutputStream myOutput = new FileOutputStream(outFileName);
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer))>0){
myOutput.write(buffer, 0, length);
}
myOutput.flush();
myOutput.close();
myInput.close();
}
public void openDataBase() throws SQLException{
String myPath = DB_PATH;
sqliteDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READWRITE);
}
@Override
public synchronized void close() {
if(sqliteDataBase != null)
sqliteDataBase.close();
super.close();
}
这可能会对您有所帮助。错误是什么,堆栈跟踪,logcat?没有错误。我只是无法更新任何列。@MayuriRuparel您在调用getwritabledatabase
时是否遇到任何错误?