问题
) I am beginner in Android programming and I have little problem. I wrote simple DataBase app(I have ready Data Base) and I need to copy it to app folder on phone. I have method for this. When I run app on emulator, all works but when I copy this app to my phone, app have crash. Can you help me? This is dbAdapter:
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import android.app.Application;
import android.content.ContentValues;
import android.content.Context;
import android.content.ContextWrapper;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;
public class dbAdapter {
private static final String DB_NAME = "names2.db";
private static final int DB_VERSION = 1;
private static final String DB_TABLE = "names";
String DB_PATH;
public static final String KEY_ID = "_id";
public static final String KEY_NAME = "name";
public static final int NAME_COLUMN = 1;
public static final String KEY_SEX = "sex";
public static final int SEX_COLUMN = 2;
public static final String KEY_RACE = "race";
public static final int RACE_COLUMN = 3;
private SQLiteDatabase db;
private final Context context;
private DatabaseHelper myDatabaseHelper;
public dbAdapter(Context _context){
context = _context;
//DB_PATH = context.getApplicationContext().getFilesDir().getPath();
DB_PATH = context.getFilesDir().getPath()+"/databases/";
myDatabaseHelper = new DatabaseHelper(_context,DB_NAME,null,DB_VERSION);
}
public dbAdapter open(){
db = myDatabaseHelper.getReadableDatabase();
return this;
}
public void close(){
db.close();
}
public long insert(rekord _rekord){
ContentValues newRekord = new ContentValues();
newRekord.put(KEY_NAME, _rekord.getName());
newRekord.put(KEY_SEX, _rekord.getSex());
newRekord.put(KEY_RACE, _rekord.getRace());
return db.insert(DB_TABLE, null, newRekord);
}
public String getData(String sex, String race) {
Cursor mycursor = db.rawQuery("SELECT name FROM names WHERE sex ="+sex+" AND race="+race+" ORDER BY RANDOM() LIMIT 1", null);
if(mycursor.moveToFirst()){ //Edited based on suggestion from SAM
String strCatName = mycursor.getString(mycursor.getColumnIndex(KEY_NAME));
return strCatName;
} else {
return null;
}
// return db.rawQuery("SELECT name FROM names WHERE sex =1 ORDER BY RANDOM() LIMIT 1", new String[]{"name"});
}
public void copyDatabase() throws IOException{ //niby kopiowanie bazy danych. Nie wiem czy dobre bo nie chce działać
//Open your local db as the input stream
InputStream myInput = context.getAssets().open(DB_NAME);
// Path to the just created empty db
String outFileName = DB_PATH + DB_NAME;
//Open the empty db as the output stream
OutputStream myOutput = new FileOutputStream(outFileName);
//transfer bytes from the inputfile to the outputfile
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer))>0){
myOutput.write(buffer, 0, length);
}
//Close the streams
myOutput.flush();
myOutput.close();
myInput.close();
}
public void del(){
File file = new File(DB_PATH+DB_NAME);
if(file.exists())
file.delete();
}
public SQLiteDatabase assetOpenDatabase() {
File dbFile = context.getDatabasePath(DB_NAME);
if (!dbFile.exists()) {
try {
assetCopyDatabase(dbFile);
} catch (IOException e) {
throw new RuntimeException("Error creating source database", e);
}
}
return SQLiteDatabase.openDatabase(dbFile.getPath(), null, SQLiteDatabase.OPEN_READONLY);
}
private void assetCopyDatabase(File dbFile) throws IOException {
InputStream is = context.getAssets().open(DB_NAME);
OutputStream os = new FileOutputStream(dbFile);
byte[] buffer = new byte[1024];
while (is.read(buffer) > 0) {
os.write(buffer);
}
os.flush();
os.close();
is.close();
}
//--------------------------------------------------------
class DatabaseHelper extends SQLiteOpenHelper{
public DatabaseHelper(Context context, String name, CursorFactory factory, int version){
super(context,name,factory,version);
}
@Override
public void onCreate(SQLiteDatabase _db){
//_db.execSQL("CREATE TABLE names(_id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, sex NUMERIC NOT NULL, race NUMERIC NOT NULL)");
}
@Override
public void onUpgrade(SQLiteDatabase _db, int oldVer, int newVer){
_db.execSQL("DROP TABLE IF EXISTS "+DB_TABLE);
onCreate(_db);
}
}
}
And that's how I copying file:
dbAdapter baza = new dbAdapter(this);
baza.copyDatabase();
or baza.assetOpenDatabase(); Same effect.
Ehh, now I have error on emulator too...
06-11 21:31:20.510: E/AndroidRuntime(537): FATAL EXCEPTION: main
06-11 21:31:20.510: E/AndroidRuntime(537): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.namesgenerator/com.example.namesgenerator.sex}: java.lang.RuntimeException: Error creating source database
06-11 21:31:20.510: E/AndroidRuntime(537): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)
06-11 21:31:20.510: E/AndroidRuntime(537): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
06-11 21:31:20.510: E/AndroidRuntime(537): at android.app.ActivityThread.access$1500(ActivityThread.java:117)
06-11 21:31:20.510: E/AndroidRuntime(537): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
06-11 21:31:20.510: E/AndroidRuntime(537): at android.os.Handler.dispatchMessage(Handler.java:99)
06-11 21:31:20.510: E/AndroidRuntime(537): at android.os.Looper.loop(Looper.java:123)
06-11 21:31:20.510: E/AndroidRuntime(537): at android.app.ActivityThread.main(ActivityThread.java:3683)
06-11 21:31:20.510: E/AndroidRuntime(537): at java.lang.reflect.Method.invokeNative(Native Method)
06-11 21:31:20.510: E/AndroidRuntime(537): at java.lang.reflect.Method.invoke(Method.java:507)
06-11 21:31:20.510: E/AndroidRuntime(537): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
06-11 21:31:20.510: E/AndroidRuntime(537): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
06-11 21:31:20.510: E/AndroidRuntime(537): at dalvik.system.NativeStart.main(Native Method)
06-11 21:31:20.510: E/AndroidRuntime(537): Caused by: java.lang.RuntimeException: Error creating source database
06-11 21:31:20.510: E/AndroidRuntime(537): at com.example.namesgenerator.dbAdapter.assetOpenDatabase(dbAdapter.java:108)
06-11 21:31:20.510: E/AndroidRuntime(537): at com.example.namesgenerator.sex.onCreate(sex.java:39)
06-11 21:31:20.510: E/AndroidRuntime(537): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
06-11 21:31:20.510: E/AndroidRuntime(537): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
06-11 21:31:20.510: E/AndroidRuntime(537): ... 11 more
06-11 21:31:20.510: E/AndroidRuntime(537): Caused by: java.io.FileNotFoundException: /data/data/com.example.namesgenerator/databases/names2.db (No such file or directory)
06-11 21:31:20.510: E/AndroidRuntime(537): at org.apache.harmony.luni.platform.OSFileSystem.open(Native Method)
06-11 21:31:20.510: E/AndroidRuntime(537): at dalvik.system.BlockGuard$WrappedFileSystem.open(BlockGuard.java:232)
06-11 21:31:20.510: E/AndroidRuntime(537): at java.io.FileOutputStream.<init>(FileOutputStream.java:94)
06-11 21:31:20.510: E/AndroidRuntime(537): at java.io.FileOutputStream.<init>(FileOutputStream.java:66)
06-11 21:31:20.510: E/AndroidRuntime(537): at com.example.namesgenerator.dbAdapter.assetCopyDatabase(dbAdapter.java:117)
06-11 21:31:20.510: E/AndroidRuntime(537): at com.example.namesgenerator.dbAdapter.assetOpenDatabase(dbAdapter.java:106)
06-11 21:31:20.510: E/AndroidRuntime(537): ... 14 more
回答1:
On your phone go to
Settings->Storage
and verify if the flag for Mass storage only isn't selected. When it is selected, your Device can't access the SD card for debugging purposes (nor other purposes in general). That's quite likely the reason the creation of your file is failing.
回答2:
The file you are using to seed your DB is not found, it must be on your filesystem on your machine (emulator can find it).
Here is the relevant error from your Logcat:
Caused by: java.io.FileNotFoundException: /data/data/com.example.namesgenerator/databases/names2.db
回答3:
Either the directory /data/data/com.example.namesgenerator/databases doesn't exist or there is a problem with access rights (you are not allowed to create a file in the directory or you are not allowed to read or modify the already existing file)
来源：https://stackoverflow.com/questions/17054115/application-error-on-phone-but-not-on-emulator