) 私は Android プログラミングの初心者で、ほとんど問題はありません。シンプルなデータベースアプリを作成しました（データベースが用意されています）。それを電話のアプリフォルダーにコピーする必要があります。これには方法があります。エミュレーターでアプリを実行するとすべて動作しますが、このアプリを携帯電話にコピーするとアプリがクラッシュします。手伝って頂けますか？これは dbAdapter です。
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);
}
}
}
そして、それが私がファイルをコピーする方法です：
dbAdapter baza = new dbAdapter(this);
baza.copyDatabase();
または baza.assetOpenDatabase(); 同じ効果。
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