1

我目前正在为 Android SDK 制作一个应用程序，它允许我打开/复制已经在应用程序之外创建的数据库。我无法让我的程序读取数据库中的表。根据我之前发布的一个问题的一些建议，我编写了一个类，它可以直接调用 SQLiteDatabase 并在 Android SDK 附带的 sqlite3 版本中创建我的数据库。现在，由于某种原因，我的程序甚至无法打开数据库。它似乎认识到它在那里，但是 Logcat（我正在使用带有 ADT 插件的 Eclipse Juno）现在一直告诉我它“无法打开数据库”。有谁知道可能是什么问题？

这是我的所有代码（为了彻底）：

public class MyDatabase
{
private static final String TABLE_OS = "OregonState";
private static final String COLUMN_ID = "_id";
private static final String COLUMN_NAME = "Name";
private static final String COLUMN_FIELD = "Field";

SQLiteDatabase database;
String path;

public MyDatabase()
{
        File file = new File("/scratch/android-sdk-linux/tools/os.sqlite");
        database = SQLiteDatabase.openOrCreateDatabase(file, null);
        path = database.getPath();
        database.close();
}

public long insert(ContentValues values, String name, String field)
{
    database = SQLiteDatabase.openDatabase(path, null, SQLiteDatabase.OPEN_READWRITE);
    values.put("Name", name);
    values.put("Field", field);
    long id = database.insert(TABLE_OS, null, values);
    database.close();
    return id;
}

public long insert(ContentValues values, String name)
{
    database = SQLiteDatabase.openDatabase(path, null, SQLiteDatabase.OPEN_READWRITE);
    values.put("Name", name);
    long id = database.insert(TABLE_OS, null, values);
    database.close();
    return id;
}

public int delete(int id)
{
    database = SQLiteDatabase.openDatabase(path, null, SQLiteDatabase.OPEN_READWRITE);
    database.delete(TABLE_OS, COLUMN_ID + "=" + id, null);
    database.close();
    return 1;
}

public int update(ContentValues values, int id, String name, String field)
{
    database = SQLiteDatabase.openDatabase(path, null, SQLiteDatabase.OPEN_READWRITE);
    values.put("Name", name);
    values.put("Field", field);
    database.update(TABLE_OS, values, COLUMN_ID + "=" + id, null);
    database.close();
    return 1;
}

public int update(ContentValues values, int id, String name)
{
    database = SQLiteDatabase.openDatabase(path, null, SQLiteDatabase.OPEN_READWRITE);
    values.put("Name", name);
    database.update(TABLE_OS, values, COLUMN_ID + "=" + id, null);
    database.close();
    return 1;
}

public Cursor get(int id)
{
    return database.query(TABLE_OS, new String[] {COLUMN_ID, COLUMN_NAME, COLUMN_FIELD}, COLUMN_ID + "=" + id, null, null, null, null);
}

public Cursor getAll()
{
    return database.query(TABLE_OS, new String[] {COLUMN_ID, COLUMN_NAME, COLUMN_FIELD}, null, null, null, null, null);
}
}


public class SQLTest extends Activity
{
SQLAdapter adapter;
MyDatabase database;

@Override
public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_sqltest);
    database = new MyDatabase();
    database.getAll();
}

@Override
public boolean onCreateOptionsMenu(Menu menu)
{
    getMenuInflater().inflate(R.menu.activity_sqltest, menu);
    return true;
} 

public long insert(String name, String field)
{
    ContentValues values = new ContentValues();
    long id = database.insert(values, name, field);
    return id;
}

public long insert(String name)
{
    ContentValues values = new ContentValues();
    long id = database.insert(values, name);
    return id;
}

public int delete(int id)
{
    int rowsDeleted = database.delete(id);
    return rowsDeleted;
}

public int update(int id, String name, String field)
{
    ContentValues values = new ContentValues();
    int rowsUpdated = database.update(values, id, name, field);
    return rowsUpdated;
}

public int update(int id, String name)
{
    ContentValues values = new ContentValues();
    int rowsUpdated = database.update(values, id, name);
    return rowsUpdated;
}

public void get(int id)
{
    Cursor cursor = database.get(id);
    TextView tv = new TextView(this);
    String table = "";
    if (cursor.moveToFirst())
        table += "\n" + cursor.getString(0) + " " + cursor.getString(1) + " " + cursor.getString(2);
    else
        table += "No hall found with ID: " + id;
    tv.setText(table);
    setContentView(tv);
    cursor.close();
}

public void getAll()
{
    TextView tv = new TextView(this);
    String table = "";
    try
    {
        Cursor cursor = database.getAll();
        if (cursor.moveToFirst())
        {
            do
            {
                table += "\n" + cursor.getString(0) + " " + cursor.getString(1) + " " + cursor.getString(2);
            } while (cursor.moveToNext());
        }
        cursor.close();
    } catch (Exception e) {}
    tv.setText(table);
    setContentView(tv);
}
}

这也是我的 Logcat 日志：

07-16 15:27:08.364: E/Trace(810): error opening trace file: No such file or directory (2)
07-16 15:27:08.504: E/SQLiteLog(810): (14) cannot open file at line 30174 of [00bb9c9ce4]
07-16 15:27:08.504: E/SQLiteLog(810): (14) os_unix.c:30174: (2) open(/scratch/android-sdk-linux/tools/os.sqlite) - 
07-16 15:27:08.524: E/SQLiteDatabase(810): Failed to open database '/scratch/android-sdk-linux/tools/os.sqlite'.
07-16 15:27:08.524: E/SQLiteDatabase(810): android.database.sqlite.SQLiteCantOpenDatabaseException: unknown error (code 14): Could not open database
07-16 15:27:08.524: E/SQLiteDatabase(810):  at android.database.sqlite.SQLiteConnection.nativeOpen(Native Method)
07-16 15:27:08.524: E/SQLiteDatabase(810):  at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:209)
07-16 15:27:08.524: E/SQLiteDatabase(810):  at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:193)
07-16 15:27:08.524: E/SQLiteDatabase(810):  at android.database.sqlite.SQLiteConnectionPool.openConnectionLocked(SQLiteConnectionPool.java:463)
07-16 15:27:08.524: E/SQLiteDatabase(810):  at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:185)
07-16 15:27:08.524: E/SQLiteDatabase(810):  at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:177)
07-16 15:27:08.524: E/SQLiteDatabase(810):  at android.database.sqlite.SQLiteDatabase.openInner(SQLiteDatabase.java:804)
07-16 15:27:08.524: E/SQLiteDatabase(810):  at android.database.sqlite.SQLiteDatabase.open(SQLiteDatabase.java:789)
07-16 15:27:08.524: E/SQLiteDatabase(810):  at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:694)
07-16 15:27:08.524: E/SQLiteDatabase(810):  at android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java:709)
07-16 15:27:08.524: E/SQLiteDatabase(810):  at android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java:702)
07-16 15:27:08.524: E/SQLiteDatabase(810):  at com.example.sql2.MyDatabase.<init>(MyDatabase.java:26)
07-16 15:27:08.524: E/SQLiteDatabase(810):  at com.example.sql2.SQLTest.onCreate(SQLTest.java:20)
07-16 15:27:08.524: E/SQLiteDatabase(810):  at android.app.Activity.performCreate(Activity.java:5008)
07-16 15:27:08.524: E/SQLiteDatabase(810):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
07-16 15:27:08.524: E/SQLiteDatabase(810):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
07-16 15:27:08.524: E/SQLiteDatabase(810):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
07-16 15:27:08.524: E/SQLiteDatabase(810):  at android.app.ActivityThread.access$600(ActivityThread.java:130)
07-16 15:27:08.524: E/SQLiteDatabase(810):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
07-16 15:27:08.524: E/SQLiteDatabase(810):  at android.os.Handler.dispatchMessage(Handler.java:99)
07-16 15:27:08.524: E/SQLiteDatabase(810):  at android.os.Looper.loop(Looper.java:137)
07-16 15:27:08.524: E/SQLiteDatabase(810):  at android.app.ActivityThread.main(ActivityThread.java:4745)
07-16 15:27:08.524: E/SQLiteDatabase(810):  at java.lang.reflect.Method.invokeNative(Native Method)
07-16 15:27:08.524: E/SQLiteDatabase(810):  at java.lang.reflect.Method.invoke(Method.java:511)
07-16 15:27:08.524: E/SQLiteDatabase(810):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
07-16 15:27:08.524: E/SQLiteDatabase(810):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
07-16 15:27:08.524: E/SQLiteDatabase(810):  at dalvik.system.NativeStart.main(Native Method)
07-16 15:27:08.524: D/AndroidRuntime(810): Shutting down VM
07-16 15:27:08.524: W/dalvikvm(810): threadid=1: thread exiting with uncaught exception (group=0x40a13300)
07-16 15:27:08.534: E/AndroidRuntime(810): FATAL EXCEPTION: main
07-16 15:27:08.534: E/AndroidRuntime(810): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.sql2/com.example.sql2.SQLTest}: android.database.sqlite.SQLiteCantOpenDatabaseException: unknown error (code 14): Could not open database
07-16 15:27:08.534: E/AndroidRuntime(810):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
07-16 15:27:08.534: E/AndroidRuntime(810):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
07-16 15:27:08.534: E/AndroidRuntime(810):  at   android.app.ActivityThread.access$600(ActivityThread.java:130)
07-16 15:27:08.534: E/AndroidRuntime(810):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
07-16 15:27:08.534: E/AndroidRuntime(810):  at android.os.Handler.dispatchMessage(Handler.java:99)
07-16 15:27:08.534: E/AndroidRuntime(810):  at android.os.Looper.loop(Looper.java:137)
07-16 15:27:08.534: E/AndroidRuntime(810):  at android.app.ActivityThread.main(ActivityThread.java:4745)
07-16 15:27:08.534: E/AndroidRuntime(810):  at java.lang.reflect.Method.invokeNative(Native Method)
07-16 15:27:08.534: E/AndroidRuntime(810):  at java.lang.reflect.Method.invoke(Method.java:511)
07-16 15:27:08.534: E/AndroidRuntime(810):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
07-16 15:27:08.534: E/AndroidRuntime(810):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
07-16 15:27:08.534: E/AndroidRuntime(810):  at dalvik.system.NativeStart.main(Native Method)
07-16 15:27:08.534: E/AndroidRuntime(810): Caused by: android.database.sqlite.SQLiteCantOpenDatabaseException: unknown error (code 14): Could not open database
07-16 15:27:08.534: E/AndroidRuntime(810):  at android.database.sqlite.SQLiteConnection.nativeOpen(Native Method)
07-16 15:27:08.534: E/AndroidRuntime(810):  at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:209)
07-16 15:27:08.534: E/AndroidRuntime(810):  at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:193)
07-16 15:27:08.534: E/AndroidRuntime(810):  at android.database.sqlite.SQLiteConnectionPool.openConnectionLocked(SQLiteConnectionPool.java:463)
07-16 15:27:08.534: E/AndroidRuntime(810):  at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:185)
07-16 15:27:08.534: E/AndroidRuntime(810):  at  android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:177)
07-16 15:27:08.534: E/AndroidRuntime(810):  at android.database.sqlite.SQLiteDatabase.openInner(SQLiteDatabase.java:804)
07-16 15:27:08.534: E/AndroidRuntime(810):  at android.database.sqlite.SQLiteDatabase.open(SQLiteDatabase.java:789)
07-16 15:27:08.534: E/AndroidRuntime(810):  at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:694)
07-16 15:27:08.534: E/AndroidRuntime(810):  at android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java:709)
07-16 15:27:08.534: E/AndroidRuntime(810):  at android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java:702)
07-16 15:27:08.534: E/AndroidRuntime(810):  at com.example.sql2.MyDatabase.<init>(MyDatabase.java:26)
07-16 15:27:08.534: E/AndroidRuntime(810):  at com.example.sql2.SQLTest.onCreate(SQLTest.java:20)
07-16 15:27:08.534: E/AndroidRuntime(810):  at android.app.Activity.performCreate(Activity.java:5008)
07-16 15:27:08.534: E/AndroidRuntime(810):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
07-16 15:27:08.534: E/AndroidRuntime(810):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
07-16 15:27:08.534: E/AndroidRuntime(810):  ... 11 more
4

5 回答 5

2

将此权限添加到您的项目

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
于 2013-11-05T06:20:29.717 回答
1

Logcat 显示该目录不存在。这并不奇怪，因为在 Android 设备的根目录下通常没有临时目录。

最好避免使用绝对路径名，因为您不能确定它们是否始终存在于您的应用程序可能运行的不同设备上。访问应用程序文件的正确方法是在打开文件时使用Environment 。例如：

File file = new File(Environment.getExternalStorageDirectory() + "/scratch/os.sqlite");

这通常存在于 sdcard 或内部存储器上指定为“sd 卡”的软链接目录中。所以这个例子会在scratch目录下的sdcard上打开一个文件。

如何将数据库文件放到设备或模拟器上取决于您。如果您使用的是模拟器，则可以使用文件资源管理器将文件推送到适当的目录中。

于 2012-07-16T23:49:51.517 回答
1

Android 默认压缩大于 1MB 的文件。旧版本的Android OS有一个bug，导致压缩的资源文件被错误读取。最简单的解决方法是使用资源文件扩展名，例如“.mp3”

于 2014-09-16T23:59:03.557 回答
0

据我所知，Android 文件系统中没有“scratch”目录。你打电话时

File file = new File("/scratch/android-sdk-linux/tools/os.sqlite");
database = SQLiteDatabase.openOrCreateDatabase(file, null);

我相信第二个语句会抛出一些错误，因为/scratch/android-sdk-linux/tools/os.sqlite文件路径不存在。尝试调用file.mkdirs()或file.createNewFile()。

于 2012-07-16T23:16:00.400 回答
0

我对另一个问题的回答做出了回应，并使用两个单独的类以及适配器和帮助器重写了我的代码，结果证明它工作得很好。我提供了代码的链接，以防其他人像我一样在开发 SQLiteDatabase 时遇到问题。

于 2012-07-18T16:58:28.463 回答