问题描述
编辑:我想这对我的手机和它的作品,谁能告诉我,为什么它不能在模拟器工作?
我想在Android上打开一个数据库,但它抛出无法打开数据库文件异常。在调试,似乎错误发生就行了 MDB = mDbHelper.getWritableDatabase();
我的code是如下:
包com.track.map;
进口android.content.Context;
进口android.database.sqlite.SQLiteDatabase;
进口android.database.sqlite.SQLiteOpenHelper;
公共类DBAdapter {
受保护的静态最后弦乐DATABASE_NAME =数据;
受保护的静态最终诠释DATABASE_VERSION = 1;
//数据库表
//跟踪表
受保护的静态最后弦乐TRACK_TABLE =轨道;
受保护的静态最后弦乐TRACK_ID =_id;
受保护的静态最后弦乐TRACK_DATE_TIME_START =date_time_start;
受保护的静态最后弦乐TRACK_DATE_TIME_END =date_time_end;
//表中创建
受保护的静态最后弦乐TRACK_TABLE_CREATE =
创建表+ TRACK_TABLE +(
+ TRACK_ID +integet promary键不为空,
+ TRACK_DATE_TIME_START +文字不为空,
+ TRACK_DATE_TIME_END +文字NOT NULL);;
保护DatabaseHelper mDbHelper;
保护SQLiteDatabase MDB;
受保护的最终上下文mContext;
公共DBAdapter(上下文的背景下){
mContext =背景;
}
公共DBAdapter的open()抛出android.database.SQLException {
mDbHelper =新DatabaseHelper(mContext);
MDB = mDbHelper.getWritableDatabase();
回到这一点;
}
公共无效的close(){
mDb.close();
}
受保护的静态类DatabaseHelper扩展SQLiteOpenHelper {
公共DatabaseHelper(上下文的背景下){
超(背景下,DATABASE_NAME,空,DATABASE_VERSION);
}
@覆盖
公共无效的onCreate(SQLiteDatabase DB){
db.execSQL(TRACK_TABLE_CREATE);
}
@覆盖
公共无效onUpgrade(SQLiteDatabase分贝,INT oldVersion,诠释静态网页){
的onCreate(DB); //现在只是重新创建数据库
}
}
}
和
包com.track.map;
进口android.os.Bundle;
进口android.app.Activity;
进口android.view.Menu;
公共类MainActivity延伸活动{
私人DBAdapter分贝;
@覆盖
保护无效的onCreate(包savedInstanceState){
super.onCreate(savedInstanceState);
的setContentView(R.layout.activity_main);
DB =新DBAdapter(本);
db.open();
}
@覆盖
公共布尔onCreateOptionsMenu(功能菜单){
//充气菜单;这增加了项目操作栏,如果它是present。
。getMenuInflater()膨胀(R.menu.main,菜单);
返回true;
}
}
有谁知道问题是什么?
编辑:
在logcat的是:
11月三号至24号:43:42.022:I /数据库(758):源码返回:错误code = 14,味精=无法打开文件的源代码行25467
11月3日至24号:43:42.022:E /数据库(758):sqlite3_open_v2(/数据/数据/ com.track.map /数据库/数据,和放大器;手柄,6,NULL)失败
11月3日至24号:43:42.032:D / AndroidRuntime(758):关闭虚拟机
11月3日至24号:43:42.032:W / dalvikvm(758):主题ID = 1:螺纹退出与未捕获的异常(组= 0x4001d800)
11月3日至24号:43:42.062:E / AndroidRuntime(758):致命异常:主要
11月3日至24号:43:42.062:E / AndroidRuntime(758):java.lang.RuntimeException的:无法启动的活动ComponentInfo {com.track.map / com.track.map.MainActivity}:android.database.sqlite.SQLiteException :无法打开数据库文件
11月3日至24号:43:42.062:E / AndroidRuntime(758):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
11月3日至24号:43:42.062:E / AndroidRuntime(758):在android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
11月3日至24号:43:42.062:E / AndroidRuntime(758):在android.app.ActivityThread.access $ 2300(ActivityThread.java:125)
11月3日至24号:43:42.062:E / AndroidRuntime(758):在android.app.ActivityThread $ H.handleMessage(ActivityThread.java:2033)
11月3日至24号:43:42.062:E / AndroidRuntime(758):在android.os.Handler.dispatchMessage(Handler.java:99)
11月3日至24号:43:42.062:E / AndroidRuntime(758):在android.os.Looper.loop(Looper.java:123)
11月3日至24号:43:42.062:E / AndroidRuntime(758):在android.app.ActivityThread.main(ActivityThread.java:4627)
11月3日至24号:43:42.062:E / AndroidRuntime(758):在java.lang.reflect.Method.invokeNative(本机方法)
11月3日至24号:43:42.062:E / AndroidRuntime(758):在java.lang.reflect.Method.invoke(Method.java:521)
11月3日至24号:43:42.062:E / AndroidRuntime(758):在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:868)
11月3日至24号:43:42.062:E / AndroidRuntime(758):在com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
11月3日至24号:43:42.062:E / AndroidRuntime(758):在dalvik.system.NativeStart.main(本机方法)
11月3日至24号:43:42.062:E / AndroidRuntime(758):android.database.sqlite.SQLiteException:无法打开数据库文件所致
11月3日至24号:43:42.062:E / AndroidRuntime(758):在android.database.sqlite.SQLiteDatabase.dbopen(本机方法)
11月3日至24号:43:42.062:E / AndroidRuntime(758):在android.database.sqlite.SQLiteDatabase< INIT>(SQLiteDatabase.java:1812)
11月3日至24号:43:42.062:E / AndroidRuntime(758):在android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:817)
11月3日至24号:43:42.062:E / AndroidRuntime(758):在android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java:851)
11月3日至24号:43:42.062:E / AndroidRuntime(758):在android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java:844)
11月3日至24号:43:42.062:E / AndroidRuntime(758):在android.app.ContextImpl.openOrCreateDatabase(ContextImpl.java:540)
11月3日至24号:43:42.062:E / AndroidRuntime(758):在android.content.ContextWrapper.openOrCreateDatabase(ContextWrapper.java:203)
11月3日至24号:43:42.062:E / AndroidRuntime(758):在android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:98)
11月3日至24号:43:42.062:E / AndroidRuntime(758):在com.track.map.DBAdapter.open(DBAdapter.java:37)
11月3日至24号:43:42.062:E / AndroidRuntime(758):在com.track.map.MainActivity.onCreate(MainActivity.java:17)
11月3日至24号:43:42.062:E / AndroidRuntime(758):在android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
11月3日至24号:43:42.062:E / AndroidRuntime(758):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
11月3日至24号:43:42.062:E / AndroidRuntime(758):11 ...更多
这可能有点晚,但希望这有助于为谁得到这个问题(因为我无法找到一个明确的解决办法各地)。
我想我知道了这个原因(至少对我而言)的原因。展望在 DDMS - > 文件管理器,你会认识到,数据库文件夹( /数据/数据//数据库/
)不存在,这是为什么应用程序不能创建在于不存在的文件夹中的数据库文件。如果你能以某种方式创建一个数据库文件夹,就可以避免这个问题。
由于我很懒,我只使用了 /数据/数据//文件/
文件夹,当我在模拟器模式。您可以使用此获得的文件目录:
context.getFilesDir()。getPath()
这在模拟器工作美丽的我。
希望这可以帮助别人。
如果你想看到一些code:
字符串dbFilename =example.db;
尝试
{
文件databaseFile = getDatabasePath(dbFilename);
SQLiteDatabase _db = SQLiteDatabase.openOrCreateDatabase(databaseFile);
}赶上(例外五)
{
串databasePath = getFilesDir()getPath()+/+ dbFilename。
文件databaseFile =新的文件(databasePath);
_db = SQLiteDatabase.openOrCreateDatabase(databaseFile);
}
编辑:
我尝试登录到Facebook的(我的应用程序有FB集成)的仿真器和/数据库文件出现后(并坚持)。不知道发生了什么,但它可能以某种方式创建该文件夹。我下一次的专家在这里阐明光。
Edit:I tried this on my phone and it works, can anyone tell me why it does not work on an emulator?
I am trying to open a database on android, but it is throwing an "Database file could not be opened" Exception. In the debugger, it seems that the error is occurring on the line mDb = mDbHelper.getWritableDatabase();
My code is as follows:
package com.track.map;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class DBAdapter {
protected static final String DATABASE_NAME = "data";
protected static final int DATABASE_VERSION = 1;
//database tables
//track table
protected static final String TRACK_TABLE = "tracks";
protected static final String TRACK_ID = "_id";
protected static final String TRACK_DATE_TIME_START = "date_time_start";
protected static final String TRACK_DATE_TIME_END = "date_time_end";
//tables create
protected static final String TRACK_TABLE_CREATE =
"create table " + TRACK_TABLE + " ("
+ TRACK_ID + " integet promary key not null, "
+ TRACK_DATE_TIME_START + " text not null, "
+ TRACK_DATE_TIME_END + " text not null);";
protected DatabaseHelper mDbHelper;
protected SQLiteDatabase mDb;
protected final Context mContext;
public DBAdapter(Context context) {
mContext = context;
}
public DBAdapter open() throws android.database.SQLException {
mDbHelper = new DatabaseHelper(mContext);
mDb = mDbHelper.getWritableDatabase();
return this;
}
public void close() {
mDb.close();
}
protected static class DatabaseHelper extends SQLiteOpenHelper {
public DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(TRACK_TABLE_CREATE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
onCreate(db); //for now just recreate the database
}
}
}
and
package com.track.map;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
public class MainActivity extends Activity {
private DBAdapter db;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
db = new DBAdapter(this);
db.open();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
Does anyone know what the problem is?
EDIT:
The logcat is:
03-24 11:43:42.022: I/Database(758): sqlite returned: error code = 14, msg = cannot open file at source line 25467
03-24 11:43:42.022: E/Database(758): sqlite3_open_v2("/data/data/com.track.map/databases/data", &handle, 6, NULL) failed
03-24 11:43:42.032: D/AndroidRuntime(758): Shutting down VM
03-24 11:43:42.032: W/dalvikvm(758): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
03-24 11:43:42.062: E/AndroidRuntime(758): FATAL EXCEPTION: main
03-24 11:43:42.062: E/AndroidRuntime(758): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.track.map/com.track.map.MainActivity}: android.database.sqlite.SQLiteException: unable to open database file
03-24 11:43:42.062: E/AndroidRuntime(758): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
03-24 11:43:42.062: E/AndroidRuntime(758): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
03-24 11:43:42.062: E/AndroidRuntime(758): at android.app.ActivityThread.access$2300(ActivityThread.java:125)
03-24 11:43:42.062: E/AndroidRuntime(758): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
03-24 11:43:42.062: E/AndroidRuntime(758): at android.os.Handler.dispatchMessage(Handler.java:99)
03-24 11:43:42.062: E/AndroidRuntime(758): at android.os.Looper.loop(Looper.java:123)
03-24 11:43:42.062: E/AndroidRuntime(758): at android.app.ActivityThread.main(ActivityThread.java:4627)
03-24 11:43:42.062: E/AndroidRuntime(758): at java.lang.reflect.Method.invokeNative(Native Method)
03-24 11:43:42.062: E/AndroidRuntime(758): at java.lang.reflect.Method.invoke(Method.java:521)
03-24 11:43:42.062: E/AndroidRuntime(758): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
03-24 11:43:42.062: E/AndroidRuntime(758): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
03-24 11:43:42.062: E/AndroidRuntime(758): at dalvik.system.NativeStart.main(Native Method)
03-24 11:43:42.062: E/AndroidRuntime(758): Caused by: android.database.sqlite.SQLiteException: unable to open database file
03-24 11:43:42.062: E/AndroidRuntime(758): at android.database.sqlite.SQLiteDatabase.dbopen(Native Method)
03-24 11:43:42.062: E/AndroidRuntime(758): at android.database.sqlite.SQLiteDatabase.<init>(SQLiteDatabase.java:1812)
03-24 11:43:42.062: E/AndroidRuntime(758): at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:817)
03-24 11:43:42.062: E/AndroidRuntime(758): at android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java:851)
03-24 11:43:42.062: E/AndroidRuntime(758): at android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java:844)
03-24 11:43:42.062: E/AndroidRuntime(758): at android.app.ContextImpl.openOrCreateDatabase(ContextImpl.java:540)
03-24 11:43:42.062: E/AndroidRuntime(758): at android.content.ContextWrapper.openOrCreateDatabase(ContextWrapper.java:203)
03-24 11:43:42.062: E/AndroidRuntime(758): at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:98)
03-24 11:43:42.062: E/AndroidRuntime(758): at com.track.map.DBAdapter.open(DBAdapter.java:37)
03-24 11:43:42.062: E/AndroidRuntime(758): at com.track.map.MainActivity.onCreate(MainActivity.java:17)
03-24 11:43:42.062: E/AndroidRuntime(758): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
03-24 11:43:42.062: E/AndroidRuntime(758): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
03-24 11:43:42.062: E/AndroidRuntime(758): ... 11 more
This may be a little late, but hope this helps for whoever gets this problem (since I can't find a definitive solution around).
I think I know the reason for this cause (at least for my case). Looking in the DDMS --> File Explorer, you'd realize that the Database Folder (/data/data//databases/
) does not exist, which is why the application cannot create the database file in that non-existent folder. If you can create a databases folder in some manner, you can avoid this problem.
Because I'm lazy, I just used the /data/data//files/
folder when I'm in Emulator mode. You can get the files dir using this:
context.getFilesDir().getPath()
This worked beautifully for me in the Emulator.
Hope this helps someone.
In case you want to see some code:
String dbFilename = "example.db";
try
{
File databaseFile = getDatabasePath(dbFilename);
SQLiteDatabase _db = SQLiteDatabase.openOrCreateDatabase(databaseFile);
} catch (Exception e)
{
String databasePath = getFilesDir().getPath() + "/" + dbFilename;
File databaseFile = new File(databasePath);
_db = SQLiteDatabase.openOrCreateDatabase(databaseFile);
}
Edit:
I tried logging into Facebook (my app has FB integration) on the Emulator and /databases folder appeared after that (and persisted). Not sure what happened, but it's possible to create that folder somehow. Something for another expert around here to shed light on.
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