未知错误(代码14):在android中外部写入时无法打开数据库
我正在使用SQLiteOpenHelper编写所有查询等。当我在内部写入和读取数据库时,一切正常,但如果我想将数据库保存到手机上的文件夹中,我会得到以下信息:未知错误(代码14):在android中外部写入时无法打开数据库,android,sqlite,Android,Sqlite,我正在使用SQLiteOpenHelper编写所有查询等。当我在内部写入和读取数据库时,一切正常,但如果我想将数据库保存到手机上的文件夹中,我会得到以下信息: 01-03 07:12:24.786 16097-16097/com.myApp.app E/SQLiteLog: (14) cannot open file at line 31278 of [2ef4f3a5b1] 01-03 07:12:24.786 16097-16097/com.myApp.app E/SQLiteLog: (1
01-03 07:12:24.786 16097-16097/com.myApp.app E/SQLiteLog: (14) cannot open file at line 31278 of [2ef4f3a5b1]
01-03 07:12:24.786 16097-16097/com.myApp.app E/SQLiteLog: (14) os_unix.c:31278: (2) open(/storage/emulated/0/myApp/db/app) -
01-03 07:12:24.787 16097-16097/com.myApp.app E/SQLiteDatabase: Failed to open database '/storage/emulated/0/myApp/db/app'.
android.database.sqlite.SQLiteCantOpenDatabaseException: unknown error (code 14): Could not open database
at android.database.sqlite.SQLiteConnection.nativeOpen(Native Method)
at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:207)
at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:191)
at android.database.sqlite.SQLiteConnectionPool.openConnectionLocked(SQLiteConnectionPool.java:463)
at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:185)
at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:177)
at android.database.sqlite.SQLiteDatabase.openInner(SQLiteDatabase.java:806)
at android.database.sqlite.SQLiteDatabase.open(SQLiteDatabase.java:791)
at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:694)
at android.app.ContextImpl.openOrCreateDatabase(ContextImpl.java:571)
at android.content.ContextWrapper.openOrCreateDatabase(ContextWrapper.java:269)
at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:223)
at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:163)
at com.myApp.db.DbMain.getCountValueForMainMenu(DbMain.java:576)
at com.myApp.app.Beginner.openApp(Beginner.java:672)
at com.myApp.app.Beginner.checkfilepermission(Beginner.java:341)
at com.myApp.app.Beginner.onCreate(Beginner.java:332)
at android.app.Activity.performCreate(Activity.java:6251)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
DBhelper类文件:
public DbMain(Context context)
{
// code to create database in internal storage
//super(context, DATABASE_NAME, null, DATABASE_VERSION);
//code to create database in External SD card
super(context, Environment.getExternalStorageDirectory()
+ File.separator + "/myApp/db/"
+ File.separator
+ DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db)
{
//1
String CREATE_TABLE_MENU = "CREATE TABLE IF NOT EXISTS " + TABLE_MENU_LOCAL +"("
+KEY_MENUID_LOCAL + " TEXT,"
+KEY_MENUNAME_LOCAL + " TEXT,"
+KEY_ISCHILD_LOCAL + " TEXT,"
+KEY_CATEGORYURL_LOCAL + " TEXT,"
+KEY_IMAGEID_LOCAL + " TEXT,"
+KEY_MENUNAME_DESCRIPTION_LOCAL + " TEXT"
+ ")";
db.execSQL(CREATE_TABLE_MENU);
}
//to get totalcount
public int getCountValueForMainMenu()
{
SQLiteDatabase db = this.getWritableDatabase();
int count = 0;
Cursor cursor = db.rawQuery("SELECT COUNT (*) FROM " + TABLE_MENU_LOCAL, null);
if(null != cursor)
{
if(cursor.moveToFirst() && 0 < cursor.getCount())
{
count = cursor.getInt(0);
}
cursor.close();
}
return count;
}
publicbmain(上下文)
{
//在内部存储器中创建数据库的代码
//super(上下文、数据库名称、null、数据库版本);
//在外部SD卡中创建数据库的代码
super(context,Environment.getExternalStorageDirectory()
+File.separator+“/myApp/db/”
+文件分隔符
+数据库名称,空,数据库版本);
}
@凌驾
public void onCreate(SQLiteDatabase db)
{
//1
String CREATE_TABLE_MENU=“如果不存在则创建表”+表_MENU_LOCAL+”(“
+键\u MENUID\u LOCAL+“TEXT,”
+按键菜单本地+“文本”
+键\u ISCHILD\u LOCAL+“TEXT,”
+键\u类别URL\u本地+“文本”
+键\u IMAGEID\u LOCAL+“TEXT,”
+关键字菜单描述本地+“文本”
+ ")";
execSQL(创建表菜单);
}
//得到总数
public int getCountValueForMainMenu()
{
SQLiteDatabase db=this.getWritableDatabase();
整数计数=0;
Cursor Cursor=db.rawQuery(“从“+表菜单本地,空)”中选择计数(*);
如果(null!=光标)
{
if(cursor.moveToFirst()&&0
在内部创建DB时,调用相同的方法等都可以
有什么不对劲吗
谢谢 确保您在清单中声明了写入权限:
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
如果您的目标是API 23或更高版本,您还需要。检查这些要点
1.READ_EXTERNAL_存储和WRITE_EXTERNAL_存储在androidmanifest.xml中定义
2.创建外部存储目录。如果未创建,则在调用db Helper的构造函数之前创建存储目录
请尝试dbHelper的以下代码
public class DbHelper extends SQLiteOpenHelper {
private static final String TABLE_MENU_LOCAL = "menu";
private static final String KEY_MENUID_LOCAL ="menuid" ;
private static final String KEY_MENUNAME_LOCAL ="menuname" ;
private static final String KEY_ISCHILD_LOCAL ="ischild" ;
private static final String KEY_CATEGORYURL_LOCAL ="categoryurl" ;
private static final String KEY_IMAGEID_LOCAL ="imageid" ;
private static final String KEY_MENUNAME_DESCRIPTION_LOCAL ="description" ;
private static String DATABASE_NAME="dbtest.db";
private static int DATABASE_VERSION=1;
public DbHelper(Context context)
{
// code to create database in internal storage
//super(context, DATABASE_NAME, null, DATABASE_VERSION);
//code to create database in External SD card
super(context, Environment.getExternalStorageDirectory()
+ File.separator + "/myapp/db/"
+ File.separator
+ DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
//1
String CREATE_TABLE_MENU = "CREATE TABLE IF NOT EXISTS " + TABLE_MENU_LOCAL +"("
+KEY_MENUID_LOCAL + " TEXT,"
+KEY_MENUNAME_LOCAL + " TEXT,"
+KEY_ISCHILD_LOCAL + " TEXT,"
+KEY_CATEGORYURL_LOCAL + " TEXT,"
+KEY_IMAGEID_LOCAL + " TEXT,"
+KEY_MENUNAME_DESCRIPTION_LOCAL + " TEXT"
+ ")";
db.execSQL(CREATE_TABLE_MENU);
}
@Override
public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
}
public void insertValues(){
SQLiteDatabase db=this.getWritableDatabase();
for(int count=0;count<5;count++) {
ContentValues insertValues = new ContentValues();
insertValues.put(KEY_MENUID_LOCAL, "1");
insertValues.put(KEY_MENUNAME_LOCAL, "Food1");
insertValues.put(KEY_ISCHILD_LOCAL, "No");
insertValues.put(KEY_CATEGORYURL_LOCAL, "Demo");
insertValues.put(KEY_IMAGEID_LOCAL, "imageid");
insertValues.put(KEY_MENUNAME_DESCRIPTION_LOCAL, "Description");
db.insert(TABLE_MENU_LOCAL, null, insertValues);
}
}
//to get totalcount
public int getCountValueForMainMenu()
{
SQLiteDatabase db = this.getWritableDatabase();
int count = 0;
Cursor cursor = db.rawQuery("SELECT COUNT (*) FROM " + TABLE_MENU_LOCAL, null);
if(null != cursor)
{
if(cursor.moveToFirst() && 0 < cursor.getCount())
{
count = cursor.getInt(0);
}
cursor.close();
}
return count;
}
让我知道它是否对您有帮助您还可以从何处调用这个sqlite类和方法吗?我在每个类上都调用这个。如下所示:dbMain=newdbmain(this),然后开始在那里使用变量。。比如int value=dbMain.getCountValueForMainMenu()嘿!这是mkdir问题。我创造了它,它开始运作良好。非常感谢。你的目标是什么API?如果它高于22,那么您还需要在运行时请求权限,因为
WRITE\u EXTERNAL\u STORAGE
属于“危险”类别。此外,您不需要声明读取权限。写需要读。所以你只需要声明其中一个。
String storage_folder = "/myapp/db";
File f = new File(Environment.getExternalStorageDirectory(), storage_folder);
if (!f.exists()) {
f.mkdirs();
}
DbHelper lDbHeper=new DbHelper(MainActivity.this);
lDbHeper.insertValues();
int count=lDbHeper.getCountValueForMainMenu();
Log.i("Count is:",""+count);