Android SQLite从外部存储文件夹读取数据库
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目前,我正在开发一个Android应用程序,我的要求是从外部位置的固定位置读取SQLite数据库.但我无法打开数据库.我正在尝试的代码如下：
DatabaseHelper：
import android.content.Context;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.os.Environment;
import android.util.Log;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
public class DataBaseHelper extends SQLiteOpenHelper
{
private static final int DB_VERSION = 1;
//private static final String DB_NAME = "MedRec.db";
private static final String DB_NAME = "MedRec";
public DataBaseHelper(Context context)
{
//super(context,DB_NAME,null,DB_VERSION);
super(context, Environment.getExternalStorageDirectory() + "/EMIS/MedRec", null, 1);
//super(context, context.getExternalFilesDir(null).getAbsolutePath() + "/EMIS/" + DB_NAME, null, 1);
Log.d("DB_PATH:", context.getExternalFilesDir(null).getAbsolutePath() + "/EMIS/" + DB_NAME);
}
@Override
public void onCreate(SQLiteDatabase database)
{
Log.d("CREATING TABLE :", "SUCCESS");
}
@Override
public void onUpgrade(SQLiteDatabase database,int oldVersion,int newVersion)
{
Log.d("UPGRADING TABLE :", "SUCCESS");
onCreate(database);
}
}
PatientDataSource：
package com.medrecordapp.main.database;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.util.Log;
import com.medrecordapp.main.model.Patient;
import java.util.ArrayList;
public class PatientDataSource
{
private SQLiteDatabase database;
private DataBaseHelper dbHelper;
public static final String TABLE_PATIENT = "Patient";
public final static String ID = "_id";
public final static String PATIENT_ID = "PatientID";
public final static String NHS_NUMBER = "NHSNumber";
public final static String FIRST_NAME = "FirstName";
public final static String LAST_NAME = "LastName";
public final static String CATEGORY = "category";
public final static String PHONE_1 = "phone1";
public final static String PHONE_2 = "phone2";
public final static String PHOTO_FILE = "photofile";
public final static String PROFESSION = "profession";
public final static String STREET = "Street";
public final static String VILLAGE = "Village";
public final static String TOWN = "Town";
public final static String COUNTRY = "County";
public final static String POST_CODE = "PostCode";
public final static String COMMENT = "comment";
public final static String E1 = "E1";
public final static String E2 = "E2";
public final static String E3 = "E3";
public final static String E4 = "E4";
public final static String E5 = "E5";
public final static String UPD_DATE = "upddate";
public PatientDataSource(Context context)
{
dbHelper = new DataBaseHelper(context);
}
public void open() throws SQLException
{
///dbHelper.openDataBase();
//dbHelper.getReadableDatabase();
//database = dbHelper.getReadableDatabase();
database = dbHelper.getWritableDatabase();
}
public void close()
{
dbHelper.close();
}
public long addPatient(Patient patient)
{
open();
ContentValues patientValue = new ContentValues();
patientValue.put(PATIENT_ID, patient.getPatientId());
patientValue.put(NHS_NUMBER, patient.getNhsNumber());
patientValue.put(FIRST_NAME, patient.getFirstName());
patientValue.put(LAST_NAME, patient.getFirstName());
patientValue.put(CATEGORY, patient.getFirstName());
patientValue.put(PHONE_1, patient.getFirstName());
patientValue.put(PHONE_2, patient.getFirstName());
patientValue.put(PHOTO_FILE, patient.getFirstName());
patientValue.put(PROFESSION, patient.getFirstName());
patientValue.put(STREET, patient.getFirstName());
patientValue.put(VILLAGE, patient.getFirstName());
patientValue.put(TOWN, patient.getFirstName());
patientValue.put(COUNTRY, patient.getFirstName());
patientValue.put(POST_CODE, patient.getFirstName());
patientValue.put(COMMENT, patient.getFirstName());
patientValue.put(E1, patient.getFirstName());
patientValue.put(E2, patient.getFirstName());
patientValue.put(E3, patient.getFirstName());
patientValue.put(E4, patient.getFirstName());
patientValue.put(E5, patient.getFirstName());
patientValue.put(UPD_DATE, patient.getFirstName());
long insertId = database.insert(TABLE_PATIENT,null,patientValue);
Log.d("RESULT :", insertId + "");
close();
return insertId;
}
public ArrayList<Patient> loadPatient()
{
open();
ArrayList<Patient> patientList = new ArrayList<Patient>();
Cursor cursor = database.rawQuery(" SELECT * FROM Patient " , null );
cursor.moveToFirst();
while (!cursor.isAfterLast())
{
Patient patient = new Patient(
cursor.getInt(cursor.getColumnIndex("_id")) , cursor.getString(cursor.getColumnIndex("PatientID")), cursor.getString(2), cursor.getString(3),
cursor.getString(4), cursor.getString(5), cursor.getString(6), cursor.getString(6),
cursor.getString(7), cursor.getString(8), cursor.getString(9), cursor.getString(10),
cursor.getString(11), cursor.getString(12), cursor.getString(13), cursor.getString(14),
cursor.getString(15), cursor.getString(16), cursor.getString(17), cursor.getString(18),
cursor.getString(19), cursor.getString(20), cursor.getString(21)
);
patientList.add(patient);
cursor.moveToNext();
}
cursor.close();
close();
return patientList;
}
public ArrayList<Patient> loadPatient(String patientId)
{
open();
ArrayList<Patient> patientList = new ArrayList<Patient>();
Cursor cursor = database.rawQuery(" SELECT * FROM Patient WHERE _id = ?" , new String[]{ patientId } );
cursor.moveToFirst();
while (!cursor.isAfterLast())
{
Patient patient = new Patient(
cursor.getInt(0) , cursor.getString(1), cursor.getString(2), cursor.getString(3),
cursor.getString(4), cursor.getString(5), cursor.getString(6), cursor.getString(6),
cursor.getString(7), cursor.getString(8), cursor.getString(9), cursor.getString(10),
cursor.getString(11), cursor.getString(12), cursor.getString(13), cursor.getString(14),
cursor.getString(15), cursor.getString(16), cursor.getString(17), cursor.getString(18),
cursor.getString(19), cursor.getString(20), cursor.getString(21)
);
patientList.add(patient);
cursor.moveToNext();
}
cursor.close();
close();
return patientList;
}
/*public void updateFavorites(Favorites favoritesInfo,String id)
{
open();
ContentValues favoritesInfoValues = new ContentValues();
String strFilter = "id = " + id;
favoritesInfoValues.put(ID, favoritesInfo.getFavoritesId());
favoritesInfoValues.put(JOKES_ID, favoritesInfo.getJokesId());
//Update using the SQLite update function.
database.update(TABLE_FAVORITES, favoritesInfoValues, strFilter, null);
//Close the opened database connection
close();
}*/
public boolean deletePatient(String id)
{
open();
String strFilter = "_id =" + id;
boolean res = database.delete(TABLE_PATIENT, strFilter , null) > 0;
close();
return res;
}
}
清单Permissions：
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
但我得到的是以下例外情况：
10-25 12:49:25.838 30502-30502/com.medrecodapp.main.database E/SQLiteLog﹕ (14) cannot open file at line 31278 of [2ef4f3a5b1]
10-25 12:49:25.838 30502-30502/com.medrecodapp.main.database E/SQLiteLog﹕ (14) os_unix.c:31278: (2) open(/storage/emulated/0/EMIS/MedRec) -
10-25 12:49:25.838 30502-30502/com.medrecodapp.main.database E/SQLiteConnection﹕ DB info: sqlite3_open_v2, path: /storage/emulated/0/EMIS/MedRec, flag: 6, ret: 14
10-25 12:49:25.838 30502-30502/com.medrecodapp.main.database E/SQLiteConnection﹕ DB info: errno = 2, errno message = No such file or directory
10-25 12:49:25.839 30502-30502/com.medrecodapp.main.database E/SQLiteDatabase﹕ Failed to open database '/storage/emulated/0/EMIS/MedRec'.
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:237)
at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:221)
at android.database.sqlite.SQLiteConnectionPool.openConnectionLocked(SQLiteConnectionPool.java:468)
at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:190)
at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:182)
at android.database.sqlite.SQLiteDatabase.openInner(SQLiteDatabase.java:876)
at android.database.sqlite.SQLiteDatabase.open(SQLiteDatabase.java:856)
at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:754)
at android.app.ContextImpl.openOrCreateDatabase(ContextImpl.java:579)
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.medrecordapp.main.database.PatientDataSource.open(PatientDataSource.java:53)
at com.medrecordapp.main.database.PatientDataSource.loadPatient(PatientDataSource.java:100)
at com.medrecordapp.main.activity.PatientListActivity.onCreate(PatientListActivity.java:90)
at android.app.Activity.performCreate(Activity.java:6262)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1125)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2462)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2569)
at android.app.ActivityThread.access$900(ActivityThread.java:150)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1399)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:168)
at android.app.ActivityThread.main(ActivityThread.java:5885)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:819)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:709)
10-25 12:49:25.840 30502-30502/com.medrecodapp.main.database E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.medrecodapp.main.database, PID: 30502
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.medrecodapp.main.database/com.medrecordapp.main.activity.PatientListActivity}: android.database.sqlite.SQLiteCantOpenDatabaseException: unknown error (code 14): Could not open database
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2509)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2569)
at android.app.ActivityThread.access$900(ActivityThread.java:150)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1399)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:168)
at android.app.ActivityThread.main(ActivityThread.java:5885)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:819)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:709)
Caused by: 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:237)
at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:221)
at android.database.sqlite.SQLiteConnectionPool.openConnectionLocked(SQLiteConnectionPool.java:468)
at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:190)
at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:182)
at android.database.sqlite.SQLiteDatabase.openInner(SQLiteDatabase.java:876)
at android.database.sqlite.SQLiteDatabase.open(SQLiteDatabase.java:856)
at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:754)
at android.app.ContextImpl.openOrCreateDatabase(ContextImpl.java:579)
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.medrecordapp.main.database.PatientDataSource.open(PatientDataSource.java:53)
at com.medrecordapp.main.database.PatientDataSource.loadPatient(PatientDataSource.java:100)
at com.medrecordapp.main.activity.PatientListActivity.onCreate(PatientListActivity.java:90)
at android.app.Activity.performCreate(Activity.java:6262)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1125)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2462)
????????????at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2569)
????????????at android.app.ActivityThread.access$900(ActivityThread.java:150)
????????????at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1399)
????????????at android.os.Handler.dispatchMessage(Handler.java:102)
????????????at android.os.Looper.loop(Looper.java:168)
????????????at android.app.ActivityThread.main(ActivityThread.java:5885)
????????????at java.lang.reflect.Method.invoke(Native Method)
????????????at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:819)
????????????at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:709)
该文件已放入以下文件夹中：
我要提到的最后一件事是我在HTC 10上测试它,它没有任何外部存储,而是模拟存储.任何帮助将受到高度赞赏.
谢谢
解决方法:
如果提供自定义ContextClass并且您具有对目标目录的写访问权,则可以将SQLiteOpenHelper与自定义路径一起使用.
public class DatabaseHelper extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 3;
.....
DatabaseHelper(final Context context, String databaseName) {
super(new DatabaseContext(context), databaseName, null, DATABASE_VERSION);
}
}
这是自定义DatabaseContext类,可以完成所有的魔术：
class DatabaseContext extends ContextWrapper {
private static final String DEBUG_CONTEXT = "DatabaseContext";
public DatabaseContext(Context base) {
super(base);
}
@Override
public File getDatabasePath(String name) {
File sdcard = Environment.getExternalStorageDirectory();
String dbfile = sdcard.getAbsolutePath() + File.separator+ "databases" + File.separator + name;
if (!dbfile.endsWith(".db")) {
dbfile += ".db" ;
}
File result = new File(dbfile);
if (!result.getParentFile().exists()) {
result.getParentFile().mkdirs();
}
if (Log.isLoggable(DEBUG_CONTEXT, Log.WARN)) {
Log.w(DEBUG_CONTEXT, "getDatabasePath(" + name + ") = " + result.getAbsolutePath());
}
return result;
}
/* this version is called for android devices >= api-11. thank to @damccull for fixing this. */
@Override
public SQLiteDatabase openOrCreateDatabase(String name, int mode, SQLiteDatabase.CursorFactory factory, DatabaseErrorHandler errorHandler) {
return openOrCreateDatabase(name,mode, factory);
}
/* this version is called for android devices < api-11 */
@Override
public SQLiteDatabase openOrCreateDatabase(String name, int mode, SQLiteDatabase.CursorFactory factory) {
SQLiteDatabase result = SQLiteDatabase.openOrCreateDatabase(getDatabasePath(name), null);
// SQLiteDatabase result = super.openOrCreateDatabase(name, mode, factory);
if (Log.isLoggable(DEBUG_CONTEXT, Log.WARN)) {
Log.w(DEBUG_CONTEXT, "openOrCreateDatabase(" + name + ",,) = " + result.getPath());
}
return result;
}
}
这是如何运作的：
普通的Android应用程序拥有相对于app文件夹的本地数据库文件.通过使用覆盖了getDatabasePath()的客户上下文,数据库现在相对于SD卡上的不同目录.
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