不断努力在设备中创建数据库由于运行方式权限问题，我在运行应用程序时无法在三星设备中创建数据库文件。所以我正在尝试从SD卡打开数据库文件，该文件已经与数据一起使用。任何人都可以提供相同的建议。我的数据库代码如下。
package com.bar.example.androidspinnerexample;
import java.util.ArrayList;
import java.util.List;
import java.io.File;
import android.os.Environment;
import android.os.StatFs;
import android.util.Log;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class DatabaseHandler extends SQLiteOpenHelper {
// Database Version
public static final int DATABASE_VERSION = 1;
// Database Name
public static final String DATABASE_NAME = "spinnerExample";
private static String DB_PATH = "/sdcard/android/com.bar.example.androidspinnerexample/databases/spinnerExample.db";
// Labels table name
public static final String TABLE_LABELS = "labels"; //<<<< Made public
public static final String TABLE_LABELS1= "labels1";
public static final String TABLE_LABELS2= "labels2";
// Labels Table Columns names
public static final String KEY_ID4 = "input_label";
public static final String KEY_ID = "id"; //<<<< Made public
public static final String KEY_NAME = "name"; //<<<< made public
public static final String KEY_ID1 = "id1"; //<<<< Made public
public static final String KEY_NAME1 = "name1";
public static final String KEY_1 = "number"; //<<<< Made public
public static final String KEY_2 = "outletname"; //<<<< made public
public static final String KEY_3 = "sunday"; //<<<< Made public
public static final String KEY_4 = "monday";
public static final String KEY_5 = "tuesday";
public static final String KEY_6 = "wednesday";
public static final String KEY_7 = "thursday";
public static final String KEY_8 = "saturday";
public static final String KEY_9 = "closed";
public static final String KEY_10 = "calling";
public DatabaseHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
// Creating Tables
@Override
public void onCreate(SQLiteDatabase db) {
// Category table create query
String CREATE_CATEGORIES_TABLE = "CREATE TABLE " + TABLE_LABELS + "("
+ KEY_ID + " TEXT," + KEY_NAME + " TEXT)";
String CREATE_CATEGORIES_TABLE1 = "CREATE TABLE " + TABLE_LABELS1 + "("
+ KEY_ID1+ " TEXT," + KEY_NAME1+ " TEXT)";
db.execSQL(CREATE_CATEGORIES_TABLE);
db.execSQL(CREATE_CATEGORIES_TABLE1);
}
// Upgrading database
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Drop older table if existed
db.execSQL("DROP TABLE IF EXISTS " + TABLE_LABELS);
db.execSQL("DROP TABLE IF EXISTS " + TABLE_LABELS1);
// Create tables again
onCreate(db);
}
// Added for adding new data
public void insertlabel(String id, String label) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues cv = new ContentValues();
cv.put(KEY_ID,id);
cv.put(KEY_NAME,label);
db.insert(TABLE_LABELS,null,cv);
db.close();
}
/**
* Inserting new lable into lables table
* */
public void insertLabel(String message1, String message2,String message3,String message4,String message5,String message6,String message7,String message8,String message9,String message10){
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_1, message1);
values.put(KEY_2, message2);
values.put(KEY_10,message10);
values.put(KEY_3,message3);
values.put(KEY_4,message4);
values.put(KEY_5,message5);
values.put(KEY_6,message6);
values.put(KEY_7,message7);
values.put(KEY_9,message9);
values.put(KEY_8,message8);
// Inserting Row
db.insert(TABLE_LABELS2, null, values);
db.close(); // Closing database connection
}
public void insertLabel1(String label){
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_NAME1, label);
// Inserting Row
db.insert(TABLE_LABELS1, null, values);
db.close(); // Closing database connection
}
public void insertLabel2(String label){
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_NAME1, label);
values.put(KEY_10, label);
values.put(KEY_ID, label);
db.insert(TABLE_LABELS2, null, values);
db.close(); // Closing database connection
}
public List<String> getAllLabels(){
List<String> labels = new ArrayList<String>();
// Select All Query
String selectQuery = "SELECT * FROM " + TABLE_LABELS1;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
labels.add(cursor.getString(1));
} while (cursor.moveToNext());
}
// closing connection
cursor.close();
db.close();
// returning lables
return labels;
}
public List<String> getAllLabels1(){
List<String> labels = new ArrayList<String>();
// Select All Query
String selectQuery = "SELECT count (*) FROM " + TABLE_LABELS;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor1 = db.rawQuery(selectQuery, null);
final ArrayList<String> row1 = new ArrayList<String>();
// looping through all rows and adding to list
if (cursor1.moveToFirst()) {
do {
labels.add(cursor1.getString(1));
} while (cursor1.moveToNext());
}
// closing connection
cursor1.close();
db.close();
// returning lables
return labels;
}
// Added to get Cursor for Simple CursorAdapter
public Cursor getAllLabelsAsCursor() {
String[] columns = new String[]{"rowid AS _id, *"}; // Need _id column for SimpleCursorAdapter
return this.getWritableDatabase().query(TABLE_LABELS,columns,null,null,null,null,null);
}
public Cursor getAllLabelsExceptedSelected(long selected) {
String[] columns = new String[]{"rowid AS _id, *"};
String whereclause = "rowid <> ?";
String[] whereargs = new String[]{String.valueOf(selected)};
return this.getWritableDatabase().query(TABLE_LABELS,
columns,
whereclause,
whereargs,
null,
null,
null
);
}
public Cursor getByRowid(long id) {
String[] columns = new String[]{"rowid AS _id, *"};
return this.getWritableDatabase().query(
TABLE_LABELS,
columns,
"rowid=?",
new String[]{String.valueOf(id)},
null,null,null
);
}
}使用此代码将数据库导出到内部存储
private void exportDatabase(){
File data = Environment.getDataDirectory();
FileChannel source=null;
FileChannel destination=null;
String currentDBPath = "/data/"+ "your_package_name" +"/databases/your_db_name.db";
String backupDBPath = "/sdcard/your_db_name.db";
File currentDB = new File(data, currentDBPath);
File backupDB = new File(backupDBPath);
try {
source = new FileInputStream(currentDB).getChannel();
destination = new FileOutputStream(backupDB).getChannel();
destination.transferFrom(source, 0, source.size());
source.close();
destination.close();
Toast.makeText(this, "DB Exported!", Toast.LENGTH_LONG).show();
} catch(IOException e) {
e.printStackTrace();
}
}
并在清单中添加权限
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />