我已经搜索了这个，但我没有得到答案。 我正在使用Budget app，因为有两种类型的数据库（Sqlite和Shared-preferences）。因为我可以在SD卡中备份/恢复sqlite数据库，但我不知道如何备份和恢复共享首选项数据库。
我可以备份共享偏好数据库，但不知道如何从SD卡恢复它。
数据库名称：
1.magicbox_database.db是sqlite数据库，
2.magicbox_database_sf.db是sharedpreferences数据库
这是两个数据库备份的代码。
if (isStoragePermissionGranted() == true) {
try {
File sd = Environment.getExternalStorageDirectory();
if (sd.canWrite()) {
String currentDBPath = "/data/data/" + getPackageName() + "/databases/OLBE_DEMO";
String backupDBPath = "magicbox_database.db";
File currentDB = new File(currentDBPath);
File backupDB = new File(sd, backupDBPath);
Toast.makeText(MainActivity.this, "backup creating....", Toast.LENGTH_SHORT).show();
if (currentDB.exists()) {
FileChannel src = new FileInputStream(currentDB).getChannel();
FileChannel dst = new FileOutputStream(backupDB).getChannel();
dst.transferFrom(src, 0, src.size());
src.close();
dst.close();
Toast.makeText(MainActivity.this, "Bckup Created !", Toast.LENGTH_SHORT).show();
Toast.makeText(MainActivity.this, "magicbox_database.db in External Storage", Toast.LENGTH_SHORT).show();
}
String currentDBPath1 = "/data/data/" + getPackageName() + "/shared_prefs/DATABASE.xml";
String backupDBPath1 = "magicbox_database_sf.xml";
File currentDB1 = new File(currentDBPath1);
File backupDB1 = new File(sd, backupDBPath1);
// Toast.makeText(MainActivity.this, "backup creating....", Toast.LENGTH_SHORT).show();
if (currentDB1.exists()) {
FileChannel src1 = new FileInputStream(currentDB1).getChannel();
FileChannel dst1 = new FileOutputStream(backupDB1).getChannel();
dst1.transferFrom(src1, 0, src1.size());
src1.close();
dst1.close();
//Toast.makeText(MainActivity.this, "Bckup Created !", Toast.LENGTH_SHORT).show();
Toast.makeText(MainActivity.this, "magicbox_database_sf.db in External Storage", Toast.LENGTH_SHORT).show();
}
}
} catch (Exception e) {
Toast.makeText(MainActivity.this, "ERROR! backup not created", Toast.LENGTH_SHORT).show();
}
}
此代码用于两者的还原
if (isStoragePermissionGranted() == true) {
try {
File sd = Environment.getExternalStorageDirectory();
if (sd.canWrite()) {
String currentDBPath = "/data/data/" + getPackageName() + "/databases/OLBE_DEMO";
String backupDBPath = "magicbox_database.db";
File currentDB = new File(currentDBPath);
File backupDB = new File(sd, backupDBPath);
Toast.makeText(MainActivity.this, "restoring......", Toast.LENGTH_SHORT).show();
if (currentDB.exists()) {
FileChannel src = new FileInputStream(backupDB).getChannel();
FileChannel dst = new FileOutputStream(currentDB).getChannel();
dst.transferFrom(src, 0, src.size());
src.close();
dst.close();
Toast.makeText(MainActivity.this, "Your data Restored !", Toast.LENGTH_SHORT).show();
}
String currentDBPath1 = "/data/data/" + getPackageName() + "/shared_prefs/DATABASE.xml";
String backupDBPath1 = "magicbox_database_sf.xml";
File currentDB1 = new File(currentDBPath1);
File backupDB1 = new File(sd, backupDBPath1);
if (currentDB1.exists()) {
FileChannel src1 = new FileInputStream(backupDB1).getChannel();
FileChannel dst1 = new FileOutputStream(currentDB1).getChannel();
dst1.transferFrom(src1, 0, src1.size());
src1.close();
dst1.close();
Toast.makeText(MainActivity.this, "magicbox_database_sf.db in External Storage", Toast.LENGTH_SHORT).show();
}
}
} catch (Exception e) {
Toast.makeText(MainActivity.this, "ERROR! data not restored", Toast.LENGTH_SHORT).show();
}
}
此代码中的更改
FileChannel src1 = new FileInputStream(backupDB1).getChannel();
FileChannel dst1 = new FileOutputStream(currentDB1).getChannel();
答案 0 :(得分：1)
是的，只是跟着this获取路径，并且可以使用所有首选项轻松提取XML文件 - 然后您可以使用此xml内容（通过解析它）来创建首选项或提取值
XML看起来像这样：
<?xml version='1.0' encoding='utf-8' standalone='yes' ?>
<map>
<int name="Key2" value="100" />
<long name="Key1" value="99" />
<string name="Key">Vikesh Dass</string>
</map>
只需解析xml以获取您的数据，这应该很简单：）
对于Parsing Xml，您可以使用此类：
public class XMLParser {
private static final String ns = null;
public void parse(InputStream in) throws XmlPullParserException, IOException {
try {
XmlPullParser parser = Xml.newPullParser();
parser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, false);
parser.setInput(in, null);
parser.nextTag();
readPreferences(parser);
} finally {
in.close();
}
}
private void readPreferences(XmlPullParser parser) throws XmlPullParserException, IOException {
parser.require(XmlPullParser.START_TAG, ns, "map");
while (parser.next() != XmlPullParser.END_TAG) {
if (parser.getEventType() != XmlPullParser.START_TAG) {
continue;
}
String node = parser.getName();
if (node.equals("string")) {
readName(parser);
} else if (node.equals("int")) {
readValueint(parser);
} else if (node.equals("long")) {
readValuelong(parser);
} else {
skip(parser);
}
}
}
private void readName(XmlPullParser parser) throws IOException, XmlPullParserException {
parser.require(XmlPullParser.START_TAG, ns, "string");
String name = readText(parser);
parser.require(XmlPullParser.END_TAG, ns, "string");
//Set the Preference again after it is fetched
}
private String readText(XmlPullParser parser) throws IOException, XmlPullParserException {
String result = "";
if (parser.next() == XmlPullParser.TEXT) {
result = parser.getText();
parser.nextTag();
}
return result;
}
private void readValueint(XmlPullParser parser) throws IOException, XmlPullParserException {
parser.require(XmlPullParser.START_TAG, ns, "int");
String ValueData = parser.getAttributeValue(null, "value");
String ValueKey = parser.getAttributeValue(null, "name");
//Set the Preference again after it is fetched
}
private void readValuelong(XmlPullParser parser) throws IOException, XmlPullParserException {
parser.require(XmlPullParser.START_TAG, ns, "long");
String ValueData = parser.getAttributeValue(null, "value");
String ValueKey = parser.getAttributeValue(null, "name");
//Set the Preference again after it is fetched
}
private void skip(XmlPullParser parser) throws XmlPullParserException, IOException {
if (parser.getEventType() != XmlPullParser.START_TAG) {
throw new IllegalStateException();
}
int depth = 1;
while (depth != 0) {
switch (parser.next()) {
case XmlPullParser.END_TAG:
depth--;
break;
case XmlPullParser.START_TAG:
depth++;
break;
}
}
}
}
从你的班级打电话给：
File sd = Environment.getExternalStorageDirectory();
String backupDBPath1 = "your_backedUpPrefDb.xml";
File backupDB1 = new File(sd, backupDBPath1);
InputStream is = new BufferedInputStream(new FileInputStream(backupDB1));
XMLParser myXMLParser = new XMLParser();
myXMLParser.parse(is);
is.close();