Android 将SQLite数据库备份到SD卡
我正在尝试将我的sqlite数据库备份到SD卡,我正在尝试按照这个方法进行备份,但我在SD卡中找不到数据库。我做错了什么Android 将SQLite数据库备份到SD卡,android,sqlite,Android,Sqlite,我正在尝试将我的sqlite数据库备份到SD卡,我正在尝试按照这个方法进行备份,但我在SD卡中找不到数据库。我做错了什么 public void exportDatabse(String DBOperations) { try { File sd = Environment.getExternalStorageDirectory(); File data = Environment.getDataDirectory(); if (sd.
public void exportDatabse(String DBOperations) {
try {
File sd = Environment.getExternalStorageDirectory();
File data = Environment.getDataDirectory();
if (sd.canWrite()) {
String currentDBPath = "//data//com.example.hp.semakoperasimampatansrc//databases//attendant_info.db";
String backupDBPath = "attendant_info_backup.db";
File currentDB = new File(data, currentDBPath);
File backupDB = new File(sd, backupDBPath);
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();
}
}
} catch (Exception e) {
}
如何调用该方法:
db.exportDatabse("attendant_info.db");
我还补充了
在我的清单中尝试添加Android 6.0(API级别23)及以上版本的运行时权限请求 获取
WRITE\u EXTERNAL\u STORAGE
权限的代码
if (Build.VERSION.SDK_INT > Build.VERSION_CODES.LOLLIPOP_MR1 && !checkIfAlreadyhavePermission()) {
requestForSpecificPermission();
}
private boolean checkIfAlreadyhavePermission() {
if (checkSelfPermission(Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
return false;
}
return true;
}
像这样请求许可
private void requestForSpecificPermission() {
requestPermissions(new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 101);
}
尝试为Android 6.0(API级别23)及更高版本添加运行时权限请求 获取
WRITE\u EXTERNAL\u STORAGE
权限的代码
if (Build.VERSION.SDK_INT > Build.VERSION_CODES.LOLLIPOP_MR1 && !checkIfAlreadyhavePermission()) {
requestForSpecificPermission();
}
private boolean checkIfAlreadyhavePermission() {
if (checkSelfPermission(Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
return false;
}
return true;
}
像这样请求许可
private void requestForSpecificPermission() {
requestPermissions(new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 101);
}
您可以按以下方式执行同样的操作,这不仅可以用于复制数据库,还可以用于复制文件和共享pref(如果有)。创建一个名为DeveloperOption的类,并使用其方法copyAppDataToLocal执行相同的操作 如果目标sdk为23或更高,则需要运行时权限
//package declaration
import android.app.Activity;
import android.os.Environment;
import android.util.Log;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
public class DeveloperOption {
public static final String BASE_PATH = Environment.getExternalStoragePublicDirectory
("App_BackUp").getAbsolutePath();
public static final String SEPARATOR = "/";
private static boolean operationStatus = true;
private static String dataDirectory = null;
private static String appName = "APP_NAME";
public static boolean copyAppDataToLocal(Activity callingActivity, String appName) {
dataDirectory = callingActivity.getApplicationInfo().dataDir;
DeveloperOption.appName = appName;
String TAG = "Developer_Option";
try {
if(dataDirectory != null) {
copyAppData(new File(dataDirectory, "shared_prefs"),"shared_prefs");
copyAppData(new File(dataDirectory, "files"),"files");
copyAppData(new File(dataDirectory, "databases"),"databases");
} else {
Log.e(TAG, "!!!!!Unable to get data directory for ACTIVITY-->" + callingActivity
.toString());
}
} catch (Exception ex) {
Log.e(TAG, "!!!!@@@Exception Occurred while copying DATA--->"+ex.getMessage(),ex.fillInStackTrace());
operationStatus = false;
}
return operationStatus;
}
private static void copyFileToStorage(String directoryName, String inFile, String fileName, boolean
isDirectory, String subdirectoryName) {
try {
FileInputStream myInput = new FileInputStream(inFile);
File out_dir;
if(!isDirectory) {
out_dir = new File(BASE_PATH+ SEPARATOR + appName +
SEPARATOR + directoryName);
} else {
out_dir = new File(BASE_PATH + SEPARATOR + appName +
SEPARATOR + directoryName + SEPARATOR + subdirectoryName);
}
if(!out_dir.exists()) {
operationStatus = out_dir.mkdirs();
}
String outFileName = out_dir + "/" + fileName;
OutputStream myOutput = new FileOutputStream(outFileName);
byte[] buffer1 = new byte[1024];
int length;
while ((length = myInput.read(buffer1)) > 0) {
myOutput.write(buffer1, 0, length);
}
myOutput.flush();
myOutput.close();
myInput.close();
} catch (IOException e) {
e.printStackTrace();
}
}
private static void copyAppData(File fileTypeToBeCopied, String outDirectoryName){
if(fileTypeToBeCopied.exists() && fileTypeToBeCopied.isDirectory()) {
File[] files = fileTypeToBeCopied.listFiles();
for (File file : files) {
if(file.isFile()) {
copyFileToStorage(outDirectoryName, file.getAbsolutePath(), file.getName(), false, "");
} else {
String folderName = file.getName();
File databaseDirsNew = new File(dataDirectory, outDirectoryName+"/" + folderName);
if(databaseDirsNew.exists() && databaseDirsNew.isDirectory()) {
File[] filesDB = databaseDirsNew.listFiles();
for (File file1 : filesDB) {
if(file1.isFile()) {
copyFileToStorage(outDirectoryName, file1.getAbsolutePath(), file1.getName(),
true, folderName);
}
}
}
}
}
}
}
}
您可以按以下方式执行同样的操作,这不仅可以用于复制数据库,还可以用于复制文件和共享pref(如果有)。创建一个名为DeveloperOption的类,并使用其方法copyAppDataToLocal执行相同的操作 如果目标sdk为23或更高,则需要运行时权限
//package declaration
import android.app.Activity;
import android.os.Environment;
import android.util.Log;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
public class DeveloperOption {
public static final String BASE_PATH = Environment.getExternalStoragePublicDirectory
("App_BackUp").getAbsolutePath();
public static final String SEPARATOR = "/";
private static boolean operationStatus = true;
private static String dataDirectory = null;
private static String appName = "APP_NAME";
public static boolean copyAppDataToLocal(Activity callingActivity, String appName) {
dataDirectory = callingActivity.getApplicationInfo().dataDir;
DeveloperOption.appName = appName;
String TAG = "Developer_Option";
try {
if(dataDirectory != null) {
copyAppData(new File(dataDirectory, "shared_prefs"),"shared_prefs");
copyAppData(new File(dataDirectory, "files"),"files");
copyAppData(new File(dataDirectory, "databases"),"databases");
} else {
Log.e(TAG, "!!!!!Unable to get data directory for ACTIVITY-->" + callingActivity
.toString());
}
} catch (Exception ex) {
Log.e(TAG, "!!!!@@@Exception Occurred while copying DATA--->"+ex.getMessage(),ex.fillInStackTrace());
operationStatus = false;
}
return operationStatus;
}
private static void copyFileToStorage(String directoryName, String inFile, String fileName, boolean
isDirectory, String subdirectoryName) {
try {
FileInputStream myInput = new FileInputStream(inFile);
File out_dir;
if(!isDirectory) {
out_dir = new File(BASE_PATH+ SEPARATOR + appName +
SEPARATOR + directoryName);
} else {
out_dir = new File(BASE_PATH + SEPARATOR + appName +
SEPARATOR + directoryName + SEPARATOR + subdirectoryName);
}
if(!out_dir.exists()) {
operationStatus = out_dir.mkdirs();
}
String outFileName = out_dir + "/" + fileName;
OutputStream myOutput = new FileOutputStream(outFileName);
byte[] buffer1 = new byte[1024];
int length;
while ((length = myInput.read(buffer1)) > 0) {
myOutput.write(buffer1, 0, length);
}
myOutput.flush();
myOutput.close();
myInput.close();
} catch (IOException e) {
e.printStackTrace();
}
}
private static void copyAppData(File fileTypeToBeCopied, String outDirectoryName){
if(fileTypeToBeCopied.exists() && fileTypeToBeCopied.isDirectory()) {
File[] files = fileTypeToBeCopied.listFiles();
for (File file : files) {
if(file.isFile()) {
copyFileToStorage(outDirectoryName, file.getAbsolutePath(), file.getName(), false, "");
} else {
String folderName = file.getName();
File databaseDirsNew = new File(dataDirectory, outDirectoryName+"/" + folderName);
if(databaseDirsNew.exists() && databaseDirsNew.isDirectory()) {
File[] filesDB = databaseDirsNew.listFiles();
for (File file1 : filesDB) {
if(file1.isFile()) {
copyFileToStorage(outDirectoryName, file1.getAbsolutePath(), file1.getName(),
true, folderName);
}
}
}
}
}
}
}
}
试试这个
试试这个
因为它是一个静态方法,所以不需要创建对象。只需使用DeveloperOption.copyAppDataToLocal(这是getString(R.string.app\u name);您需要将活动上下文和应用程序名称作为参数传递,因为它是一个静态方法,所以不应从非静态上下文调用它。否则,您可以删除静态关键字并按照您的方法进行操作。因为它是一个静态方法,所以您不需要创建对象。只需使用DeveloperOption.copyAppDataToLocal(这是getString(R.string.app_name);您需要将活动上下文和应用程序名称作为参数传递,因为它是一个静态方法,所以不应从非静态上下文调用它。否则,您可以删除静态关键字并按照您的方法进行操作。