Gabriel Delfino :
Good evening, I'm developing an android app, it has SQLite database, I need a way to copy the database to the external storage of the device, where I can copy to another device and so I can import the database into the another device.
For example:
Suppose the application calls "example", the database is in the "/data/data/com.gnd.example/databases" folder and it is called data.db, need to copy it to the "example / backup" folder ", for example" / storage / emulated / 0 / Example / Backup ". This is the first part.
The second part is the import, where the application should copy the file from the "example / import" folder to the folder "/data/data/com.gnd.example/databases"
For this I have a two button activity, btn_export and btn_import.
I have already relied on the following solutions:
import / export to android sqlite database Simple export and import of SQLite database on Android
I already inserted it in AndroidManifest
How do I ask the user for permission?
I tried copying using this code that I took in one of the examples
private void backupDatabase () throws IOException {
String inFileName = "/data/data/com.gnd.example/databases/dados.db";
File dbFile = new File (inFileName);
FileInputStream fis = new FileInputStream (dbFile);
String outFileName = Environment.getExternalStorageDirectory () + "/ example / backup / data.db";
OutputStream output = new FileOutputStream (outFileName);
byte [] buffer = new byte [1024];
int length;
while ((length = fis.read (buffer))> 0) {
output.write (buffer, 0, length);
}
output.flush ();
output.close ();
fis.close ();
}
The button looks like this:
@Override
public void onClick (View view) {
try {
backupDatabase ();
} catch (IOException e1) {
e1.printStackTrace ();
}
});
Log when I press the button:
07/01 19:35:39: Launching app
$ adb shell am start -n "com.gnd.keepkey / com.gnd.keepkey.Telephone" -a android.intent.action.MAIN -c android.intent.category.LAUNCHER
Client not ready yet..Waiting for process to come online
Waiting for process to come online
Connected to process 27724 on device motorola-moto_z2_play-0039635857
Capturing and displaying logcat messages from application. This behavior can be disabled in the "Logcat output" section of the "Debugger" settings page.
I / zygote: Do partial code cache collection, code = 20KB, data = 29KB
I / zygote: After code cache collection, code = 20KB, data = 29KB
Increasing code cache capacity to 128KB
I / zygote: Do partial code cache collection, code = 20KB, data = 47KB
I / zygote: After code cache collection, code = 20KB, data = 47KB
Increasing code cache capacity to 256KB
I / zygote: Compiler allocated 4MB to compile void android.widget.TextView. <Init> (android.content.Context, android.util.AttributeSet, int, int)
I / zygote: Full code cache collection, code = 120KB, data = 82KB
I / zygote: After code cache collection, code = 117KB, data = 62KB
I / zygote: Do partial code cache collection, code = 125KB, date = 79KB
I / zygote: After code cache collection, code = 125KB, data = 79KB
Increasing code cache capacity to 512KB
W / System.err: java.io.FileNotFoundException: /storage/emulated/0/teste/dados.db (No such file or directory)
at java.io.FileOutputStream.open0 (Native Method)
W / System.err: at java.io.FileOutputStream.open (FileOutputStream.java:287)
at java.io.FileOutputStream. <init> (FileOutputStream.java:223)
at java.io.FileOutputStream. <init> (FileOutputStream.java:110)
at com.gnd.keepkey.funcoes.Exportar_Importar.backupDatabase (Export_Importar.java:87)
at com.gnd.keepkey.funcoes.Exportar_Importar.access $ 000 (Export_Importar.java:42)
at com.gnd.keepkey.funcoes.Export_Import $ 1.onClick (Export_Import.java:69)
W / System.err: at android.view.View.performClick (View.java:6259)
at android.view.View $ PerformClick.run (View.java:24732)
at android.os.Handler.handleCallback (Handler.java:789)
at android.os.Handler.dispatchMessage (Handler.java:98)
at android.os.Looper.loop (Looper.java:164)
at android.app.ActivityThread.main (ActivityThread.java:6592)
at java.lang.reflect.Method.invoke (Native Method)
W / System.err: at com.android.internal.os.Zygote $ MethodAndArgsCaller.run (Zygote.java:240)
at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:769)
MikeT :
FileNotFoundException is likely due to the directory teste not existing, perhaps due to permissions.
Using :-
private void backupDatabase () throws IOException {
String inFileName = "/data/data/com.gnd.example/databases/dados.db";
File dbFile = new File (inFileName);
FileInputStream fis = new FileInputStream (dbFile);
String outFileName = Environment.getExternalStorageDirectory () + "/ example / backup / data.db";
//<<<<<<<<<<< CODE ADDED >>>>>>>>>>
File os = new File(outFileName);
if (!os.getParentFile().exists()) {
os.getParentFile().mkdirs();
}
//<<<<<<<<<< END Of ADDED CODE >>>>>>>>>>
OutputStream output = new FileOutputStream(os); //<<<<<<<<<< CHANGED
byte [] buffer = new byte [1024];
int length;
while ((length = fis.read (buffer))> 0) {
output.write (buffer, 0, length);
}
output.flush ();
output.close ();
fis.close ();
}
will create the directories if they do not exist (assuming permissions are correct)
Working Example :-
The following is a working app
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="aso.so56843045backup">
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
- Note the
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>(for earlier devices)
ExternalStoragePermissions.java
class ExternalStoragePermissions {
public int API_VERSION = Build.VERSION.SDK_INT;
private static final int REQUEST_EXTERNAL_STORAGE = 1;
private static String[] PERMISSIONS_STORAGE = {
//Manifest.permission.READ_EXTERNAL_STORAGE,
Manifest.permission.WRITE_EXTERNAL_STORAGE
};
public static final String THISCLASS = ExternalStoragePermissions.class.getSimpleName();
private static final String LOGTAG = "SW_ESP";
public ExternalStoragePermissions() {}
// Note call this method
public static void verifyStoragePermissions(Activity activity) {
int permission = ActivityCompat.checkSelfPermission(
activity,
Manifest.permission.WRITE_EXTERNAL_STORAGE);
if(permission != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(
activity,
PERMISSIONS_STORAGE,
REQUEST_EXTERNAL_STORAGE
);
}
}
}
- If permissions not given then the directories cannot be created resulting in FileNotFoundException.
DBHelper.java
public class DBHelper extends SQLiteOpenHelper {
public static final String DBNAME = "dados.db";
public static final int DBVERSION = 1;
public DBHelper(Context context) {
super(context, DBNAME, null, DBVERSION);
this.getWritableDatabase();
}
@Override
public void onCreate(SQLiteDatabase db) {
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}
- A Very basic empty database (exception android_metadata table), enough to check backup.
MainActivity.java
public class MainActivity extends AppCompatActivity {
DBHelper mDBHlpr;
Button mBackup;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mBackup = this.findViewById(R.id.backup);
mBackup.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
mDBHlpr.close();
try {
backupDatabase();
} catch (IOException e) {
e.printStackTrace();
}
}
});
ExternalStoragePermissions.verifyStoragePermissions(this);
mDBHlpr = new DBHelper(this);
}
private void backupDatabase () throws IOException {
FileInputStream fis = new FileInputStream (this.getDatabasePath("dados.db").getPath());
String outFileName = Environment.getExternalStorageDirectory () + "/example/backup/" + String.valueOf(System.currentTimeMillis()) + "data.db";
Log.d("OSFILEPATH",outFileName);
File os = new File(outFileName);
if (!os.getParentFile().exists()) {
os.getParentFile().mkdirs();
}
OutputStream output = new FileOutputStream(os);
byte [] buffer = new byte [1024];
int length;
while ((length = fis.read (buffer))> 0) {
output.write (buffer, 0, length);
}
output.flush ();
output.close ();
fis.close ();
}
}
Notes
When first run after install permission will be requested for later devices (click allow).
Backup has been named with a timestamp so multiple backups can exist.
Database is closed, (this should cope with Android Pie+ wehere default is WAL mode, the close should empty (commit the changes) the -wal and -shm files, thus negating the need to backup the additional files).
Result
