backup of database to sd card

Question

i am try to make back up feature in my app but it give force close error

can any one give some idea whats wrong in my code

pls help me out

here is my code

public class Mydatabase {

 private String appName = "";
  private String packageName = "";
  public static final String DATABASE_NAME = "data.db";
  public boolean backup() {
    boolean rc = false;

    boolean writeable = isSDCardWriteable();
    if (writeable) {
      File file = new File(Environment.getDataDirectory() + "/data/" + packageName + "/databases/" + DATABASE_NAME);

      File fileBackupDir = new File(Environment.getExternalStorageDirectory(), appName + "/backup");
      if (!fileBackupDir.exists()) {
        fileBackupDir.mkdirs();
      }

      if (file.exists()) {
        File fileBackup = new File(fileBackupDir, DATABASE_NAME);
        try {
          fileBackup.createNewFile();
          FileUtils..copyFile(file, fileBackup);
          rc = true;
        } catch (IOException ioException) {
          //
        } catch (Exception exception) {
          //
        }
      }
    }

    return rc;
  }

  private boolean isSDCardWriteable() {
    boolean rc = false;

    String state = Environment.getExternalStorageState();
    if (Environment.MEDIA_MOUNTED.equals(state)) {
      rc = true;
    }

    return rc;
  }

    public Mydatabase(final Context context, final String appName) {
        this.appName = appName;
        packageName = context.getPackageName();
    }

}

this is my log

04-03 00:39:18.595: E/AndroidRuntime(674): FATAL EXCEPTION: main
04-03 00:39:18.595: E/AndroidRuntime(674): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.neelrazin.noteit/com.neelrazin.noteit.Mydatabase}: java.lang.InstantiationException: com.neelrazin.noteit.Mydatabase
04-03 00:39:18.595: E/AndroidRuntime(674):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1569)
04-03 00:39:18.595: E/AndroidRuntime(674):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
04-03 00:39:18.595: E/AndroidRuntime(674):  at android.app.ActivityThread.access$1500(ActivityThread.java:117)
04-03 00:39:18.595: E/AndroidRuntime(674):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
04-03 00:39:18.595: E/AndroidRuntime(674):  at android.os.Handler.dispatchMessage(Handler.java:99)
04-03 00:39:18.595: E/AndroidRuntime(674):  at android.os.Looper.loop(Looper.java:123)
04-03 00:39:18.595: E/AndroidRuntime(674):  at android.app.ActivityThread.main(ActivityThread.java:3683)
04-03 00:39:18.595: E/AndroidRuntime(674):  at java.lang.reflect.Method.invokeNative(Native Method)
04-03 00:39:18.595: E/AndroidRuntime(674):  at java.lang.reflect.Method.invoke(Method.java:507)
04-03 00:39:18.595: E/AndroidRuntime(674):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
04-03 00:39:18.595: E/AndroidRuntime(674):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
04-03 00:39:18.595: E/AndroidRuntime(674):  at dalvik.system.NativeStart.main(Native Method)
04-03 00:39:18.595: E/AndroidRuntime(674): Caused by: java.lang.InstantiationException: com.neelrazin.noteit.Mydatabase
04-03 00:39:18.595: E/AndroidRuntime(674):  at java.lang.Class.newInstanceImpl(Native Method)
04-03 00:39:18.595: E/AndroidRuntime(674):  at java.lang.Class.newInstance(Class.java:1409)
04-03 00:39:18.595: E/AndroidRuntime(674):  at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
04-03 00:39:18.595: E/AndroidRuntime(674):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1561)
04-03 00:39:18.595: E/AndroidRuntime(674):  ... 11 more

`Caused by: java.lang.InstantiationException: com.neelrazin.noteit.Mydatabase` show us the code where you use `Mydatabase` — WarrenFaith, Apr 02 '13 at 19:50
You need to have this `` in your manifest in order to write the backup on the phone memory if it's not in the application private directory and it's the case here with `Environment.getExternalStorageDirectory()`. — Stephane Mathis, Apr 02 '13 at 19:53

score 3 · Answer 1 · answered Apr 02 '13 at 20:06

You seem a bit lost. Here is a functional method to backup your database, you can place it in any class.

public static void backupDatabase() throws IOException {
    //Open your local db as the input stream
    String inFileName = "/data/data/com.android.exemple/databases/databename.db";
    File dbFile = new File(inFileName);
    FileInputStream fis = new FileInputStream(dbFile);

    String outFileName = Environment.getExternalStorageDirectory()+"/database.db";
    //Open the empty db as the output stream
    OutputStream output = new FileOutputStream(outFileName);
    //transfer bytes from the inputfile to the outputfile
    byte[] buffer = new byte[1024];
    int length;
    while ((length = fis.read(buffer))>0){
        output.write(buffer, 0, length);
    }
    //Close the streams
    output.flush();
    output.close();
    fis.close();
}

You need to add this line in your manifest before the application element

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

Don't forget to change the package name in the inFileName variable and the databasename at both place.

@ Stephane : i tried as u have said but nothing happened.It just shows a plain screen when click on my "BackUp" button.Can you explain why this is happening? — Neel, Apr 03 '13 at 06:50
This metof doesn't display anything on the screen, but if you take a look at the root of you sdcard memory you should see the file database.db. — Stephane Mathis, Apr 03 '13 at 09:54

score 0 · Answer 2 · answered Apr 02 '13 at 19:54

0

The trace points the finger at the fact that you're trying to launch an Activity called Mydatabase. As we can see from your code snippet, Mydatabase doesn't extend Activity. The system is looking for an Activity to launch, not a class that just derives from Object.

answered Apr 02 '13 at 19:54

James

3,729
3
20
16

i get this code form this website there is not extend Activity – Neel Apr 02 '13 at 19:58

backup of database to sd card

2 Answers2