CODEWITHSUNDEEP
javaandroidlogout
user3034944
user3034944

Reputation: 1761

Clearing application data programmatically Android

I have a app with SharedPreferences. I would like to clear the complete apps data on a button click so that the application starts fresh as it would when it is installed first.

I have tried:

ClearData.java

public class ClearData extends Application 
{
    private static ClearData instance;

    @Override
    public void onCreate() {
        super.onCreate();
        instance = this;
    }

    public static ClearData getInstance() {
        return instance;
    }

    public void clearApplicationData() {
        File cache = getCacheDir();
        File appDir = new File(cache.getParent());
        if (appDir.exists()) {
            String[] children = appDir.list();
            for (String s : children) {
                if (!s.equals("lib")) {
                    deleteDir(new File(appDir, s));
                    Log.i("TAG", "**************** File /data/data/mypackage/" + s + " DELETED *******************");
                }
            }
        }
    }

    public static boolean deleteDir(File dir) {
        if (dir != null && dir.isDirectory()) {
            String[] children = dir.list();
            for (int i = 0; i < children.length; i++) {
                boolean success = deleteDir(new File(dir, children[i]));
                if (!success) {
                    return false;
                }
            }
        }

        return dir.delete();
    }
}

Main.java

btnLogout.setOnclickListener(new View.OnClickListner(
{
 @Override
    public void onClick(View v) 
{
       ClearData.getInstance().clearApplicationData(); // Gettin error
    }
});

But I get a NullPointerException on the above line

Upvotes: 1

Views: 7740

Answers (2)

Milind Mevada
Milind Mevada

Reputation: 3285

Here is another way to clear the App data completely:

private void clearAppData() {
        try {
            Runtime runtime = Runtime.getRuntime();
            runtime.exec("pm clear " + getApplicationContext().getPackageName() + " HERE");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

Upvotes: 3

shradha16
shradha16

Reputation: 31

Don't use a class which extends application, declare 

clearApplicationData(Context mContext)

instead of 

clearApplicationData()

and 

File cache = mContext.getCacheDir();

instead of 

File cache = getCacheDir();

in main activity itself. Then call

clearApplicationData(getBaseContext());

on click of button btnLogout. Hope this helps.

Upvotes: 3

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