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How to Include CSS and JS files via HTTPS when needed?

I am adding an external CSS file and an external JS file to my headers and footers. When loading an HTTPS page, some browsers complain that I am loading unsecured content.

Is there an easy way to make the browser load the external content via HTTPS when the page itself is HTTPS?

Answer

Use protocol-relative paths.

Thus not

<link rel="stylesheet" href="http://example.com/style.css">
<script src="http://example.com/script.js"></script>

but so

<link rel="stylesheet" href="//example.com/style.css">
<script src="//example.com/script.js"></script>

then it will use the protocol of the parent page.

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discuss

change background of an ImageView (the old image stays there!)

how can I change the background of an ImageView from java? I have an ImageView and at a certain point I need to change the image that it displays (set in the styles). I tried to do it like this:

placeHolder.setImageDrawable(myDrawb);

but it looks like the old image remains there and it is partially covered but the new one (which in my case has different shape).

hope you guys can help!

cheers

Answer

You don’t need to touch the XML to use src instead of background!

An ImageView can display two drawables! One in the background and other in the foreground. It seems that you are always changing the background image.

Instead of setBackgroundResource(resId) use setImageResource(resId) to change the foreground image!

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discuss

Hibernate @OneToOne @NotNull

Is it valid to declare @OneToOne and @NotNull on both sides of a relationship, such as:

class ChangeEntry
{
    @OneToOne(cascade=CascadeType.ALL)
    @NotNull
    ChangeEntryDetails changeEntryDetails;

    public void addDetails(ChangeEntryDetails details) {
       this.changeEntryDetails = details;
       details.setChangeEntry(this);
    }
 }

 class ChangeEntryDetails
 {
     @OneToOne(cascase=CascadeType.ALL)
     @NotNull
     ChangeEntry changeEntry;

     public void setChangeEntry(ChangeEntry changeEntry)
     {
          this.changeEntry = changeEntry;
     }
 }

I can’t find anything that says this is invalid, but it seems that during persistence at least one side of the relationship must be violated. (Eg., if writing changeEntry first, changeEntryDetails will be null temporarily).

When trying this, I see an exception thrown not-null property references a null or transient value.

I’d like to avoid relaxing the constraint if possible, because both sides must be present.

Answer

Is it valid to declare @OneToOne and @NotNull on both sides of a relationship (…) I can’t find anything that says this is invalid, but it seems that during persistence at least one side of the relationship must be violated. (e.g. if writing changeEntry first, changeEntryDetails will be null temporarily).

It is valid and everything works fine with properly mapped entities. You need to declare one side of your bi-directional association as the “owning” side (this “control” the order of inserts). One possible working solution:

@Entity
@NamedQueries( { @NamedQuery(name = ChangeEntry.FIND_ALL_CHANGEENTRIES, query = "SELECT c FROM ChangeEntry c") })
public class ChangeEntry implements Serializable {
    public final static String FIND_ALL_CHANGEENTRIES = "findAllChangeEntries";

    @Id
    @GeneratedValue
    private Long id;

    @OneToOne(optional = false, cascade = CascadeType.ALL)
    @JoinColumn(name = "DETAILS_ID", unique = true, nullable = false)
    @NotNull
    private ChangeEntryDetails changeEntryDetails;

    public void addDetails(ChangeEntryDetails details) {
        this.changeEntryDetails = details;
        details.setChangeEntry(this);
    }

    // constructor, getters and setters
}

And for the other entity (note the mappedBy attribute set on the non-owning side of the association):

@Entity
public class ChangeEntryDetails implements Serializable {
    @Id
    @GeneratedValue
    private Long id;

    @OneToOne(optional = false, mappedBy = "changeEntryDetails")
    @NotNull
    private ChangeEntry changeEntry;

    // constructor, getters and setters
}

With these entities, the following test (for demonstration purposes) passes:

public class ChangeEntryTest {
    private static EntityManagerFactory emf;    
    private EntityManager em;

    @BeforeClass
    public static void createEntityManagerFactory() {
        emf = Persistence.createEntityManagerFactory("TestPu");
    }    
    @AfterClass
    public static void closeEntityManagerFactory() {
        emf.close();
    }    
    @Before
    public void beginTransaction() {
        em = emf.createEntityManager();
        em.getTransaction().begin();
    }    
    @After
    public void rollbackTransaction() {   
        if (em.getTransaction().isActive()) {
            em.getTransaction().rollback();
        }
        if (em.isOpen()) {
            em.close();
        }
    }

    @Test 
    public void testCreateEntryWithoutDetails() {
        try {
            ChangeEntry entry = new ChangeEntry();
            em.persist(entry);
            fail("Expected ConstraintViolationException wasn't thrown.");
        } catch (ConstraintViolationException e) {
            assertEquals(1, e.getConstraintViolations().size());
            ConstraintViolation<?> violation = e.getConstraintViolations()
                .iterator().next();

            assertEquals("changeEntryDetails", violation.getPropertyPath()
                .toString());
            assertEquals(NotNull.class, violation.getConstraintDescriptor()
                .getAnnotation().annotationType());
        }
    }

    @Test
    public void testCreateDetailsWithoutEntry() {    
        try {
            ChangeEntryDetails details = new ChangeEntryDetails();
            em.persist(details);
            fail("Expected ConstraintViolationException wasn't thrown.");
        } catch (ConstraintViolationException e) {
            assertEquals(1, e.getConstraintViolations().size());
            ConstraintViolation<?> violation = e.getConstraintViolations()
                .iterator().next();

            assertEquals("changeEntry", violation.getPropertyPath()
                .toString());
            assertEquals(NotNull.class, violation.getConstraintDescriptor()
                .getAnnotation().annotationType());
        }
    }

    @Test
    public void validEntryWithDetails() {
        ChangeEntry entry = new ChangeEntry();
        ChangeEntryDetails details = new ChangeEntryDetails();
        entry.addDetails(details);
        em.persist(entry);

        Query query = em.createNamedQuery(ChangeEntry.FIND_ALL_CHANGEENTRIES);
        assertEquals(1, query.getResultList().size());
    }
}
Categories
discuss

How to use a servlet filter in Java to change an incoming servlet request url?

How can I use a servlet filter to change an incoming servlet request url from

http://nm-java.appspot.com/Check_License/Dir_My_App/Dir_ABC/My_Obj_123

to

http://nm-java.appspot.com/Check_License?Contact_Id=My_Obj_123

?


Update: according to BalusC’s steps below, I came up with the following code:

public class UrlRewriteFilter implements Filter {

    @Override
    public void init(FilterConfig config) throws ServletException {
        //
    }

    @Override
    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws ServletException, IOException {
        HttpServletRequest request = (HttpServletRequest) req;
        String requestURI = request.getRequestURI();

        if (requestURI.startsWith("/Check_License/Dir_My_App/")) {
            String toReplace = requestURI.substring(requestURI.indexOf("/Dir_My_App"), requestURI.lastIndexOf("/") + 1);
            String newURI = requestURI.replace(toReplace, "?Contact_Id=");
            req.getRequestDispatcher(newURI).forward(req, res);
        } else {
            chain.doFilter(req, res);
        }
    }

    @Override
    public void destroy() {
        //
    }
}

The relevant entry in web.xml look like this:

<filter>
    <filter-name>urlRewriteFilter</filter-name>
    <filter-class>com.example.UrlRewriteFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>urlRewriteFilter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

I tried both server-side and client-side redirect with the expected results. It worked, thanks BalusC!

Answer

  1. Implement javax.servlet.Filter.
  2. In doFilter() method, cast the incoming ServletRequest to HttpServletRequest.
  3. Use HttpServletRequest#getRequestURI() to grab the path.
  4. Use straightforward java.lang.String methods like substring(), split(), concat() and so on to extract the part of interest and compose the new path.
  5. Use either ServletRequest#getRequestDispatcher() and then RequestDispatcher#forward() to forward the request/response to the new URL (server-side redirect, not reflected in browser address bar), or cast the incoming ServletResponse to HttpServletResponse and then HttpServletResponse#sendRedirect() to redirect the response to the new URL (client side redirect, reflected in browser address bar).
  6. Register the filter in web.xml on an url-pattern of /* or /Check_License/*, depending on the context path, or if you’re on Servlet 3.0 already, use the @WebFilter annotation for that instead.

Don’t forget to add a check in the code if the URL needs to be changed and if not, then just call FilterChain#doFilter(), else it will call itself in an infinite loop.

Alternatively you can also just use an existing 3rd party API to do all the work for you, such as Tuckey’s UrlRewriteFilter which can be configured the way as you would do with Apache’s mod_rewrite.

Categories
discuss

How to bring up list of available notification sounds on Android

I’m creating notifications in my Android application, and would like to have an option in my preferences to set what sound is used for the notification. I know that in the Settings application you can choose a default notification sound from a list. Where does that list come from, and is there a way for me to display the same list in my application?

Answer

Just copy/pasting some code from one of my apps that does what you are looking for.

This is in an onClick handler of a button labeled “set ringtone” or something similar:

Intent intent = new Intent(RingtoneManager.ACTION_RINGTONE_PICKER);
intent.putExtra(RingtoneManager.EXTRA_RINGTONE_TYPE, RingtoneManager.TYPE_NOTIFICATION);
intent.putExtra(RingtoneManager.EXTRA_RINGTONE_TITLE, "Select Tone");
intent.putExtra(RingtoneManager.EXTRA_RINGTONE_EXISTING_URI, (Uri) null);
this.startActivityForResult(intent, 5);

And this code captures the choice made by the user:

@Override
protected void onActivityResult(final int requestCode, final int resultCode, final Intent intent) {
    if (resultCode == Activity.RESULT_OK && requestCode == 5) {
        Uri uri = intent.getParcelableExtra(RingtoneManager.EXTRA_RINGTONE_PICKED_URI);

        if (uri != null) {
            this.chosenRingtone = uri.toString();
        } else {
            this.chosenRingtone = null;
        }
    }            
}

Also, I advise my users to install the “Rings Extended” app from the Android Market. Then whenever this dialog is opened on their device, such as from my app or from the phone’s settings menu, the user will have the additional choice of picking any of the mp3s stored on their device, not just the built in ringtones.

Source: stackoverflow
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