**All the answers here show a _dp-&gt;px_ conversion rather than _px-&gt;dp_, which is what the OP asked for.** 
Note that [`TypedValue.applyDimension`](http://developer.android.com/reference/android/util/TypedValue.html#applyDimension%28int,%20float,%20android.util.DisplayMetrics%29) cannot be used to convert px-&gt;dp, for that you must use the method described here: https://stackoverflow.com/a/17880012/504611 (quoted below for convenience).


    fun Context.dpToPx(dp: Int): Int {
        return (dp * resources.displayMetrics.density).toInt()
    }
    
    fun Context.pxToDp(px: Int): Int {
        return (px / resources.displayMetrics.density).toInt()
    }

    float ht_px = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, ht, getResources().getDisplayMetrics());
    float wt_px = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, wt, getResources().getDisplayMetrics());

This should give you the conversion pixels -&gt; dp:

    DisplayMetrics displaymetrics = new DisplayMetrics();
    int dp = (int) TypedValue.applyDimension( TypedValue.COMPLEX_UNIT_DIP, myPixels, displaymetrics );

    DisplayMetrics dm = new DisplayMetrics();
            getWindowManager().getDefaultDisplay().getMetrics(dm);
            String str_ScreenSize = &quot;The Android Screen is: &quot;
                        + dm.widthPixels
                        + &quot; x &quot;
                        + dm.heightPixels;
    
            TextView mScreenSize = (TextView) findViewById(R.id.strScreenSize);
            mScreenSize.setText(str_ScreenSize);

can u cheeck it out..

or this may also help u

    int value = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 
                         (float) 123.4, getResources().getDisplayMetrics());



My project missing `System.Windows.Interactivity`. Google says that I have to install Expression Blend, but on my other computer I have this library and I don&#39;t have Expression Blend installed. So there should be another way to obtain `System.Windows.Interactivity`? What should I do? (right now i don&#39;t have another computer so I can not just copy this library :)

How to add System.Windows.Interactivity to project?

I&#39;m trying to figure out how to properly use the [OpenSSL.Session][1] API in a concurrent context

E.g. assume I want to implement a `stunnel-style ssl-wrapper`, I&#39;d expect to have the following basic skeleton structure, which implements a naive `full-duplex tcp-port-forwarder:`

    runProxy :: PortID -&gt; AddrInfo -&gt; IO ()
    runProxy localPort@(PortNumber lpn) serverAddrInfo = do
      listener &lt;- listenOn localPort

      forever $ do
        (sClient, clientAddr) &lt;- accept listener

        let finalize sServer = do
                sClose sServer
                sClose sClient

        forkIO $ do
            tidToServer &lt;- myThreadId
            bracket (connectToServer serverAddrInfo) finalize $ \sServer -&gt; do
                -- execute one &#39;copySocket&#39; thread for each data direction
                -- and make sure that if one direction dies, the other gets
                -- pulled down as well
                bracket (forkIO (copySocket sServer sClient
                                 `finally` killThread tidToServer))
                        (killThread) $ \_ -&gt; do
                    copySocket sClient sServer -- &quot;controlling&quot; thread

     where
      -- |Copy data from source to dest until EOF occurs on source
      -- Copying may also be aborted due to exceptions
      copySocket :: Socket -&gt; Socket -&gt; IO ()
      copySocket src dst = go
       where
        go = do
            buf &lt;- B.recv src 4096
            unless (B.null buf) $ do
                B.sendAll dst buf
                go

      -- |Create connection to given AddrInfo target and return socket
      connectToServer saddr = do
        sServer &lt;- socket (addrFamily saddr) Stream defaultProtocol
        connect sServer (addrAddress saddr)
        return sServer


How do I transform the above skeleton into a `full-duplex ssl-wrapping tcp-forwarding proxy`? Where are the dangers W.R.T to concurrent/parallel execution (in the context of the above use-case) of the function calls provided by the HsOpenSSL API?

PS: I&#39;m still struggling to fully comprehend how to make the code robust w.r.t. to exceptions and resource-leaks. So, albeit not being the primary focus of this question, if you notice something bad in the code above, please leave a comment.


  [1]: http://hackage.haskell.org/packages/archive/HsOpenSSL/0.10.3.1/doc/html/OpenSSL-Session.html

Proper use of the HsOpenSSL API to implement a TLS Server

I want to calculate `dp` from `px` programmatically. How to do it?
I get resolution from:
      
    DisplayMetrics displaymetrics = new DisplayMetrics();
    getWindowManager().getDefaultDisplay().getMetrics(displaymetrics);
    ht = displaymetrics.heightPixels;
    wt = displaymetrics.widthPixels;

        

How to calculate dp from pixels in android programmatically

I want to calculate <code>dp</code> from <code>px</code> programmatically. How to do it?
I get resolution from:
<pre><code class="hljs language-ini">DisplayMetrics displaymetrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(displaymetrics);
ht = displaymetrics.heightPixels;
wt = displaymetrics.widthPixels;

 
</code></pre>

Given an APK, is it possible to determine which version of Android platform it targets?

Android: How to find which platform version an APK targets?

Given

    ImageView image = R.findViewById(R.id.imageView);
    image.setImageBitmap(someBitmap);

Is it possible to retrieve the bitmap?

Get Bitmap attached to ImageView

I am trying to add an item to the options menu from a group of fragments.

I have created a new `MenuFragment` class and extended this for the fragments I wish to include the menu item in. Here is the code:

Java:

    public class MenuFragment extends Fragment {

        MenuItem fav;

        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setHasOptionsMenu(true);
        }

        public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
            fav = menu.add(&quot;add&quot;);
            fav.setIcon(R.drawable.btn_star_big_off);
        }
    }

Kotlin: 

    class MenuFragment : Fragment {

        lateinit var fav: MenuItem

        override fun onCreate(savedInstanceState: Bundle) {
            super.onCreate(savedInstanceState)
            setHasOptionsMenu(true)
        }

        override fun onCreateOptionsMenu(menu: Menu, inflater: MenuInflater) {
            fav = menu.add(&quot;add&quot;);
            fav.setIcon(R.drawable.btn_star_big_off);
        }
    }

For some reason the `onCreateOptionsMenu` appears not to run.


How to add Options Menu to Fragment in Android

I am trying to calculate a variable amount of pixels to density independent pixels and vice-versa. 

This formula `(px to dp): dp = (int)(px / (displayMetrics.densityDpi / 160));` does not work on small devices because it is divided by zero. 

This is my dp to px formula: 

    px = (int)(dp * (displayMetrics.densityDpi / 160));

Could someone give me some pointers?


Formula px to dp, dp to px android

In my Android Honeycomb application I use Tabs as the navigation style. I would like to add one item next to the overflow button, but I want that item to be a dropdown list, and the user will be able to select an option there, but not related to navigation. What is the easiest way since I&#39;m using `mActionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);`

Is it possible to do it without using a custom view?


How to add a Dropdown item on the action bar

Ran the new Lint tool against my code.  It came up with a lot of good suggestions, but this one I cannot understand.

&gt;This tag and its children can be replaced by one &lt;TextView/&gt; and a compound drawable
&gt;
&gt;Issue: Checks whether the current node can be replaced by a TextView using compound drawables.
&gt;
&gt;A LinearLayout which contains an ImageView and a TextView can be more efficiently handled as a compound drawable

And here is my layout

    &lt;LinearLayout
    android:layout_width=&quot;wrap_content&quot;
    android:layout_height=&quot;wrap_content&quot;
    android:orientation=&quot;horizontal&quot;
    android:layout_centerInParent=&quot;true&quot;&gt;
    
    &lt;ImageView 
        android:id=&quot;@+id/upImage&quot;
        android:layout_width=&quot;20dp&quot;
        android:layout_height=&quot;20dp&quot;
        android:layout_gravity=&quot;center_vertical&quot;
        android:scaleType=&quot;centerInside&quot;
        android:src=&quot;@drawable/up_count_big&quot;&gt;
    &lt;/ImageView&gt;
    
    &lt;TextView
        android:id=&quot;@+id/LikeCount&quot;
        android:layout_width=&quot;wrap_content&quot;
        android:layout_height=&quot;wrap_content&quot;
        android:layout_marginLeft=&quot;2dp&quot;
        android:layout_marginBottom=&quot;1dp&quot;
        android:textColor=&quot;@color/gray&quot;
        android:textSize=&quot;16sp&quot;
        android:layout_gravity=&quot;center_vertical&quot;&gt;
    &lt;/TextView&gt;
    &lt;/LinearLayout&gt;

Can someone provide a concrete example of how to make a compound drawable in this case?

How do I use a compound drawable instead of a LinearLayout that contains an ImageView and a TextView

I want to create a file in external storage sdCard and write to it.I have searched through internet and try but not getting the result,I have added permission in Android Manifest file as well,I am doing this on Emulator,I am trying the following code and getting a ERRR&quot;, &quot;Could not create file&quot;.

    btnWriteSDFile = (Button) findViewById(R.id.btnWriteSDFile);
    btnWriteSDFile.setOnClickListener(new OnClickListener() {
      	//private Throwable e;

		@Override
       	public void onClick(View v) {
           	// write on SD card file data from the text box
        	try {
            	File myFile = new File(&quot;/sdcard/mysdfile.txt&quot;);
            	myFile.createNewFile();
            	FileOutputStream fOut = new FileOutputStream(myFile);
            	OutputStreamWriter myOutWriter = new OutputStreamWriter(fOut);
            	myOutWriter.append(txtData.getText());
            	myOutWriter.close();
            	fOut.close();
    
        	} catch (Exception e) {
                  Log.e(&quot;ERRR&quot;, &quot;Could not create file&quot;,e);
        	} 
    	}// onClick
    }); // btnWriteSDFile



Write a file in external storage in Android

I have implemented a custom dialog for my application. I want to implement that when the user clicks outside the dialog, the dialog will be dismissed.
What do I have to do for this?

How to dismiss the dialog with click on outside of the dialog?

I have an ImageView and I do a simple scale animation to it. Very standard code.

My scale_up.xml:

    &lt;set xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;&gt;
        &lt;scale android:fromXScale=&quot;1&quot;
               android:fromYScale=&quot;1&quot;
               android:toXScale=&quot;1.2&quot;
               android:toYScale=&quot;1.2&quot;
               android:duration=&quot;175&quot;/&gt;
    &lt;/set&gt;

My animation code:

    Animation a = AnimationUtils.loadAnimation(this, R.anim.scale_up);
    ((ImageView) findViewById(R.id.circle_image)).startAnimation(a);

The problem:

When the image scales it doesn&#39;t scale from the center, but from the top left corner. In other words, the scaled version of the image doesn&#39;t have the same point as the center, but it has the same top-left point. 
Here&#39;s an image that explains what I mean:

[![How the animation scales][1]][1]
[![How I want it][2]][2]

The first image is how the animation scales and the second image is how I want it to scale. It should keep the center point the same. 
I have tried setting up gravity on the image, on the container, aligning left or right, it always scales the same.

I&#39;m using RelativeLayout for the main screen and ImageView is located into another RelativeLayout, but I tried other layouts, no change.


  [1]: https://i.stack.imgur.com/p1MYpt.png
  [2]: https://i.stack.imgur.com/YGxgwt.png

Android image scale animation relative to center point

I have looked on few articles and discussion like [one here][1] and [Here][2] about image resolutions that new iPhones will use @3x images for display. Is it true? 

So does it mean we will have to keep three images? Say for example I have an image of 50 X 50, will I have to keep 3 images for optimizing the look for new iPhones?


 - Normal (50 X 50)
 - @2x - Retina (100 X 100)
 - @3x - Retina HD (150 X 150)

Or will the new phones use @2x images only and there is nothing like @3x?

I have tested by making a sample project and all simulators seem to use @3x images, this is confusing.

**Edit**

Here is some more info

 - 3GS ( 163 ppi so use Normal)
 - 4, 4s, 5 and 5s (326 ppi so we use @2x)
 - 6 (326 ppi so it seems like it will use @2x)
 - 6 plus (401 ppi here lies the confusion )

**Edit**

Based on Answers given by Tsob and nitin, I added @3x images to my project. 

**Informational Edit**

I see few users are confused about why iPhone 6 uses @2x images even though it has higher resolution , the reason is 

iPhone 6 might have different resolution but has same density of per pixel inch (PPI)

 - **Resolution** concerns an absolute number of pixels.
 - **Density** (aka Pixels per inch - PPI) concerns a relative number of pixels per inch which is same in case of iPhone 6 and previous iPhones , but different in iPhone 6 plus. 

Check more about this [here in this  thread][3]

Hence iPhone 6 uses @2x image same as  iPhones 4 , 5 and 5S as it has same PPI and iPhone 6 plus uses @3x.

  [1]: http://www.macrumors.com/2014/05/14/3x-iphone-6-transition/
  [2]: http://9to5mac.com/2014/08/29/support-for-3x-image-assets-found-in-latest-ios-8-beta-ahead-of-larger-display-iphone-6/
[3]: https://stackoverflow.com/questions/5518852/android-what-is-the-difference-between-resolution-and-density

Image resolution for new iPhone 6 and 6+, @3x support added?

Why do we need these 3 particular image types?

If I have a button on my app with a background image say, 50 pixels x 50 pixels, why do I need 3 versions of this image?  What&#39;s stopping me from just making one image that&#39;s much higher in res, say, 700x700 so when it shrinks down on any iPhone it won&#39;t fall under the max res the device would want?

Only thing I can think of is it just takes up more space, but for simple apps / a simple button it seems like it wouldn&#39;t cause any issues.  I&#39;ve tried it on a few devices and see no difference between them when I simulate it and do this method.  However, as I dive more into apps and stuff I&#39;m sure there is substance behind this technique.

Content Type	Original Author	Original Content on Stackoverflow
Question	Dawid Hyży	View Question on Stackoverflow
Solution 1 - Android	Vicky Chijwani	View Answer on Stackoverflow
Solution 2 - Android	Vladimir	View Answer on Stackoverflow
Solution 3 - Android	kaspermoerch	View Answer on Stackoverflow
Solution 4 - Android	NikhilReddy	View Answer on Stackoverflow

How to calculate dp from pixels in android programmatically

Android Problem Overview

Android Solutions

Solution 1 - Android

Solution 2 - Android

Solution 3 - Android

Solution 4 - Android

Proper use of the HsOpenSSL API to implement a TLS Server

How to add System.Windows.Interactivity to project?

Attributions