CODEWITHSUNDEEP
androidapkandroid-drawablexml-drawable
Hejazi
Hejazi

Reputation: 17005

Downlaod drawables from server to reduce APK file size

To reduce the APK file size, I want to remove the drawables (images and XML files) from my project and download the proper ones from my server on the first app start.

The problem is how to load and use the downloaded drawables in my code?

This is what I found after some research:

But I still don't know how to load and use XML drawables that have references to other drawables, like this:

<layer-list>
  <item>
    <bitmap android:src="@drawable/other_drawable" />
  </item>
</layer-list>

Any thoughts on this or other effective ideas to reduce the APK file size would be appreciated.

Notes:

Update:

After some more research, it seems to me possible to load/use downloaded XML drawables after modifying them a little by using custom attributes for referenced drawables and a subclass of Drawable instead of native BitmapDrawable. So the above XML drawable example will become something like this:

<layer-list xmlns:custom="http://schemas.android.com/apk/res-auto">
  <item>
    <custom-bitmap custom:ref="other_drawable" />
  </item>
</layer-list>

Though, it's not a very easy solution and I'm not sure it's better than doing things manually.

References:

Upvotes: 0

Views: 1864

Answers (5)

Michael
Michael

Reputation: 1496

You could use expansion files (see http://developer.android.com/google/play/expansion-files.html) and move your resources there using the jobb tool (http://developer.android.com/tools/help/jobb.html).

You would still have to handle unavailable resources as long as the expansion file has not been downloaded though.

Upvotes: 0

4gus71n
4gus71n

Reputation: 4073

First of all, that size isn't too bad if your application have intense ui interaction. Also, in some moment the user will need download that drawables, why not in the installation from the google playstore?. Anyways, If you really want to do it, you can do the following:

For the reference in your layouts, you will need hook up from every widget that have a reference to a drawable and implement your own tag. For example, if you old layout looks like this:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity" >

<ImageView
    android:id="@+id/someImageView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:layout_centerVertical="true"
    android:src="@drawable/somePicture" />

</RelativeLayout>

Now should look like this:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:custom="http://schemas.android.com/apk/res/com.example.custom"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity" >

<com.example.custom.RemoteImageView
    android:id="@+id/someImageView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:layout_centerVertical="true"
    custom:remoteSrc="somePicture" />

</RelativeLayout>

Remember add the custom tag definition in your attrs.xml. In the implementation of the class you can get the image (if exist) from some cache like this:

public class RemoteImageView extends ImageView {

private String remoteSrc;
private DiskLruImageCache diskCache;

public RemoteImageView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
}

public RemoteImageView(Context context, AttributeSet attrs) {
    super(context, attrs);
    diskCache = new DiskLruImageCache(this, "cache", 1024 * 1024 * 30, CompressFormat.PNG, 70);
    TypedArray a = context.getTheme().obtainStyledAttributes(attrs,
            R.styleable.RemoteImageView, 0, 0);

    try {
        remoteSrc = a.getString(R.styleable.RemoteImageView_remoteSrc);
        Bitmap cachedImage;
        if (!diskCache.containsKey(remoteSrc)) {
            //Download it from Internet and save it into the cache
            //...
            diskCache.put(remoteSrc, bitmapThatYouDownload);
        }
        cachedImage = diskCache.getBitmap(remoteSrc);
        //Use the cachedImage as the bitmap for this view.
    } finally {
        a.recycle();
    }
}

public RemoteImageView(Context context) {
    super(context);
}

}

To see about DiskLruImageCache you can check this links:

DiskLruCache

You can do some tricks with this like have a two-levels cache, the first one with a memory cache and the second one with a disk cache. Already exist libraries that does stuff like this, but how you need your custom tags, you can either modify those libraries or use the cache library in your classes like I show you above.

For the AnimationDrawable's like animation-list you will need build the animation in runtime. For example like this:

AnimationDrawable animation = new AnimationDrawable();
animation.addFrame(new BitmapDrawable(getResources(),diskCache.get(myFirstFreame)), 100);
animation.addFrame(new BitmapDrawable(getResources(),diskCache.get(mySecondFrame)), 1000);
animation.addFrame(new BitmapDrawable(getResources(),diskCache.get(myThirdFrame)), 1000);
animation.setOneShot(false);

ImageView imageAnim =  (ImageView) findViewById(R.id.img);
imageAnim.setBackgroundDrawable(animation);

Remember check if myFirstFrame,mySecondFrame and myThirdFrame are already in the cache. If not then download them and add them.

Hope this help, but if I was you, I would keep that size, personally isn't so much, I've developed a tumblr client with a lot of animation and ui features, and the apk size was around 15 MiB.

Upvotes: 2

Mohit
Mohit

Reputation: 11314

I doubt if your drawable goes this much (20MB) here i mean to drawable is xml Files only. Coz these can not be downloaded later, Have you properly optimize your code for Re-useability?

but you are free with the Images/raw's like audio files or something like this

My Suggestions

Note: If you are looking for downloadable xml drawables then answer is no it is not possible it must be withing apk and also you can follow the following to optimize

  • You shall download All of your Audio/images and other files on installation cause this is the only solution to reduce the apk size
  • You can't do anything with your xml Drawables you will have to have with apk so you shall optimize code as much as possible.
  • For xml Drawable you can look for Re-useability

As your question says how to use Downloaded drawable to you code

so the answer is You can not go with xml drawable but yes you can do these things with images and there is clear method of setting drawable from file or creating Bitmap from file

Upvotes: 1

Muhammad Ali Hassan
Muhammad Ali Hassan

Reputation: 192

XML Files and drawables are only to help developers, these are not the essential part of the programming in android. If you want to download from server you can do this. what you have to do is Create Layouts and other things manually in Java files. i-e 

RelativeLayout rl =new Relativelayout(Context);// To create Layout
Button button = new Button(Context); // Create Components Like this
button.setText("abc");// Set Properties

Now add components to layout as a child.

rl.addView(button,new          Layoutparams(Layoutparams.WRAP_CONTENT,Layoutparams.WRAP_CONTENT));

In onCreate return this Layout!

For drawables include very important in your drawable and download others through HTTP Calls.

Hope it helps.

Upvotes: 2

Utsav
Utsav

Reputation: 1

As per your requirement you can not change the xml drawables at runtime.

Other that if you still need this functionality you can download it on your application's splash screen and set it runtime as you have suggest using BitmapDrawable.

But as per my opinion this is not right way to use this, as when you create your activity that time your view already render on setContentView(layoutID). So when you call your activity it will display the blank views without images.

And from other resources i have read that you can not change the resources file like drawable, raw,strings at runtime as it's id's can't create on runtime.

Upvotes: 0

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