Develop Reference

Displaying an HD image

I have recently started to learn android application development. Now I have some troubles in the image insertion. When i use the default images (launcher_background) my application seems to work fine. But any time I try to insert a HD image the application seems to stop. This has been going on for quite a while now.

Mybe it's because your image size is too big if your image is too big you should change image width and height to size of the image view or device display
There are thred party libaries you can use like :
https://github.com/Piasy/BigImageViewer
For more information see the links below :
https://developer.android.com/topic/performance/graphics/load-bitmap.html
https://android.jlelse.eu/loading-large-bitmaps-efficiently-in-android-66826cd4ad53

How to use high resolution images in a way that application don't lag?

High/medium resolution photo takes time to load from drawable and affects application performance, whereas low resolution photo looks blurred; I want to use high resolution images but not compromise with the performance, How to do that?
I am trying to set a high resolution background image of layout login from drawable, so when switching between components of the same activity lagging occurs.
For instance: switching between field email to password, keyboard appears/disappear in slow motion.

If I were you , I would use the Glide library. Its faster than Picasso and ideal when you want to load large images.
From the github documentation :
Glide's primary focus is on making scrolling any kind of a list of images as smooth and fast as possible, but Glide is also effective for almost any case where you need to fetch, resize, and display a remote image

Yes, use Piccaso. It will adjust and load a correct image size depending on your device and size of imageview.

Hard to know what you need, but you can use a FrameLayout to download multiple pictures in the background and set them invisible till you need it with android:visibility attribute.This solution is for one activity. Asynchronous work and cache can be the answer.
You should consider resize your pic anyway, users prefer see the pic than wait and quit, they know the limitations of their devices (so does android ;-).

Thread assistance

I need some help,
I am creating an app, and want it to run faster I mean when the app is started first it shows a blank white screen for o 1-2 seconds and then loads images. I have a layout background image, and 4 imageviews which are clickable and take you to the next activity. I read somewhere i should use threads to load images and it will load them on a separate thread faster, but i have some problem using it.
So here are the problems and android studio explanations:
Thread thread=new Thread(
public void run(){
ImageView tipka=(ImageView)findViewById(R.id.tipkaproba);
tipka.setImageResource(R.drawable.instructions);
LinearLayout asd=(LinearLayout)findViewById(R.id.layoutproba);
asd.setBackgroundResource(R.drawable.backfround123);
}
).start();
Now the android studio says: 
After
"Thread(" )expected
Before
"public void run(){"
; expected
On ").start();"
Invalid method declaration; return type required, Missing method body, or declare abstract.
Now i would like to know:
Does this speed up loading images, ( if not how to do it then)
How to fix my errors.
Thanks anyway !

Do all images fit in the screen?! If users need to scroll to view other images why load all of them at once? Use a grid view with adapter to load the image. In this way when the app start only images on the screen will be loaded and then when the user scrolls other images show up!
another thing you can do is to have 2 version of each image. one low quality with small size that loads first and one for high quality image. that will load latter. You can also calculate the base color for each image (use open source code or do it manually). then set the background image of iamgeview to this color. So when the image finally loads on the screen. The difference is not as dramatic as it was before.
If you want to use thread try AsyncTask first. Using AsyncTask is simpler than defining thread yourself.
Try to decrease the size of your images! If you be able to do this. it works better than any other trick! It's mobile, you don't have to show supper high quality images. users don't even notice most of the time
You probably took care of this but it worth mentioning that you need to provide different images for different screen densities and it's critical for performance as well as quality.

Android OutOfMemory exception - Is there another approach for my needs?

My app is loading a large image (a house floorplan), then drawing touch-reactive objects (furniture, lamps etc.) on the image. I have a base image file included with my app but the objects come from coords in my database.
I've successfully deployed the app in multiple iterations, but now I need to use larger base images and BitmapFactory is causing an OutOfMemory exception on many devices (both old and new devices; anything with < 32MB heap seems to crash). I've read the 157 OOM questions on SO, but I'm afraid the link they all seem to point to won't help me since resolution / zooming is critical to the app's function.
I've tried to test the device's available memory before loading, but the results are spotty at best (some devices like the galaxy S3 report plenty of heap but still crash). I've also tried decreasing resolution but the image became unusable when reduced to a safe size based on the above test.
Is there another way to implement this design without ever using bitmaps?
I need to:
Load large base image
Create clickable shapes on top of the base image, maintaining their position / scale relative to the base image
BONUS: in the iOS version of my app, I can do SVG-style text scaling so a long label on a small object will stay inside the object
instead of running across the map(and will be invisible until the
image is zoomed). Replicating this in android would make me a happy
code monkey.
I can post code if needed, but you've all seen it before (almost all of it came from SO).
Thanks in advance for reading, and for any help you can give.

you have a few options:
break your large image into tiles, load these tiles into an array, and move a camera object around and only load tiles that need to be drawn, as the comments suggest.
make your image small and scale it up using 'android:scaletype`
Draw lines and curves on a Canvas object at runtime.
Use OpenGL
The appropriate solution really depends on how you want it to look. Tiling will take more dev effort but will look better, just be careful that you are properly cleaning up any tiles that aren't being drawn...
dynamically scaling will be easier, but you cannot guarantee the image won't be blurry.
Drawing on a Canvas object at runtime could work well-- just use Lines of different width and circles and Rects etc.
Using OpenGL will have the steepest learning curve, and might be overkill. This depends on your purpose.

You might like to look into using a "largeHeap"
http://developer.android.com/reference/android/R.styleable.html#AndroidManifestApplication_largeHeap

Here are some options:
1) Use tiles. Use tiles and dynamically load your data. Honestly, this is the best solution. With this solution you can load arbitrarily large images.
I've successfully used this approach for an endless paint canvas and it works quite well. You really only need to draw what is directly visible to the user. Tiles is a way to cast away pieces you don't need. A pyramid of tiles (where you pre-downsample your images and create more tiles), allows you to do this in a clean and fast way.
2) Use native code. The memory restrictions on native code are not the same as Java code. You can get away with allocating more memory.
3) Use OpenGL. Once again, the memory restriction for OpenGL are not the same as Java code.
4) Convert your original plan to an SVG and use an SVG library like this one.
5) Use "largeHeap". I strongly discourage this, as I think a largeHeap is rarely the solution, there are generally cleaner ways to approach the problem.

if the image is static , you might wish to use this nice library:
https://github.com/ManuelPeinado/ImageLayout
if the library doesn't support auto-downsampling of the image, you should do it by yourself, in order to use the best image for the current device (so that you won't get OOM).
for auto-sizing text , you might have some luch with the next post:
Auto-fit TextView for Android

Cocos2D android background image gets messed up

so im trying to make a game with just a simple static background at the moment, but when i draw it to the screen (no scaling being done as the resolution of the image is the same as the screen) it draws the bottom portion of the image incorrectly where the bottom few hundred pixels of the image are exactly the same going down the image. Sorry it's so difficult to explain but being new here i cant actually post an image of what is going wrong.
Now im just using a simple sprite to render this background image. Here is the code being used:
// background layer: another image
background = CCSprite.sprite("WaterBackground.png");
// change the transform anchor point (optional)
background.setPosition(CGPoint.make(GAME_WIDTH/2, GAME_HEIGHT/2));
addChild(background);
am i doing something wrong here? Does Cocos2D not support such large images for sprites? (resolution of 800*1280)
Any help would be greatly appreciated!
Since i am now able to upload images, here are visuals of what is going wrong:
And the problem in my game:
As you can see, the problem is hard to describe. The problem only exists with this larger image; i scaled it down manually in GIMP and then scaled it up for the game and it looked fine (except for being a lower resolution). I also tried scaling down this larger image which still resulted in the same problem. Hopefully you guys can help me as I have no clue what could possibly cause this error. Especially since i read that Cocos2D's max supported image size is 2048*2048 and my image is well within that.
Thanks for any help you guys can provide!

This is due to limitations on the size of textures. Coсos2d-android supports images with a maximum size of 1024 x 1024 pixels.
I faced the same problem and looking for a way to solve it.
EDIT
I found the solution
In cocos2d project open file CCTexture2d.java in org.cocos2d.opengl package and change kMaxTextureSize from 1024 to 2048

I'm not certain, as from your code and looking at the cocos2d code I can't see a definite reason why this would be happening, but given the number of sprites you've got on the screen, i'd definitely take a look at my answer to this question as you may well be hitting one of cocos2d's quirky little rendering faults around multiple sprites. can't hurt to try spritesheets, and it's certainly the correct way to actually do sprites in cocos.
also, definitely create yourself a helper utility to determine the scaling ratio of a device compared to your original image sizes, as unlike on iphone, android does have a pretty much unlimited variation of screen resolutions, and a simple bit of "scale as you load" utility code now will save you lots of time in the future if you want to use this on any other device.

you should try to make one method for adding background,i am doing this this like this way try this hope it will help full for you...here addBackGroundScene is my method and i am adding my background with this method,scrXScaleFactor is maintaining scaling part of my screen try this...
private void addBackGroundScene() {
CCSprite bgForLevel1 = addBackgroundAtOrigin("prelevel1/bgMenu.jpg");
bgForLevel1 .setScaleX(scrXScaleFactor);
bgForLevel1 .setAnchorPoint(0, 0);
addChild(bgForLevel1 );
}