i am trying to do the folowing: set up a large image (larger than the screen or zoomed in at some point) and by swiping left or right to be able to focus the users view to a specific part on the image(pan and zoom to that point). similar to the map view when you center on some location (or zoom to). any pointers for how i can achieve this?
i saw the zoom and swipe examples JohnNick has provided and went to search further and i found these 2 tutorials for creating scroll and zoom on an image
link Long-press and Scroll Large Images Using Low Level Events
link Large Image Scrolling Using Low Level Touch Events
but i still need a way to swipe to a specific part of an image. but now i have a dillema. as i read on there seem to be some issues with outOfMemoryException when working with large bitmaps, so my problem is: is it better to make the swipes as changing small bitmaps like the view transition example or is there a way to maybe only render the visible part of the image or something like that or maybe a map-like functionality ( dividing the image in ex. 8 parts and showing only the ones visible)?
Click Here Example for Image Zoom and Pan
Click Here Example for Image swiping
Related
I've been following the Camera2 example (android/camera-samples/Camera2Video) to create an abstraction over the Camera2 library. The idea of my abstraction is to give the user the ability to use a Camera view from React Native, so it's just a <Camera> view which can be whatever size/aspect ratio.
While this works out of the box on iOS, I can't seem to get the preview on Android to display "what the camera sees" in the correct aspect ratio.
The official example from Android works like this:
They create a custom SurfaceView extension that should automatically fit to the correct aspect ratio (see: AutoFitSurfaceView)
They use that AutoFitSurfaceView in their layout
They add a listener to the AutoFitSurfaceView's Surface to find out when it has been created (source)
Once the Surface has been created, they call getPreviewOutputSize(...) to get the best matching camera preview size (e.g. so you don't stream 4k for a 1080p screen, that's wasted pixels)
Then they pass the best matching camera preview size to the AutoFitSurfaceView::setAspectRatio(...) function
By knowing the desired aspect ratio, the AutoFitSurfaceView should then automatically perform a center-crop transform in it's onMeasure override
If you read the source code of their getPreviewOutputSize(...) function, you might notice that this uses a Display to find the best matching preview size. If I understood the code correctly, this would only work if the camera preview (AutoFitSurfaceView) is exactly the same size as the device's screen. This is poorly designed, as there are lots of cases where that simply isn't true. In my case, the Camera has a bit of a bottom spacing/margin, so it doesn't fill the screen and therefore has weird resolutions (1080x1585 on a 1080x1920 screen)
With that long introduction, here comes my question: How do I actually perform a correct center crop transform (aka scaleType = CENTER_CROP) on my SurfaceView? I've tried the following:
Set the size of my SurfaceView using SurfaceHolder::setFixedSize(...), but that didn't change anything at all
Remove their getPreviewOutputSize(...) stuff and simply use the highest resolution available
Use the Android View properties scaleX and scaleY to scale the view by the aspect-ratio difference of the view <-> camera input scaler size (this somewhat worked, but is giving me errors if I try to use high-speed capture: Surface size 1080x1585 is not part of the high speed supported size list [1280x720, 1920x1080])
Any help appreciated!
I'm not sure if this is possible, or If I am approaching this challenge wrong. I am making a 2D Platformer, so when you hit the edge of the screen(Width), a new portion of the map would appear. Currently, I made single Images for each Portion of the map. Problem is, on larger devices, this would leave a lot of blank screen, and the Image would only fit a specific device.
Now I am wondering, can I make my ImageView (MAP) at a negative X value then when the character hits the edge, the map would move right (X would go higher).
I am using XML (Java is also fine), and I have NO CLUE how to approach this.
Since you are using constraint layout, you need to set android:layout_width="0dip".
This will fit any image to its screen width.(Image width should be greater than screen horizontal width).
Apply some conditions something like,
If image width < screen width then call next image to remaining screen, else call next image for entire screen.
Hope it helps for code-flow.
:)
You could use android:translationX or Android:translationY which actually support negative values. But in your particular case I think you are trying to use a nail clipper to cut your hair... You are using stuff that are not designed for that purpose. Using multiple big Image views can become a performance issue (I don't know about your particular case), I recommended you instead to be brave and make your own wiew and paint it dynamically (it can sound difficult but I'm sure will be easier than what you are trying), or make a comprehensive googling for a view meant for what you want.
Specifically for games you should try andengine lib or something like that, believe me... It would be easier in the end and you may earn something new :)
An alternative solution is to draw a layout (e.g. RelativeLayout) larger than your screen size, with an equal amount of padding on all sides.
For example, if you want to make a 50dp x 50dp ImageView appear from off the right hand side of the screen, your RelativeLayout would be 100dp taller and wider than your screen (50dp on each side). You could then position your ImageView at the far right of the RelativeLayout, and move it onto the visible area at will. So drawing something at -20dp, would actually be drawing it at 30dp in this example.
Programmatically getting the screen size and resizing a layout is very straightforward, and this approach would let you control your map loading in the manner you described.
Currently I seek a solution to simple situation, which appeares to become tricky. I need 7 togglebuttons in android app, which are a simple black circles, but I need them to be in the row and fill parent (screen) horizontally. As a resource I use big .jpeg image of a circle. To make them fill all screens in the same mode, I put them into LinearLayout with
#android:layout_width = "fill_parent";
#android:layout_height = "wrap_content";
#android:weight="70";
Weight is 70, so each button received 10. The problem is that source image is too big, which unfortunately results in...this:
(because I dont have enough reputation for posting images, here is the link
http://postimg.org/image/f8wvs5si1/ )
Sorry for small amount of code and this picture taken via phone, I do not have an internet access on the computer with eclipse and this project for some time. I tried of course to change layout_height on other possibilites, but it didnt work. I could put a weight sum also on the vertical position, but on different screens it wouldn't look same.
I also tried to change the height programmatically in onCreate method,
buttonX.setHeight(buttonX.getWidth());
or do the same with a layout, but nothing helped
Perhaps the question is dumm, but I would be glad to hear some ideas.
This is due to screen density variations. There are several things you can do to fix this:
Use different images for each density (but I'm assuming you're looking for another solution)
Use DisplayMetrics to get the actual width of the screen and then set width/height accordingly.
This code:
buttonX.setHeight(buttonX.getWidth());
probably doesn't work because you are calling it before the layout is drawn, and therefore the width is not the drawn width. You can fix this using ViewTreeObserver like here:
How can you tell when a layout has been drawn?
Use an XML attribute like scaleType="centerFit" Personally, I find these confusing because scaleType attributes don't always seem to behave the same way to me. You might have to try different ones, but sometimes they come in handy if you need an XML only solution.
So, I'm trying to make the background to one of my apps look "futuristic." I thought of an idea to make the screen look almost transparent yet have views over it. So, it would look something like this:
(source: rackspacecloud.com)
I'm thinking that I can use the camera to capture the background of the phone (without taking a picture, just having the real time view in the background) and then, if possible, place a semi-transparent slightly blurred ImageView over that. Finally, on top of that I can place the other views including the ImageButtons.
So, my question is how would I go about doing this? I have searched but haven't found anything relevant. It must be possible; its just how to do it? I don't expect you to give me all the code as an answer, just if you have any ideas that can help or links or code that can point me in the right direction, it would be greatly appreciated! Thanks!
It shouldn't be too hard to get started. There are samples located here that show you how to open the camera and draw the preview onto a SurfaceView. Since you want to overlay your other Views on top of the camera preview, just make sure that the SurfaceView that you are using for the camera preview is contained inside a FrameLayout (docs located here). The FrameLayout lets you insert child views and they are z-indexed using the order they are inserted. Therefore, if you insert your SurfaceView and then insert a Button of some kind it will be z-ordered in front of the SurfaceView and you can set its alpha value so that it can be more or less transparent. All that said, you will have to do some trial and error for how you want to position your views that are being rendered in front of the camera preview because a FrameLayout used on different screen sizes might position the Views differently. Also, I'd stay away from layering too many Views on top of one another because the compositor will have to figure out how to render all of it into a single window which could impact performance.
This is my first post and i have (i think) a uncommon request...
I'm programming on the last Eclipse Mac, for every android SDK, and i'm using more XML for layout than runtime... So i search a solution in XML if possible.
Here is the situation: i work with an image background wich simulate item like buttons, image, text... etc. On this image, i put buttons, image, and text (buttonview textview etc...) and place it precisely on their places on the image. This solution is very powerful to have good design BUT, if i change the resolution of the screen, and/or its size, each item won't be at its place, and will be translated (horiz and/or vertic) for some "dp"... (and yes i use dp, not mm or px or whatever)
I'm really embarrased because i think thanks to "dp" it keep proportionnality but.. not !
My question is how can i fix my items at their places on the image background, for different screen size/resolution !!
Thanks in advance everyone,
My Best From Lyon,France
First realise that if you want to make it pixel perfect for all screen sizes your out of luck.
Second accept that you can't make it perfect for all screen sizes.
Third you can get far with creating different layout for different screen sizes. You can read a lot about supporting multiple screen sizes here. One important thing to take from here is that you can make layout for the different screen sizes or different density sizes.