I'm trying to layer graphics one top of each other, like an icon over a background, with the second layer (icon) at a certain pixel offset from the top left corner of first layer (background). Since each layer will eventually have its own animation, I'm placing each in its own View.
For my implementation I have two ImageViews, one for each layer, inside a RelativeLayout, which in turn is inside a ScrollView. ImageViews are positioned using layout_margin relative to the top left corner (0,0). The first ImageView is larger than the screen (background), while the second ImageView is smaller than it (icon). ScrollView automatically resizes the first ImageView (background) since it is larger than the screen, it does not resize the second since it is smaller (icon).
I need both of them to scale together, and I also need the positioning of the second layer over the first layer to adjust itself accordingly. This actually works well in a layer-list, but due to the animations I am forced to use Views. How can I scale and position multiple Views together, or do I need to build my own class for something that seems like it should be fairly basic?
Thanks in advance.
I had a similar problem in my android application. Android has introduced new set of API's to help us on this, setScaleX() and setScaleY().
Just call layout.getParent().setScaleX(); and layout.getParent().setScaleY();
Related
I am trying to create an android app where I have a single relatively big button in the middle (the light blue in the picture) and it is surrounded by other smaller buttons as shown in the picture (some of small buttons might be visible or invisible based on some criteria).
I started with the RelativLayout setting the big on in the center and making the rest placed in relation to it, but it is a miss and the central button get shifted and doesn't stay in the center. I tried placing them in FrameLayout and used margin to adjust their locations, that worked the best however, the spacing changes on different screen resolutions.
So what is the best way to achieve such layout that will look consistent on any device?
Android's Percent Support Library allows you to use proportions to lay out your views, which may allow you to get closer to your goal.
http://developer.android.com/tools/support-library/features.html#percent
I am creating an app that allows a user to build a custom 2D avatar by specifying things like shoes, socks, skin color, etc...
Currently my solution has been to create a .PNG of each item and then to 'stack' them all on top of each other in a RelativeLayout. So for example, I create an ImageView of two shoes and align the ImageView to the center of the relative layout and the bottom of the Relative Layout. Next I 'stack' the bottom edge of the socks to the top edge of the shoe. And on and on.
This method works, but I feel like I don't have much control over where the parts sit and would much rather be able to calculate the x,y coordinates at run time and place the images that way. For instance, this works well if all of the ImageViews are stacked, but if I need to place one ImageView 10 pixels below the top edge of another ImageView I can't do it (or at least I haven't figured out how yet).
I am looking for a solution that will allow me to control the x,y position of ImageViews and allow ImageView to be offset from each other.
If you'd rather place the images by x,y coordinates, then you should consider using a single view and simply drawing the images on top. See this doc on custom drawing. You'll find drawBitmap and some of its overloads useful.
I would like to make a simple Android game where a large background image is displayed and some other images are displayed in specific locations over it, where the other images may be clickable.
Here's a quick sample image of what I'm talking about:
The user should be able to tap the soccer player or the moose (ah, the classic "soccer player moose problem"!)
How should I render this screen (which layouts and views?) so the user can interact with it and it will scale properly on different devices?
I would use a RelativeLayout.
You can set the you background image to the layout (fill_parent for height and width).
You can then put your ImageViews, containing your moose and soccer player down on the layout relative to the top or sides of the sceen, or relative to each other (making sure to specify "dp" units for everything). Set the backgrounds of your ImageViews to be transparent, and there won't be a bounding box problem (and/or you can also set your ImageViews alignment to be relative to each other, ensuring they don't overlap).
I think this is the simplest way to do this - it is then super easy to attach onClickListener to your ImageViews in your Activity, and you are done.
This type of layout will work the same on all devices and screen sizes.
There are some small gotcha's with RelativeLayouts, but they are pretty simple once you get into them, and provide fast rendering (since the view hierarchy is usually shallow). Good Luck.
ImageView for the clickable elements seems like a fine choice to me. For the background I would just set your image as the background of the parent layout i.e. RelativeLayout
SurfaceView for the whole thing (with your field as a background) and regular *ImageView*s for added elements. You can easily recover the click coordinates from the SurfaceView and thus know what element has been touched.
SurfaceView might offer you additional possibilities anyway.
For most images, I'd use an ImageView for each one, like FoamyGuy said.
If they're close enough for overlapping bounding boxes to be an issue, you can still use an ImageView for each, but with a variation of this answer, testing alpha for each ImageView in range.
I would agree with both FoamyGuy and Booger that if your only goal is to place static images onto the screen that do something when you click them, RelativeLayout and ImageViews all the way.
But...
If you are looking to randomly spawn multiple images onto the screen in intervals and have them move around for the player to interact with while explosions are going off and maidens are being kidnapped, you should look into SurfaceView, Canvas, Drawable, TouchEvents, and FrameBuffers.
In Android, I know how to overlay two images and to animate them. The question is how to overlay the second image at a specific location over the first image.
As an example, the first image is the image of an appliance with a power switch, the second image is the power LED that will glow when animated.
I would like to know how I can specify the location of the power LED in the overlay so that it covers the power switch.
One thing you can do is to put both images inside a FrameLayout, with the width/height on both set to wrap_content. The last one you add to the FrameLayout will be on top. Then you can position the two images independently in one of several ways:
1) You could set the layout_gravity of both items to top|left, then set layout_marginTop and layout_marginLeft to position the two images relative to the upper left corner of the FrameLayout.
2) If you want to, say center image B on top of image A, you could set image A to layout_gravity top|left, layout_marginLeft 0, layout_marginTop 0, then set layout_gravity on image B to center. This approach is a bit more robust with respect to running on various devices. You can even use the margins to offset image B with respect to its centered position.
You should get the idea at this point. You can combine layout_gravity along with margins to position the images as you need.
Some caveats:
1) This is not a very efficient way to go about things. If it's just two images in a larger layout, no big deal. But rendering performance will suffer if you do this technique many times in a layout. If that's the case, you should consider creating a custom view instead.
2) You need to explicitly set the layout_gravity on an item contained within a FrameLayout. Otherwise FrameLayout will ignore the layout_marginTop and layout_marginLeft attributes on your child views.
Finally, you can do this same trick with RelativeLayout, using its attributes to position the images in relation to one another. Like FrameLayout, the last view added to the layout shows up on top of the others.
I'm working on the controls for a game, and require part of the control panel (gray in the figure below) to change dynamically, either showing a single canvas (left) or 5 buttons (right). The border between the lower-row views should always be positioned at exactly the same x-position as the border between the buttons on the upper row, as shown. At the same time, all twelve upper buttons should be scaled and distributed evenly.
I've considered several approaches, but as of yet none do all of what I want:
Using two LinearLayouts, one for each row of controls: reliably aligning the borders seems to be impossible, and replacing part of the layout is difficult at best.
Using a TableLayout: again, replacing a portion of the layout is difficult.
Using a RelativeLayout: resizing and aligning buttons independently of the screen size doesn't seem possible
Any suggestions for an alternative method, or on how to make one of the above approaches work? It would also be nice if there were some way to animate the change of views, i.e. sliding in the buttons from the left over the canvas. Thanks!
Interesting, I've done this several weeks ago. What I did is to make use of this property of View object: "Visibility". So that means at a fixed position, I can set any View to display on to, not depending on any type of Layout, it can be Visibility.GONE, Visibility.VISIBLE or Visibility.INVISIBLE.
In my app, I used RelativeLayout to set relative position to the right side TextView.
Give it a try :)
In order to close this question: I have solved the problem by writing a custom layout class that places and sizes the child views without heeding the measured size of the children. Effectively this gives me the behavior of a linear layout with layout weights, but is more deterministic with border placement.
A ViewAnimator is used to switch between the Canvas and the Buttons.