the question "What is a usefull alternative to AbsoluteLayout?" seems to be a question which is often asked, but never really answered. My situation is as follows:
I want to position Circles (for the sake of simplicity i used RadioButtons for testing) so that the distances between the circles are proportional on all possible display sizes.
Also i need to know the position of the circles to match onTouchEvent.
This seems fairly easy with AbsoluteLayout since i can get (at runtime) the defaultDisplay's width and height and so i can position Objects in an AbsoluteLayout relative to the display metrics.
Now I want to avoid AbsoluteLayout for obvious reasons, but RelativeLayout doesn't seem to be an alternative since - as far as i know - one can only say "put that object right next to that other object" or below or whatever. How to fix this?
In my Opinion the best way to achieve your goal is to use the Canvas and draw everything yourself. In the Canvas you have the information of the screen at runtime and you have full control of the things to draw.
If you only need to draw your own shapes (and handle all normal touch events) and do not need other UI Widgets on the same view, then use Canvas.
If you do need Widgets on this view then your only option is AbsoluteLayout.
Related
I've been working on this for a while but can't find anything that exactly addresses my question (at least not something easy to understand).
I have a main layout XML file where I define various layout objects like a Button or a TextView (and I know I can add SurfaceView, View, and view and other things too). I want to draw a shape (in my case it's an arc) in just one of these objects so it doesn't take up the whole screen and so I can position it relative to other things.
(In my case it will ultimately re-draw the arc kind of like a circle with a gap in a different position every time I call a method depending on a value I pass to the method, but that's separate from my basic question.)
I know the answer will have something to do with a canvas, an onDraw method, maybe Paint, probably a view. I have been able to draw a circle from a custom View object by setting the main java file's layout as that View (as opposed to R.layouts.main), but that takes up the whole screen, and I'm unsure how I might be able to have that dynamically draw with modifications.
A really clear explanation or better yet an actual example would just be awesome.
As i see it u need to draw a specific shape on widget and not on complete screen. Try using layer List.
you can refer this link for sample Link
Without going into too much detail, I want to be able to 'slide' elements in a ListView similar to the 'slide to archive' feature in GMail. I'm fine with the onTouchListener and all that, my question is regarding the slide animation.
The first two things that come to mind are..
view.setPadding(slideOffset, 0, 0, 0);
and..
view.setX(slideOffset);
The former is very buttery, even on the emulator.
The latter is a bit janky on my Galaxy Nexus.
My questions:
* Regardless of what I've tried, what's the correct way to do this?
Why is setX less smooth than setPadding?
Does one approach conform to Android best practices more than the other?
Are tweened translation animations an option? If so, can you provide a brief example to point me in the right direction please?
Edit:
To be clear, I am attaching an image of the effect I am trying to emulate.
I'm pretty sure the setX() is slower because it affects its parents. When changing the X of a view, it calls the onLayout/onMeasure of the parent every time you update the value. That's because the X value of the child may cause other items on the parent to move, therefor the parent needs to redraw itself.
You can test this easily by extending the ViewGroup and writing to the log on those methods. Then, you can use both approaches, padding vs. setX, and see what happens.
Are you trying to animate the item? Or do you want the user to move it like on Gmail? You can use the ObjectAnimator to handle the "X" value of your item. Combined with a "hardware layer" for your item, it will create a smoother experience. You can find more details about how to do that here: http://developer.android.com/guide/topics/graphics/hardware-accel.html
Yeah, if you're targeting higher APIs, ViewPropertyAnimator is probably a great solution. If you have to support lower APIs, my thought process for implementation would be (and I haven't implemented this myself personally, but this should be good for performance) to:
In your touch handler, once you've determined that the user is "sliding", set the View's visibility to INVISIBLE, and store the drawing cache into a separate bitmap (Bitmap bmp = myView.getDrawingCache();)
Draw that bitmap in the same place as the view, and use the Canvas translate methods to shift the position according to the x-position of the user's touch point.
After the user lets go, translate back (preferably smoothly with an animation), recycle the bitmap, and set the view back to VISIBLE.
Check out the 3 devBytes posted on AndroidDev:
https://www.youtube.com/watch?v=8MIfSxgsHIs&list=PLWz5rJ2EKKc_XOgcRukSoKKjewFJZrKV0&index=12
https://www.youtube.com/watch?v=NewCSg2JKLk&list=PLWz5rJ2EKKc_XOgcRukSoKKjewFJZrKV0&index=11
https://www.youtube.com/watch?v=NewCSg2JKLk&list=PLWz5rJ2EKKc_XOgcRukSoKKjewFJZrKV0&index=11
https://www.youtube.com/watch?v=YCHNAi9kJI4&list=PLWz5rJ2EKKc_XOgcRukSoKKjewFJZrKV0&index=4
https://www.youtube.com/watch?v=PeuVuoa13S8&list=PLWz5rJ2EKKc_XOgcRukSoKKjewFJZrKV0&index=3
I need to draw a tournament bracket in Android. I already calculated the positions for all games (i.e. an (x,y) tuple that defines where to place teams in a spreadsheet-like structure). However, I don't know the preferred way of drawing the bracket. I found an example that shows what I need:Example
My first idea was to programmatically create and fill a TableLayout. However, borders are not really supported and a lot of TextViews are needed to fill the space between games. So I am not sure if this is the best way to do it.
Does anyone have better suggestions or maybe even an example of something similar?
I'd suggest custom drawing using Canvas. That way you can draw wherever it makes sense and probably even support zooming without too much work.
I am looking to create a custom EditText, where each character entered should lie within its own cell (see image).
My best guess is that I need to create my own .png's for the various states of the EditText, which provide the rectangular outline, then extend EditText's onDraw method to draw the vertical lines that separate adjacent characters.
I've never made a custom view before, and I know little about manual drawing in Android, so some guidance is needed.
Am I on the right path here?
How can I determine how tall and at what location to draw the vertical lines?
What is the best way to eat an oreo?
This is gonna be a very difficult task. Just look at TextView.onDraw() (which you are thinking of override). If I were you, I'd immediately change my mind :)
Instead, I'd use a LinearLayout to hold an array of customized EditText, but I don't know what kind of interaction you are looking for
Finally, to measure text you use Paint.getTextBounds(). Where to draw vertical separators depends on your design. If you have a fixed number of fixed length cells, you know where, otherwise you need to measure text
I am working on a project that involves painting on images.
To delete the unwanted lines or curves i have to draw a border and X button to delete it.
I have a relative layout where i have the freehand drawing canvas. on edit mode i should make them as u see in the pic, where i have to create button on a varying x,y positions.
i am confused how to achieve this.
Thanks in advance.
Jana.
I suggest doing this manually rather than using the Button widget. Override the onTouchEvent on the view holding your painting and use MotionEvent.getX and MotionEvent.getY in combination with MotionEvent.getAction to determine behaviour when the user touches the 'button'. Skipping widget creation will improve performance and open up doors to other types of functionality.
You could use the deprecated AbsoluteLayout container for this or keep the RelativeLayout and use layoutMargins to set the location of the buttons. The former is the route you should take despite the container being deprecated as the later breaks the layout paradigm by misusing margins...
You should keep in mind that there are a variety of devices with different screen sizes and setting explicit, pixel based locations is going to be awkward.