Develop Reference

Center a view up to a barrier

Using Android views, I've stumbled upon a recurring issue and thought it was about time to ask if anyone has a solution.
I have a parent ConstraintLayout, the blue one in the picture.
This layout contains two views: a green view constrained to the left of the parent, and the red view constrained to the center of the parent.
Both red view and green view are text views, and their actual size may vary depending on the language.
My wish is for the red view to always stay centered, so to grow symmetrically left and right until it reaches the green view. At its maximum width, the red view will touch the green view on the left, and there will be empty space on the right of the same width as the width of the green view.
Problem is that I can't find a way using regular XML layouts to do it. I can think of several hacks to do it, but thinking there should be a clean way.
Any idea?

Not sure but just an idea, maybe you can try to add two more barriers. One at the end of the green box at left. And one for it's symmetric. Because you said
and there will be empty space on the right of the same width as the
width of the green view
So with these two barriers you can mark the borders of the red one.
And you can set the constraints of the red to the barriers, and with 0dp width may work. Let us know :)

If you are certain that the width of the red view will not ever need to go to two lines because it runs out of space (maybe it is truncated, marque'd or ellipsised) then you would simply constrain the start and end of the red view to a guideline set in the center of the ConstraintLayout.
However, if you can't guarantee that the red view will never need two lines then you are stuck with a hack. The simplest hack would be to create an invisible view on the right that has the same width as the green view. (It could simply be another TextView with the same text and characteristics.) You would then constrain the start of the red view to the end of the green view and the end to the start of the invisible view.

Multiple rounded layouts

Any idea how to create a control like this one?
Basically there's 5 different rounded elements (two green views, one yellow text view at top, one blue text view at bottom, and image view in the middle).

How to make a blur transparent linear layout

I have a transparent layout in android, and behind the layout there is an image. how to make the linear blur ? I found examples to make the image itself blur but I don't want to make whole image blue, just only the part that is behind the linear layout.

Set a semitransparent Blur image to the linear layout or simplest set a color to linear layout and set it to semitransparent by defining alpha
edited solution
do this...
1.) create a blur copy of the image u have on background.
2.) clip the image by using
Bitmap croppedBmp = Bitmap.createBitmap(originalBmp, startX, startY, widthLayout , heightOfLayout);
3.) set this image in the Linear Layout using an image-view with height and width attribute as fill-parent.

I have pretty complex solution, so there won't be any code. So, here is idea, step by step:
Let's assume that your layout have just single custom LinearLayout. No ImageView as a background.
What we going to do, is draw background drawable of LinearLayout by our own, so it will first draw full image and then draw blurred square from the same image on top. Content of LinearLayout might be moved to desired position using paddings.
So, create something like MyLinearLayout and put it to your layout resource. Provide required constructors.
Override onAttachedToWindow() and onDetachedFromWindow() methods. Inside them we should load our background Bitmap and recycle it accordingly. Let's name it mBackground
Override draw() method. Inside it we're going to first draw our mBackground.
Then, you can use Canvas#clipRect() method to crop drawing area of Canvas to some specified rectangle. In your case, this rectangle should be the area below your content. You can figure it out using View#getPadding*() methods. Don't forget to call canvas#save() before clipping drawing area.
Now you can draw your bitmap once again with blur (I don't know which method exactly you're using, so let's assume that you know how to do it... but you still can share it with us :) ). Cool thing is that you can just draw the same Bitmap once again in full scale - since we had called clipRect before, it will be drawn only within this area. Don't forget to call canvas#restore() after drawing background.
Call super.draw() to draw rest of the stuff, that your LinearLayout contains.

Draw Rectangles Over An Image In Horizontal and Vertical Direction

I want to draw A Rectangle over a Image In Horizontal And Vertical Direction Just Like a Grid.
I can use grid but when I Pan(Drag) image this won't work. The rectangle should also Pan with the Image or shold move with the Image.

The easiest way should be to have a view that draws the shape you want and your image together in a frame layout.
And then you should move the layout of both view rather than the view alone.

Stretching a Shape Beyond the Screen

I am trying to implement a line with selectors at each end that a user can then click on and drag to stretch the line.
The way I've approached this is to draw a line inside a view, draw a selector inside a view, and then add the line and selector views to a ViewGroup.
Problem: If I try to change the length of the ViewGroup container, it will not re-size beyond the width of the screen. If I try to stretch the ViewGroup container, then sizing is OK, but it stretches the selectors as well.
Drawing the selectors outside of the ViewGroup will become quite messy fast, especially during shape rotations.
Any suggestions?