Develop Reference

How to stop scrolling as half item can be visible in HorizontalScrollView

Can you plz share any suggestion or library to achieve below,
e.g. If you see in Google Play Store, when you scroll HorizontalScrollView, your scrolling will stop as half of the next item user can able to see. App forcefully stops scroll like this so the user gets to know, there are more items available.
I do not have any code to share. I just want your hints/libs.
Thank you!

You can achieve this by using Snaphelper in RecycleView its available in support libraries
You can attached SnapHelper like this
SnapHelper startSnapHelper = new StartSnapHelper();
startSnapHelper.attachToRecyclerView(yourRecyclerView);

You can achieve this task via using Horizontal recycler view and by adding pull to refresh technique. Set limited amount of items to be displayed by default and load on demand. Hope that answers your question.

You can change item's width dynamically based on device's width to manage this scenario.
horizontalScrollView.post(new Runnable() {
#Override
public void run() {
DisplayMetrics dm = getResources().getDisplayMetrics();
int screenWidth = dm.widthPixels;
// based on this width, the space between the children and their
// widths calculate new widths so you get a half clipped
// children on the right side.
}
});

Layout width return is zero in first call to onResume()

I have to set an image in my activity and in my scenario the image covers fairly large portion of the activity. However I want to keep its width/height to be no more than 33% of its parent viewGroup's width.
I am dynamically changing the ImageView's dimension at runtime using this code.
#Override
protected void onResume() {
super.onResume();
//try to resize the imageview according to current width of container layout
int nWidthPix = findViewById(R.id.layout_info).getWidth();
ImageView imView = (ImageView)findViewById(R.id.imageView_main);
imView.setAdjustViewBounds(true);
int imViewWidth = nWidthPix/3;
imView.setMaxWidth(imViewWidth);
imView.setMaxHeight(imViewWidth);
//
}
The problem is that nWidthPix which is width of RelativeLayout which contains my ImageView is returned 0 in the first call to onResume() that is when the app is launched for first time. As a result image is not shown , in the subsequent calls to onResume() it returns 720 which is correct.
I am guessing that since the view is not really shown yet before the first call on onResume it does not know the width ? but then we can find views on the other hand even before the activity is shown for the first time. .. Not sure what's causing it.
Help

You can use the ViewTreeObserver of the root layout and set an OnGlobalLayoutListener to know when the layout finishes loading. Take a look at this answer for a reference.

View always report 0 as their width and height before they've been measured by the framework. onResume() is too soon to query this information, unfortunately.
If the parent view is the Activity itself, then you can get the window's dimensions (for example with this method) and use those values. Otherwise you need to postpone execution of this code until the layout pass is complete (via an OnGlobalLayoutListener).

How do I get a view position relative to another view in Android?

I'm making a app for Android that shows a camera image (after going through some manipulation) on screen using an ImageView and I want to allow to move other ImageViews on the screen - but only inside the the parent ImageView.
Also, I need to get the coordinates of the child views relative to the coordinates of the parent ImageView. i.e - So that (0,0) will not be the whole screen, but the ImageView that shows the camera.
Is that possible at all? If so - How?
Help is much appreciated! Thanks

If you want to move the views by drag here's a lot of info around, e.g Moving image with touch events .
What about getting the top and left side of minorView relative to majorView it's also straightforward with some plain substraction minorViewRelativeTop = minorViewTop - majorViewTop. Use View.getLocationInWindow() for getting these absolute positions.
N.B. That View.getLocationInWindow() will usually not work just inside Activity.onCreate() so better call it after some delay. For testing it could be sth like:
majorView.postDelayed(new Runnable() {
#Override
public void run() {
int[] location = new int[2];
majorView.getLocationInWindow(location);
int majorViewLeft = location[0];
int majorViewTop = location[1];
}
}, 1000);

Android- Image Rendering

Is there a way the this problem can be fixed? I tried invalidate() but, it still displays the same problem. What happens is that, after opening the page/ the Activity, the images behaves like the one in Figure A. It only renders to my desired layout (Figure B) after scrolling it back and forth.
What I'm trying to do is set the width and heigth of the image during runtime. So this is also in relation to my previous questions : Images in my HorizontalListView changes it size randomly and ImageView dynamic width and height which received a very little help.
Any tips regarding this matter, please?
EDIT: btw, my classes are:
MyCustomAdapter (extends baseadapter, this calls the displayimage() from ImageLoader ),
MyActivity and
ImageLoader (this is where my image url are loaded, decoded, displayed asynchronously)
Im also confused as to where i will set the height and width of the imageView. For now, i set it at ImageLoader. It was okay. but i dont know if i did the right thing.

If you want to set the width and height manually at runtime, grab a reference to the ImageView's LayoutParams AFTER the View has been measured by the layout system. If you do this too early in the rendering phase, your view's width and height as well as its parent view and so on will be 0.
I have some code in an open source library that might help you. The process is two parts:
Set up an OnPreDrawListener attached to the ViewTreeObserver for your control. My example does this inside of a custom control, but you can do this in your activity as well.
Inside the onPreDraw method, your image and it's parent will now have their width and height values assigned to them. You can make your calculations and then set your width and/or height manually to the LayoutParams object of your view (don't forget to set it back).
Check out this example where I'm applying an aspect ratio to a custom ImageView just before it's rendered to the screen. I don't know if this exactly fits your use case, but this will demonstrate how to add an OnPreDrawListener to a ViewTreeObserver, removing it when you're done, and applying dynamic sizing to a View at runtime
https://github.com/aguynamedrich/beacon-utils/blob/master/Library/src/us/beacondigital/utils/RemoteImageView.java#L78
Here's a modified version that removes my particular resizing logic. It also grabs the ViewTreeObserver from the imageView, which is a more likely scenario if you're not implementing a custom control and you only want to do this in the Activity
private void initResizeLogic() {
final ViewTreeObserver obs = imageView.getViewTreeObserver();
obs.addOnPreDrawListener(new OnPreDrawListener() {
public boolean onPreDraw() {
dynamicResize();
obs.removeOnPreDrawListener(this);
return true;
}
});
}
protected void dynamicResize() {
ViewGroup.LayoutParams lp = imageView.getLayoutParams();
// resize logic goes here...
// imageView.getWidth() and imageView.getHeight() now return
// their initial layout values
lp.height = someCalculatedHeight;
lp.width = someCalculatedWidth;
imageView.setLayoutParams(lp);
}
}

Moving views inside a layout/view in Android

I have more than one question, but I'll start with the more important and problematic one:
I have a FrameLayout with a ImageView inside it. I need to get the size of the "usable area" of the screen my activity is ocupping, so I set the onSizeChanged on my View (I extended the ImageView class). Everything worked fine here. Now I have a 1000x1000 image that I want to show on the screen, but without scaling. I want it to be clipped, really. If I set the ImageView dimensions using viewObject.setLayoutParams(new Gallery.LayoutParams(1000, 1000)); I get the image being showed correctly, but then the onSizeChanged event returns me always the "1000 x 1000" custom size rather than the real screen size value.
Any ideas of how can I show an image with its real size (no scale!) and still get the view to report the screen available space? I can change the layout as needed as well, of course.
. Amplexos.

Are you asking to get the dimensions of the ImageView? If so then you can get that using getLocalVisibleRect. Here's roughly how it's done:
ImageView yourImageView;
public void onCreate(...){
setContentView(...)
yourImageView = (ImageView) findViewById(...);
(...)
}
getImageViewSize(){
Rect imageViewSize = new Rect();
yourImageView.getLocalVisibleRect(imageViewSize);
// imageViewSize now has all the values you need
Log.d("Your log tag", "ImageView width = " + (imageViewSize.right -
imageViewSize.left));
}
There is however a catch. You have to make sure that you don't try to get the size of the view until after view is finished being laid out on the screen. In other words, if you try to get its size in onCreate, its size will be 0. You have to get it afterwards, for example at the same time as you resize your image, assuming that's done with a button. (If you're using a SurfaceHolder you can also call it during the surfaceCreated callback, but I doubt you're using one of those...)