Develop Reference

Custom view added to WindowManager, pass events to underlying window depending on state

I have a fairly complicated situation where I need to either process events in a custom view, which is added via WindowManager, or pass them to the underlying window if it is outside of the wanted area. The wanted area is the containerView where it can be smaller from the root view itself, or may have equal width / height.
The view has a size of 28x28, but it can grow up until 60x60. The growing part is done with ValueAnimator where current width and target width is determined by the ValueAnimator.getAnimatedValue() (in this case, between 28 and 60). The window needs to consume the event if it has been clicked on, or the target view which may be smaller than the window itself, is clicked.
An example of the layout looks like this:
<FrameLayout android:layout_width="wrap_content"
android:layout_height="wrap_content">
<FrameLayout android:id="#+id/containerView"
android:layout_width="28dp"
android:layout_height="28dp"
android:layout_gravity="center">
<!-- rest of the view, not important -->
<!-- the containerView can have 28x28 size or
60x60 size -->
</FrameLayout>
</FrameLayout>
The animated view is the one that is defined with android:id="#+id/containerView".
I've tried to attach the view using regular layout params, like this, to make the window layout dynamic:
WindowManager manager = context.getSystemService(WindowManager.class);
View rootView = LayoutInflater.from(context).inflate(resId, null, false);
WindowManager.LayoutParams params = new WindowManager.LayoutParams();
params.width = WindowManager.LayoutParams.WRAP_CONTENT;
params.height = WindowManager.LayoutParams.WRAP_CONTENT;
params.type = WindowManager.LayoutParams.TYPE_APPLICATION_OVERLAY;
params.flags = FLAG_NOT_FOCUSABLE | FLAG_WATCH_OUTSIDE_TOUCH;
manager.addView(rootView, params);
And this similar code block adds the view with 28x28 size, that's not a problem. However, while animating to 60x60 size depending on a state change (on containerView), the animation flickers a lot. I guess it happens because both view itself and the window needs to be re-sized. I've tried to use setLayerType(HARDWARE, null) but that didn't seem to work. Then I've found another workaround, which is increasing the size of the window directly, before starting the animation, by giving it fixed width-height values, like this:
params.width = dpToPx(60);
params.height = dpToPx(60);
manager.updateViewLayout(rootView, params);
And after this, I start the growing animation, which changes the containerView width and height gradually. With this way, animation is smooth, even on lower-end devices so I think it's a good optimization.
The problem begins with the window size change. You see, containerView has to have the attribute android:layout_gravity="center" to position the view to window's center. But, increasing the window width and height changes the view's position. To overcome that, I've decided to write another approach by doing something like this:
// This method is inside the root view, which contains
// the WindowManager.LayoutParams as its layout params.
private void setWindowSize(int widthPx, int heightPx)
{
WindowManager.LayoutParams params = getLayoutParams(); // ignore cast
int oldWidth = params.width;
int oldHeight = params.height;
int differenceWidth = widthPx - oldWidth;
int differenceHeight = heightPx - oldHeight;
// Position the view relatively to the window so
// it should look like its position is not changed
// due to containerView's center layout_gravity.
params.x -= differenceWidth / 2;
params.y -= differenceHeight / 2;
params.width = widthPx;
params.height = heightPx;
// Update itself since this is already the root view.
manager.updateViewLayout(this, params);
}
The code above was causing the position change happening with animation. Hence, I've searched if this animation can be disabled, and found an answer here which seems to be working with Android 10 emulator. However, I don't think this is a reliable approach, as most manufacturers change source codes of framework classes to implement their own themes etc. so I'm looking for a more reliable approach. The change also cause a flicker due to the containerView.onLayout() operation, presumably happening after manager.updateViewLayout() is executed, where it appears on top-left for one frame and on center on the 2nd frame, visible to the eyes.
At this point, I can only think of some ways to prevent these bugs:
1) Process touch events only on certain states (such as the coordinates intercepting the containerView)
2) Make the view non-touchable after receiving MotionEvent.ACTION_OUTSIDE which will indicate a touch event happened outside of the view's boundaries.
1st one has a flaw: If the view is clickable in all cases, it becomes clickable starting from the root view, and once the touch event is received from that view, it is not transferred to other windows (a.k.a underlying applications) which cause an issue.
2nd one seemed a good approach for me, but the event MotionEvent.ACTION_OUTSIDE does not contain any specific x or y coordinates so it is impossible to tell if the event occurred in window's boundaries. If this was possible, I'd add FLAG_NOT_TOUCHABLE to layout params and updated the view, and removed that flag if the touch is to be processed.
So, my question is:
Can a custom view, that has been added with a WindowManager choose to deliver the events further based on, i don't know, returning false from dispatchTouchEvent() or something? Or, is there a way to receive all touch events even outside our application with the specific screen coordinates so I can change the window flags depending on it?
Any help is appreciated, thank you very much.

I was able to resolve the issue by applying an ugly hack. I've used a second window, where the window itself is full screen and contains flags FLAG_NOT_FOCUSABLE and FLAG_NOT_TOUCHABLE and since the touch is disabled the events are passed below window.
The window-resize flickering depending on the animation was the cause, so I've thought about using a temporary view, added the view to a second window, by getting the cache of the view itself using a bitmap and a canvas (the states are cached and recycled by the way), and making the image view visible, setting the view on the original window as INVISIBLE and after making sure it became invisible (by using ViewTreeObserver.addOnDrawListener because the draw function is called) changing window size.
With this approach, the view becomes already invisible while the window size is changed, and translated accordingly, which eliminated the possibility of the buggy view.
Then, after the layout is complete (I've also made sure by using ViewTreeObserver.addOnGlobalLayoutListener() and waiting for the view to be placed on the target coordinates relative to parent), switched the views. Extra memory is used because of the extra added window and image view and bitmap, but the issue seems to be resolved.
The only remaining thing is how to disable window animations with the call windowManager.updateViewLayout() because the flag that the other question mentioned is apparently added in API 18, whereas this app targets to API 16. On the rest of the emulators and the devices that I've tested on seem to have this flag consistently, and the window translate animations seem to be disabled successfully.

control dimensions of custom alert dialog in different screen orientations

I want to set dimensions for my custom alert dialog, based on screen orientation. My intention is to swap height and width values to keep the box look like being the same size, yet handled various screen sizes of various devices, thanks to Android fragmentation it seems difficult to achieve the same effect on all devices. Android's auto-resizing seems weird to me.
Portrait:
alertDialog.width=screen.width*0.8
alertDialog.height=screen.height=0.5
Landscape:
alertDialog.width=screen.width*0.5;
alertDialog.height=screen.height*0.8
Please note that the Custom Alert Dialog must use the same code and support Android versions from JellyBean (at least 4.2) to Nougat (7).
i am using android.support.v7.AlertDialog (the latest available thing)
i assume android.app.Dialog should be avoided now (being old)
Also, i need a black border and white background for the same. i am unable to achieve same effect on all devices, (i need transparency for rounded corners)
i have used android:windowMinWidthMajor and android:windowMinWidthMinor but they affect both layouts (portrait and landscape) and seem to be ignored if content does not fit within the specified constraints.
I wish there was android:windowMaxWidthMinor & android:windowMaxWidthMajor

This is something that I've used for resizing specific views on a page:
myView.getViewTreeObserver().addOnGlobalLayoutListener(() -> {
item.height = myView.getHeight();
});
Applying it to what you want to do:
myView.getViewTreeObserver().addOnGlobalLayoutListener(() -> {
LayoutParams params = (get the layout params according to the layout);
params.width = myView.getWidth() * 0.5;
params.height = myView.getHeight() * 0.8;
myView.setLayoutParams(params);
});
You have to use the listener because the object will be added to the view tree, will be measured and prepared for display, but won't yet be displayed, so you can change its dimensions before it is visible.

Update:
I could achieve it by setting android:layout_centerInParent="true" for my Layout. and layout values for each component in the style to
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center"
android:layout_gravity="center"
to achieve the center alignment.
XML Code available at https://github.com/computingfreak/CFTest/blob/master/app/src/main/res/layout/alert_popup.xml
Java Code available at
https://github.com/computingfreak/CFTest/blob/master/app/src/main/java/net/cf/sms/cftest/MainActivity.java
I wonder this line of code is redundant
view.setTextAlignment(View.TEXT_ALIGNMENT_CENTER);
and thus left it to Android System to decide dimensions and resizing based on content. It works for my case, but will fail in case of long text, maybe some kind of Scroll Layout will help. Cheers!

Android/XML: Is there a way to set images in specific places, rather than relative? Can they be set to scale properly when on a bigger device?

I have several images, that need to be in specific places, but remain separate images. For example, imagine I have an image of a face. The separate images would be the nose, the eyes, the lips, etc...
I need them in specific places on the face. The problem is two-fold:
1: I need to put them in specific locations. Relative layout doesn't seem to work super well. Unless I type the margin gaps in exactly.
2: The other issue is when I change to a different device, it screws up the positioning. If I manually enter in margins, when I move to a tablet, everything is screwed up again.
What is the best way to accomplish this?

You can create nested Linear layouts , include your components and use android:layout_weight in each of them .If you have high alignment constraints , create a separate layout for each component and accordingly use android:orientation in it. This way you won't have any positioning issues when you switch devices .

FYR
FrameLayout.LayoutParams layoutParams = new FrameLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
layoutParams.gravity = Gravity.LEFT|Gravity.TOP;
layoutParams.leftMargin = x;
layoutParams.topMargin = y;
imageView.setLayoutParams(layoutParams);

Changing view dimensions programmatically on android

I have two views which overlap each other and one of them acts as a master to other. I am translating all the pinching and panning to scale and adjust the master view.
Now I wanna send this info over to the slave(Subclass of android.view.View). Being said that the other view doesn't respond to this dimensions. I have tried following methods
ViewGroup.LayoutParams params = this.getLayoutParams();
params.height = height;
params.width = width;
this.setLayoutParams(params);this.requestLayout();
setMeasuredDimension(width, height);
this.setMinimumHeight(height);
this.setMinimumWidth(width)
None of these seem to work.
Using the onTouchEvent I resize my TextureView and send the same to the other View object. On getting this Info about change in size which is in most cases greater than the parent dimensions(and screen size) the other view should also increase/change its size.
The subclassed view doesn't grow to the dimensions supplied to it. Moreover the increase is limited to the parent size(in my case its width: 1080 height: 1776) while it can go above that in the textureView which uses
textureView.setMinimumWidth(newWidth);
textureView.setMinimumHeight(newHeight);
Any ideas as to what maybe going wrong or a trusted way to change layout/dimensions across two views?

setLayoutParams => that would be the canonical way to position a View inside its parent.
setMeasuredDimension => this is used from View.onMeasure to tell the layout system what size your particular View wants. Use only if you're implementing your own View subclass.
setMinimumWidth/setMinimumHeight => tells the default View implementation what minimum size the View should have. If you implement View.onMeasure yourself, that shouldn't be needed.
All in all, if you stick with the standard Android framework components, setLayoutParams should be the place to look into.

The methods you've listed are all valid ways of setting sizes if used correctly, and in the right situations.
This is difficult to solve without further information.
In what way isn't it working? Is it causing a crash, or are the view sizes just not what you expect?
Where does that snippet sit in your code? I would guess its part of a custom class of your own which extends ViewGroup, but as you're new to stackoverflow we have no idea of your level of programming experience. It might be in completely the wrong place, and this refers to some other object entirely.
One thing I can suggest you check :
You mention your slave is a subclass of android.view.View, but this on its own is not enough to be able to use ViewGroup.LayoutParams. You need to ensure your slave is a direct or indirect subclass of android.view.ViewGroup.
Provide more of your code and info on what you are observing, and we will try and help you further.
Update:
Ok, so it's a TextureView that you are trying to resize.
I'd recommend you check the reported size of your TextureView after you set it's height and width. You could do this with break-points and run a debug, or you could use myTextureView.getWidth() and .getHeight(), and use Log statments to output them to the LogCat.
You can also check the size of the SurfaceTexture associated with your TextureView. Set a SurfaceTextureListener on your TextureView. When this listener is triggered, onSurfaceTextureAvailable() will provide the width and height of the SurfaceTexture.
I suggest this because you may find that you are able to change the size of the TextureView, but it is the content of the the TextureView that is not changing size. In this case you can override TextureView.onSizeChanged(int w, int h, int oldw, int oldh) to define the necessary transform to scale your content between the old and new sizes.

Android - How to draw a letter at a specific point?

I want to fill the screen with a 100 different letters in random positions. On the iPhone I just created a bunch of UILabels set their x and y positions and then used animations to move them about.
On Android it doesn't look like I can add a TextView to my view and specify its X and Y. Is there a way to do this?
View gameView = findViewById(R.id.gameboard);
tv = new TextView(gameView.getContext());
tv.setText("A");
tv.setWidth(w); tv.setHeight(h);
// How to set the X and Y?
EDIT: The solution was to use AbsoluteLayout:
AbsoluteLayout al = (AbsoluteLayout)findViewById(R.id.gb_layout);
tv = new TextView(this);
AbsoluteLayout.LayoutParams params = new AbsoluteLayout.LayoutParams(
AbsoluteLayout.LayoutParams.WRAP_CONTENT,
AbsoluteLayout.LayoutParams.WRAP_CONTENT,10,10);
params.x = 50;
params.y = 50;
al.addView(tv, params);
and to move it base on MotionEvent me:
AbsoluteLayout.LayoutParams p = new AbsoluteLayout.LayoutParams(
AbsoluteLayout.LayoutParams.WRAP_CONTENT,
AbsoluteLayout.LayoutParams.WRAP_CONTENT,(int)me.getX(), (int)me.getY());
mTV.setLayoutParams (p);

I think you are making a game and for this you should look into SurfaceView here is an good example then
1...if you look into code there is onDraw method where you will get the width of screen and height
2...Now taking this width and height as seed for random generator get x and y position.
3...Iterate through point 2 100 times and you will get the desired result

You can use a FrameLayout for this. Set each TextView's background to transparent and add it to the FrameLayout. Make each TextView, and the FrameLayout, fill their parent. The FrameLayout places all its child views at (0,0). To move letters around, just change the top and left padding of the corresponding TextView.

In android positioning child views is the responsibility of the layout class.
You need to create a custom.layout and overide the onLayout method. In this method you can iterate through all the child views calling View.layout(left,top,right,bottom) on each child.
i found this example code whilst trawling the net :
https://gist.github.com/882650
You should also check out view.setTranslationX (and Y) which might be exactly what you need

I'm not entirely sure how you'd go about doing this in code, but you need to use an absolute layout as your root element. (edit: Do not use absolute layout, as it was pointed out that it is deprecated. The closest alternative seems to be RelativeLayout.)
The properties in the XML format for the absolute layout coordinates are layout_x and layout_y.
edit: A little research is saying you need to be using setLayoutParams, but my Eclipse IDE is not working properly, so unfortunately I can't test exactly what you're looking for.