I have the next question:
Im developing an app that when i move a imageView and drop it, if the view drops under the half height of the screen goes to a (X,Y) position and if is over the half height screen, goes to another position.
I need to calculate the half of the screen generic, so i use the next code:
DisplayMetrics displaymetrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(displaymetrics);
halfHeight = displaymetrics.heightPixels / 2;
This works great, im trying in a screen 1920x1080, the code returns 540.
But when im going to see if when i drop the view is under or over the half, here is what i dont understand. i get the Y position of the view and is ok, what i dont understand is why the Y = 0 is not on the TOP of the screen, if i move the view to the top, i get a negative Y position like -260.
Someone can explain me why this happen?
Is there i way that the (0,0) position starts in the top left of the screen?
Greets, hope you understand
If you call getX() or getY() then you are getting relative values for x and y (relative to the view that the call was dispatched from). If you call getRawX() or getRawY() it will give you the absolute position of the view relative to the device's screen.
Most likely you are getting negative values of -260 because you are dragging the ImageView 260 away from the view in which the call was made (perhaps the view on the top of the screen has a height of 260). If you are trying to use getX() or getY() to calculate the middle of the screen then you would have to take all sizes of all views into consideration but I think you want to use getRawX() and getRawY()
An angle of 0 degrees correspond to the geometric angle of 0 degrees (3 o'clock on a watch.)
try using translate to translate the co-ordinates to top of the screen.
http://developer.android.com/reference/android/graphics/Canvas.html#translate(float, float)
Related
I have a smartphone of 2560 x 1440 px. Now I am using this function for my TextView:
int[] locationOnScreen = new int[2];
txtAp.GetLocationInWindow(locationOnScreen);
It is supposed to give me the total x and y coordinates in pixels.
My TextView is pretty much in the middle of the screen, so supposedly at
(1280,770). But the function returns [69, 1111].
How can that be? If that is not the way of doing that, then what is?
I have a smartphone of 2560 x 1440 px... My TextView is pretty much in the middle of the screen, so supposedly at (1280,770).
Not correct, unless you talk about the center of the TextView. Any view is rendered on screen within its rectangle, so its coordinates are considered to be of [left, top, right, bottom].
The GetLocationInWindow() method returns (left, top) coordinates of a view. So (x = 69, y = 1111) looks to be meaningful for the left top corner of your TextView located in the middle of screen.
Important note: GetLocationInWindow() returns the coordinates w.r.t the root view, not actual window. You should take the status bar height into consideration. And here is how you can calculate Height of status bar in Android.
I am creating layout for finger selection. In this I am trying to achieve click events for each individual finger. This layout should be uniform on any type of screen resolution.
My approach:
Inside relative layout, I am assigning radio buttons (not radio group but individual) to each finger inside hand image using margins and padding but it is not resting properly over finger image. They are slightly moving left or right.
Problem in this - radio button positions is changing if screen resolution changes.
I failed to find library for such click events. Also in SO I didn't find any related questions. Can someone guide me in this to library or example or better approach than this?
A several years ago I worked on the similar task. Unfortunately, I don't remember the whole solution, but idea was pretty simple. In my case it was an image of the map where a user could select a district by tapping the map. I knew the resolution of the original image that I used to display in UI. I encoded each district against its boundaries so it gave me a list of pair's number. I had a touch listener attached to ImageView that was used to display the map. So every time a user clicked on the map I got a position of his click, multiply this value by a scale factor(this one was calculated based on the size of original image and the one that was scaled by Android). Then I checked if that value laid in any polygons.
So to make it more clear:
Let width, height = size of original image
x, y = user touch
scaleWidth, scaleHeight = size of the image displayed by Android on the user device
scaleX = scaleWidth / width, scaleY = scaleHeight / height
originalX = scaleX * x, originalY = scaleY * y
Then check if originalX and originalY fits in polygons. In your case those polygons could be just squares around every finger.
To get view right edge after rotating it around Y-axis with fixed pivot point I'm using the below code and that is working like it should.
view.setPivotX(0);
view.setPivotY(view.getHeight() / 2);
view.animate().rotationY(rotationAngle).start();
view.getMatrix().mapRect(rectF);
int rightEdge = rectF.right;
Now what I want to do next is to calculate rotationAngle so the right edge of the view will be a specified value (let say 1000px). Any idea how to reach this ?
I know I can use:
myPopup.showAtLocation(layout, Gravity.NO_GRAVITY, x, y);
// OR
myPopup.showAtLocation(layout, Gravity.TOP|Gravity.LEFT, x, y);
To open a PopupWindow that's drawn from [x, y] as the Top-Left of the PopupWindow, drawn towards to Bottom-Right.
What I want instead however, is to draw from [x, y] as the Top-Right of the PopupWindow, drawn towards the Bottom-Left.
Here is a picture to make it more clear (The dot is my [x, y] position and the rectangle is my PopupWindow. The first picture shows how it's normally done, and the second is what I want to achieve.):
So how do I correctly calculate the x and y of the second picture's gray point's location, while knowing the black point's location? I know the y can stay the same, but the x should be changed to something like:
x minus PopupWindow-width
The problem is that the PopupWindow's width and height are both set to wrap_content, so I don't know the size until after I draw it.
Does this mean I have to draw it (but make it invisible at first), then calculate the new x with the PopupWindow's MeasuredWidth in it's ViewTreeObserver's OnGlobalLayoutListener (to know when it's done rendering and the MeasuredWidth is known), then apply this new x and then make it Visible? Or is there an easier way to just let it draw at the correct position?
PS: I've also changed Gravity.NO_GRAVITY to Gravity.TOP|Gravity.RIGHT, if the PopupWindow is out of the screen it will automatically place it at the border of the Right/Top side (whichever side it's out of the screen).
You could get the size of your popup window by overriding the onMeasure method of the popup window (note that you have to subclass a View in order to do this). After that, you can calculate the offset of the x and y coordinates. Hope this helps.
I have an android View X and Y where X has to be manipulated based on the dimensions of Y (specifically, X and all its contents must be scaled up to Y without its aspect ratio being changed). I do this by working out the new (larger) size of X and setting scaleX and scaleY accordingly. Please tell me if there is a better way! If not, my second problem is - I would like this to be done in Activity.onCreate or onStart or onResume. But in these the dimensions of X and Y are reported as 0.0. Is there any way I can do this on activity start after Y is laid out so its dimensions are not 0.0.
Regards,
Steve Kucera
Any view in android goes through several steps before it appears on screen. Firat of all it goes to measure() - here will be field measuredHeight and measuredWidth. Then it goes to layout() and only after this method finish view has params width and height. So, you can provide your own view, that will contains both X and Y, and there, while measure and layout, change width or height of child X.