How to not lose the updated variable in flutter? - flutter

Situation
I have a variable called number = 0 in my stateful widget in the second screen. Now, when a plus button is pressed it increases by 1 every time. Now when I go to first screen and come back to the second screen the variable again starts from 0 which I don't want.
Needed
When came back to second screen from first screen. I should have the updated variable.
How can I do that?

Try to create a static variable instead of a normal variable.
You can also try initializing the static variable in the first screen and pass it as an argument for better control.
But if you want the variable to be same even after reopening the app, you will have to save it to internal memory.
Hope it works!

Related

Code to click a radio button does not work the second time in my Protractor script

I am calling a function twice to execute a piece of code in my protractor script. A snapshot of the code of my function that is failing when called the second time is below. sessionNo is an argument passed to this function. It could be either 0 or 1. Depending on the value of this argument, either the radio button with index 0 will be selected or the radio button with index 1 will be selected.
function sessionBegin(sessionNo)
{
element.all(by.repeater('type in types')).all(by.css ("input[type='radio']")).isPresent(). then(function()
{
var sessionType = element.all(by.repeater('type in types')).all(by.css ("input[type='radio']")).get(sessionNo);
sessionType.click();
});
}
This code works great when this function is called for the first time. But when it is called the second time with a different value for sessionNo, it fails with "Failed: element not visible" error. I can't figure out why is the above code unable to locate the same element for the second time as it did for the first time with the exact same code.
It depends on your application code, may be your element becomes invisible between it's found and click action, or it's not visible yet. For the first case you should investigate what happens in application side, for second case (if it's not visible yet), you can wait until it became visible, for example: browser.wait(EC.visibilityOf(element), 5000, Element not visible: ${element.locator()});
it will wait for for element 5 seconds.

How can I get my program to automatically perform a carriage return when string value superseeds the screen size?

I am making a quiz game that displays questions fetched from parse. I create the label programmatically, but stumble upon some issues when the string value is too long. Is there a way to make the label automatically print on a new line when it goes beyond the screen width?
I figured this out. I decided to make the frame a bit bigger and add in lines using the label.numberOfLines function. Now it returns perfectly.

Display route.steps (swift )

I am having some problem when it comes to display the steps from MKDirections route into a UILabel. I tried get each index from the steps array using the for in loop, it only show the Arrive at destination which means that all the instructions within the loop went by so fast, therefore i am seeing the last index in the array . Can someone help me please ...
it shows "Arrive at destination" because you are cycling the whole array and the label gets only the object at the end, you are basically overwriting it over and over until the for cycle arrives to its final element
You are seeing only the last value from the array in the UILabel, though it is actually displaying all the values very, very quickly. If you just want to see each of the values in the UILabel, you could either use UITimeInterval to change the value every few seconds, or add a UIButton that would handle updating of the text on the UILabel.

Erratic UIPageControls

I'm using two UIPageControls in a view to reflect chapters and pages. So I have defined one UIPageControl named chapterCount and one named pageCount just to show where the user is. I handle the flipping of the pages with swipes rather than using the UIPageControls (so no methods defined for them).
I change their values as the user change pages with the following code:
chapterCount.numberOfPages = chapters;
chapterCount.currentPage = chapterNumber;
pageCount.numberOfPages = pages;
pageCount.currentPage = pageNumber;
[chapterCount updateCurrentPageDisplay];
[pageCount updateCurrentPageDisplay];
Where chapters, chapterNumber, pages and pageNumber all are integers.
The first time I flip through the pages it normally works fine, but when I go to a previous chapter or start a new chapter, the first (or last depending on direction) dot is not showed. Please see picture (upper half is missing a dot, lower one OK).
alt text http://img80.imageshack.us/img80/3339/pagecontrol.png
Its the same code updating the controls and sometime I get a dot, sometimes not. When I check the variables with NSLOG they are correct (eg the same for both pictures above).
I have checked Apple's documentation and tried their example but no luck.
Where should I start troubleshooting? I'm getting crazy!!
I finally found the problem :-)
An UIPageControl that is given a value 0 for number of pages will not show correctly the next time it is updated. I was reading chapter and page numbers from an array and in the beginning (let's say cover of the book) there are no pages and no chapters to show, so I happily set these to 0. Since I did not want to change the source data in my array I used MAX(pages , 1) for numberOfPages, so now it's working like clockwork.
Are you sure your chapterCount and pageCount views are not nil? You can have valid values all day, a message to nil does nothing and returns nil. Double check your view and controller wiring/unwiring when you change chapters.
EDIT:
confirm the size of the control is big enough to hold all your pages, and the view bounds is not clipped. For example, if you had 10 pages, and the "current" page was 10, but there were only 9 dots visible, it would appear as though nothing is highlighted because the white dot would be clipped from the visible area by being outside the viewable bounds. You can adjust the size dynamically using this:
- (CGSize)sizeForNumberOfPages:(NSInteger)pageCount

GTK detecting window resize from the user

In GTK (or pygtk or gtkmm...)
How can I detect that an application window has been manually resized by the user, as is typically done by dragging the window's edge?
I need to find a way to differentiate manual resizes from resizes that originate from gtk, such as changes in window content.
Have you tried connecting to the GDK_CONFIGURE event?
Check out this example under the
"Moving window" section. The example shows a callback doing something when the window is moved, but the configure event is a catch-all for moving, resizing and stack order events.
I managed to pull this off by watching for size_allocate and size_request signals on the GtkWindow. If size_request ever got smaller, I called resize(1,1). If size_allocate was ever bigger than expected, I turned the system off.
One thing I made sure to handle was size_request returning big, then small, and having size_allocate be big and then small. I don't know if this is possible, but I fixed it by making sure to only decrease the expected values for size_allocate when I got a smaller size_allocate, not when I got a smaller size_request.
Make sure that your size_request handler comes after the base class' handler so that you get the right values. I did this by overriding the method and then calling the base class method first.
I've tried this in both 1 and 2 dimensions and it seems to work either way.
In my case I was trying to distinguish between a user resizing a Gtk.Paned from the user resizing the whole window. Both emitted the notify::position signal.
My solution was, since I can't know if the user is resizing the window from the widget, reverse what I wanted to know. Record if the user has re-positioned the widget and ignore updates if the user didn't initiate them on my widget.
That is to say, instead of testing "if window being resized" I recorded the button-press-event and button-release-event's locally so I could instead test "if widget being re-positioned"
from gi.repository import Gtk
class MyPaned(Gtk.Paned):
_user_activated = False
def on_position(self, _, gparamspec):
if self._user_activated:
# widget touched
else:
# window resized (probably)
def on_button_press(self, *_):
self._user_activated = True
def on_button_release(self, *_):
self._user_activated = False
dev __init__(self, *args):
super(MyPaned, self).__init__(*args)
self.connect('notify::position', self.on_position)
self.connect('button-press-event', self.on_button_press)
self.connect('button-release-event', self.on_button_release)
Effectively by recorded when the user started and ended interacting with my widget directly, I could assume the rest of the time was due to the window being resized. (Until I find more cases)
In PyGTK, I've always watched for the expose_event for a window resize, then use the get_allocation method to get the new size.
You may be able to throw something together by using gdk_window_get_root_origin to get the top left corner of the window and gdk_window_get_geometry to get the width and height. Then you could hook a callback into the GDK_BUTTON_PRESS_MASK and check to see if the button press occurs near/on one of the edges of the window.
Of course, this seems quite hackish and it really bothers me that I couldn't find some simple way in the documentation for GdkWindow to do this. There is a gdk_window_begin_resize_drag function which really makes me think there's a cleaner way to do this, but I didn't see anything more obvious than my answer.