UIView and UIWindow's explanation

One, window and view

1. In iOS, use Windows and views to display the contents of the application on the screen. The window itself does not have any visible content, but it provides a basic container for the view of the application. The view defines a portion of the window that you want to populate with some content. For example, you might display images, text, shapes, or some combination of views. You can also use views to organize and manage other views.

Window

• What is a window?

• At least one window is required for each application, and typically the window is represented by an instance of the UIWindow class. Note that UIWindow inherits from UIView.

The Window object has the following responsibilities:

• It contains the visual content of the application • It provides a critical role for views and other application objects in touch events • Collaborate with view controllers to present data

Most iOS apps have only one uiwindow in their life cycle. And during the lifetime of the application, the window spans the entire device's home screen and the main nib file from the application is loaded (or created programmatically). However, if the application supports an external monitor that uses video output, it can create additional windows to display the content on that external monitor. All other windows are typically created by the system and are typically created when responding to specific events, such as incoming phone calls.

2. Create and configure UIWindow

Create a full-screen window    self.window = [[UIWindow alloc] Initwithframe:[[uiscreen Mainscreen]bounds]];    Self.window.backgroundColor = [Uicolor whitecolor];    The Viewcontroller as a window with the controller    self.window.rootViewController = [[Uiviewcontroller alloc]init];    Show Window    [Self.window makekeyandvisible];

3. Get current UIWindow and levels

• Get current Keywindow through uiapplication.

Keywindow is a message used to manage keyboards and non-touch classes, and only one window is Keywindow.

· UIWindow *keywindow = [uiapplication sharedapplication].keywindow; each UIWindow object configuration Windowlevel property, Most of the time should not change windowlevel.

· The UIWindow has 3 levels and corresponds to 3 display priorities. With the Windowlevel setting, the priority is: Uiwindowlevelalert>uiwindowlevelstatusbar>uiwindowlevelnormal

Two. UIScreen

The 1.UIScreen object can act as a replacement for the physical screen of the iOS device, [UIScreen mainscreen] bounds] get the device screen size, such as the size of the iphone and ipad, if you want to do more than

The UIScreen class should be used to get the dimensions. The latest IPHONE5 adaptation issues!

2. While iOS supports stacking a window over other windows, your application should never create multiple windows because it affects the delivery of events.

3. Several concepts of mobile screen

· Screen Size: The display size, which refers to the physical length of the screen, as indicated by the length of the screen diagonal.

· Resolution: screen resolution, which refers to the total physical pixels on the screen.

· Density: Density, indicating how many display points per inch. Density is based on resolution, that is, the pixel points scattered at fixed resolution, that is to say, the density of the screen is bigger.

· ASPECT RATIO: High ratio of screen width. Which is what we call the aspect ratio 4:3. Device-independent Pixe:dip, device independent pixels. Dip is a virtual pixel unit that specializes in

Used to define the UI for the program.

• Color scale: that is, usually we say 65536 colors, 260,000 colors, 16 million colors and no number looks different so big, this is actually just to represent the adjacent three levels only, of course, 16 million color display is the best.

Three. UIView

UIView represents a rectangular area on the screen that occupies an absolutely important place in the app because almost all visual controls in iOS are UIView subclasses.

Responsible for rendering the content of the area and responding to touch events that occur within that area

Features of the UIView:

1. Managing content in a rectangular area

2. Handling events in a rectangular area

3. Management of child views

4. Also can realize the animation UIView subclass also has these functions

is the inner level of the view

5. View structure and related functions

Cgpoint point = Cgpointmake (x, y); Position

Cgsize size = Cgsizemake (width,height); Size

CGRect rect = CGRectMake (x,y,width,height); Location and size

6. Create a View

  View    UIView *view1 = [[[UIView Alloc]initwithframe:cgrectmake] [[]];    View1.backgroundcolor = [Uicolor whitecolor];   View1.clipstobounds=yes;    [Self.window Addsubview:view1];

7. Common Properties of view:

Alpha//Transparency

backgroundcolor//Background color Uicolor

subviews//Child View collection Nsarray

hidden//whether to hide bool

tag//Tag Value

Superview//Parent View UIView

Clipstobound//Remove part of bool that is out of view

multipletouchenabled//Whether to turn on multi-touch bool

userinteractionenabled//whether to respond to touch event bool

8. Coordinate system transformations are changed by transform properties

· Cgaffinetransformscale Scaling A View

· Cgaffinetransformrotate zoom rotation on the view

· Cgaffinetransformtranslate panning the view in its original position

· Cgaffinetransformidentity revert to the original state of the view

Amplification
-(ibaction) enlarge: (ID) Sender {    Cgaffinetransform t = _colorview.transform;    _colorview.transform = Cgaffinetransformscale (t, 1.2,1.2);} Narrowing-(ibaction) Narrow: (ID) Sender {    Cgaffinetransform t = _colorview.transform;    _colorview.transform = Cgaffinetransformscale (t,0.7,0.7);} Rotation-(ibaction) rotate: (id) Sender {    Cgaffinetransform t = _colorview.transform;    _colorview.transform = Cgaffinetransformrotate (T,M_PI/18);}
Restore-(ibaction) Reduction: (UIButton *) Sender {   //cgaffinetransform t = _colorview.transform;    _colorview.transform = cgaffinetransformidentity;    } Pan-(Ibaction) Translation: (UIButton *) Sender {    Cgaffinetransform t = _colorview.transform;    _colorview.transform = Cgaffinetransformtranslate (T, 20, 20);}

9. View Animations

There are several properties in the UIView object that support animation:

• Frame- You can use this to animate the size and position of the view
• Bounds -Use this to animate the size of the view
• Center -Use this to animate the position of the view
• Transform -Use this to flip or zoom in on a view
• Alpha -Use this to change the transparency of the view
• BackgroundColor -Use this to change the background color of the view
• Contentstetch- Use this to change how the view content is stretched

Steps:

1) Start and design the animation

   [UIView Beginanimations:nil Context:nil];     How many seconds each animation lasts   [UIView setanimationbeginsfromcurrentstate:10];   Set number of repetitions   [UIView setanimationrepeatcount:1];

2) What to do with animation

    Cgaffinetransform t = self.tuview.transform;    Self.tuview.transform = Cgaffinetransformscale (t,100, n);    Self.tuview.center = Self.view.center;    Self.tuview.transform = Cgaffinetransformrotate (T,M_PI/4);     Self.tuview.alpha = 0.1;

3) Submission Screen

[UIView commitanimations];

UIView and UIWindow's explanation