IOS UI basics 01 and iosui01

IOS UI basics 01 and iosui01

• Controller

  • 1. What is a controller? Any class inherited from UIViewController is called a controller.
  • 2. Role of the Controller: Manage the UI interface (responsible for managing the creation of the UI interface and handling of some events)

• IBAction

  • Connection Mode
    • 1. Connect from "controller" to "Storyboard"
    • 2. Connect from "Storyboard" to "controller"
    • 3. connect directly to the top of the "Storyboard" Interface
    • 4. Connect the toolbar directly to the Storyboard in "Storyboard ".
    • 5. You do not need to define a method to connect directly from "Storyboard" to "controller ".
  • Notes for connecting IBAction lines
    • 1. Notes When copying elements in Storyboard
    • 2. The previous connections will be copied together during the copy operation.
    • 3. One method can associate multiple controls
    • 4. A control can be connected to many methods in development. Generally, it is not written in this way.
    • 5. If you delete the method associated with the button, a classic error reason: '-[ViewController redBtnClick]: unrecognized selector sent to instance 0x7fb4aa618e50' will be reported after the operation'
    • 6. IBAction can only be returned as a method. IBAction = viod

• UI widget size

  • Most UI controls do not have the default size, so UIButton is invisible.
  • Frame
    • Frame is 0, 0 in the upper left corner of the parent control.

    • UIButton *btn = [[UIButton alloc] init];btn.frame = CGRectMake(100, 100, 100, 100);

  • Bounds
    • Bounds is set to 00 in the upper left corner. Therefore, setting the bounds x/y is invalid. Generally, you can use bounds to modify the bounds size.

    • UIButton *btn = [[UIButton alloc] init];btn.bounds = CGRectMake(0, 0, 100, 100);

  • Center
    • The center is the point of intersection of the control width and height, half of the width and height.
    • Generally, the center is used to modify the location.

    • UIButton *btn = [[UIButton alloc] init];btn.center = CGPointMake(200, 200);

• ViewWithTag
  • ViewWithTag can only find the current control and the Child control of the current control. It cannot find the sibling control or the parent control.
  • Search order: 1. First find yourself 2. Find child Control 3. Find indirect child control (Sun Tzu ..)
  • Obtain the value of the corresponding tag using the tag

• Anonymous Classification
  • Differences between anonymous and Classification
    • 1. The anonymous category has no name, and the category has a name.
    • 2. The implementation of anonymous classification is not required, but the implementation of classification is required.
    • 3. for anonymous classification, you can declare attributes or methods. For classification, you can only declare methods.
  • Notes
    • Attributes and methods that are being developed but do not need to be exposed to the outside world will be uninstalled from the anonymous category.
    • We recommend that you write attributes in anonymous categories (extension/class extension)