This article mainly introduces how to force object pointers and basic data types in iOS. I won’t say much about it below, just take a look at the examples in detail.
1. Forced rotation of object pointer:
UIView *view = [UIView new];//new an object of UIView classUILabel *label = (UILabel *)view;//Forcibly convert to UILabel pointer = @"123";//GivelabeloftextAttribute assignment（CalllabelofsetTextmethod）
The above code will cause a crash, and the crash information is as follows:
-[UIView setText:]: unrecognized selector sent to instance 0x7ff1e14e03a0
Summarize:The strongly rotated object pointer will not change the object type stored in memory. What kind of object is originally an object, and it will not change after a strong rotation, but it can facilitate calling the methods and properties in the class that is forced to be called.
2. Strong rotation of C basic data type:
float weight = 60.12; NSLog(@"%d",(int)weight);
The printed information is: 60
Then the original value was modified: 0.12 was discarded
int height = 70; NSLog(@"%f",(float)height);
The printed information is: 70.000000
Adding .000000 to the original value is added to the float type. Maybe it can use %f to correctly print the height value after a strong rotation.
because
int height = 70; NSLog(@"%f",height);
The printed information is: 0.000000
The exploration of strong rotation of C basic data types is for reference only.
Summarize
The above is the entire content of this article. I hope the content of this article will be helpful to all iOS developers. If you have any questions, you can leave a message to communicate.