What are the disadvantages of using static variables in Android programming? How should it be regula

In fact, whether to use static or not, it completely depends on the applicable environment, and it is good to use it if it is not good.

static can only work within a process, cross-process is useless.

In most cases, if you share data between multiple activity services in the same application, you can consider using static variables, but the other option is to put them in the application, and the effect is similar in most cases. But in general, static is used to reduce the number of variables, while non-static needs to use some singleton pattern to store variables.

Generally speaking, if there is a problem with multi-threaded access, pay attention to the lock.

In addition, the biggest use of static is the constant of the const class such as static final.

Static variables have the following disadvantages:

1. Static local variables are allocated storage units in the static storage area. It is not released during the entire running period of the program, that is, it takes up a lot of space.

2. Dynamic data cannot be saved.

3. Static variables are easy to cause confusion when multiple forms are accessed together, and they are not independent of each other when they are passed between multiple instances of multiple form classes, and it is more resource-saving when they are frequently accessed.

4. Static variables are stored in the heap area of memory, which can be saved until the end of the whole program, and the life cycle is long.

It's okay to use static variables sparingly, but not everywhere.

1. Static application scope: It can be used for internal classes, methods and variables.

2. Mark a method as static, which means that this method is shared by all instances of the class in which it is located, and is executed first when the class is loaded, and is shared by all instances of the class when it is executed once, which also means:

a. Non-static variables cannot be referenced inside the static method.

b. Static methods cannot be rewritten as non-static methods by subclasses.

c. The non-static method of the parent class cannot be overridden as a static method by the child class.

d. The static block can be done with static {}, which is initialized when the class is loaded for the first time, before the execution of static methods and other methods.

3. Mark a variable as static, then the variable has an unchanged position in memory, which is equivalent to a global variable, and all instances of the class access the same storage variable area. Modifications to it are visible and consistent for all instances of the class.

The disadvantage is obvious, if it doesn't play a reasonable role it takes up a lot of space and won't be automatically taken up by the **mechanism until the end of the program.

When using it, you should make sure that this variable is used frequently, and you can use static variables to avoid repeated instantiation and unnecessary overhead.

This mainly depends on the design of **, and there are no major shortcomings. Static variables, once initialized, allocate memory and are held by the object until the object is **. If it is a public static variable, even if the object is **, the variable will already be in memory and occupy memory.

If it is private static, the object that holds the static variable will be cleared after the object is **. Half of the objects in Android development should not be defined as static, such as context, when the activity is finished, the static context will still exist, but it is not released, which may cause OOMIn short, there are no disadvantages to static variables, it mainly depends on the project requirements and your ** design.

My approach is that if I need to define an object with static variables and more than I need, I define a singleton pattern. If it's a normal variable, like final static int flag = 1, I'll define it in a constant class.