如何在 Android 中完全执行第一种方法后执行第二种方法？

Question

I have four methods, which have to execute one after another. So It means, second method have to wait until first method executes fully.

In my case I have methods inside my IfElse statements Like below. They are executing like second method is executing after some part execution in first method. Its like Asynchronous way.

if(flag.equalsIgnoreCase("flag2"))
{method1();
}else if(flag.equalsIgnoreCase("flag3")){
method2();
}else if(flag.equalsIgnoreCase("flag4"))
{ method3();
}

setCommonData();
setRecyclerAdapter();

and below is my method implementation after adding synchronization keyword.

 synchronized void method1()
    {
    Log.e("filter","======");
    Class 1 class1=new Class1(this,GET,response->{
    Log.e("response",""===success====);
    });
NetworkManager.getInstance(this).sendRequest(class1);
    }

Remaining methods are same as method 1 implementation.

I have used AsyncTasks Also by calling two methods inside onBackground and onPostExecute .

I have used Threads with t.start() and t.join(); . But same those calling Asynchronously. In my case I need to execute these methods one by one. Please some help me on this issue.

Answer 1

When you're calling these methods from different threads, you can add the synchronized keyword to the method declaration to make method2 wait until method1 returns:

synchronized void method1() { ...code for method1... }
synchronized void method2() { ...code for method2... }
synchronized void method3() { ...code for method3... }

The synchronized keyword makes the thread acquire an exclusive lock on the current object's monitor. If another thread already holds the lock, the new call waits until the lock is free. Methods not using the synchronized keyword are not affected, since they don't need the lock.

A potentially simpler solution is to not have different threads in the first place . If you used a thread pool with only one thread, naturally one method call would have to wait for the previous to finish. But to show you how to do that, you should first show us how these methods get called in the first place.

Answer 2

You might wanna use callbacks, passing the methods to one another.

I'm linking a solution to an accepted answer on P Burke 's post (it's in JS but you need the logic anyways) that can also specify the order of the calls.