如何遍历嵌套类？

Question

Another simple one!

I'm trying to iterate through nested classes in an android project.

The class structure is:

    public class clsMessage {
    public String Username = "";
    public String Password = "";
    public String Request = "";

    public class Parameters {
        public String Name = "";
        public String Value = "";
    }
}

The outer class is instantiated as "msg". Then I thought I'd query it like this:

    for (clsMessage.Parameters params : msg) {
    //    do stuff
    }

But that doesn't work and I can't find an example on Google surprisingly, unless I should be using an iterator in the outer class?

Answer 1

I am guessing you are looking for something like the following.

public class ClsMessage 
{
    public String username = "";
    public String password = "";
    public String request = "";

    public List<Parameters> parameters = new ArrayList<Parameters>();

    public static class Parameters {
        public String name = "";
        public String value = "";
    }
}

for(ClsMessage.Parameters param : clsMessage.parameters)
{
    ....
}

Just declaring an inner class won't actually have an "inner class" as a field. You would need to make a field for it. Considering you wanted to iterate through it with a for-loop, I assumed you wanted more than one Parameters in your message, so I added a List .

Answer 2

Iterate over list of messages and then get inner class object each ClsMessage .

for (clsMessage msg : msgs) {
    clsMessage.Parameters params = msg.getParameter();
    //do stuff like params.getName()...
}

Answer 3

If your outer class should hold a list of inner class instances, it should have some array or Collection of Parameters.

public class clsMessage {
    ....
    private Parameters[] params; // or private List<Parameters> params;

    public Parameters[] getParams() // or public List<Parameters> getParams()
    {
        return params;
    }

    public class Parameters {
        public String Name = "";
        public String Value = "";
    }
}

Then you can access them :

for (clsMessage.Parameters params : msg.getParams()) {
//    do stuff
}