将数据从一个活动传递到另一个活动，但稍后将 go 传递到另一个活动

Question

My work flow is as follows:

LoginActivity -> ActivityB -> ActivityC -> ActivityD

I'd like to pass data from LoginActivity to ActivityD, but not go directly to ActivityD. ie, I'd like to pass data from LoginActivity to ActivityD, but go to ActivityB and ActivityC before I get to ActivityD and get the data there.

Is this possible?

I know to pass data from one activity to another the code is as follows:

        Intent i = new Intent(getApplicationContext(), AnotherActivity.class); 
        i.putExtra("key", (int)1); 
        i.putExtra("something", something); 
        startActivity(i);

And in AnotherActivity you do the following to get the data:

        Bundle extras = getIntent().getExtras();   
        if(extras !=null) 
        {  
            String var = extras.getString("something");
        }

But this does not work if I want to delay going straight to the activity. So if I take out startActivity(i); and go to another activity. The program crashes when tyring get the data in the final activity. The good old NullPointerExeption pops up.

Does anyone know a way of doing what I've described? Get the data from one activity to another, but not go (or start) that activity right away?

Answer 1

If you want to pass the data like this, it is preferable to use shared preferences. It is simple to use and you can use the data any where in your program.

SharedPreferences.Editor editor = prefs.edit();
editor.putString("key", (int)1);
editor.putString("something", something);
editor.commit(); 

at the time of receiving:

SharedPreferences prefs = getSharedPreferences(prefName, MODE_PRIVATE); 
String something = prefs.getString("something", null);

Answer 2

You can always use any of these for it

•A singleton pattern to share the date across multiple non-consecutive activities.

•A shared preference.

•An external storage

•Entry into db.

•passing data with intents.

This link will give you some more details.

Answer 3

I can think of two options to solving your problem. One is that you just keep passing the data, which means in ACtivityB and ACtivityC you need to run the code

Intent i = new Intent(getApplicationContext(), AnotherActivity.class); 
i.putExtra("key", (int)1); 
i.putExtra("something", something); 
startActivity(i);

The other option (which I think is more practical) is to create a seperate class with static members and static methods for accessing the data. It could look something like this

public class SharedResource{
public static String mPassedName;
}

This class would not necessarily be threadsafe so be forewarned, if you have mutlithreaded access take the appropriate precautions.

Answer 4

You can do it by two approaches. 1 ) Shared Preferences

SharedPreferences.Editor editor = prefs.edit();
editor.putString("key", "Value");
editor.commit(); 

// fetching Shared Pref.

  String value = pref.getString("key" , "");

2 ) Defining application level class and access same.

Class Consisting of getter and setter functions for variables. setting in one activity and getting into another activity.