HI all,
actually i m new in android development.
i have one activity class and one simple class(Without Activity). in Simple class i m calling some web service and storing the response in array. after that this array i want to access in my activity class. m not able to make the object. how can i do that? i don't want to use bundle. as this array i want to access in more than one class.
please help me.
thanks in advance.
The activity calls/creates the Simple class, right? Pass a reference to the activity object to the Simple class, have the Simple class call the activity back with the data.
You can also use static, but it depends of data.
Related
I need to start an Activity with parameters. I know i can do it with Intents and Bundles, but as far as i know it's only possible with String, boolean, etc...
I have to do it with custom parameters, like user-made classes.
For example, i got PLC-class in main activity, which contains many variables and methods, and i need to use it in the other activity.
I know the "public static" method, but i'm not a fan of it, and i'm sure i can find something else that fits my need.
I hope you guys can help me
Bye
Or you can make your class implementing parcelable interface, and put it in a parcel that you send from your source activity to destination activity..
In my opinion you can make bean class... which have getter/setter method.. you can set value there, and retrieve those values in any other Activities.Using it class.
E.g
public class Constants{
public static Bean userBeen=new Bean();
}
Main activity
Constants.userBeen.setValue("anything");
In other Activity,, you can get value using userBeenobj;
Other Activity
String s=Constants.userBeen.getValue();
Hope this helps to you. I mostly use this.!
make your custom made class serializable and then put it in bundle like this
bundle.putSerializable(key, value);
Using itent.putExtra makes a copy of my object. So changes make on this object on the activity that recive this itent does no reflect on others activity.
In my case will be good have reference to this object instead a copy, this is possible ?
ps: I know i can use onActivityResult to retrive the changes make on the object, but in my case the changes make on the object need to be done before the end of the activity.
Other way is: set a reference to a common property from activity1 (I am using MyApplication). The activity2 knows where to find that reference via a getter and it will use it. Decide if you want to modify the properties in activity2, when finished / every time you can have the reference in activity1.
This way is not needed to serialize / deserialize the object either. ( performance improvement too)
You can just store a reference to the object in a static member variable, like this:
public class Globals {
public static MyObject myObject;
}
Now, in the code that has the object, you just do:
Globals.myObject = object;
and in the new activity, you can get it like this:
doSomethingWith(Globals.myObject);
Now, having said that, you need to be aware of the following:
Android can kill your process if your application is in the background pretty much any time it wants to. When the user then returns to your application, Android will create a new process for your application and then it will recreate only the activity that was on the top of the activity stack (ie: the one that was showing). In that case, the newly created activity will not be able to get the iobject by accesing Globals.myObject because the process has been newly created and that member variable is null.
You should use an Application class, which you can get a reference to using the getApplicationContext() method.
Bottom line, create an Application class, which you will be able to reference from any class in your App, then you can reference a variable that is local to that class.
Here is a good SO question about this:
Using the Android Application class to persist data
My app contains two classes: MainActivity, Activity2.
Activity2 needs to access a non-static method of MainActivity. How to do that?
I'm new with Java and Android, if you can, please explain clearly for beginners what to do.
Thanking you in advance.
Instead of calling methods from a different activity you should use Bundles to pass values from ActivityA to ActivityB when B is started from A.
Alternatively if you want to reuse code you should create a non-activity object which you can create two instances of. Say if you do a lot of heavy calculations in both activities, you can put your calculating code in a "Calculate" object. And just initiate it like you would any other Java object. Just note that these two instance will not share any data between each other.
Calculate calc = new Calculate();
calc.codeIdLikeToReuse(numbersAndStuff);
Hope this helps. I would recommend that you read up on the Activity Life Cycle to get an idea on how the life on an activity is.
Use Broad cast receiver to call methods in different activities you can find help here
and one example
Basically, you can't do that. Two activities don't communicate this way. Usually, only one activity is alive at a time (also this might not be always true). The real answer is to use Intents.
You should read some basic Android tutorial like the anddev book.
you also can use libraries like EventBus to link the code.
refer to this post
hi to all
I what to know how to save data in next activity
Use Intent to pass data from one Activity to another Activity.
But these Intents may carry native data types like String, int, float, double etc.
If you want your own Object to be passed, you would have to implement Serializable interface.
An odd way is to use a static Object in a class which is globally accessible.
you should explain clearly about your requirement. As i have understood, i think you want to access data which belongs to one activity in the other activity.
Refer the link below, you will get a clear idea.
http://developer.android.com/resources/faq/framework.html#3
u can use intents, bundles, or any other static variables to holds data from one activity to another
How do you pass an instance of ArrayList<ArrayList<HashMap<String, String>>> from one Android activity to another via an instance of Bundle?
(I could use JSON strings. I'd like to know if there are better ways.)
Thanking you kindly in advance.
You can pass it as an extra in the Intent that you use to fire up the new activity. Since ArrayList implements Serializable, you don't have to do anything special to feed it to Intent.putExtra().
In general it is not good to pass too many or too large data between activities via Intents. It's better to store them somewhere centrally and pass a lightweight identifier or something like this, so the other activity can retrieve them from the store.
E.g. you can use an Application class to store these data. An application class is always available as long as you application is running. You get it from each Activity by calling the getApplication() method.