android-context

In Apress Pro Android 4 the author has said that: [...] context of currently running activity will no longer be valid when the device is rotated. [...] One approach is to use a weak reference to the activity instead of a hard reference [...] But the author just suggest this, and does not tell how it is done. Who has done this before please give me an example. Somewhere in your AsyncTask you'll want to pass in your activity. Then you'll save that reference in a weak reference. Then you can dereference and use it again in onPostExecute . Class member: WeakReference<Activity> weakActivity;

I am very confused with the usage of all these that where should we use them. this - return self reference getContext() - return Context getActivity() - return Activity Context. Quote from original answer : As the name suggests, its the context of current state of the application/object. It lets newly created objects understand what has been going on. Typically you call it to get information regarding another part of your program (activity, package/application) Activity Activity is a Java code that supports a screen or UI. In other words, building block of the user interface is the activity.

What is difference between this and getContext() , when I say this I mean this within an Activity . In general there are two type of classes. Ones that extend ContextWrapper class ( Activity , Service , Application ) and those that do not extend it (like View ). If class extends ContextWrapper then you can use this as Context . Such classes normally do not have getContext() method. Those classes that do not extend ContextWrapper but still save and use Context normally expose getContext() function. And you cannot use this as Context in such cases. And these two cases are mutually exclusive. At

If I have a reference to Context , is it possible to finish the current activity? I don't have the reference to current activity. yes, with a cast: ((Activity) ctx).finish(); I know it's an old post but, perhaps it could be a good idea to call it this way: if(context instanceof Activity){ ((Activity)context).finish(); } This way we make sure we don't get any unnecesary ClassCastExceptions Kartihkraj Duraisamy In my Case following worked, I need to finish my activity in a AsyncTask onPostExcute(). Where my AsyncTask class is separate public class , which has a constructor with param of Context.

I'm trying to use picasso library to be able to load url to imageView, but I'm not able to get the context to use the picasso library correctly. public class FeedAdapter extends RecyclerView.Adapter<FeedAdapter.ViewHolder> { private List<Post> mDataset; // Provide a reference to the views for each data item // Complex data items may need more than one view per item, and // you provide access to all the views for a data item in a view holder public class ViewHolder extends RecyclerView.ViewHolder { // each data item is just a string in this case public TextView txtHeader; public ImageView pub

I need to get a Drawable object to display on an image button. Is there a way to use the code below (or something like it) to get an object from the android.R.drawable.* package? for example if drawableId was android.R.drawable.ic_delete mContext.getResources().getDrawable(drawableId) Pete Houston Drawable d = getResources().getDrawable(android.R.drawable.ic_dialog_email); ImageView image = (ImageView)findViewById(R.id.image); image.setImageDrawable(d); Muhammad Soliman As of API 21 , you should use the getDrawable(int, Theme) method instead of getDrawable(int) , as it allows you to fetch a

I have TextView for showing time. I want to use Android's DataBinding plugin. For formatting time I am using DateUtils.formatDateTime(context, int, int) method which takes Context instance. Is it possible to get context include element? Or do I have to use old school way? Thanks Thought I should answer instead of putting in a comment. You'll have more options when rc2 is released. In rc1, you can pass the context in a variable to the Binding, then pass it as a parameter to the method. Alternatively, you can create a custom attribute for data binding: @BindingAdapter({"timeMillis", "dateFlags"}

I have a custom View class that extends Spinner. I'm trying to figure out what the correct way to talk to the Activity that it's embedded in is, when the user makes a selection. I see that the OnItemSelected listener gets a reference to the Adapter, but I'm not clear on whether or not I should be using this adapter and walking up its parent chain somehow, or if I should just talk directly to the context (for some reason that doesn't feel safe, even though I can't think of a way in which it might fail, offhand). Tal Kanel the right way to do that, is to "listen" to your custom view by exposing