To start an Activity you need an Intent, like:
Intent i = new Intent(context, class)
So to fill in the context parameter, a couple of options are available:
MyActivity.this
or just this
getApplicationContext()
getBaseContext()
And I'm sure there are one or two more options. These options all appear in some sort of tutorial, one uses the first, the next uses the third option.
So which one should I use? Does it even matter? Is it different for different cases?
To start an activity, call startActivity() and pass it your Intent . The system receives this call and starts an instance of the Activity specified by the Intent .
Yup, simply use the context and call the startActivity() method from that context.
To start an activity, use the method startActivity(intent) . This method is defined on the Context object which Activity extends. The following code demonstrates how you can start another activity via an intent. # Start the activity connect to the # specified class Intent i = new Intent(this, ActivityTwo.
In android, Context is the main important concept and the wrong usage of it leads to memory leakage. Activity refers to an individual screen and Application refers to the whole app and both extend the Context class.
There is no way to pass the context to the target activity using Intent. However, you can pass context, integers, booleans, strings, instances and so on using a static method as shown above.
If both application have the same signature (meaning that both APPS are yours and signed with the same key), you can call your other app activity as follows: Intent LaunchIntent = getActivity(). getPackageManager(). getLaunchIntentForPackage(CALC_PACKAGE_NAME); startActivity(LaunchIntent);
Yes its different for different cases,
It depends on the scope. Suppose if you are creating a method in a global class that extends
Application
to create a Toast
that is used in every class of your Application
you can use getApplicationContext()
to create it.
If you want to create a view that is restricted to that particular Activity you can use Activity.this
Also if you want to create an AlertDialog in some inner class say AsyncTask
, then you have to use Activity.this
, because the AlertDialog
is to be linked to Activity
itself.
Also don't use getBaseContext()
just use the Context
that you are having. For getting further information for the same you can see this Answer
.
So, the answer to the real question is better to use Activity.this
to start a new Activity
.
Intent intent = new Intent(Current_Activity.this, Calling.class);
startActivity(intent);
They are different for sure. These are different contexts, and should be used with the least possible scope(context).
For example if we can use Activity's Context instead of ApplicationContext, one should use the activity context, same applies to application context, and base context.
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