Week 4 - ScrollView, SharedPreferences, Intents, LayoutInflater, AlertDialog, AndroidManifest.xml

Question 0

How does one gain access to the shared preferences?

Answer 0

This is typically done by requesting the default shared preferences for this activity from the preferences manager. The activity and default shared preferences can be substituted with other things.

Example:

SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(this);

Question 1

What are Shared Preferences used for?

Answer 1

Shared Preferences are used to store simple data in the form of key-value pairs that needs to persist between invocations of an app.

Question 2

How does one add data to, read, and remove data from the shared preferences?

Answer 2

After requesting the appropriate shared preferences, data can be added and removed by calling the getXXXXX(), putXXXXX(), and remove() methods of the shared preferences object.

Question 3

What does the layout inflater do?

Answer 3

It constructs a concrete GUI that will be presented to the user from an XML layout file.

Question 4

How is the layout inflator used?

Answer 4

LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);

View v = inflater.inflate(R.layout.xmlLayoutID, null);

Question 5

How is an alert dialog created and shown?

Answer 5

AlertDialog.Builder b = AlertDialog.Builder(this);

b. setTitle(“Foo”);
b. setMessage(“Bar.”);

AlertDialog a = b.create();

a.show();

Question 6

How does one make custom code execute when alert dialog buttons are clicked?

Answer 6

By setting a DialogInterface.OnClickListener.

Example:

builder.setPositiveButton("Text",
     New DialogInterface.OnClickListener() {
          // Some action
     }
}

Question 7

What does a ScrollView do?

Answer 7

A ScrollView is a container for views that can be scrolled by the user, allowing them to be larger than the screen. It is a FrameLayout and therefore should only contain one child view.

Question 8

What is the difference between a ScrollView and a ListView?

Answer 8

A ScrollView offers more flexibility, whereas a ListView is optimised for scrollable lists.

Question 9

What is the purpose of the Android Manifest XML file?

Answer 9

It contains important information about the app, such as:

• The activities that the app contains.
• Information about the SDK the app uses, e.g. minimum and target SDK versions.
• Which types on intents the app can listen for.