Questions and Answers about Android

How do we tell Android that we'd like a menu item to show up as a button on the Toolbar?
Add the showAsAction XML attribute to the menu item.

 
<menu xmlns:android="http://schemas.android.com/apk/res/android"   
      xmlns:app="http://schemas.android.com/apk/res-auto">
    <item        
       android:title="@string/search"        
       android:orderInCategory="1"       
       app:showAsAction="ifRoom"
       android:id="@+id/action_search"/>
</menu>

Which of the following activities can only be done after declaring a uses-permission in the manifest (rather than by using a system app)? 

Hint: Take a moment to explore http://developer.android.com/guide/topics/security/permissions.html


    

  • Taking a photo
    • 

  • Making a phone call
    • 

  • Getting the user’s current location <-- The answer
    • 

  • Accessing the details for a contact the user selects from the contact manager
    • 


Which methods are run on the main UI thread ?

execute() -->True
onPreExecute()
onProgressUpdate()
onPostExecute()
publishProgress ->Wrong
doInBackground()










What is the Adapter responsible for? Place a check next to each statement that is true: 






The adapter does create ViewHolder objects and inflates item views in its onCreateViewHolder function, it also returns the number of items in the data source, and binds data from the data source to each item (even if we pass the responsibility to the ViewHolder). It doesn't cache views associated with each item (that's the job of the ViewHolder class) nor does it recycle them; that’s what our RecyclerView does.






-Creating a ViewHolder object for each RecyclerView item.


-Returning the number of items in the data source


-Binding data from the data source to each item


-Inflating each item view that will be displayed



xCaching the views associated with each item



xRecycling items so they can be used again 





**Corrects are red colored.**






Which of the following actions would be executed with an implicit intent ?


xOpening a web link


-Opening an activity in your app



xSharing a content from an app to Twitter











Opening a web link would be an implicit intent because you aren’t specifying a specific browser to use, the user gets to choose.



Opening an activity uses an explicit intent because you know exactly where to go.





Sharing content to Twitter is a bit of a curveball. We’ve taught you the best way to do it using an implicit intent. It is possible as an explicit intent but not recommended.



Why use an AsyncTaskLoader for threads bound to an Activity rather than AsyncTask?

AsyncTaskLoader will deliver the result to the current active Activity

AsyncTaskLoader prevents duplication of background threads

AsyncTaskLoader makes background threads run faster

AsyncTaskLoader helps eliminate duplication of zombie activities













































































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About Android padding, margin, width, height, wrap_content, match_parent, R Class





















 Padding and Margin   padding  and  layout_margin  are two very similar attributes. Both determine the space around a View. The difference is that  padding  determines space within the boundaries of the view, and  layout_margin  determines the space outside the boundaries of the view.   Width and Height   Some of the most important properties are the width property and height property - those must be defined for every view. Remember that all views occupy a rectangular area on the screen - the width and height are the width and height of that area. You can define this in pixels, or better yet dp (stands for density-independent pixels):  android:layout_width="200dp" android:layout_height="300dp"   For the sake of having a layout be responsive and adjust to different devices, two common values are not numbers at all, but  wrap_content  and  match_parent  used as shown here:  android:layout_width="wrap_content" android:layout_height="match_parent"   








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@SerializedName and @Expose annotations





















 The  @SerializedName  annotation is needed for Gson to map the JSON keys with our fields. In keeping with Java's camelCase naming convention for class member properties, it is not recommended to use underscores to separate words in a variable.  @SerializedName  helps translate between the two.    @SerializedName ( "quota_remaining" )  @Expose   private  Integer quotaRemaining;    In the example above, we are telling Gson that our JSON key  quota_remaining  should be mapped to the Java field  quotaRemaining .  If both of these values were the same, i.e. if our JSON key was  quotaRemaining  just like the Java field, then there would be no need for the  @SerializedName  annotation on the field because Gson would map them automatically.   The  @Expose  annotation indicates that this member should be exposed for JSON serialization or deserialization.   








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