Ch 7: Using Internet Resources

Question 1

Using Internet Resources:

Important Concepts

Answer 1

• Android Network APIs
• Creating Network Connections
• Performing Network operations on Background Threads
• Using View Model and Live Data
• Parsing Files
• Download Manager
• Best Practices: Energy Conservation
• Internet Services

Question 2

Android Network APIs:

Kinds of tasks they allow you to accomplish

Answer 2

• Connect to remote server endpoints
• Make HTTP requests
• Process server results and data feeds
  
  • Use parser to process data

Question 3

Android Network APIs:

Two connection types available

Answer 3

Mobile Internet:

• GPRS, EDGE, 3G, 4G, LTE Internet access

Wi-Fi:

Private and Public Wi-Fi access points

Question 4

Android Network Connections:

Basic Considerations when using Internet Resources

Answer 4

• Some connections will have very low bandwidth
• Wi-Fi connections may be unreliable:
  
  • User might pass out of range
• Mobile connections can be costly to the user due to data charges
• Transmitting data drains power from the battery
• Quantity of data transmitted should be minimized
• App should be robust enough to handle:
  
  • Network outages
  • Bandwidth/Latency limitations

Question 5

Benefits of a Native Internet Applications

vs

Web Apps accessed with Browser

Answer 5

• Less bandwidth required
  
  • Only update things that change
• Offline Availability
• Lower Latency
• Better UX
  
  • Consistent with OS
• Reduce battery drain
  
  • using bundled connections
• Access to native features

Question 6

Android Network APIs

Connecting to an Internet Resource:

Important Classes

Answer 6

• URL
• URLConnection
• HttpURLConnection
• InputStream

Question 7

Android Network APIs

Two Major Packages for Networking

Answer 7

java. net
android. net

Question 8

Android Network APIs

Connecting to an Internet Resource:

Basic Steps (HTTP Connection)

Answer 8

Add an INTERNET uses-permission node to the application manifest

Create a URL instance:

URL url = new URL(myFeed);

Open a connection, cast to connection type:

HttpURLConnection conn = (HttpURLConnection)url.openConnection();

Check the response code of the connection:

httpConnection.getResponseCode();

Get an InputStream from connection:

InputStream in = conn.getInputStream();

When done, disconnect:

conn.disconnect();