Basic Android

Android Basics

• Install 32 bit Java JDK http://www.oracle.com/technetwork/java/javase/downloads/index.html

• App Inventor Pretty basic web interface an blocks editor to build simple android apps http://appinventor.googlelabs.com/about/
  • Setup App Inventor http://appinventor.googlelabs.com/learn/setup/

• Android SDK
  • http://developer.android.com/sdk/index.html
  • Install SDK Installer http://developer.android.com/sdk/tools-notes.html
  • Install Eclipse http://www.eclipse.org/downloads/
  • Install Eclipse ADT Plugin http://developer.android.com/sdk/eclipse-adt.html#installing

• Android NDK
  • we're not covering this http://developer.android.com/sdk/ndk/index.html

Basics

• src folder containg all the source
• res folder containing all the resources

Resources

No DPI or PPI Andoid uses dp density independent pixels or sp scale interdependent pixels http://developer.android.com/guide/topics/resources/more-resources.html#Dimension

also see supporting multiple screens http://developer.android.com/guide/practices/screens_support.html

Activities

Activity life cycle http://developer.android.com/guide/topics/fundamentals/activities.html#Lifecycle

Get an instance of an object from the R class

<java>/** Called when the activity is first created. */

   @Override
   public void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.main);
       
       //Get the Button and the TextView from the Resource class
       Button btn = (Button)this.findViewById(R.id.button1);
       final TextView tv = (TextView)this.findViewById(R.id.textView1);  
       String s = "hello";
       tv.setText(s);
   }

</java>

notice the cast to the type also notice that the TextView is marked as final this is so that we can use it in an inner method

handle a click event <java> btn.setOnClickListener(new View.OnClickListener() {

@Override public void onClick(View v) { // TODO Auto-generated method stub tv.setText(d.About()); } });</java>

Events

Lots more good reading http://developer.android.com/guide/topics/fundamentals.html

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