Android Cheatsheet for Beginners

Also check out Boxing Clock for Android (and MABG), search Stack Overflow, read Android Developers Guide and Reference.

Toast

private void tToast(String s) {
    Context context = getApplicationContext();
    int duration = Toast.LENGTH_SHORT;
    Toast toast = Toast.makeText(context, s, duration);
    toast.show();
}

Lifecycle

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
}

The rest have a shorter syntax: onResume(), onStop()…

public void onResume() {
   super.onResume();
   tToast("onResume");
}

Button

public void goButtonClicked(View v) { }

<Button android:text="Go!" android:onClick="goButtonClicked"
        android:id="@+id/goButton"></Button>

TextView

final TextView q = (TextView) findViewById(R.id.q);
String s = q.getText().toString();

out.setText("Foo bar");

out.setText(String.valueOf(x*x));

Canvas

public class HelloCanvasActivity extends Activity {
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		TCanvas tCanvas = new TCanvas(this);
		setContentView(tCanvas);
	}
	public class TCanvas extends View {
		public TCanvas(Context context) {
			super(context);
		}
		public void onDraw(Canvas canvas) {
			canvas.drawColor(Color.GREEN);
		}

	}
}

Install

$ sudo apt-get -y intall eclipse

Eclipse: Help: Install New Software: https://dl-ssl.google.com/android/eclipse/ (IIRC, try without SSL if doesn’t work).
Follow instructions, accept licenses, restart eclipse when asked.

New Android Project

Eclipse: File: New: Project…: Android: Android Project
Project name: BoxingClock (One word, small or camelcase, will be folder name)
Build target: 2.2 API 8 (what you installed & what’s popular in the market)
Application name: BoxingClock the Nyrkkeilykello (Anything, shows in Android title bar)
Package name: com.botbook.foo (domain reversed, use example.com if you don’t have one)
Create Activity: BoxingClock (Class name, start Capitalized, camelcase)
Min SDK version: 8 (same as build target)
Edit: Fixed typo in code. Drawing on Canvas