CSS circle style html

Try insert + before R.drawable.xxxx

// error
InputStream is = context.getResources().openRawResource(R.drawable.app_sample_code);

// ok
InputStream is = context.getResources().openRawResource(+R.drawable.app_sample_code);

How install Android emulator on PC
//developer.android.com/sdk/installing.html

Download links:
Java Development Kit JDK download
Eclipse download
Android SDK download

Click Handler Android Java example source code. Open new class as activity and open URL in browser.
In layout.xml file:

 android:layout_height="wrap_content" android:onClick="@string/clickHandler">

In string.xml

myClickHandler

In MainClass.java file

	public void myClickHandler(View view) {
		switch (view.getId()) {
		// open new class as activity
		case R.id.btnOpenClass: {
				Intent pictureActivity = new Intent(getBaseContext(),
						MyClass.class);
				startActivity(pictureActivity);
		}
		break;			
			
		case R.id.btnAbout: {
			//aboutDialogCreate();
		}
			break;
			
		// open url	
		 case R.id.btnHome: {
		 String url = "//android.okhelp.cz/";
		 Intent i = new Intent(Intent.ACTION_VIEW);
		 i.setData(Uri.parse(url));
		 startActivity(i);
		 }break;

		}

	}// end myClickHandler

// listener .. if click on button will scrolling to mTextView bottom
private OnClickListener mButtonListener = new OnClickListener() {
	    public void onClick(View v) {
	      // do something when the button is clicked
	    int nBottom =	mTextView.getBottom();
	    hScrollView.scrollTo(0, nBottom);
	    }
	};

Set, get string , array of array of strings, Java example code

	public final static String[][]_arArOfString_1 = {
		new String[] {"bla","bla","hello world!"},
		new String[] {},
		new String[] {},
		new String[] {},
		new String[] {},
		new String[] {}
	};
String sOut = _arArOfString_1[0][2]; // hello world!

How set rounded corners and own styles ActivityMy.java

Button btn.setBackgroundResource(R.drawable.back_button_answer);

\res\drawable\back_button_answer.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="//schemas.android.com/apk/res/android" android:shape="rectangle" >
   <corners android:radius="10dip" />
   <!-- background -->
   
   <gradient
                android:startColor="#D6D7D6"
                android:centerColor="#E2E2E2"
                android:centerY="0.75"
                android:endColor="#D6D7D6"
                android:angle="270"
        />
   
   <stroke android:width="2dip" android:color="#fff"/>
</shape>