NoClassDefFoundError: com.google.ads.AdView ADT 17

        android:maxLines="1"
        android:inputType="text"

TextView mIdTextOk = (TextView)findViewById(R.id.idTextOk);
int _nOk = 57;
// number 57 will bold style
mIdTextOk.setText(Html.fromHtml( "OK: "+"<b>"+_nOk+"</b>")); 

try {
		String MYFILE = "my_file";
		String strText = "My text";

                // MODE_APPEND, MODE_WORLD_READABLE, MODE_WORLD_WRITEABLE
		// create new file or rewrite existing
                FileOutputStream fos = openFileOutput(MYFILE, getApplicationContext().MODE_PRIVATE);
                // append to file
                FileOutputStream fos = openFileOutput(MYFILE, getApplicationContext().MODE_APPEND);

		fos.write(strText.getBytes());
		fos.close();					
	} catch (IOException e) {
		e.toString();
    }	

try {
// new file    
BufferedWriter out = new BufferedWriter(
    		new FileWriter("outfilename"));
    // append text 
   BufferedWriter out = new BufferedWriter(new FileWriter("outfilename", true));
    out.write("some text");
    out.close();
 } catch (IOException e) {
   e.toString();
}			

  defaultConfig {
        applicationId "cz.okhelp.pocasiwidget"
        minSdkVersion 11
        targetSdkVersion 23
        versionCode 224
        versionName "2.2.4"
    }

public class ApokusActivity extends Activity {
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(new SampleView(this));
	}

	private static class SampleView extends View {

		// CONSTRUCTOR
		public SampleView(Context context) {
			super(context);
			setFocusable(true);

		}
		@Override
		protected void onDraw(Canvas canvas) {
			Paint paint = new Paint();
			
            paint.setColor(Color.YELLOW);
            paint.setTextSize(60);
            //paint.setTextAlign(Paint.Align.CENTER);

            canvas.drawText("Hello world!", 0, 50, paint);
		}

	}
}