It comes to Log1 then crashes.Whats wrong? - imageswitcher

Question

"is" is the ID of Imageswitcher
s is images number in array
The Array contains 5 images:play stop next previous pause
public class MainActivity extends AppCompatActivity {
Button btnnext,btnprev;
ImageSwitcher is;
int s;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final Integer[] img=new Integer[]{R.drawable.next,R.drawable.play,R.drawable.previous,R.drawable.stop,R.drawable.pause,};
btnnext=(Button)findViewById(R.id.btnnext);
btnprev=(Button)findViewById(R.id.btnprev);
is =(ImageSwitcher) findViewById(R.id.is);
Log.i("log1","1");
is.setFactory(new ViewSwitcher.ViewFactory() {
#Override
public View makeView() {
ImageView imageView=new ImageView(getApplicationContext());
imageView.setScaleType(ImageView.ScaleType.FIT_CENTER);
Whats wrong with the line below?
imageView.setLayoutParams(new ImageSwitcher.LayoutParams
(LinearLayout.LayoutParams.MATCH_PARENT,LinearLayout.LayoutParams.MATCH_PARENT));
is.setImageResource(img[s]);
Log.i("log","4");
return imageView;
}
});
Log.i("log2", "2");
Button Next codes:
btnnext.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Animation right= AnimationUtils.loadAnimation(MainActivity.this,android.R.anim.slide_out_right);
Animation left= AnimationUtils.loadAnimation(MainActivity.this,android.R.anim.slide_in_left);
is.setAnimation(left);
is.setAnimation(right);
is.setImageResource(img[(s+1)]);
}
});
Log.i("log3", "3");
Button Previous codes:
btnprev.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Animation right= AnimationUtils.loadAnimation(MainActivity.this,android.R.anim.slide_out_right);
Animation left= AnimationUtils.loadAnimation(MainActivity.this,android.R.anim.slide_in_left);
is.setAnimation(left);
is.setAnimation(right);
is.setImageResource(img[(s-1)]);
}
});
}
}

Answer 1

this code should be removed:
is.setImageResource(img[s]);
instead of:
is.setImageResource(img[(s+1)]);
I shoul use:
currentImage++;
currentImage = currentImage % img.length;
is.setImageResource(img[currentImage]);
and instead of:
is.setImageResource(img[(s-1)]);
I should use:
currentImage--;
currentImage = (currentImage + img.length) % img.length;
is.setImageResource(img[currentImage]);