You avtually have to provide the context of the activity in the intent that you create.
so your code is going to be like this
public void registerCallClickBack() {
ListView list = (ListView) findViewById(your list);
list.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View viewClicked,
int position, long id) {
Intent intent = new Intent(MainActivity.this, Descriptions.class);
startActivity(intent);
}
});
}
and in your MainActivity in onCreate method you need
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.description);
registerCallClickBack();