Use:
public void onClick(View v) {
switch(v.getId()){
case R.id.Button_MyCards: /** Start a new Activity MyCards.java */
Intent intent = new Intent(this, MyCards.class);
this.startActivity(intent);
break;
case R.id.Button_Exit: /** AlerDialog when click on Exit */
MyAlertDialog();
break;
}
}
Note that this will not work in Android library projects (due to http://tools.android.com/tips/non-constant-fields) where you will need to use something like:
int id = view.getId();
if (id == R.id.Button_MyCards) {
action1();
} else if (id == R.id.Button_Exit) {
action2();
}