android studio 程序退出提示

int count=0;
@Override
public void onBackPressed() {
//        super.onBackPressed();
if (count<1){
Toast.makeText(this,"exit?",Toast.LENGTH_SHORT).show();
count++;
}else {
finish();
}
}

private long lastClick=0;

@Override
public void onBackPressed() {
//        super.onBackPressed();
if (lastClick<=0){
Toast.makeText(this,"exit?",Toast.LENGTH_SHORT).show();
lastClick=System.currentTimeMillis();
}else {
long currentClick=System.currentTimeMillis();
if (currentClick-lastClick<2000){

finish();
}else {
Toast.makeText(this,"exit?",Toast.LENGTH_SHORT).show();
lastClick=currentClick;
}
}
}