android弹窗dialog和AlertDialog

protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_daily_list);
/*    通过LayoutInflater来加载一个xml的布局文件作为一个View对象
*     而且因为是在原来的activity_daily_list的activity上加载viewdialog，所以要viewdialog定义成private而且inflate方法写在onCreate（）里*/
viewdialog = (View) LayoutInflater.from(DailyListActivity.this).inflate(R.layout.dialog_addlist_input, null);

setUpViews();
addlist_button=(Button)findViewById(R.id.addlist_button);
addlist_button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
AlertDialog.Builder builder = new AlertDialog.Builder(DailyListActivity.this);
builder.setTitle("新建任务");
builder.setView(viewdialog);
builder.show();/*记得这一行，不然不显示弹框*/
bt_ok = (Button) viewdialog.findViewById(R.id.bt_ok);

bt_ok.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
add();
setUpViews();
}
});

}
});

}