将片段链接到 Activity 错误

Linking Fragment to Activity error

我正在尝试将片段附加到 activity,我已经学习了多个教程,但我的代码似乎与教程中的代码完全相同(适用于我的应用程序),但我找不到我的代码在哪里错误是。

  import android.os.Bundle;
  import android.support.design.widget.FloatingActionButton;
  import android.support.design.widget.Snackbar;
  import android.content.Intent;
  import android.support.v4.app.FragmentActivity;
  import android.view.View;


protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_comments);
    if (savedInstanceState == null) {
        getSupportFragmentManager().beginTransaction()
                .add(R.id.id_layout_comments, new CommentsFragment())
                .commit();
    }

我在“.add(R.id.id_layout_comments, new CommentsFragment())”处收到错误,它说:"cant resolve method add(int, package.CommentsFragment)".

这是我要调用片段的 class 的 header:

 public class CommentsActivity extends FragmentActivity 

这是片段本身之一:

 public class CommentsFragment extends Fragment

如果您需要更多信息,请告诉我。非常感谢!

真的不需要扩展 FragmentActivity,扩展 Activity 就够了。

看这个例子:

评论Activity:

public class CommentsActivity extends FragmentActivity {
...
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_comments);
    if (savedInstanceState == null) {
        getSupportFragmentManager().beginTransaction()
                .add(R.id.id_layout_comments, new CommentsFragment())
                .commit();
    }
...
}

评论片段:

public class CommentsFragment extends Fragment{
...
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.your_resource, container, false);
    return view;
}
...
}

就是这样 :D