Question

按下actionBar图标我应该转到之前的片段，但它不会。我的意思是当我按下操作栏图标时没有任何事情发生。

import java.awt.*;
import java.util.LinkedList;
import java.util.List;
public class Project1GUI {
    static JFrame Frame;
    static TextArea unsorted_words, sorted_words, linked_words;
    public Project1GUI(String title){
            //All this does is make an empty GUI FRAME. 
                    Frame=new JFrame();//i made a new variable from the JFrame class
                    Frame.setSize(400,400);//Used the Variable from JFrame and used some of it functions. This function sets the hieght and width of the Frame
                    Frame.setLocation(200,200);//This sets where the Empty Frame should be
                    Frame.setTitle(title);//This puts a title up top of the Frame
                    Frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//places an x box that closes when clicked on
                    Frame.setVisible(true);//This activates the JFram when is set true.
                    Frame.setLayout(new GridLayout(1,2));//This sets the layout of the Frame and since i want a Grid i used a GirdLayout
                    //Functions and placed it inside the setlayout functions. to  get 2 grids i places 1 meaning 1 row and 2 for 2 cols
                    unsorted_words=new TextArea(); //From the TextArea class i made three variables
                    sorted_words= new TextArea();
                    linked_words= new TextArea();
                    Container panel=new Container();
                    panel=Frame.getContentPane();
                    panel.add(unsorted_words);
                    panel.add(sorted_words);
                    panel.add(linked_words);

    }


    public void add_unsorted(String words){
        unsorted_words.append(words+"\n");//add words to GUI

    }

    public void add_sorted(String words){
        sorted_words.append(words+"\n");
    }

    public void add_linked(List<String> linked_words2){
        linked_words.append(linked_words2+"\n");
    }

}

所以它不会在switch语句中触发public class SecFrag extends Fragment { // constructor and onCreateView goes here @Override public void onActivityCreated(@Nullable Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); Toolbar toolbar = (Toolbar)getActivity().findViewById(R.id.toolbar); ((AppCompatActivity)getActivity()).setSupportActionBar(toolbar); ActionBar actionBar=((AppCompatActivity) getActivity()).getSupportActionBar(); actionBar.setDisplayShowHomeEnabled(true); actionBar.setDisplayHomeAsUpEnabled(true); actionBar.setHomeButtonEnabled(true); recyclerView= (RecyclerView) getActivity().findViewById(R.id.recyclerViewInSecFragment); RecyclerAdapter adapter=new RecyclerAdapter(MainActivity.musicList,null,null); recyclerView.setAdapter(adapter); recyclerView.setLayoutManager(new LinearLayoutManager(getContext())); } @Override public boolean onOptionsItemSelected(MenuItem item) { Log.e("SEC",item.getItemId()+""); switch (item.getItemId()) { case android.R.id.home: { Log.e("SECFRAG","CLICKED"); break; } default:break; } return super.onOptionsItemSelected(item); } }。所以请说明为什么这不起作用。

Answer 1

您需要通过调用setHasOptionsMenu(true)来指示Android堆栈，您的片段将处理选项菜单而不是持有者活动，并且文档推荐将其放入您的片段中onCreate()回调。这将使您的日志消息被适当调用。

后退按钮在actionBar中不起作用

1 个答案: