Android的 - 如何隐藏当前片段菜单选项 [英] Android - How to hide menu option for current fragment

问题描述

我有一个的FrameLayout和菜单中的ActionBar活动。当用户点击菜单项我替换为相关的新片段的片段。不过，我看不到一个明显的方式来删除的菜单项所选择的片段。

 公共类MainActivity扩展ActionBarActivity {
    @覆盖
    保护无效的onCreate（捆绑savedInstanceState）{
        super.onCreate（savedInstanceState）;
        的setContentView（R.layout.activity_main）;
        如果（savedInstanceState == NULL）{
            StudyFragment startFragment =新StudyFragment（）;
            startFragment.setArguments（getIntent（）getExtras（））;
            getSupportFragmentManager（）调用BeginTransaction（）。加
                                      （R.id.container，startFragment）.commit（）;
        }
    }    @覆盖
    公共布尔onCreateOptionsMenu（菜单菜单）{
        。getMenuInflater（）膨胀（R.menu.main，菜单）;
        返回true;
    }    @覆盖
    公共布尔onOptionsItemSelected（菜单项项）{
        INT ID = item.getItemId（）;        开关（ID）{
        案例R.id.action_study：
            replaceFragment（（片段）新StudyFragment（））;
            打破;
        案例R.id.action_list：
            replaceFragment（（片段）新ListFragment（））;
            打破;
        //等
        }
        返回super.onOptionsItemSelected（项目）;
    }    私人无效replaceFragment（片f）{
        FragmentTransaction交易=
                                。getSupportFragmentManager（）的BeginTransaction（）;
        transaction.replace（R.id.container，F）;
        transaction.addToBackStack（NULL）;        器transaction.commit（）;
      }
 

在更换的菜单表示禁用菜单上prepareOptionsMenu - 但我怎么会知道哪些项目被选中

？

- 解决方案实现 -

使用穆罕默德Refaat的解决方案，下面我添加了两个新成员到类：

 私人菜单activityMenu;
私人菜单项curMenuItem;
 

设置他们onCreateOptionsMenu

  activityMenu =菜单;
curMenuItem = activityMenu.findItem（R.id.action_study）;
curMenuItem.setVisible（假）;
 

和改变了他们对onOptionsItemSelected

  curMenuItem.setVisible（真）;
curMenuItem = activityMenu.findItem（ID）;
curMenuItem.setVisible（假）;
 

解决方案

首先得到你想要删除的项目：

 菜单项项目= menu.findItem（R.id.your_action）;
 

然后设置它的能见度假：

  item.setVisible（假）;
 

如果问题是获得菜单（因为它不是在片段），你可以很容易地得到一个背景从包含菜单，并获得活动通过它的菜单。

I have an ActionBar activity with a FrameLayout and a menu. when the user clicks the menu item I replace the fragment with the relevant new fragment. However, I cannot see an obvious way to remove the menu item for the selected fragment.

public class MainActivity extends ActionBarActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        if (savedInstanceState == null) {
            StudyFragment startFragment = new StudyFragment();
            startFragment.setArguments(getIntent().getExtras());
            getSupportFragmentManager().beginTransaction().add
                                      (R.id.container, startFragment).commit();
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();

        switch (id) {
        case R.id.action_study:
            replaceFragment((Fragment)new StudyFragment());
            break;
        case R.id.action_list: 
            replaceFragment((Fragment)new ListFragment());
            break;
        // etc
        }
        return super.onOptionsItemSelected(item);
    }

    private void replaceFragment(Fragment f) {
        FragmentTransaction transaction =
                                getSupportFragmentManager().beginTransaction();
        transaction.replace(R.id.container, f);
        transaction.addToBackStack(null);

        transaction.commit();
      }

The Google documentation on changing menus says to disable the menu in onPrepareOptionsMenu - but how will I know which item has been selected?

--Solution Implemented--

Using Muhammed Refaat's solution below I added two new members to the class:

private Menu activityMenu;
private MenuItem curMenuItem;

Set them in onCreateOptionsMenu

activityMenu = menu;
curMenuItem = activityMenu.findItem(R.id.action_study);
curMenuItem.setVisible(false);

And changed them on onOptionsItemSelected

curMenuItem.setVisible(true);
curMenuItem = activityMenu.findItem(id);
curMenuItem.setVisible(false);

解决方案

First get the item you want to remove :

MenuItem item = menu.findItem(R.id.your_action);

then set it's Visibility false :

item.setVisible(false);

and if the problem is in getting the menu (as it's not in the fragment), you can easily get a context from the activity that contains the menu and get the menu by it.

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