Question

我是Android编程的新手，我有一个问题。在我的应用程序中，我有ViewPager（带有一些片段），在顶部我有带菜单图标的工具栏。当用户选择ViewPager的不同页面时，是否可以显示不同的图标。我知道OnPageChangeListener的onPageSelected方法在用户选择页面时有效，但我不知道如何更改图标。任何人都可以给我这方面的例子或文章。谢谢！

Answer 1

在视图寻呼机使用的所有片段中使用：

@Override
    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
        inflater.inflate(R.menu.grid_to_list, menu);
        MenuItem item = menu.findItem(R.id.grid_to_list);
        item.setOnMenuItemClickListener(new MenuItem.OnMenuItemClickListener() {
            @Override
            public boolean onMenuItemClick(MenuItem item) {
                switch (item.getItemId()) {
                case R.id.grid_to_list:

                    //Your stuff
                    break;

                }
                return false;
            }

        });
        super.onCreateOptionsMenu(menu, inflater);
    }

并在onCreateView方法中写下：

setHasOptionsMenu(true);

Answer 2

这是可能的。如果您有2个页面，请创建2个菜单资源文件res > menu。 e.g。

menu_one.xml

<menu xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    tools:context="mcrime.com.mcrime.MainActivity">



      <item
            android:id="@+id/send_icon"
            android:orderInCategory="100"
            android:icon="@drawable/ic_send_white_24dp"
            android:title="Send Report"
            app:showAsAction="always" />

    </menu>

menu_2.xml

<menu xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    tools:context="mcrime.com.mcrime.MainActivity">

    <item
        android:id="@+id/make_a_call"
        android:orderInCategory="100"
        android:icon="@drawable/ic_call_white_24dp"
        android:title="Make Call"
        app:showAsAction="always" />

</menu>

然后在您的MainActivity上：

private ToolBar toolbar; 
 @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.your_activity_name);
        toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        setUpVariables();

        getSupportActionBar().setDisplayShowHomeEnabled(true);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    }

 private void setUpVariables(){

        ViewPager viewPager = (ViewPager) findViewById(R.id.view_pager);
        SlidingTabLayout slidingTabLayout = (SlidingTabLayout) findViewById(R.id.tab_layout);

        viewPager.setAdapter(new ViewPagerAdapter(getSupportFragmentManager()));
        slidingTabLayout.setCustomTabView(R.layout.tab_view, R.id.tab_text_view);
        slidingTabLayout.setCustomTabColorizer(new SlidingTabLayout.TabColorizer() {
            @Override
            public int getIndicatorColor(int position) {
                return getResources().getColor(R.color.colorAccent) ;
            }
        });

        slidingTabLayout.setDistributeEvenly(true);
        slidingTabLayout.setViewPager(viewPager);

        viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
            @Override
            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

            }

            @Override
            public void onPageSelected(int position) {
                if(position == 0){
                    MCrime.this.setTitle("Your custom title");
                    toolbar.getMenu().clear();
                    toolbar.inflateMenu(R.menu.menu_one);
                } else if(position == 1){
                    MCrime.this.setTitle("Your custom title");
                    toolbar.getMenu().clear();
                    toolbar.inflateMenu(R.menu.menu_2);
                }
            }

            @Override
            public void onPageScrollStateChanged(int state) {

            }
        });

    }

您需要创建寻呼机适配器

 public class ViewPagerAdapter extends FragmentStatePagerAdapter {

        String [] titles = {"Title One", "Title Two", };

        public ViewPagerAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public Fragment getItem(int position) {
            Fragment fragment;
            if(position == 0){
                fragment = new FragmentOne();
                return fragment;
            }

            if(position == 1){
                fragment = new FragmentTwo();
                return fragment;
            }


            return null;
        }

        @Override
        public int getCount() {
            return 2;
        }

        @Override
        public CharSequence getPageTitle(int position) {
            return titles[position];
        }
    }

不同的菜单图标在viewpager的不同页面

2 个答案: