Question

我正在使用listview来增加导航菜单。我在遇到上述错误时主要活动启动。我正在共享适配器和主要活动的代码。

@BindView(R.id.drawer_layout) DrawerLayout drawerLayout;
//NavigationView navigationView;
@BindView(R.id.toolbar) Toolbar toolbar;
@BindView(R.id.lv_drawer) ListView listView;
@BindView(R.id.dr_profile) ImageButton profileButton;
@BindView(R.id.dr_schedule) ImageButton scheduleButton;
@BindView(R.id.live) ImageButton liveButton;
@BindView(R.id.dr_message) ImageButton messageButton;
@BindView(R.id.dr_logout) ImageButton logoutButton;

private ActionBar actionBar;

ArrayList<String> nav_items;

int[] icons = {R.drawable.time, R.drawable.appointment_history, R.drawable.live_appointment, R.drawable.medicine_reminder,
        R.drawable.video, R.drawable.blog, R.drawable.faq, R.drawable.live_appointment};
DrDrawerListAdapter listAdapter;
ActionBarDrawerToggle toggle;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.dr_main);
    ButterKnife.bind(this);

    setSupportActionBar(toolbar);
    actionBar = getSupportActionBar();
    actionBar.setBackgroundDrawable(new ColorDrawable(getResources().getColor(R.color.app_bar_color)));
    actionBar.setDisplayHomeAsUpEnabled(true);
    actionBar.setHomeAsUpIndicator(R.drawable.menu);

    FragmentManager fm = getSupportFragmentManager();
    FragmentTransaction ft = fm.beginTransaction();
    ft.replace(R.id.frame_main, new DashboardFragment());
    ft.commit();

    setDrawer();
    init();
    initClickListener();
}

private void setDrawer(){
    if (toggle == null){
        toggle = new ActionBarDrawerToggle(DrMainActivity.this,drawerLayout,R.string.open, R.string.close){
            @Override
            public void onDrawerOpened(View drawerView) {
                super.onDrawerOpened(drawerView);
            }

            @Override
            public void onDrawerClosed(View drawerView) {
                super.onDrawerClosed(drawerView);
            }

            @Override
            public void onDrawerSlide(View drawerView, float slideOffset) {
                super.onDrawerSlide(drawerView, slideOffset);
            }

            @Override
            public void onDrawerStateChanged(int newState) {
                super.onDrawerStateChanged(newState);
            }
        };
        drawerLayout.addDrawerListener(toggle);

    }
    toggle.syncState();
    listAdapter = new DrDrawerListAdapter(DrMainActivity.this, nav_items, icons);
    listView.setAdapter(listAdapter);
    listView.setOnItemClickListener(new DrDrawerItemClickListener());

}

@Override
public void onClick(View v) {
    switch (v.getId()){
        case R.id.live:
            setLiveQueue();
            break;
        case R.id.dr_profile:
            setProfile();
            break;
        case R.id.dr_schedule:
            setSchedule();
            break;
        case R.id.dr_message:
            setMessage();
            break;
        case R.id.dr_logout:
            setLogout();
            break;
    }

}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    if (toggle.onOptionsItemSelected(item)){
        return true;
    }switch (item.getItemId()){
        default:
            return super.onOptionsItemSelected(item);
    }
}

private class DrDrawerItemClickListener implements ListView.OnItemClickListener{
    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
       selectItem(position);
    }

    private void selectItem(int position){
        switch (position){
            case 0:
                setDashBoard();
                drawerLayout.closeDrawers();
                break;
            case 1:
                setAppointment();
                drawerLayout.closeDrawers();
                break;
            case 2:
                setLiveQueue();
                drawerLayout.closeDrawers();
                break;
            case 3:
                setMessage();
                drawerLayout.closeDrawers();
                break;
            case 4:
                setVideos();
                drawerLayout.closeDrawers();
                break;
            case 5:
                setBlog();
                drawerLayout.closeDrawers();
                break;
        }
    }
}

private void initClickListener(){
    profileButton.setOnClickListener(this);
    scheduleButton.setOnClickListener(this);
    liveButton.setOnClickListener(this);
    messageButton.setOnClickListener(this);
    logoutButton.setOnClickListener(this);
}

private void init(){
    nav_items = new ArrayList<>();
    nav_items.add("My Account");
    nav_items.add("Search");
    nav_items.add("Live Appointmet");
    nav_items.add("My Appointments");
    nav_items.add("Upgrade to Premium");
    nav_items.add("FAQ");
    nav_items.add("Vedios");
    nav_items.add("Blog");
    //icons = getResources().getIntArray(R.array.dr_drawer_icons);

}

private void setDashBoard(){
    FragmentManager fm = getSupportFragmentManager();
    FragmentTransaction ft = fm.beginTransaction();
    ft.replace(R.id.frame_main, new DashboardFragment());
    ft.addToBackStack(null);
    ft.commit();
}

private void setAppointment(){}

private void setProfile(){
    FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
    ft.replace(R.id.frame_main, new DrProfileFragment());
    ft.addToBackStack(null);
    ft.commit();
}

private void setLiveQueue(){
    FragmentManager fm = getSupportFragmentManager();
    FragmentTransaction ft = fm.beginTransaction();
    ft.replace(R.id.frame_main, new DrLiveQueueFragment());
    ft.addToBackStack(null);
    ft.commit();
}

private void setVideos(){}

private void setMessage(){
    FragmentManager fm = getSupportFragmentManager();
    FragmentTransaction ft = fm.beginTransaction();
    ft.replace(R.id.frame_main, new DrMessageFragment());
    ft.addToBackStack(null);
    ft.commit();
}

private void setLogout(){
    FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
    ft.replace(R.id.frame_main, new DrLogoutFragment());
    ft.addToBackStack(null);
    ft.commit();
}

private void setBlog(){}

private void setFaq(){}

private void setContactUs(){}


private void setSchedule() {
    FragmentManager fm = getSupportFragmentManager();
    FragmentTransaction ft = fm.beginTransaction();
    ft.replace(R.id.frame_main, new DrScheduleFragment());
    ft.addToBackStack(null);
    ft.commit();
}

} ***这是我的mainactivity文件包com.example.azim.qphew.Dr.view.uiactivity;

导入butterknife.BindView; 进口黄油刀。黄油刀;

公共类DrMainActivity扩展了AppCompatActivity实现的View.OnClickListener { 私有静态最终字符串TAG = DrMainActivity.class.getSimpleName（）;

<item>
<guid isPermaLink="false">1006943</guid>
<title>
<![CDATA[
अब 'उड़ें जब-जब जुल्फें तेरी...' पर इस बुजुर्ग कपल का डांस देखिए
]]>
</title>
<pubDate>2018-06-02 12:04:32</pubDate>
<category>
<![CDATA[ viral_news ]]>
</category>
<enclosure url="http://akamaized.net/video/2018_06/02_jun_18_jodey_ka_dance_1024_996.mp4" type="video/mp4"/>
<media:content url="http://akamaized.net/video/2018_06/02_jun_18_buzurg_ka_dance_1024_996.mp4" type="video/mp4" duration="42">
    <media:category>viral_news</media:category>
    <media:tags>
    <![CDATA[
    Old couple dance video, Old couple dance viral, Ude ude jab jab zulfen teri song dance 
    ]]>
    </media:tags>
    <media:keywords>
    <![CDATA[
    Old couple dance video, Old couple dance viral, Ude ude jab jab zulfen teri song dance 
    ]]>
    </media:keywords>
    <media:thumbnail url="http://media2.intoday.in/aajtak/images/stories/062018/video_1024_1527921114_749x421.jpeg"/>
</media:content>
</item>

}

Answer 1

您应该在调用setDrawer方法之前初始化数组

使用setDrawer更改init（）订单行

 @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.dr_main);
    ButterKnife.bind(this);

    setSupportActionBar(toolbar);
    actionBar = getSupportActionBar();
    actionBar.setBackgroundDrawable(new  ColorDrawable(getResources().getColor(R.color.app_bar_color)));
    actionBar.setDisplayHomeAsUpEnabled(true);
    actionBar.setHomeAsUpIndicator(R.drawable.menu);

    FragmentManager fm = getSupportFragmentManager();
    FragmentTransaction ft = fm.beginTransaction();
    ft.replace(R.id.frame_main, new DashboardFragment());
    ft.commit();

    init();
    setDrawer();

    initClickListener();
}

Answer 2

Call init() before setDrawer method.Before initialising the arraylist you are setting adapter with null 
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.dr_main);
    ButterKnife.bind(this);

    setSupportActionBar(toolbar);
    actionBar = getSupportActionBar();
    actionBar.setBackgroundDrawable(new 
    ColorDrawable(getResources().getColor(R.color.app_bar_color)));
    actionBar.setDisplayHomeAsUpEnabled(true);
    actionBar.setHomeAsUpIndicator(R.drawable.menu);

    FragmentManager fm = getSupportFragmentManager();
    FragmentTransaction ft = fm.beginTransaction();
    ft.replace(R.id.frame_main, new DashboardFragment());
    ft.commit();
    init();

    setDrawer();
    initClickListener();

我在适配器中得到空指针异常

2 个答案: