如何设置默认主页片段

Question

我的导航抽屉菜单有替换内容框架，但我不知道如何设置默认的主页片段。

这是我的代码

    @Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    menu = getResources().getStringArray(R.array.menu);
    dLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
    dList = (ListView) findViewById(R.id.left_drawer);
    adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, menu);
    dList.setAdapter(adapter);
    dList.setSelector(R.color.pick);
    dList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> arg0, View v, int position, long id) {
            dLayout.closeDrawers();
            Bundle args = new Bundle();
            args.putString("Menu", menu[position]);
            Fragment detail = null;
            FragmentManager FM = getFragmentManager();
            switch (position) {
                case 0:
                    detail = new HomeFragment();
                    break;
                case 1:
                    detail = new DataBase();
                    break;
                case 2:
                    detail = new MappingFragment();
                    break;
                case 3:
                    detail = new HelpFragment();
                    break;
                default:
                    break;
            }
            FM.beginTransaction().replace(R.id.content_frame, detail).commit();
        }
    });
}

我想将HomeFragment设置为默认选择/主页

Answer 1

default:
    detail = new HomeFragment();
    break;

如果没有其他情况适用，则选择默认情况

Answer 2

谢谢你的回答，问题解决了。

    @Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    menu = getResources().getStringArray(R.array.menu);
    dLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
    dList = (ListView) findViewById(R.id.left_drawer);
    adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, menu);

    Fragment home = new HomeFragment();
    FragmentManager FM = getFragmentManager();
    FM
        .beginTransaction()
        .replace(R.id.content_frame, home)
        .commit();

    dList.setAdapter(adapter);
    dList.setSelector(R.color.pick);
    dList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> arg0, View v, int position, long id) {
            dLayout.closeDrawers();
            Bundle args = new Bundle();
            args.putString("Menu", menu[position]);
            Fragment detail = null;
            FragmentManager FM = getFragmentManager();
            switch (position) {
                case 0:
                    detail = new HomeFragment();
                    break;
                case 1:
                    detail = new DataBase();
                    break;
                case 2:
                    detail = new MappingFragment();
                    break;
                case 3:
                    detail = new HelpFragment();
                    break;
                default:
                    break;
            }
            FM.beginTransaction().replace(R.id.content_frame, detail).commit();
        }
    });
}

Answer 3

在主活动的onCreate方法中添加以下代码：

getFragmentManager().beginTrasaction().replace(r.id.frame_layout, new HomeFragment()).commit();

Answer 4

在导航抽屉中，更好的解决方案是在onCreate方法中添加以下代码：

if (savedInstanceState == null) {
    getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,
            new FRAGMENT_CLASS_NAME_HERE()).commit();
    navigationView.setCheckedItem(R.id.DRAWE_NAV_ITEM_ID_HERE);
}

这比许多其他选项简单得多，并且还选择了导航菜单项。