Question

我的应用程序中有两项活动：

MainActivity（包含3个片段）

FragmentHome
FragmentOrders
FragmentAccount

AccountEditActivity

在MainActivity中设置片段的代码是：

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

    BottomNavigationView navigation = (BottomNavigationView) findViewById(R.id.navigation);
    navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener);

    // set Home as the default fragment
    setFragment(FragmentMainHome.getInstance());
}

private void setFragment(Fragment fragment){
    FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
    transaction.replace(R.id.frame_layout, fragment);
    transaction.commit();
}

FragmentAccount的代码为：

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    rootView = inflater.inflate(R.layout.fragment_activity_main_account, container, false);
    layout = rootView.findViewById(R.id.layout_fragment_main_account);

    etName = (EditText) layout.findViewById(R.id.etNameLabelValue);
    etEmail = (EditText) layout.findViewById(R.id.etEmailLabelValue);
    etGender = (EditText) layout.findViewById(R.id.etGenderLabelValue);
    etPhoneNumber = (EditText) layout.findViewById(R.id.etPhoneNumberLabelValue);

    btnEditAccount = (ImageButton) layout.findViewById(R.id.btnEditAccount);
    btnManageAddresses = (ImageButton) layout.findViewById(R.id.btnAccountManageAddresses);

    btnManageAddresses.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
        }
    });

    btnEditAccount.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
        }
    });

    return rootView;
}

FragmentOrders的代码为：

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    rootView = inflater.inflate(R.layout.fragment_activity_main_order_history, container, false);
    layout = rootView.findViewById(R.id.layout_fragment_main_order_history);

    lvOrders = (ListView) layout.findViewById(R.id.lvOrders);
    tvNoOrdersFound = (TextView) layout.findViewById(R.id.tvNoOrdersFound);

    final SwipeRefreshLayout pullToRefresh = rootView.findViewById(R.id.swipe_refresh_layout_order_history);
    pullToRefresh.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
        @Override
        public void onRefresh() {
            // load orders
            pullToRefresh.setRefreshing(false);
        }
    });

    lvOrders.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view,
                                int position, long id) {
        }
    });

    return rootView;
}

和类似的代码用于FragmentHome

问题

我可以在片段之间移动，并且视图可以正常工作。现在从“帐户”片段中，转到“ AccountEditActivity” 我在那里进行了一些更新，然后通过按硬件后退按钮返回到MainActivity

FragmentHome正常显示，但是当我单击FragmentAccount时，屏幕变为空白

现在，如果我单击“主页”片段，然后再次单击“ FragmentAccount”，它将显示正常。

这是怎么了？

Answer 1

在活动中更好地使用viewpager来显示片段使用Viewpagers时很容易管理

看看链接 Fragments in viewpager

，您只需将这段代码从onCreate移到onResume

setFragment(FragmentMainHome.getInstance());

为了更好地理解，请查看android中活动的生命周期

Activity life cycle

从另一个活动返回时，片段变为空白

1 个答案: