Question

我使用BackStack存储片段，它工作正常。但是，当我想从BackStack中删除片段时，没有任何反应。我检查了一些像this这样的问题，看到他们确实通过像我一样使用popBackStack从BackStack中删除了一个项目，但它对我不起作用。

这是我的代码：

        String previousTag = getSupportFragmentManager().getBackStackEntryAt(getSupportFragmentManager().getBackStackEntryCount() - 1).getName();
        Fragment previousInstance = getSupportFragmentManager().findFragmentByTag(previousTag);

        fragmentTransaction.replace(R.id.container_body, previousInstance,previousTag);
        fragmentTransaction.commit();

currentInstance正确显示最顶层的片段。有趣的是count和count1是等于，并且使用popBackStack命令后堆栈中最顶层的项目仍然存在。所以我无法从堆栈中删除最顶层的片段。

如果使用此代码：

<head>
 <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
</head>

<script>

    function IsValidTest(Control) {

        name = Control.name;

        var list = document.getElementById("TxtEmpcode");

        var contents = $("[id=TxtEmpcode]");

        var TextboxId = name;

        var Txtbox = document.getElementsByName(name);
        var TextboxValue = Txtbox[0].value;

        for (i = 0; i < contents.length; i++) 
        { 

            var currenttextboxName=contents[i].name;
            var currenttextboxValue=contents[i].value;


            //Compare currently changed value with existing values in other textboxes
            if (name != currenttextboxName && currenttextboxValue == TextboxValue)
            {
                alert('Employee Code has already been entered');
                Txtbox[0].value = '';

                return false;
            }        
        }

        return true;
    }

</script>

    <div>
        <asp:GridView ID="GridView2" runat="server" Style="margin-left: 23px; margin-top: 11px;"
            Width="420px" CellPadding="4" AutoGenerateColumns="False" ForeColor="#333333"
            GridLines="None" Height="213px">
            <AlternatingRowStyle BackColor="White" />
            <Columns>
                <asp:TemplateField HeaderText="Employee Code">
                    <ItemTemplate>
                        <asp:TextBox ID="TxtEmpcode" runat="server"  AutoPostBack="true" ClientIDMode="Static" onchange="javascript: return IsValidTest(this);"></asp:TextBox>
                    </ItemTemplate>
                </asp:TemplateField>
            </Columns>
        </asp:GridView>        

    </div>
</asp:Content>

我可以用前一个替换片段，但这不是正确的方法，因为我无法回复多个片段。

Answer 1

我发现了：popBackStack方法在调用后不会立即弹出。所以在我必须使用popBackStackImmediate方法而不是popBackStack。这是我最后更正的代码：

FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
if (getSupportFragmentManager().getBackStackEntryCount()> 0) {
   fragmentManager.popBackStackImmediate(getSupportFragmentManager().getBackStackEntryCount() - 1, FragmentManager.POP_BACK_STACK_INCLUSIVE);

   String previousTag = getSupportFragmentManager().getBackStackEntryAt(getSupportFragmentManager().getBackStackEntryCount() - 1).getName();
   Fragment previousInstance = getSupportFragmentManager().findFragmentByTag(previousTag);

  fragmentTransaction.replace(R.id.container_body, previousInstance, previousTag);
  fragmentTransaction.commit();
}

片段未从BackStack中删除

1 个答案: