Android:以编程方式使用片段

Question

由于某些原因,我不能使用xml布局文件.

但我需要创建一个平板电脑Android应用程序.

我决定使用碎片.

我想创建此xml生成的相同布局:

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal"
    android:layout_width="fill_parent" android:layout_height="fill_parent">

    <fragment class="com.example.ItemsList"
            android:id="@+id/items_list" android:layout_weight="1"
            android:layout_width="0dp" android:layout_height="fill_parent" />

    <FrameLayout android:id="@+id/item_details" android:layout_weight="1"
            android:layout_width="0dp" android:layout_height="fill_parent"
            android:background="?android:attr/detailsElementBackground" />

</LinearLayout>

但我在向linearLayout添加片段时遇到问题:

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(createUI());
    }

    private View createUI() {
        LinearLayout layout = new LinearLayout(this);

        layout.setOrientation(LinearLayout.HORIZONTAL);
        layout.setLayoutParams(new LinearLayout.LayoutParams(AbsListView.LayoutParams.FILL_PARENT, AbsListView.LayoutParams.FILL_PARENT));
        layout.setId(0x101);
        {
            FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();
            fragmentTransaction.add(0x101, new ItemsList());
            fragmentTransaction.add(0x101, new ItemDetails());
            fragmentTransaction.commit();
        }
        return layout;
    }

实际上我甚至无法使用两个相同的片段创建LinearLayout:

            ...
            fragmentTransaction.add(0x101, new ItemsList());
            fragmentTransaction.add(0x101, new ItemsList());
            ...

请帮忙

顺便说一句我无法弄清楚为什么我们需要为itemDetails片段声明"FrameLayout",但"fragment"对于itemsList ListFragment来说已经足够了？

UPD:

为此,我们应该添加第三个参数:

            ...
            fragmentTransaction.add(0x101, new ItemsList(), "uniqueTag1");
            fragmentTransaction.add(0x101, new ItemsList(), "uniqueTag2");
            ...

tag参数的默认值为null,因此我尝试使用相同的id创建两个不同的元素.感谢p-lo的评论.

Answer 1

我找到了解决方案.

(更好的方法被添加到问题中.谢谢,p-lo)

如果要在活动上放置多个片段,则应为每个片段创建布局:

    private View createUI() {
        LinearLayout layout = new LinearLayout(this);

        layout.setOrientation(LinearLayout.HORIZONTAL);
        layout.setLayoutParams(new LinearLayout.LayoutParams(AbsListView.LayoutParams.FILL_PARENT, AbsListView.LayoutParams.FILL_PARENT));


        LinearLayout innerLayout1 = new LinearLayout(this);
        innerLayout1.setLayoutParams(new LinearLayout.LayoutParams(300, ViewGroup.LayoutParams.FILL_PARENT));
        innerLayout1.setId(ITEMS_LIST_ID);
        {
            FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();
            fragmentTransaction.add(ITEMS_LIST_ID, new ItemsList());
            fragmentTransaction.commit();
        }
        layout.addView(innerLayout1);

        LinearLayout innerLayout2 = new LinearLayout(this);
        innerLayout2.setLayoutParams(new LinearLayout.LayoutParams(300, ViewGroup.LayoutParams.FILL_PARENT));
        innerLayout2.setId(ITEM_DETAILS_ID);
        {
            FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();
            fragmentTransaction.add(ITEM_DETAILS_ID, new ItemDetails());
            fragmentTransaction.commit();
        }
        layout.addView(innerLayout2);

        return layout;


    }