在我们的应用程序中,我们试图动态地向gridlayout添加片段。空网格布局是用XML定义的,就像片段的布局一样。在运行时,我们检查一些数据,并根据这些数据确定要添加到布局的片段数以及要为每个片段使用的布局。当我们让片段为它生成的视图分配一个大小时,它都可以工作,但是如果我们在布局文件中为片段指定大小,网格布局中就不会显示任何内容。显然,我们可以在创建视图时简单地指定大小,但我们更愿意在片段的xml布局中这样做,因为这将允许我们利用android的内置系统为每个设备选择正确的布局。
我正在使用支持库片段。我不使用支持库gridlayout,如果这有区别的话
相关代码和XML如下:
GridLayout XML:

<?xml version="1.0" encoding="utf-8"?>
<merge xmlns:android="http://schemas.android.com/apk/res/android">
    <ScrollView
        android:id="@+id/grid_scroll"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_above="@+id/bottom_fragment"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginRight="8dp"
        android:layout_marginTop="?android:attr/actionBarSize"
        android:overScrollMode="ifContentScrolls" >

        <GridLayout
            android:id="@+id/grid"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:alignmentMode="alignMargins"
            android:animateLayoutChanges="true"
            android:columnCount="3"
            android:columnOrderPreserved="true"
            android:orientation="horizontal"
            android:overScrollMode="ifContentScrolls"
            android:rowOrderPreserved="true" >
        </GridLayout>
    </ScrollView>
</merge>

片段xml的一个示例
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="200dp"
    android:layout_height="100dp"
    android:alpha="1" >

    <Button
        android:id="@+id/button1"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:alpha="1.0" />
</RelativeLayout>

fragment oncreateview()方法
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    super.onCreateView(inflater, container, savedInstanceState);
    View view;
    GridLayout.Spec rowSpec = GridLayout.spec(mRowStart, mRowSpan);
    GridLayout.Spec columnSpec;
    GridLayout.LayoutParams childParams;
    if (large) {;
        view = inflater.inflate(R.layout.my_place_large, container, false);
        columnSpec = GridLayout.spec(mColumnStart, 2);
        childParams = new GridLayout.LayoutParams(rowSpec, columnSpec);
        //childParams.width = 200; //If I do this everything works regardless of the layout size
    } else {
        view = inflater.inflate(R.layout.my_place_small, container, false);
        columnSpec = GridLayout.spec(mColumnStart, 1);
        childParams = new GridLayout.LayoutParams(rowSpec, columnSpec);
        //childParams.width = 100; //If I do this everything works regardless of the layout size
    }
    childParams.setMargins(0, 0, 0, 0);
    //childParams.height = 100; //If I do this everything works regardless of the layout size
    view.setLayoutParams(childParams);
    view.setId(ID);
    return view;
}

向布局添加片段
private void populateGrid() {
    RelativeLayout gridParent = (RelativeLayout) mParentActivity.findViewById(R.id.locations);
    mLocationsGrid = (GridLayout) gridParent.findViewById(R.id.grid);
    nColumns = mLocationsGrid.getColumnCount();
    mAdapter = new MyAdapter(mContext, this, mResolver); //This is how I keep track of the various fragments depending on my app's state
    int nCards = mAdapter.getNumberOfCards();
    FragmentManager fragmentManager = mParentActivity.getSupportFragmentManager();
    FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
    for (int i = 0; i < nCards; ++i) {
        fragmentTransaction.add(mLocationsGrid.getId(), mAdapter.getFragmentAtIndex(i), String.valueOf(i));
    }
    fragmentTransaction.commit();
    mPopulated = true;
}

我想这应该可以弥补。只是重申一下,如果我取消注释在oncreateview()中显式设置维度的行,它们将正确显示在gridlayout中,这样我就知道跟踪片段的所有内容,以及片段事务。当我试图在片段的xml中指定大小时,问题就来了,在这种情况下,我会得到一个空白屏幕。
感谢您的想法、建议和思考。
谢谢,
贾里德

最佳答案

这来得很晚,但在不太可能的情况下,这可能仍然有用。问题是,当动态设置新的layoutparams时,您正在重写xml布局参数。也就是说,当你这样做的时候:

 view.setLayoutParams(childParams);

这将删除xmls的原始高度和宽度设置。仅仅因为代码中的childparams width/height为空并不意味着没有设置值。在gridlayout的情况下,它们被设置为undefined
修复方法是首先保存视图的现有layoutparam的高度/宽度,并在动态创建新的layoutparam时使用它。例子:
if (large) {;
    view = inflater.inflate(R.layout.my_place_large, container, false);
    ViewGroup.LayoutParams oldParams = view.getLayoutParams();
    columnSpec = GridLayout.spec(mColumnStart, 2);
    childParams = new GridLayout.LayoutParams(rowSpec, columnSpec);
    childParams.width = oldParams.width;
}

这将允许您在应用代码中的行/列规格时,将宽度/高度保持为XML格式。

07-24 09:50
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