Question

我试图在GridView中显示一个动态增长的字符串列表，其中包含一个复选框，GridView本身位于TableLayout中。

我可以连续显示这些“已选中”的字符串。当我让用户在GridView中动态添加新字符串时，就会出现问题。

我创建了一个接收字符串列表的自定义适配器。假设我们有n个字符串。适配器为项目计数返回'n + 1';在getView中，它返回：

具有LinearLayout的视图，其本身具有CheckBox和前n个项目的EditText，
带有简单按钮的LinearLayout，第n + 1个项目带有'+'标题。

到目前为止一切顺利。单击“+”按钮时，我将一个空字符串添加到字符串列表中，并在适配器中调用notifyDataSetChanged。

GridView重绘了一个项目。但它保持原始高度并创建一个垂直滚动条。我希望GridView扩展它的高度（即在屏幕上占用更多空间并显示所有项目）。

我尝试将屏幕更改为垂直LinearLayout而不是TableLayout，但结果是一样的。

以下是我的屏幕布局：

<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:scrollbars="none">
<LinearLayout
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    >

    <!-- other lines omitted -->

    <LinearLayout android:layout_width="fill_parent" 
                  android:layout_height="wrap_content" >
        <TextView
            android:layout_width="wrap_content" 
            android:layout_height="wrap_content"
            android:text="@string/wine_rack_explanation"
            android:layout_gravity="center_vertical" />
          <GridView
            android:layout_width="fill_parent" 
            android:layout_height="wrap_content"
            android:id="@+id/gvRack"
            android:columnWidth="90dp"    
            android:numColumns="auto_fit" />
    </LinearLayout>

<!-- other lines omitted -->

</LinearLayout>
</ScrollView>

适配器中的复选框+字符串项定义如下：

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

  android:layout_width="wrap_content"
  android:layout_height="wrap_content">
    <CheckBox android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:id="@+id/cbCoordinate"
              android:checked="true"
              />
    <EditText android:id="@+id/txtCoordinate"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content" />
</LinearLayout>

'+'按钮项的定义如下：

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

    <Button android:id="@+id/btnAddBottle"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/add_bottle_caption" />
</LinearLayout>

我在添加项目后尝试在GridView上调用invalidate或invalideViews。在TableLayout和TableRow上也称为invalidate（在屏幕的先前布局中）。没有成功。

任何想法为什么GridView拒绝扩展它的高度？

（请注意，我完全可以使用除GridView之外的其他视图组）

Answer 1

使用此代码

public class MyGridView  extends GridView {

    public MyGridView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public MyGridView(Context context) {
        super(context);
    }

    public MyGridView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    @Override
    public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        int expandSpec = MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE >> 2,
                MeasureSpec.AT_MOST);
        super.onMeasure(widthMeasureSpec, expandSpec);
    }
}

Answer 2

我这样做了：

此代码会根据儿童的数字设置GridView高度。

注意：其中5是列数。

private void setDynamicHeight(GridView gridView) {
        ListAdapter gridViewAdapter = gridView.getAdapter();
        if (gridViewAdapter == null) {
            // pre-condition
            return;
        }

        int totalHeight = 0;
        int items = gridViewAdapter.getCount();
        int rows = 0;

        View listItem = gridViewAdapter.getView(0, null, gridView);
        listItem.measure(0, 0);
        totalHeight = listItem.getMeasuredHeight();

        float x = 1;
        if( items > 5 ){
            x = items/5;
            rows = (int) (x + 1);
            totalHeight *= rows;
        }

        ViewGroup.LayoutParams params = gridView.getLayoutParams();
        params.height = totalHeight;
        gridView.setLayoutParams(params);
    }

希望这会对你有所帮助。

Answer 3

当为GridView调用onMeasure（）时，如果heightMode是MeasureSpec.UNSPECIFIED，则gridview将与所有包含的元素一样高（加上一些填充）。

为了确保这种情况，您可以创建一个快速自定义视图来扩展GridView并包括以下覆盖：

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, MeasureSpec.UNSPECIFIED);
    }

Answer 4

这对我有用：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/root"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/background" >

        <!-- MORE LAYOUTS IF YOU WANT -->

    <ScrollView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_weight="1"
    android:fillViewport="true" >

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >

                <!-- MORE LAYOUTS IF YOU WANT -->

       <GridView
            android:id="@+id/gridview"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:layout_marginBottom="10dp"
            android:layout_marginLeft="20dp"
            android:layout_marginRight="20dp"
            android:layout_marginTop="5dp"
            android:gravity="center"
            android:horizontalSpacing="10dp"
            android:numColumns="auto_fit"
            android:stretchMode="columnWidth"
            android:verticalSpacing="10dp" >
       </GridView>

             <!-- MORE LAYOUTS IF YOU WANT -->

    </RelativeLayout>

    </ScrollView>

</RelativeLayout>

Answer 5

格雷厄姆的解决方案对我不起作用。然而，这个（更多的黑客攻击）做了：https://stackoverflow.com/a/8483078/479478

Answer 6

基于https://stackoverflow.com/users/4233197/hiren-patel的共同想法而开发，因此谢谢：）

通过此函数将GridView及其列数传递给您，

private void setGridViewHeightBasedOnChildren(GridView gridView, int noOfColumns) {
        ListAdapter gridViewAdapter = gridView.getAdapter();
        if (gridViewAdapter == null) {
            // adapter is not set yet
            return;
        }

        int totalHeight; //total height to set on grid view
        int items = gridViewAdapter.getCount(); //no. of items in the grid
        int rows; //no. of rows in grid

        View listItem = gridViewAdapter.getView(0, null, gridView);
        listItem.measure(0, 0);
        totalHeight = listItem.getMeasuredHeight();

        float x;
        if( items > noOfColumns ){
            x = items/noOfColumns;

            //Check if exact no. of rows of rows are available, if not adding 1 extra row
            if(items%noOfColumns != 0) {
                rows = (int) (x + 1);
            }else {
                rows = (int) (x);
            }
            totalHeight *= rows;

            //Adding any vertical space set on grid view
            totalHeight += gridView.getVerticalSpacing() * rows;
        }

        //Setting height on grid view
        ViewGroup.LayoutParams params = gridView.getLayoutParams();
        params.height = totalHeight;
        gridView.setLayoutParams(params);
    }

Answer 7

这对我有用

public class MyGridView extends GridView {
    public MyGridView(Context context) {
        super(context);
    }

    public MyGridView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public MyGridView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);

        // set childs height to same value as child that has highest value
        for(int i=0; i<getChildCount(); i++) {
            MyLinearLayout child = (MyLinearLayout) getChildAt(i);
            AbsListView.LayoutParams params = (AbsListView.LayoutParams) child.getLayoutParams();
            params.height = MyLinearLayout.maxHeight;
            child.setLayoutParams(params);
        }

        // calculate total height and apply to the grid
        double numRow = Math.ceil((double) getCount() / (double) getNumColumns());
        LinearLayout.LayoutParams params = (LinearLayout.LayoutParams) this.getLayoutParams();
        params.height = (int) numRow *  MyLinearLayout.maxHeight;
        this.setLayoutParams(params);

        // invalidate after change grid's height
        this.invalidate();
    }
}

MyLinearLayout类

public class MyLinearLayout extends LinearLayout {
    public static int maxHeight = 0;

    public MyLinearLayout(Context context) {
        super(context);
    }

    public MyLinearLayout(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
    }

    public MyLinearLayout(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        if (maxHeight<this.getMeasuredHeight()) maxHeight=this.getMeasuredHeight();
    }
}

GridView包含MyLinearLayout的一些子项，这就是布局

<?xml version="1.0" encoding="utf-8"?>
<com.mysystem.view.MyLinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:layout_width="100dp"
              android:layout_height="100dp"
              android:background="#ddd"
              android:padding="0.5dp"
              android:layout_gravity="top"
              android:gravity="center_horizontal"
              android:orientation="vertical">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="#fff"
        android:padding="20dp"
        android:orientation="vertical">

        <ImageView
            android:id="@+id/img_menu"
            android:layout_width="30dp"
            android:layout_gravity="center_horizontal"
            android:layout_height="30dp"
            android:layout_marginTop="5dp"/>

        <TextView
            android:id="@+id/tv_menu"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="5dp"
            android:textAlignment="center"
            android:textColor="#000"
            android:text="Title"
            android:textSize="10sp"/>

    </LinearLayout>
</com.mysystem.view.MyLinearLayout>

如何在添加项目时使GridView适应其高度

7 个答案: