Question

我正在尝试在运行时将多个网格视图添加到线性布局的滚动视图中。但只有第一行显示。请帮忙

Answer 1

您无法在Android中嵌套可滚动视图 - 即ListView，GridView，ScrollView。

您可以查看以下代码：

import android.content.Context;
import android.util.AttributeSet;
import android.view.ViewGroup;
import android.widget.GridView;

public class ScrollableGridView extends GridView {
    boolean expanded = true;

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

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

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

    public boolean isExpanded()
    {
        return expanded;
    }


    @Override
    public void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
    {
        // HACK! TAKE THAT ANDROID!
        if (isExpanded())
        {
            // Calculate entire height by providing a very large height hint.
            // But do not use the highest 2 bits of this integer; those are
            // reserved for the MeasureSpec mode.
            int expandSpec = MeasureSpec.makeMeasureSpec(
                    Integer.MAX_VALUE >> 2, MeasureSpec.AT_MOST);
            super.onMeasure(widthMeasureSpec, expandSpec);

            ViewGroup.LayoutParams params = getLayoutParams();
            params.height = getMeasuredHeight();
        }
        else
        {
            super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        }
    }

    public void setExpanded(boolean expanded)
    {
        this.expanded = expanded;
    }
}

这是一个更好的GridView版本，允许它在嵌套在ScrollView中时几乎可以工作。我说“几乎工作”，因为我发现它有时太短或太长20-30像素。您应该注意，这会阻止视图被重用，因此它比普通的GridView更重。

在我的情况下，我最终扩展了LinearLayout并使用它来将其子项与列对齐。这不是很难 - 如果你愿意，我可以给你一些例子。：）

我从this answer获得了GridView示例。

以下是基于LinearLayout的GridView示例：

import java.util.List;
import android.content.Context;
import android.content.res.TypedArray;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;

public class GridLikeLayout extends LinearLayout {
    private static final int DEFAULT_ITEMS_PER_ROW = 1;
    private final int DEFAULT_COLUMN_WIDTH = (int) TypedValue.applyDimension(
            TypedValue.COMPLEX_UNIT_DIP, 150, getContext().getResources()
                    .getDisplayMetrics());

    private int itemsPerRow = DEFAULT_ITEMS_PER_ROW;
    private List<View> innerViews = null;

    private int columnWidth;

    public GridLikeLayout(Context context, AttributeSet attrs) {
        super(context, attrs);

        TypedArray a = context.obtainStyledAttributes(attrs,
                R.styleable.GridLikeLayout);

        // itemsPerRow = a.getInt( R.styleable.GridLikeLayout_columns,
        // DEFAULT_ITEMS_PER_ROW);

        try {
            columnWidth = (int) a.getDimension(
                    R.styleable.GridLikeLayout_column_width, DEFAULT_COLUMN_WIDTH);
        } catch (UnsupportedOperationException uoe) {
            columnWidth = (int) a.getInt(
                    R.styleable.GridLikeLayout_column_width, DEFAULT_COLUMN_WIDTH);
        }

        setOrientation(LinearLayout.VERTICAL);
    }

    public GridLikeLayout(Context context) {
        super(context);
        setOrientation(LinearLayout.VERTICAL);
    }

    public void setInnerViews(List<View> innerViews) {
        this.innerViews = innerViews;
        processViews();
    }

    public List<View> getInnerViews() {
        return innerViews;
    }

    protected void processViews() {
        if (null != innerViews) {
            LinearLayout innerContainer = null;
            innerContainer = generateInnerContainer();
            int childrenCount = innerViews.size();
            for (int index = 0; index < childrenCount; ++index) {
                if (isFull(innerContainer)) {
                    addInnerContainer(innerContainer);
                    innerContainer = generateInnerContainer();
                }
                View child = innerViews.get(index);
                if (null != child.getParent()) {
                    ((ViewGroup) child.getParent()).removeView(child);
                }
                addInnerView(innerContainer, child);
            }

            addInnerContainer(innerContainer);
        }
    }

    protected boolean isFull(LinearLayout innerContainer) {
        return 0 == (innerContainer.getChildCount() % itemsPerRow)
                && 0 < innerContainer.getChildCount();
    }

    protected void addInnerView(LinearLayout innerContainer, View child) {
        int width = LayoutParams.WRAP_CONTENT;
        int height = LayoutParams.WRAP_CONTENT;
        LayoutParams innerParams = new LayoutParams(width, height);
        innerParams.weight = 1;
        innerParams.gravity = Gravity.CENTER;
        innerContainer.addView(child, innerParams);
    }

    protected void addInnerContainer(LinearLayout innerContainer) {
        LayoutParams params = generateDefaultLayoutParams();
        params.width = LayoutParams.MATCH_PARENT;
        addView(innerContainer, params);
    }

    protected LinearLayout generateInnerContainer() {
        LinearLayout innerContainer;
        innerContainer = new LinearLayout(getContext());
        innerContainer.setGravity(Gravity.CENTER);
        return innerContainer;
    }

    public void setOnInnerViewClickListener(OnClickListener listener) {
        for (View innerView : innerViews) {
            innerView.setOnClickListener(listener);
        }
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        // Sets up mListPadding
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);

        int widthMode = MeasureSpec.getMode(widthMeasureSpec);
        int widthSize = MeasureSpec.getSize(widthMeasureSpec);

        if (widthMode == MeasureSpec.UNSPECIFIED) {
            if (columnWidth > 0) {
                widthSize = columnWidth + getPaddingLeft() + getPaddingRight();
            } else {
                widthSize = getPaddingLeft() + getPaddingRight();
            }
            widthSize += getVerticalScrollbarWidth();
        }

        int childWidth = widthSize - getPaddingLeft() - getPaddingRight();
        int columnsNumber = determineColumns(childWidth);
        if (columnsNumber > 0 && columnsNumber != itemsPerRow) {
            itemsPerRow = columnsNumber;
            removeAllViews();
            processViews();
        }
    }

    protected int  determineColumns(int availableSpace) {
        int columnsNumber = itemsPerRow;
        if (0 < columnWidth) {
            columnsNumber = availableSpace / columnWidth;
        } 
        return columnsNumber;
    }

}

以下是自定义属性的资源文件：

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

    <attr name="column_width" format="dimension|integer">
        <enum name="single_column" value="-1" />
    </attr>
    <declare-styleable name="GridLikeLayout">
        <attr name="column_width" />
    </declare-styleable>

</resources>

以下是一个示例用法：

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/layoutContainer"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

    <ScrollView
        android:id="@+id/itemsScroller"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" >

        <LinearLayout
            android:id="@+id/itemsLayout"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical" >

            <your_package.view.GridLikeLayout
                xmlns:my="YOUR APPLICATION PACKAGE"
                android:id="@+id/MyGrid"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                my:column_width="260dp"
                android:focusable="true"
                android:gravity="center_horizontal"
                android:padding="5dp" >
            </your_package.GridLikeLayout>

            <View
                android:id="@+id/viewSeparator"
                android:layout_width="fill_parent"
                android:layout_height="2dp" />

            <your_package.GridLikeLayout
                xmlns:my="YOUR APPLICATION PACKAGE"
                android:id="@+id/list"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                my:column_width="single_column" >
            </your_package.GridLikeLayout>

        </LinearLayout>
    </ScrollView>

</FrameLayout>

请告诉我你是否有任何麻烦来运行这个例子 - 我现在无法尝试。所以如果你有问题，我会稍后再检查一下。不要忘记更改软件包名称 - “your_package”应该是存储GridLikeLayout的软件包，“您的应用程序包”是应用程序的软件包 - 应用程序清单中指定的软件包。：）

Answer 2

直到你把布局放在这里我才能假设你在线性布局中设置了错误的水平/垂直参数。

Answer 3

您的第一个解决方案确实有效，但没有考虑到GridViews通常意味着图像缓存，例如在我的情况下。每次我开始滚动时，你的第一个解决方案会导致OutOfMemoryError。有没有人已经有一个考虑图像缓存的示例解决方案？

如何在android java中的scrollview中添加多个gridviews？

3 个答案: