android:GridView行重叠：如何使行高適合最高專案？

我使用靜態陣列来驅動最大高度 行.這是不完美的，因為在重新顯示该單元格之前，不会調整前几列的大小.這是膨脹的可重用內容视圖的代碼。

Edit ：我正確地完成了這項工作，但是在渲染之前我已经預先測量了所有單元格.我是通過子類化GridView並在onLayout方法中添加一个測量钩子来實現的。

/**
 * Custom view group that shares a common max height
 * @author Chase Colburn
 */
public class GridViewItemLayout extends LinearLayout {
    // Array of max cell heights for each row
    private static int[] mMaxRowHeight;
    // The number of columns in the grid view
    private static int mNumColumns;
    // The position of the view cell
    private int mPosition;
    // Public constructor
    public GridViewItemLayout(Context context) {
        super(context);
    }
    // Public constructor
    public GridViewItemLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
    }
    /**
     * Set the position of the view cell
     * @param position
     */
    public void setPosition(int position) {
        mPosition = position;
    }
    /**
     * Set the number of columns and item count in order to accurately store the
     * max height for each row. This must be called whenever there is a change to the layout
     * or content data.
     * 
     * @param numColumns
     * @param itemCount
     */
    public static void initItemLayout(int numColumns, int itemCount) {
        mNumColumns = numColumns;
        mMaxRowHeight = new int[itemCount];
    }
    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        // Do not calculate max height if column count is only one
        if(mNumColumns <= 1 || mMaxRowHeight == null) {
            return;
        }
        // Get the current view cell index for the grid row
        int rowIndex = mPosition / mNumColumns;
        // Get the measured height for this layout
        int measuredHeight = getMeasuredHeight();
        // If the current height is larger than previous measurements, update the array
        if(measuredHeight > mMaxRowHeight[rowIndex]) {
            mMaxRowHeight[rowIndex] = measuredHeight;
        }
        // Update the dimensions of the layout to reflect the max height
        setMeasuredDimension(getMeasuredWidth(), mMaxRowHeight[rowIndex]);
    }
}

這是我的BaseAdapter子類中的測量功能.請註意，我有一个方法 updateItemDisplay 在视圖單元格上設置所有適当的文字和圖像。

   /**
     * Run a pass through each item and force a measure to determine the max height for each row
     */
    public void measureItems(int columnWidth) {
        // Obtain system inflater
        LayoutInflater inflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        // Inflate temp layout object for measuring
        GridViewItemLayout itemView = (GridViewItemLayout)inflater.inflate(R.layout.list_confirm_item, null);
        // Create measuring specs
        int widthMeasureSpec = MeasureSpec.makeMeasureSpec(columnWidth, MeasureSpec.EXACTLY);
        int heightMeasureSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
        // Loop through each data object
        for(int index = 0; index < mItems.size(); index++) {
            String[] item = mItems.get(index);
            // Set position and data
            itemView.setPosition(index);
            itemView.updateItemDisplay(item, mLanguage);
            // Force measuring
            itemView.requestLayout();
            itemView.measure(widthMeasureSpec, heightMeasureSpec);
        }
    }

最後，這是GridView子類，用於在佈局期間測量视圖單元：

/**
 * Custom subclass of grid view to measure all view cells
 * in order to determine the max height of the row
 * 
 * @author Chase Colburn
 */
public class AutoMeasureGridView extends GridView {
    public AutoMeasureGridView(Context context) {
        super(context);
    }
    public AutoMeasureGridView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }
    public AutoMeasureGridView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }
    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        if(changed) {
            CustomAdapter adapter = (CustomAdapter)getAdapter();
            int numColumns = getContext().getResources().getInteger(R.integer.list_num_columns);
            GridViewItemLayout.initItemLayout(numColumns, adapter.getCount());
            if(numColumns > 1) {
                int columnWidth = getMeasuredWidth() / numColumns;
                adapter.measureItems(columnWidth);
            }
        }
        super.onLayout(changed, l, t, r, b);
    }
}

我將列數作為資源的原因是，以便可以根据方向等获得不同的列數。

基於Chris的資訊，我使用了此變通方法 確定其他GridView項的高度時，本機GridView使用的引用视圖的大小。

我建立了這个GridViewItemContainer自定義類：

/**
 * This class makes sure that all items in a GridView row are of the same height.
 * (Could extend FrameLayout, LinearLayout etc as well, RelativeLayout was just my choice here)
 * @author Anton Spaans
 *
*/
public class GridViewItemContainer extends RelativeLayout {
private View[] viewsInRow;
public GridViewItemContainer(Context context) {
    super(context);
}
public GridViewItemContainer(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
}
public GridViewItemContainer(Context context, AttributeSet attrs) {
    super(context, attrs);
}
public void setViewsInRow(View[] viewsInRow) {
    if  (viewsInRow != null) {
        if (this.viewsInRow == null) {
            this.viewsInRow = Arrays.copyOf(viewsInRow, viewsInRow.length);
        }
        else {
            System.arraycopy(viewsInRow, 0, this.viewsInRow, 0, viewsInRow.length);
        }
    }
    else if (this.viewsInRow != null){
        Arrays.fill(this.viewsInRow, null);
    }
}
@Override
protected LayoutParams generateDefaultLayoutParams() {
    return new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    if (viewsInRow == null) {
        return;
    }
    int measuredHeight = getMeasuredHeight();
    int maxHeight      = measuredHeight;
    for (View siblingInRow : viewsInRow) {
        if  (siblingInRow != null) {
            maxHeight = Math.max(maxHeight, siblingInRow.getMeasuredHeight());
        }
    }
    if (maxHeight == measuredHeight) {
        return;
    }
    int heightMode = MeasureSpec.getMode(heightMeasureSpec);
    int heightSize = MeasureSpec.getSize(heightMeasureSpec);
    switch(heightMode) {
    case MeasureSpec.AT_MOST:
        heightMeasureSpec = MeasureSpec.makeMeasureSpec(Math.min(maxHeight, heightSize), MeasureSpec.EXACTLY);
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        break;
    case MeasureSpec.EXACTLY:
        // No debate here. Final measuring already took place. That's it.
        break;
    case MeasureSpec.UNSPECIFIED:
        heightMeasureSpec = MeasureSpec.makeMeasureSpec(maxHeight, MeasureSpec.EXACTLY);
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        break;
    }
}

在適配器的getView方法中，將convertView作為子級包裝在新的GridViewItemContainer中，或使其成為專案佈局的頂部XML元素：

       // convertView has been just been inflated or came from getView parameter.
        if (!(convertView instanceof GridViewItemContainer)) {
            ViewGroup container = new GridViewItemContainer(inflater.getContext());
            // If you have tags, move them to the new top element. E.g.:
            container.setTag(convertView.getTag());
            convertView.setTag(null);
            container.addView(convertView);
            convertView = container;
        }
        ...
        ...
        viewsInRow[position % numColumns] = convertView;
        GridViewItemContainer referenceView = (GridViewItemContainer)convertView;
        if ((position % numColumns == (numColumns-1)) || (position == getCount()-1)) {
            referenceView.setViewsInRow(viewsInRow);
        }
        else {
            referenceView.setViewsInRow(null);
        }

其中numColumns是GridView中的列數，" viewsInRow"是"位置"所在当前行的View列表。

我做了很多研究，但發現不完整 答案或很难理解解決方案的內容，但最终找到了一个正確解釋的答案。

我的問题是正確地將gridview專案調整為高度.這个 Grid-view 当您所有视圖的高度相同時，效果很好.但是，当您的视圖具有不同的高度時，網格將無法達到預期的效果.视圖將彼此重叠，从而匯致 an-aesthetically 令人愉悦的網格。

在此解決方案中，我在XML佈局中使用了此類。

我使用了此解決方案，並且效果很好，非常感谢。--Abhishek Mittal

如果將GridView或ListView轉換為RecyclerView，則不会發生此問题.而且，您無需建立自定義的GridView類。

為GridView賦予權重也可以作為子元素在LinearLayouts內的GridView上使用.這樣，GridView会將子項填充到视口中，因此只要它们適合螢幕，您就可以查看它的項（然後滚動）。

但始终避免在ScrollViews中使用GridViews.否則，您將需要計算每个child的身高，並將其重新分配為上面的蔡斯答案。

<GridView
    android:id="@+id/gvFriends"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_weight="1"
    android:verticalSpacing="5dp"
    android:horizontalSpacing="5dp"
    android:clipChildren="false"
    android:listSelector="@android:color/transparent"
    android:scrollbarAlwaysDrawHorizontalTrack="false"
    android:scrollbarAlwaysDrawVerticalTrack="false"
    android:stretchMode="columnWidth"
    android:scrollbars="none"
    android:numColumns="4"/>