Android gridview Square元素？

Question

我想将我的 gridview 设置为具有屏幕宽度/行数平方大小的单元格。我从网上下载的图片有问题。我可以在 XML 中对其进行硬编码，并且一切正常，但是我需要每个布局尺寸的尺寸。有两种图像视图，一种是如果图像本身不是正方形，则具有背景图块。我似乎无法找到如何在代码中动态设置它。我尝试设置最小高度，并尝试设置布局以填充父级，然后在膨胀时设置图像视图的大小。从一开始它的大小就合适了，或者它失败了，看起来..

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/gridview_parent"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:paddingBottom="@dimen/element_spacing"
android:paddingTop="@dimen/element_spacing"
android:layout_centerHorizontal="true"
>


<ImageView
    android:id="@+id/gridview_adapter_background_iv"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:layout_margin="@dimen/element_spacing"
    android:background="@color/color_primary"
    android:contentDescription="@string/content_description_ui"
    />

<ImageView
    android:id="@+id/gridview_adapter_iv"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_margin="@dimen/element_spacing"
    android:layout_centerInParent="true"
    android:contentDescription="@string/content_description_result"
    />


<ProgressBar
    android:id="@+id/grid_adapter_spinner"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerInParent="true" />


</RelativeLayout>

获取视图..

@Override
    public View getView(final int position, View convertView, ViewGroup parent) {
        LayoutInflater inflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        final ImageDataViewHolder imageDataViewHolder;

        /*
         * see if we need to inflate the view, or if we can make use of the view holder pattern
         */
        if (convertView == null) {
            convertView = inflater.inflate(R.layout.adapter_gridview, parent, false);
            imageDataViewHolder = new ImageDataViewHolder();
            imageDataViewHolder.gridview_adapter_iv = (ImageView) convertView.findViewById(R.id.gridview_adapter_iv);
            imageDataViewHolder.gridview_adapter_background_iv = (ImageView) convertView.findViewById(R.id.gridview_adapter_background_iv);


            imageDataViewHolder.grid_adapter_spinner = (ProgressBar) convertView.findViewById(R.id.grid_adapter_spinner);
        } else {
            imageDataViewHolder = (ImageDataViewHolder) convertView.getTag();
        }

        /*
         * Set the UI elements, reset the spinner
         */


        imageDataViewHolder.position = position;
        imageDataViewHolder.grid_adapter_spinner.setVisibility(View.VISIBLE);

        final String url = mValues.get(position).getUrl();

        imageDataViewHolder.gridview_adapter_iv.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                mCallbacks.click(url);
            }

        });

        convertView.setTag(imageDataViewHolder);

        /*
         * Process the bitmap. If it exists, set it. If not, create a volley request to try to access
         * it. If it succeeds, save the bitmap to the cache. If it fails put up error icon.
         */
        Bitmap bm = mCache.get(url);
        if (bm != null) {
            imageDataViewHolder.gridview_adapter_iv.setImageBitmap(bm);
            imageDataViewHolder.grid_adapter_spinner.setVisibility(View.INVISIBLE);
        } else {
            imageDataViewHolder.gridview_adapter_iv.setImageBitmap(null);
            ImageRequest imageRequest = new ImageRequest(url, new Response.Listener<Bitmap>() {

                @Override
                public void onResponse(Bitmap response) {
                    mCache.put(url, response);
                    /*
                     * Check to make sure its the same view is visible before making edits.
                     * Else we will get a flicker effect as different images are downloaded.
                     *
                     */
                    if (imageDataViewHolder.position == position) {
                        imageDataViewHolder.gridview_adapter_iv.setImageBitmap(response);
                        imageDataViewHolder.grid_adapter_spinner.setVisibility(View.INVISIBLE);
                    }
                }

            }, mSize, mSize, null, new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError volleyError) {
                    imageDataViewHolder.grid_adapter_spinner.setVisibility(View.INVISIBLE);
                    imageDataViewHolder.gridview_adapter_iv.setImageResource(R.drawable.ic_error_outline_white_24dp);
                }
            });
            mVolleySingleton.addRequest(imageRequest);
        }
        return convertView;
    }

Answer 1

最好的办法是继承RelativeLayout 并覆盖onMeasure()：

public class SquareRelativeLayout extends RelativeLayout{

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

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

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

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

}

这应该适用于GridView，因为它将使用MeasureSpec.EXACTLY，IIRC 的模式。如果它不起作用，您可以使用此处的建议调整代码：Simple way to do dynamic but square layout

顺便说一句，您应该可以通过设置背景然后为位图指定android:scaleType="fitCenter" 来使用单个ImageView。