Android drawSelectorOnTop 与 GridView [英] Android drawSelectorOnTop with GridView

问题描述

我正在开发一个选项卡式应用程序，其中一个片段 CollectionsFragment 包含一个 GridView，每个插槽中都有一个 ImageView.当用户单击其中一张图像时，我希望使用选择器向用户提供反馈.

I am developing a tabbed application in which one of the fragments, CollectionsFragment, contains a GridView with an ImageView in each slot. I would like the to use a selector to give feedback to users when the user clicks on one of the images.

我已经成功实现了选择器，但是，我的问题是选择器仅在图像的背景中绘制，但我希望选择器绘制整个图像.我在别处看到过这个问题，但是，很多人选择的解决方案，设置了 GridView 的 drawSelectorOnTop 属性，对我不起作用.

I have successfully implemented the selector, however, my problem is that the selector is only drawing in the background of the image, but I would like to the selector to draw over the entire image. I have seen this problem referenced elsewhere, however, the solution selected by many, setting the drawSelectorOnTop property of the GridView, is not working for me.

具有相关适配器代码的相关片段:

The relevant fragment with the relevant adapter code:

public class CollectionsFragment extends Fragment {
    @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
             View view = inflater.inflate(R.layout.activity_collections, container, false);
             // Grid view is inside the xml view inflated above
             GridView gridView = (GridView)view.findViewById(R.id.gridview);
             gridView.setDrawSelectorOnTop(true);
             ((GridView) gridView).setAdapter(new CustomGridViewAdapter(getActivity()));
             return view;
        }

        private class CustomGridViewAdapter extends BaseAdapter {
            @Override
            public View getView(int i, View view, ViewGroup viewGroup) {
                View v = view;
                ImageView picture;
                TextView name;

                if(v == null) {
                    v = inflater.inflate(R.layout.collections_item, viewGroup, false);
                    v.setTag(R.id.picture, v.findViewById(R.id.picture));
                    v.setTag(R.id.text, v.findViewById(R.id.text));
                }

                picture = (ImageView)v.getTag(R.id.picture);

                name = (TextView)v.getTag(R.id.text);

                Item item = (Item)getItem(i);
                name.setText(item.name);

                picture.setImageResource(item.drawableId);
                picture.setBackgroundResource(R.drawable.selector);

                return v;
            }
        }
}

为了完整起见，还有我的选择器:

And my selector for completeness sake:

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_pressed="true" 
      android:drawable="@color/buttonhighlight"/> <!-- pressed state -->
<item android:state_focused="true" 
      android:drawable="@color/buttonhighlight"/> <!-- focused state -->
<item android:drawable="@android:color/transparent"/> <!-- default state --> 
</selector>

感谢您的帮助，

推荐答案

我认为您对 setDrawSelectorOnTop(boolean) 有误解.此处引用的 selector drawable 是 GridView 的内部 selector drawable.

I think you are mistaken about setDrawSelectorOnTop(boolean). The selector drawable that is being referenced here is GridView's internal selector drawable.

即使在 GridView 的最简单实现中，当点击一个网格项时，它周围会绘制蓝色边框.这是因为，默认情况下，gridview 自己的选择器绘制在 behind 项目.如果你调用 setDrawSelectorOnTop(true)，选择器(蓝色)将被绘制在项目上.

Even in the simplest implementation of GridView, when a grid item is clicked, the blue border is drawn around it. This is because, by default, gridview's own selector is drawn behind the item. If you call setDrawSelectorOnTop(true), the selector (blue) will be drawn over the item.

但是 setDrawSelectorOnTop(boolean) 与您在适配器中设置的选择器无关.无论您传递 true 还是 false，ImageView 的选择器的行为都不会改变.

But setDrawSelectorOnTop(boolean) has nothing to do with the selector you are setting in the adapter. Whether you pass true, or false, the ImageView's selector's behavior won't change.

解决方案:

不要在适配器内的每个 ImageView 上设置选择器，而是让 GridView 使用您的选择器可绘制:

Instead of setting the selector on each ImageView inside the adapter, make the GridView use your selector drawable:

GridView gridView = (GridView)view.findViewById(R.id.gridview);
gridView.setDrawSelectorOnTop(true);

// Make GridView use your custom selector drawable
gridView.setSelector(getResources().getDrawable(R.drawable.selector));

现在，不需要:

picture.setBackgroundResource(R.drawable.selector);

虽然我不推荐这样做(明显的开销)，但它应该可以工作:

Although I don't recommend this (obvious overhead), it should work:

@Override
public View getView(int i, View view, ViewGroup viewGroup) {
    View v = view;
    ImageView picture;

    ....
    ....

    LayerDrawable ld = new LayerDrawable(new Drawable[] 

                           // Drawable from item
                           { getResources().getDrawable(item.drawableId), 

                           // Selector
                           getResources().getDrawable(R.drawable.selector)});

    // Set the LayerDrawable
    picture.setImageDrawable(ld);

    // Don't need this
    // picture.setBackgroundResource(R.drawable.selector);

    return v;
}

这篇关于Android drawSelectorOnTop 与 GridView的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！