java - Android GridView 项目在按下时更改图像并更改回来

Question

问题描述

在我的应用程序中，我有 GridView，其中包含 12 个项目。 GridView 中的每个项目都有自己的图标，如下图所示。对于每个图标，我都有两张图像，一张是按下的，一张是正常的。

问题

我尝试找到一些标准机制，当用户按下该项目然后释放按钮时将图像从正常状态更改为按下状态，但找不到。相反，我使用 public boolean onTouch(View v, MotionEvent event) 方法，但它会带来一些副作用，例如当用户向下滚动或滑动屏幕以更改选项卡时，单击项目。

源代码

@Override
public boolean onTouch(View v, MotionEvent event) {
    /* Get Action on Touch. */
    int action = event.getActionMasked();
    if (action == MotionEvent.ACTION_DOWN) {
        float currentXPosition = event.getX();
        float currentYPosition = event.getY();
        
        lastPressedPosition = gvCategories.pointToPosition((int) currentXPosition, (int) currentYPosition);
        if(lastPressedPosition < 0 || lastPressedPosition > sDefaultArray.length)
            return false;
    
        /* Set Pressed Image. */
        Drawable drawable = getActivity().getResources().getDrawable(sPressedArray[lastPressedPosition]);
        Category category = (Category) gvCategories.getItemAtPosition(lastPressedPosition);
        category.setImage(((BitmapDrawable) drawable).getBitmap());
        CategoriesGridAdapter adapter = (CategoriesGridAdapter)gvCategories.getAdapter();
        adapter.notifyDataSetChanged();
        
    }
    else if (action == MotionEvent.ACTION_UP || action == MotionEvent.ACTION_CANCEL) {
        
        /* Get current possition to compare with the last one. */
        float currentXPosition = event.getX();
        float currentYPosition = event.getY();
        int currentPosition = gvCategories.pointToPosition((int) currentXPosition, (int) currentYPosition);
        if(currentPosition == -1 && lastPressedPosition == -1)
            return false;
        if (currentPosition == lastPressedPosition && action == MotionEvent.ACTION_UP) {
            
            Category category = (Category) gvCategories.getItemAtPosition(currentPosition);
            Log.i(TAG, String.format("Category Title is: %s", category.getTitle()));
            
            if (category == Category.More) {
                
                //tracker.trackEvent("Category Clicked", "More", "", 0L);
                
                /* Get current selected language. */
                final SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(getActivity());
                final String lang = preferences.getString(Preferences.LANGUAGE, "en");
                /* Load All categories available in the application. */
                updateCategoriesAdapter(lang, true);
            }
            else {
                
                //tracker.trackEvent("Category Clicked", category.getTitle(), "", 0L);
                
                CategoryDetailsActivity.sFragmentManager = getFragmentManager();
                /* Start categories detail activity. */
                Intent intent = new Intent(getActivity().getApplicationContext(), CategoryDetailsActivity.class);
                intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                intent.putExtra(CategoryDetailsActivity.CATEGORIES_IDS, category.getIDs());
                intent.putExtra(CategoryDetailsActivity.CATEGORY_NAME, category.getTitle());
                getActivity().getApplicationContext().startActivity(intent);
            }
            
            
        }
        
        if(lastPressedPosition == -1)
            return false;
        
        /* Set Pressed Image. */
        Drawable drawable = getActivity().getResources().getDrawable(sDefaultArray[lastPressedPosition]);
        Category category = (Category) gvCategories.getItemAtPosition(lastPressedPosition);
        category.setImage(((BitmapDrawable) drawable).getBitmap());
        CategoriesGridAdapter adapter = (CategoriesGridAdapter)gvCategories.getAdapter();
        adapter.notifyDataSetChanged();
    }

    return false;
}

Answer 1

如果您已经制作了两个图像，请在 GridView 中使用 Button 元素，并将按钮的背景元素设置为可绘制的状态选择器。请参阅此链接以获取有关使选择器可绘制的 XML 声明 example here 。 对于您的场景，您必须为每个按钮创建不同的选择器 XML 文件。