Question

我正在开发一个用于显示项目列表的Android应用程序，这是我的代码：

 public class CategoryAdapter extends 
  RecyclerView.Adapter<CategoryAdapter.CategoryAdapterViewHolder> {

   private String[] categoriesData;
   private int numberOfCategories;
   private CategoriesListListener cOnClickListener;

   public interface CategoriesListListener {
    void onCategoryItemClick(int categoryItemIndex, int height, int width, 
         View view);
   }

   public CategoryAdapter(int numberOfCategories, CategoriesListListener listener) {
    this.numberOfCategories = numberOfCategories;
    cOnClickListener = listener;
   }

   public class CategoryAdapterViewHolder extends RecyclerView.ViewHolder
            implements View.OnClickListener{


    public final TextView categoryTextView;
    public int adapterCounter;
    public CategoryAdapter categoryAdapter;


    public void setCounter(int counter){
        adapterCounter = counter;
    }

    public void setCategoryAdapter(CategoryAdapter categoryAdapter){
        this.categoryAdapter = categoryAdapter;
    }

    public CategoryAdapterViewHolder(View view) {
        super(view);
        categoryTextView = (TextView) view.findViewById(R.id.category_name);
        itemView.setOnClickListener(this);
    }

     @Override
    public void onClick(View view){

        int clickedPosition = getAdapterPosition();
        int height = view.getHeight();
        int width = view.getWidth();
        cOnClickListener.onCategoryItemClick(clickedPosition, height, width, view);
        }
   }

  @Override
public CategoryAdapterViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {
    Context context = viewGroup.getContext();
    int layoutIdForListItem = R.layout.category_item;
    LayoutInflater inflater = LayoutInflater.from(context);
    boolean shouldAttachToParentImmediately = false;

    View view = inflater.inflate(layoutIdForListItem, viewGroup, shouldAttachToParentImmediately);
    CategoryAdapterViewHolder categoryAdapterViewHolder = new CategoryAdapterViewHolder(view);
    categoryAdapterViewHolder.setCounter(getItemCount());
    categoryAdapterViewHolder.setCategoryAdapter(this);
    return categoryAdapterViewHolder;
     }

       @Override
public void onBindViewHolder(CategoryAdapterViewHolder forecastAdapterViewHolder, int position) {
    String currentCategory = mCategoriesData[position];
    forecastAdapterViewHolder.categoryTextView.setText(currentCategory);
}

 @Override
public int getItemCount() {
    if (null == mCategoriesData) return 0;
    return mCategoriesData.length;
}

  public void setCategoriesData(String[] categoriesData) {
     this.mCategoriesData = categoriesData;
     notifyDataSetChanged();
  }
 }

当单击一个Item时，将调用Listener的回调，这个Listener由Fragment实现，它将自身的实例传递给上面的CategoryAdapter

  public class CategoriesFragment extends Fragment implements 
     CategoryAdapter.CategoriesListListener {

    //some code here
    public interface OnCategoryClickListener{
        public void onCategoryClick(int position, String name, String 
             description,int height, int width, View view);
    }
    //some code here 
     @Override
    public void onCategoryItemClick(int categoryItemIndex,int height, int 
         width, View view) {
         cCallback.onCategoryClick(categoryItemIndex, 
                     categoriesName[categoryItemIndex],
         categories[categoryItemIndex], height, width, view);
     }

  }

然后Activity在interface

中实施了Fragment

     public class MainActivity extends AppCompatActivity implements
               CategoriesFragment.OnCategoryClickListener{
               //some code here
                @Override
               public void onCategoryClick(int position, String name, String 
                   description, int height, int width, View view){

                           //some code here 
                     int finalRaduis = (int)Math.hypot(height/2, width/2);
                     Animator animator = 
        ViewAnimationUtils.createCircularReveal(view, width/2, height/2, 0, 
                            finalRaduis);                
     view.setBackgroundColor(ContextCompat.getColor(getApplicationContext(),
                R.color.colorAccent2));
        animator.start();
       //some code here
    }

然后在ManActivity点击view后，我成功更改了视图的背景颜色，但在此情况下单击新视图时出现问题，之前点击的{{1}背景颜色没有变为默认颜色。

问题我应该如何修改我的代码，以便在单击新视图时，之前单击的一种颜色变为默认颜色？

Answer 1

您可以在适配器类中创建一个成员变量clickedPosition，其中deafult值为-1。在onBindViewHolder方法中，您可以检查clikedPostion == current postion然后将选择颜色设置为默认颜色。调用notififydataset从onclick方法更改方法以刷新视图。在适配器类

中添加以下代码

> curl localhost:8000
{ worker: 5, message: 'msg' }
{ worker: 5, message: 'msg' }
{ worker: 8, message: 'msg' }
{ worker: 8, message: 'msg' }
{ worker: 7, message: 'msg' }
{ worker: 7, message: 'msg' }
{ worker: 6, message: 'msg' }
{ worker: 6, message: 'msg' }

Answer 2

尝试在 MainActivity 中添加一些代码的以下解决方案： -

public class MainActivity extends AppCompatActivity implements
    CategoriesFragment.OnCategoryClickListener{


//Define
int prevClickPos = -1;
View prevView = null;


//some code here
@Override
public void onCategoryClick(int position, String name, String
        description, int height, int width, View view){

    //some code here
    int finalRaduis = (int)Math.hypot(height/2, width/2);
    Animator animator =
            ViewAnimationUtils.createCircularReveal(view, width/2, height/2, 0,
                    finalRaduis);
    view.setBackgroundColor(ContextCompat.getColor(getApplicationContext(),
            R.color.colorAccent2));
    animator.start();


    //Change Background Default
    if(prevClickPos != -1 && prevClickPos != position) {
        prevView.setBackgroundColor(ContextCompat.getColor(getApplicationContext(),
                R.color.defaultColor));    //Apply Default color
    }
    prevClickPos = position;
    prevView = view;

    //some code here
}

单击另一个项目时，在RecyclerView.Adapter中更改ViewItem的背景颜色

2 个答案: