android - 如何在 Activity 中显示 DialogFragment

Question

我在 Activity 适配器的 Activity 上下文中显示 DialogFragment 时遇到问题。所以我有一个名为 AddDialogFragment 的自定义类，它扩展了 DialogFragment。当我用它在我的 fragment 适配器中显示该对话框时，一切都很顺利。我只是在那个 fragment 中那样做(上下文来 self 传递给 Adapter 的构造函数的 fragment :

FragmentActivity fragmentActivity = (FragmentActivity) context;
FragmentManager fragmentManager = fragmentActivity.getSupportFragmentManager();
RecipeRemoveDialogFragment recipeDialogFragment = new RecipeRemoveDialogFragment();
recipeDialogFragment.show(fragmentManager, "recipeDialogFragment"); 

现在我想显示相同的 DialogFragment 但在 Activty 的适配器中。我是这样做的:

holder.setClickListener(new ItemClickListener2() {

    @Override
    public void onClick(View view, int position, boolean isLongClick) {
        if (!isLongClick) {
            // go to recipes site
        } else {
            RecipeItem recipeItem = recipeItems.get(position);
            FragmentManager fragmentManager = ((FragmentActivity) context).getSupportFragmentManager();
            RecipeAddDialogFragment recipeDialogFragment = new RecipeAddDialogFragment();
            Log.d(TAG, "Ustawiono recipeUniqueId, coordinatorLayout oraz " +
                    "recipeDialogFragment w klasie RecipeAddDialogFragment");
            recipeDialogFragment.setReferences(recipeItem.getRecipeUniqueID(),
                    coordinatorLayout, recipeDialogFragment);

            Log.d(TAG, "Uruchamiam okno dialogowe RecipeAddDialogFragment");
            recipeDialogFragment.show(fragmentManager, "recipeDialogFragment");
        }
    }

});

但当我单击适配器的列表项时它不起作用并且应用程序崩溃。出现错误:

12-05 18:17:47.700 8926-8926/com.example.nazwamarki.myapplication E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.nazwamarki.myapplication, PID: 8926
java.lang.ClassCastException: com.example.nazwamarki.myapplication.app.AppController cannot be cast to android.support.v4.app.FragmentActivity
at com.example.nazwamarki.myapplication.recipe.RecipeAdapter$1.onClick(RecipeAdapter.java:63)
at com.example.nazwamarki.myapplication.recipe.RecipeAdapter$ViewHolder.onLongClick(RecipeAdapter.java:119)
at android.view.View.performLongClick(View.java:4836)
at android.view.View$CheckForLongPress.run(View.java:19873)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5294)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:904)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:699)

编辑

上下文来自这里(我将其传递给Adapter 的 构造函数:

recipeAdapter = new RecipeAdapter(getApplicationContext(), recipeItems);

这是我所有的适配器以防万一:

  public class RecipeAdapter extends RecyclerView.Adapter<RecipeAdapter.ViewHolder> {

    private static String TAG = RecipeAdapter.class.getSimpleName().toString();

    private Context context;
    private ArrayList<RecipeItem> recipeItems;
    private CoordinatorLayout coordinatorLayout;

    public RecipeAdapter(Context context, ArrayList<RecipeItem> recipeItems) {
        this.context = context;
        this.recipeItems = recipeItems;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.recipe_item, parent,
                false);

        return new ViewHolder(v);
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        RecipeItem recipeItem = recipeItems.get(position);
        Picasso.with(context).load(recipeItem.getRecipeImgThumbnailLink()).into(
                holder.recipeItemImgThumbnail);
        holder.recipeItemTitle.setText(recipeItem.getRecipeTitle());
        holder.recipeItemKitchenMealType.setText("Kuchnia " + recipeItem.getRecipeKitchenType() +
                ", " + recipeItem.getRecipeMealType());
        holder.recipeItemAddDate.setText(recipeItem.getRecipeAddDate());
        holder.recipeItemLikeCount.setText(recipeItem.getRecipeLikeCount());
        holder.setClickListener(new ItemClickListener2() {

            @Override
            public void onClick(View view, int position, boolean isLongClick) {
                if (!isLongClick) {
                    // go to recipes site
                } else {
                    RecipeItem recipeItem = recipeItems.get(position);
                    FragmentManager fragmentManager = ((FragmentActivity) context).getSupportFragmentManager();
                    RecipeAddDialogFragment recipeDialogFragment = new RecipeAddDialogFragment();
                    Log.d(TAG, "Ustawiono recipeUniqueId, coordinatorLayout oraz " +
                            "recipeDialogFragment w klasie RecipeAddDialogFragment");
                    recipeDialogFragment.setReferences(recipeItem.getRecipeUniqueID(),
                            coordinatorLayout, recipeDialogFragment);

                    Log.d(TAG, "Uruchamiam okno dialogowe RecipeAddDialogFragment");
                    recipeDialogFragment.show(fragmentManager, "recipeDialogFragment");
                }
            }

        });
    }

    @Override
    public int getItemCount() {
        return recipeItems.size();
    }

    // Recipe Item Holder
    class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener,
            View.OnLongClickListener {

        private ImageView recipeItemImgThumbnail;
        private TextView recipeItemTitle;
        private TextView recipeItemKitchenMealType;
        private TextView recipeItemAddDate;
        private TextView recipeItemLikeCount;
        private ItemClickListener2 clickListener2;

        public ViewHolder(View itemView) {
            super(itemView);
            recipeItemImgThumbnail = (ImageView) itemView.findViewById(
                    R.id.recipe_item_img_thumbnail);
            recipeItemTitle = (TextView) itemView.findViewById(R.id.recipe_item_title);
            recipeItemKitchenMealType = (TextView) itemView.findViewById(
                    R.id.recipe_item_kitchen_meal_type);
            recipeItemAddDate = (TextView) itemView.findViewById(R.id.recipe_item_add_date);
            recipeItemLikeCount = (TextView) itemView.findViewById(R.id.recipe_item_like_count);

            itemView.setOnClickListener(this);
            itemView.setOnLongClickListener(this);
        }

        public void setClickListener(ItemClickListener2 itemClickListener2) {
            this.clickListener2 = itemClickListener2;
        }

        @Override
        public void onClick(View view) {
            clickListener2.onClick(view, getAdapterPosition(), false);
        }

        @Override
        public boolean onLongClick(View view) {
            clickListener2.onClick(view, getAdapterPosition(), true);

            return true;
        }
    }

    public void setCoordinatorLayout(CoordinatorLayout coordinatorLayout) {
        this.coordinatorLayout = coordinatorLayout;
    }
}

Answer 1

改变

recipeAdapter = new RecipeAdapter(getApplicationContext(), recipeItems);

到

recipeAdapter = new RecipeAdapter(this, recipeItems);

适配器需要一个 Activity 上下文。如果您从 回调 中对其进行初始化，则使用 ClassName.this 而不是 this。