android.view.ContextThemeWrapper无法转换为android.app.Activity [英] android.view.ContextThemeWrapper cannot be cast to android.app.Activity

问题描述

我不是设计师，但是当我得到这个项目时，我无法专门打开某些屏幕，我认为它们是屏幕，我们仅重复使用已创建的某些布局. 无论如何有人可以帮助我吗? @Override public void onBindViewHolder(@NonNull final ProductsAdapter.ViewHolder持有人，最终int位置){ 字符串imageUrl = ProductsList.get(position).getImage();

I'm not a designer but when i got this project i can`t open specifically some screens, i think that they are screens and we only reuse some of the layouts have been created. Anyway can somebody help me? @Override public void onBindViewHolder(@NonNull final ProductsAdapter.ViewHolder holder, final int position) { String imageUrl = ProductsList.get(position).getImage();

    holder.itemName.setText(ProductsList.get(position).getName());
    Picasso.with(context).load(imageUrl).into(holder.itemImage);

    holder.parentLayot.setOnClickListener(new View.OnClickListener() {
        public String currentActivity;

        @Override
        public void onClick(View v) {
            Activity activity = (Activity) v.getContext();
            activity.runOnUiThread(bd);
            String activityName = activity.getClass().getSimpleName();
            // Toast.makeText(activity,ProductsList.get(position).getId(),Toast.LENGTH_SHORT).show();

            if (activityName.equals("Product_View")){
                // Toast.makeText(activity,"Click and pass",Toast.LENGTH_SHORT).show();

                Intent intent = new Intent(activity, Second_Product_View.class);
                intent.putExtra("item_name", ProductsList.get(position).getName());
                intent.putExtra("item_id", ProductsList.get(position).getId());
                intent.putExtra("item_category_name", ProductsList.get(position).getName());
                intent.putExtra("item_category_id", ProductsList.get(position).getId());

                activity.startActivity(intent);
            } else if(activityName.equals("Second_Product_View")){
                Intent intent = new Intent(activity, Third_Product_View.class);

                intent.putExtra("item_category_name", activity.getIntent().getStringExtra("item_category_name"));
                intent.putExtra("item_category_id", activity.getIntent().getStringExtra("item_category_id"));

                intent.putExtra("item_subcategory_name", ProductsList.get(position).getName());
                intent.putExtra("item_subcategory_id", ProductsList.get(position).getId());

                intent.putExtra("item_name", ProductsList.get(position).getName());
                intent.putExtra("item_id", ProductsList.get(position).getId());

                activity.startActivity(intent);
            } else if(activityName.equals("Third_Product_View")){
                Intent intent = new Intent(activity, Fourth_Product_View.class);

                intent.putExtra("item_category_name", activity.getIntent().getStringExtra("item_category_name"));
                intent.putExtra("item_category_id", activity.getIntent().getStringExtra("item_category_id"));

                intent.putExtra("item_subcategory_name", activity.getIntent().getStringExtra("item_subcategory_name"));
                intent.putExtra("item_subcategory_id", activity.getIntent().getStringExtra("item_subcategory_id"));

                intent.putExtra("item_section_name", ProductsList.get(position).getName());
                intent.putExtra("item_section_id", ProductsList.get(position).getId());

                intent.putExtra("item_name", ProductsList.get(position).getName());
                intent.putExtra("item_id", ProductsList.get(position).getId());
                activity.startActivity(intent);
            } else if(activityName.equals("Fourth_Product_View")){
                holder.downloadManager = (DownloadManager)activity.getSystemService(Context.DOWNLOAD_SERVICE);
                String file = activity.getString(R.string.base_url) + "files/example-" + ProductsList.get(position).getId() + ".pdf";
                Uri uri = Uri.parse(file);
                DownloadManager.Request request = new DownloadManager.Request(uri);
                request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
                Long reference = holder.downloadManager.enqueue(request);
            } else if (activityName.equals("Formation_View")){
                Intent intent = new Intent(activity, Second_Formation_View.class);
                intent.putExtra("item_name", ProductsList.get(position).getName());
                intent.putExtra("item_id", ProductsList.get(position).getId());
                intent.putExtra("item_category_name", ProductsList.get(position).getName());
                intent.putExtra("item_category_id", ProductsList.get(position).getId());

                activity.startActivity(intent);
            } else if(activityName.equals("Second_Formation_View")){
                Intent intent = new Intent(activity, Third_Formation_View.class);

                intent.putExtra("item_category_name", activity.getIntent().getStringExtra("item_category_name"));
                intent.putExtra("item_category_id", activity.getIntent().getStringExtra("item_category_id"));

                intent.putExtra("item_subcategory_name", ProductsList.get(position).getName());
                intent.putExtra("item_subcategory_id", ProductsList.get(position).getId());

                intent.putExtra("item_name", ProductsList.get(position).getName());
                intent.putExtra("item_id", ProductsList.get(position).getId());

                activity.startActivity(intent);
            } else if(activityName.equals("Third_Formation_View")){
                holder.downloadManager = (DownloadManager)activity.getSystemService(Context.DOWNLOAD_SERVICE);
                String file = activity.getString(R.string.base_url) + "files/example-" + ProductsList.get(position).getId() + ".pdf";
                Uri uri = Uri.parse(file);
                DownloadManager.Request request = new DownloadManager.Request(uri);
                request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
                Long reference = holder.downloadManager.enqueue(request);
            } else if (activityName.equals("Tools_View")){
                Intent intent = new Intent(activity, Second_Tools_View.class);
                intent.putExtra("item_name", ProductsList.get(position).getName());
                intent.putExtra("item_id", ProductsList.get(position).getId());
                intent.putExtra("item_category_name", ProductsList.get(position).getName());
                intent.putExtra("item_category_id", ProductsList.get(position).getId());

                activity.startActivity(intent);
            } else if(activityName.equals("Second_Tools_View")){
                holder.downloadManager = (DownloadManager)activity.getSystemService(Context.DOWNLOAD_SERVICE);
                String file = activity.getString(R.string.base_url) + "files/example-" + ProductsList.get(position).getId() + ".pdf";
                Uri uri = Uri.parse(file);
                DownloadManager.Request request = new DownloadManager.Request(uri);
                request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
                Long reference = holder.downloadManager.enqueue(request);
            }

        }
    });
} 

日志显示此内容

java.lang.ClassCastException: android.view.ContextThemeWrapper cannot be cast to android.app.Activity

    at android.view.View.performClick(View.java:6256)
    at android.view.View$PerformClick.run(View.java:24701)
    at android.os.Handler.handleCallback(Handler.java:789)
    at android.os.Handler.dispatchMessage(Handler.java:98)
    at android.os.Looper.loop(Looper.java:164)
    at android.app.ActivityThread.main(ActivityThread.java:6541)
    at java.lang.reflect.Method.invoke(Native Method)
    at 

推荐答案

此行可能是罪魁祸首:

Activity activity = (Activity) v.getContext();

传递给onClick()方法的视图v与您为其分配侦听器的视图相同，因此v与holder.parentLayot相同.我不知道holder.parentLayot的确切来源，但是很有可能该视图(或其父视图之一)具有android:theme属性(在XML中).

The view v passed to the onClick() method is the same view that you assigned the listener to, so v is the same as holder.parentLayot. I don't know exactly where holder.parentLayot came from, but chances are very good that (in XML) this view (or one of its parents) has an android:theme attribute.

当视图具有android:theme属性时，它不会直接使用其活动的上下文.取而代之的是，Android框架将在ContextThemeWrapper中包装"活动的上下文，以修改视图的主题.

When a view has the android:theme attribute, it doesn't use its activity's context directly. Instead, the android framework will "wrap" the activity's context in a ContextThemeWrapper in order to modify the view's theme.

要从此包装器访问活动，您必须对其进行解包".尝试这样的事情:

To access the activity from this wrapper, you'll have to "unwrap" it. Try something like this:

private static Activity unwrap(Context context) {
    while (!(context instanceof Activity) && context instanceof ContextWrapper) {
        context = ((ContextWrapper) context).getBaseContext();
    }

    return (Activity) context;
}

然后，您可以在onClick()中使用此方法，而不是直接强制转换上下文:

Then, you can use this method in your onClick() instead of casting the context directly:

Activity activity = unwrap(v.getContext());

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