调用progressBar.dismiss()时出现DecorView未绑定窗口管理器错误求助

Hey there! That error you're hitting is super common with asynchronous operations like Volley requests—let's sort this out quickly.

Why This Happens #

The DecorView not attached to window manager error pops up because your ProgressDialog is trying to dismiss itself after the parent Fragment/Activity has already been destroyed or detached. Volley requests run in the background, and by the time the response comes back, your Fragment might have been removed from the screen (like if the user navigated away), leaving the Dialog without a valid window to attach to.

Quick Fixes for Your Code #

Let's adjust your existing code to add safety checks before dismissing the dialog. Here's how to modify your onResponse and onErrorResponse methods:

Updated onResponse Method

@Override
public void onResponse(JSONObject response) {
    try {
        JSONArray a=response.getJSONArray("heroes");
        for(int i=0;i<a.length();i++) {
            JSONObject obj=a.getJSONObject(i);
            ListItem m = new ListItem();
            m.setHead(obj.getString("name"));
            m.setDesc(obj.getString("about"));
            m.setImageUrl(obj.getString("image"));
            m.setTrailer(obj.getString("trailer"));
            listItems.add(m);
        }
        adapter = new MyNewAdapter(activity,listItems);
        horizontalInfiniteCycleViewPager.setAdapter(adapter);
        adapter.notifyDataSetChanged();
    } catch (JSONException e) {
        e.printStackTrace();
    }

    // Safe dismiss with validity checks
    if (getActivity() != null && !getActivity().isFinishing() 
        && progressDialog != null && progressDialog.isShowing()) {
        progressDialog.dismiss();
    }
    running=false;
}

Updated onErrorResponse Method

@Override
public void onErrorResponse(VolleyError error) {
    // Safe dismiss with validity checks
    if (getActivity() != null && !getActivity().isFinishing() 
        && progressDialog != null && progressDialog.isShowing()) {
        progressDialog.dismiss();
    }
    Toast.makeText(getActivity().getApplicationContext(),"Sorry, something went wrong",Toast.LENGTH_LONG).show(); // Don't forget to call show() on your Toast!
    running=false;
}

Key Checks Explained #

• getActivity() != null: Ensures the Fragment is still attached to a valid Activity
• !getActivity().isFinishing(): Makes sure the Activity hasn't been marked for closure
• progressDialog != null && progressDialog.isShowing(): Avoids null pointer exceptions and unnecessary dismiss calls

Bonus: Modern Alternative to ProgressDialog #

Just a heads-up—ProgressDialog has been deprecated since API 26. For a more robust, future-proof solution, consider using a Material Design ProgressIndicator (either embedded in your layout or as a dialog) paired with LifecycleObserver or ViewModel. This setup automatically handles lifecycle events, so you won't have to manually check for context validity anymore.

内容的提问来源于stack exchange，提问作者Vijeth Kashyap