Android，Volley Request，响应是阻塞主线程 [英] Android, Volley Request, the response is blocking main thread

问题描述

使用Volley处理大量回复时发生了一些不好的事情：

Something bad is happening when using Volley to treat a large response:

String url = AppHelper.DOMAIN + "/service/pages/profile_update.json";

this.infoTextView.setText(getString(R.string.profile_info_updating));

final StringRequest stringRequest = new StringRequest(Request.Method.POST, url,
        new Response.Listener<String>() {
            @Override
            public void onResponse(String response) {
                try {
                    JSONObject json = new JSONObject(response);

                    if (json.getBoolean("success")) {
                        // manage JSON object here
                    } else {
                        Toast.makeText(ProfileActivity.this,
                                getString(R.string.connection_problem_server),
                                Toast.LENGTH_LONG).show();
                    }
                } catch (JSONException e) {
                    ProfileActivity.this.infoTextView.setText(
                            getString(R.string.profile_info_updating_error));

                    e.printStackTrace();
                }
            }
        }, new Response.ErrorListener() {
    @Override
    public void onErrorResponse(VolleyError error) {
        ProfileActivity.this.infoTextView.setText(
                getString(R.string.profile_info_updating_error));

        if (error.networkResponse != null && error.networkResponse.statusCode == 401) {
            Toast.makeText(ProfileActivity.this,
                    getString(R.string.connection_problem_permission),
                    Toast.LENGTH_LONG).show();
        }

        new android.os.Handler().postDelayed(new Runnable() {
            @Override
            public void run() {
                if (ProfileActivity.this.swipeRefreshLayout != null) {
                    ProfileActivity.this.swipeRefreshLayout.setRefreshing(false);
                }
            }
        }, 1000);

        error.printStackTrace();
    }
}) {
    @Override
    protected Map<String, String> getParams() {
        Map<String, String> params = new HashMap<>();
        params.put("auth_token", ProfileActivity.this.defaultUser.getAuthenticationToken());
        return params;
    }

    @Override
    public Map<String, String> getHeaders() throws AuthFailureError {
        Map<String, String> params = new HashMap<>();
        params.putAll(super.getHeaders());
        params.put("Accept-Encoding", "gzip,deflate");
        return params;
    }

    @Override
    protected Response<String> parseNetworkResponse(NetworkResponse response) {
        StringBuilder output = new StringBuilder();
        try {
            GZIPInputStream gStream = new GZIPInputStream(new ByteArrayInputStream(response.data));
            InputStreamReader reader = new InputStreamReader(gStream);
            BufferedReader in = new BufferedReader(reader, 16384);

            String read;

            while ((read = in.readLine()) != null) {
                output.append(read).append("\n");
            }
            reader.close();
            in.close();
            gStream.close();
        } catch (IOException error) {
            error.printStackTrace();
            return Response.error(new ParseError());
        }

        return Response.success(output.toString(), HttpHeaderParser.parseCacheHeaders(response));
    }
};

stringRequest.setRetryPolicy(new RetryPolicy() {
    @Override
    public int getCurrentTimeout() {
        // 40 seconds
        return 40000;
    }

    @Override
    public int getCurrentRetryCount() {
        return DefaultRetryPolicy.DEFAULT_MAX_RETRIES;
    }

    @Override
    public void retry(VolleyError error) throws VolleyError {
        throw error;
    }
});

Volley.newRequestQueue(this).add(stringRequest);

此代码阻止主线程冻结应用程序。

this code block the main thread, freezing the application.

此外，我设置了一些标头值以允许gzip响应和一个代码来处理数据。但这不是造成不良行为的因素。应用程序仅在 onResponse（字符串响应）启动时冻结。

Additionally, I set some header values to allow gzip response and a code to handle the data. But it is not the piece that make the undesired behavior. The application freeze only when onResponse(String response) starts.

我该怎么做才能避免这种情况？

What can I do to avoid this?

推荐答案

在UI线程上调用onResponse和onErrorResponse，因此在这些方法中完成的任何繁重操作都会使应用程序响应性降低。我猜你试图在onResponse（）中解析不正确的响应。

onResponse and onErrorResponse is called on UI thread hence any heavy operation done inside these methods will make you application less responsive. I guess you are trying to parse the response in onResponse() which is incorrect.

你必须转向解析逻辑到parseNetworkResponse，因为这
是在后台线程中调用的方法。有关详细信息，请参阅以下链接：

You have to move to parsing logic to parseNetworkResponse since this is the method which is called in background thread. Refer the below link for more details :

https://developer.android.com/training/volley/request-custom.html

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