在 AsyncTask 中调用 okhttp3.Callback 中的方法发现不是线程阻塞的，关键代码如下：

public class HttpUtil {
    //以上代码省略

    public static void sendPostHttpRequestOkHttp(String address, PostFormBuilder builder, okhttp3.Callback callback) {
        OkHttpClient client = new OkHttpClient();
        RequestBody body = builder.onBuild();
        Request request = new Request.Builder().url(address).post(body).build();
        client.newCall(request).enqueue(callback);

    }

    public interface PostFormBuilder {
        RequestBody onBuild();
    }

}

MainActivity 中调用的相关代码：

public class LoginActivity extends AppCompatActivity {

    //以上代码省略
    private class LoginTask extends AsyncTask<Void, Void, Boolean> {
        String mPassword;
        String mUsername;

        boolean success = false;

        LoginTask(String mPassword, String mUsername) {
            this.mPassword = mPassword;
            this.mUsername = mUsername;
        }

        @Override
        protected Boolean doInBackground(Void... params) {


            HttpUtil.sendPostHttpRequestOkHttp(LOGIN_URL, new HttpUtil.PostFormBuilder() {
                @Override
                public RequestBody onBuild() {
                    return new FormBody.Builder().add("username", mUsername).add("password", mPassword).build();
                }
            }, new Callback() {
                @Override
                public void onFailure(Call call, IOException e) {
                    e.printStackTrace();
                }

                @Override
                public void onResponse(Call call, final Response response) throws IOException {
                    String respData = response.body().string();
                    Log.d("Main", respData);
                    try {
                        JSONObject object = new JSONObject(respData);
                        int res = object.getInt("result");
                        success = (res == 100);
                        Log.d("Main","resp "+success);
                    } catch (JSONException e) {
                        e.printStackTrace();
                    }
                }
            });
            Log.d("Main","return "+success);
            return success;
        }

        @Override
        protected void onPreExecute() {
            loginProgress.setVisibility(ProgressBar.VISIBLE);
        }

        @Override
        protected void onPostExecute(Boolean suc) {
            loginProgress.setVisibility(ProgressBar.GONE);
            if (suc) {
                showDialog();
            } else {
                inputPassword.setError("密码错误");
                inputPassword.requestFocus();
            }
        }

        @Override
        protected void onCancelled() {
            Toast.makeText(LoginActivity.this, "Login Canceled", Toast.LENGTH_SHORT).show();
        }

    }
}

实际执行的时候总是先return false 然后才修改success的值为true,发现callback是异步执行的，自己实现一个callback如下之后运行达到期望目标

public class HttpUtil {

    public static void sendPostHttpRequestOkHttp(String address, PostFormBuilder builder, RequestCallback callback){
        OkHttpClient client = new OkHttpClient();
        RequestBody body = builder.onBuild();
        Request request = new Request.Builder().url(address).post(body).build();
        Response resp = null;
        try {
            resp = client.newCall(request).execute();
        } catch (IOException e) {
            callback.exceptionHandler(e);
        }
        callback.responseHandler(resp);

    }

    public interface PostFormBuilder {
        RequestBody onBuild();
    }

    public interface RequestCallback {
        void responseHandler(Response response);
        void exceptionHandler(Exception e);
    }
}