Android:ProgressDialog未在适配器类中显示

Question

在我的应用程序中,我有一个listview,每个项目都有一个按钮.如果用户单击该按钮,我想执行一些http连接.所以我在Adapter类中使用AsyncTask.现在问题是进度对话框没有显示.

private class MyClass extends AsyncTask<Void, Long, Boolean> {
        private Context context;
        private ServerCall call = new ServerCall();
        private ProgressDialog progressDialog1;

        public MyClass(Context context) {
            this.context = context;
        }

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            try {
                progressDialog1 = ProgressDialog.show(context, "",
                        "Please wait...", true);
                progressDialog1.setIndeterminate(true);

            } catch (final Throwable th) {

            }

        }

        @Override
        protected void onProgressUpdate(Long... values) {

            super.onProgressUpdate(values);
        }

        @Override
        protected Boolean doInBackground(Void... params) {
            //some tasks

            return true;
        }

        @Override
        protected void onPostExecute(Boolean result) {
            if (mode.equalsIgnoreCase("History")) {

                Intent order = new Intent(context, ActicityA.class);
                order.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                context.startActivity(order);

            } else {
                Intent order = new Intent(context, ActivityB.class);
                order.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                context.startActivity(order);
            }

        }
    }

Answer 1

该ProgressDialog.show()方法确实返回一个ProgressDialog对象，但最好首先创建一个 ProgressDialog 对象，如下所示：

ProgressDialog progressDialog1 = new ProgressDialog();

进而

progressDialog1 = ProgressDialog.show(context, "",
                        "Please wait...", true);

并且，尝试通过调用其方法来完成progressDialog1in 。onPostExecute()dismiss()