android - 如何聚合进度对话框？

Question

我的应用程序需要与服务器进行大量通信。有些电话需要很长时间，所以我需要显示进度对话框。之前，我把:

ProgressDialog pd;

        @Override
        protected void onPreExecute() {
             pd = new ProgressDialog(app);
             pd.setOwnerActivity(app);
             pd.setTitle("Идет загрузка...");
             pd.setCancelable(true);
             pd.show();
        }
protected void onPostExecute(JSONObject result) {
            super.onPostExecute(result);
             pd.dismiss();
                         //some code
                }

扩展异步任务的每个类。但是，现在我必须在 asynctask 类上使用 .get() ，因此进度对话框仅在执行任务时才会闪烁。

在那之后，我尝试从 asynctask 类中删除 progressdialog 调用并将其放入 JsonParser:

public class JSONParser {

    static InputStream is = null;
    static JSONObject jObj = null;
    static JSONArray jObj1 = null;
    static String json = "";
    DefaultHttpClient httpClient = null;
    static Context context;
    ProgressDialog pd;

    // constructor
    public JSONParser() {

    }


    private static Boolean isOnline() {

        context = UILApplication.getAppContext();
        Log.d("CONTEXT",context.toString());
        ConnectivityManager connectivity = (ConnectivityManager) context
                .getSystemService(Context.CONNECTIVITY_SERVICE);
        if (connectivity != null) {
            NetworkInfo[] info = connectivity.getAllNetworkInfo();
            if (info != null) {
                for (int i = 0; i < info.length; i++) {
                    if (info[i].getState() == NetworkInfo.State.CONNECTED) {
                        Log.d("Conected", "Conected");
                        return true;
                    }
                }
            }
        }
        Log.d("disconected", "disconected");
        return false;
    }



    public JSONObject getJSONFromUrl(String url, List<NameValuePair> params) {

        if (isOnline()) {

            pd = new ProgressDialog(context);
            //pd.setOwnerActivity(context);
            pd.setTitle("Идет загрузка...");
            pd.setCancelable(true);
            pd.show();
            try {


                String u = url;
                u = u + "?";

                httpClient = HttpClientFactory.getThreadSafeClient();

                HttpPost httpPost = new HttpPost(url);
                httpPost.setEntity(new UrlEncodedFormEntity(params, HTTP.UTF_8));
                for (int i = 0; i < params.size(); i++) {
                    u = u + params.get(i).getName() + "="
                            + params.get(i).getValue() + "&";
                }
                Log.d("your url is", u);
                HttpResponse httpResponse = httpClient.execute(httpPost);
                HttpEntity httpEntity = httpResponse.getEntity();
                is = httpEntity.getContent();
                Log.d("data is sent", "true");

            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
                return null;
            } catch (ClientProtocolException e) {
                e.printStackTrace();
                return null;
            } catch (IOException e) {
                e.printStackTrace();
                return null;

            }
            Log.d("wait", "true");
            try {

                BufferedReader reader = new BufferedReader(
                        new InputStreamReader(is, "UTF-8"), 8);
                StringBuilder sb = new StringBuilder();
                String line = null;
                while ((line = reader.readLine()) != null) {

                    sb.append(line + "\n");
                }
                is.close();
                json = sb.toString();
                if (json.contains("error:2")) {
                    return null;
                }
                Log.d("JSON", json);
            } catch (Exception e) {
                Log.e("Buffer Error", "Error converting result " + e.toString());
                return null;
            }
            // try parse the string to a JSON object
            try {
                jObj = new JSONObject(json);
            } catch (JSONException e) {
                Log.e("JSON Parser", "Error parsing data " + e.toString());
                return null;
            }
            pd.dismiss();
            return jObj;
        }
        pd.dismiss();
        error();
        return null;

    }
}

不幸的是，它给了我错误。据我了解，我应该在 UIthread 中调用对话框。

06-20 13:46:01.368: W/System.err(1244): java.util.concurrent.ExecutionException: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare() 06-20 13:46:01.368: W/System.err(1244): at java.util.concurrent.FutureTask$Sync.innerGet(FutureTask.java:223) 06-20 13:46:01.377: W/System.err(1244): at java.util.concurrent.FutureTask.get(FutureTask.java:82) 06-20 13:46:01.377: W/System.err(1244): at android.os.AsyncTask.get(AsyncTask.java:482) 06-20 13:46:01.377: W/System.err(1244): at ua.mirkvartir.android.frontend.LoginActivity$2.onClick(LoginActivity.java:108) 06-20 13:46:01.377: W/System.err(1244): at android.view.View.performClick(View.java:4084) 06-20 13:46:01.377: W/System.err(1244): at android.view.View$PerformClick.run(View.java:16966) 06-20 13:46:01.387: W/System.err(1244): at android.os.Handler.handleCallback(Handler.java:615) 06-20 13:46:01.387: W/System.err(1244): at android.os.Handler.dispatchMessage(Handler.java:92) 06-20 13:46:01.387: W/System.err(1244): at android.os.Looper.loop(Looper.java:137) 06-20 13:46:01.387: W/System.err(1244): at android.app.ActivityThread.main(ActivityThread.java:4745) 06-20 13:46:01.397: W/System.err(1244): at java.lang.reflect.Method.invokeNative(Native Method) 06-20 13:46:01.397: W/System.err(1244): at java.lang.reflect.Method.invoke(Method.java:511) 06-20 13:46:01.397: W/System.err(1244): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786) 06-20 13:46:01.397: W/System.err(1244): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 06-20 13:46:01.407: W/System.err(1244): at dalvik.system.NativeStart.main(Native Method) 06-20 13:46:01.407: W/System.err(1244): Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare() 06-20 13:46:01.418: W/System.err(1244): at android.os.Handler.(Handler.java:121) 06-20 13:46:01.418: W/System.err(1244): at android.app.Dialog.(Dialog.java:107) 06-20 13:46:01.418: W/System.err(1244): at android.app.AlertDialog.(AlertDialog.java:114) 06-20 13:46:01.427: W/System.err(1244): at android.app.AlertDialog.(AlertDialog.java:98) 06-20 13:46:01.427: W/System.err(1244): at android.app.ProgressDialog.(ProgressDialog.java:77) 06-20 13:46:01.427: W/System.err(1244): at ua.mirkvartir.android.frontend.adapter.JSONParser.getJSONFromUrl(JSONParser.java:79) 06-20 13:46:01.437: W/System.err(1244): at ua.mirkvartir.android.frontend.UserFunctions.loginUser(UserFunctions.java:64) 06-20 13:46:01.437: W/System.err(1244): at ua.mirkvartir.android.frontend.LoginActivity$Login.doInBackground(LoginActivity.java:280) 06-20 13:46:01.437: W/System.err(1244): at ua.mirkvartir.android.frontend.LoginActivity$Login.doInBackground(LoginActivity.java:1) 06-20 13:46:01.447: W/System.err(1244): at android.os.AsyncTask$2.call(AsyncTask.java:287) 06-20 13:46:01.447: W/System.err(1244): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305) 06-20 13:46:01.447: W/System.err(1244): at java.util.concurrent.FutureTask.run(FutureTask.java:137) 06-20 13:46:01.457: W/System.err(1244): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230) 06-20 13:46:01.457: W/System.err(1244): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076) 06-20 13:46:01.457: W/System.err(1244): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569) 06-20 13:46:01.457: W/System.err(1244): at java.lang.Thread.run(Thread.java:856) 06-20 13:46:01.457: D/getting response(1244): true 06-20 13:46:01.467: D/work done(1244): true 06-20 13:46:01.477: W/dalvikvm(1244): threadid=11: thread exiting with uncaught exception (group=0x40a13300) 06-20 13:46:01.517: E/AndroidRuntime(1244): FATAL EXCEPTION: AsyncTask #1 06-20 13:46:01.517: E/AndroidRuntime(1244): java.lang.RuntimeException: An error occured while executing doInBackground() 06-20 13:46:01.517: E/AndroidRuntime(1244): at android.os.AsyncTask$3.done(AsyncTask.java:299) 06-20 13:46:01.517: E/AndroidRuntime(1244): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273) 06-20 13:46:01.517: E/AndroidRuntime(1244): at java.util.concurrent.FutureTask.setException(FutureTask.java:124) 06-20 13:46:01.517: E/AndroidRuntime(1244): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307) 06-20 13:46:01.517: E/AndroidRuntime(1244): at java.util.concurrent.FutureTask.run(FutureTask.java:137) 06-20 13:46:01.517: E/AndroidRuntime(1244): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230) 06-20 13:46:01.517: E/AndroidRuntime(1244): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076) 06-20 13:46:01.517: E/AndroidRuntime(1244): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569) 06-20 13:46:01.517: E/AndroidRuntime(1244): at java.lang.Thread.run(Thread.java:856) 06-20 13:46:01.517: E/AndroidRuntime(1244): Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare() 06-20 13:46:01.517: E/AndroidRuntime(1244): at android.os.Handler.(Handler.java:121) 06-20 13:46:01.517: E/AndroidRuntime(1244): at android.app.Dialog.(Dialog.java:107) 06-20 13:46:01.517: E/AndroidRuntime(1244): at android.app.AlertDialog.(AlertDialog.java:114) 06-20 13:46:01.517: E/AndroidRuntime(1244): at android.app.AlertDialog.(AlertDialog.java:98) 06-20 13:46:01.517: E/AndroidRuntime(1244): at android.app.ProgressDialog.(ProgressDialog.java:77) 06-20 13:46:01.517: E/AndroidRuntime(1244): at ua.mirkvartir.android.frontend.adapter.JSONParser.getJSONFromUrl(JSONParser.java:79) 06-20 13:46:01.517: E/AndroidRuntime(1244): at ua.mirkvartir.android.frontend.UserFunctions.loginUser(UserFunctions.java:64) 06-20 13:46:01.517: E/AndroidRuntime(1244): at ua.mirkvartir.android.frontend.LoginActivity$Login.doInBackground(LoginActivity.java:280) 06-20 13:46:01.517: E/AndroidRuntime(1244): at ua.mirkvartir.android.frontend.LoginActivity$Login.doInBackground(LoginActivity.java:1) 06-20 13:46:01.517: E/AndroidRuntime(1244): at android.os.AsyncTask$2.call(AsyncTask.java:287) 06-20 13:46:01.517: E/AndroidRuntime(1244): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305) 06-20 13:46:01.517: E/AndroidRuntime(1244): ... 5 more 06-20 13:46:01.857: W/EGL_emulation(1244): eglSurfaceAttrib not implemented

所以我想知道显示进度对话框的方法，它会在我需要的任何地方弹出。我可以在调用 getJsonFromUrl 时显示它并在 getJsonFromUrl 返回时关闭吗？

Answer 1

创建一个类:(只是一个模型代码..)

class Dialog{
 public void showDialog(){
         pd = new ProgressDialog(app);
         pd.setOwnerActivity(app);
         pd.setTitle("Идет загрузка...");
         pd.setCancelable(true);
         pd.show();
 }
 public void dismissDialog(){
      pd.dismiss();
 }
}

现在，只要您需要对话框，就可以通过您的应用访问它。