跳过60帧！应用程序可能在其主线程上做了太多工作

Question

我正在开发一个应用程序，它应该从网络服务中获取JSON响应，并将每个元素写入列表视图，我读到我应该使用Asyncask来获取HTTP响应，我做到了，我可以从网络服务中检索数据并在TextViews中显示它们。但是当我尝试在列表视图中显示元素时，它不会显示任何内容，并在logcat中给我以下消息：06-05 19:44:27.418：我/编舞家（20731）：跳过了60帧！应用程序可能在其主线程上做了太多工作。

这是我的主要代码：

public class MainActivity extends Activity {

    private static JsonObject response = new JsonObject();
    private ArrayList<SearchResults> results = new ArrayList<SearchResults>(); 
    private SearchResults sr1 = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        new LoginAction().execute("");  

        ArrayList<SearchResults> searchResults = results;
        final ListView lv1 = (ListView) findViewById(R.id.ListView01);
        lv1.setAdapter(new MyCustomBaseAdapter(this, searchResults));
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    private class LoginAction extends AsyncTask<String, Void, String> {

        @Override
        protected String doInBackground(String... params) {

            Map<String, String> callArgs = new HashMap<String, String>(1);

            callArgs.put("suuid", "dtr0bdQGcqwSh3QO7fVwgVfBNWog6mvEbAyljlLX9E642Yfmur");

            try {
                response = EventPulseCloud.call("ListEvents", callArgs);
            } catch (HttpClientException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } catch (JsonException e) {
                e.printStackTrace();
            } 

            return response.get("Type").toString();
        }

        protected void onPostExecute(String result) {

            if(result.equals("success")) {
                JsonArray records = null;
                try {
                    records = response.getObject ("Data").getArray ("Records");
                } catch (JsonException e) {
                    e.printStackTrace();
                }

                for(int i = 0; i < records.count(); i++) {
                    JsonObject record = (JsonObject) records.get(i);
                    sr1 = new SearchResults();
                    sr1.setAddress(record.get("address").toString());
                    results.add(sr1);
                }
            }   
        }   
    }
    }

我的列表适配器：

public class MyCustomBaseAdapter extends BaseAdapter {
    private static ArrayList<SearchResults> searchArrayList;

    private LayoutInflater mInflater;

    public MyCustomBaseAdapter(Context context, ArrayList<SearchResults> results) {
        searchArrayList = results;
        mInflater = LayoutInflater.from(context);
    }

    public int getCount() {
        return searchArrayList.size();
    }

    public Object getItem(int position) {
        return searchArrayList.get(position);
    }

    public long getItemId(int position) {
        return position;
    }

    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder;
        if (convertView == null) {
            convertView = mInflater.inflate(R.layout.custom_row_view, null);
            holder = new ViewHolder();
            holder.txtAddress = (TextView) convertView.findViewById(R.id.address);

            convertView.setTag(holder);
        } else {
            holder = (ViewHolder) convertView.getTag();
        }

        holder.txtAddress.setText(searchArrayList.get(position).getAddress());

        return convertView;
    }

    static class ViewHolder {
        TextView txtAddress;
    }
}

最后是搜索结果。java：

public class SearchResults {
    private String address = "";

    public void setAddress(String address) {
        this.address = address;
    }

    public String getAddress() {
        return address;
    }
}

那么，我做错了什么？你对此有什么想法吗？

非常感谢。

Answer 1

private class LoginAction extends AsyncTaskList<String, Void, ArrayList<SearchResult>> {

    @Override
    protected ArrayList<SearchResult> doInBackground(String... params) {
        List<SearchResults> resultList =  new ArrayList<SearchResults>();

        Map<String, String> callArgs = new HashMap<String, String>(1);

        callArgs.put("suuid", "dtr0bdQGcqwSh3QO7fVwgVfBNWog6mvEbAyljlLX9E642Yfmur");

        try {
            response = EventPulseCloud.call("ListEvents", callArgs);
        } catch (HttpClientException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (JsonException e) {
            e.printStackTrace();
        } 
      //See here I am running the loop in the background so its not on the main thread, then passing the list off to the onpostexecute that way all the main thread does is set the adapter list and notify it of the data update and the list should be updated on the screen
       if( response.get("Type").toString().equals("success")) {
            JsonArray records = null;
            try {
                records = response.getObject ("Data").getArray ("Records");
            } catch (JsonException e) {
                e.printStackTrace();
            }

            for(int i = 0; i < records.count(); i++) {
                JsonObject record = (JsonObject) records.get(i);
                sr1 = new SearchResults();
                sr1.setAddress(record.get("address").toString());
                resultList.add(sr1);
            }
        }  
        return resultList;
    }

    protected void onPostExecute(ArrayList<SearchResult> resultList) {
          setListItems(resultList);

    }   
}
}

将此行添加到oncreate之前，并使用所有其他全局变量

   //here you want to create an adapter var with your base adapter so you can set it the updated list later when you have populated data from the internet
         ArrayList<SearchResults> searchResults = new ArrayList<SearchResults>();
         MyCustomBaseAdapter adapter = new MyCustomBaseAdapter(this, searchResults)

将其粘贴到oncreate方法上（替换它）

//here is just the code to update your main method to reflect all the changes I made
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    new LoginAction().execute("");  

    final ListView lv1 = (ListView) findViewById(R.id.ListView01);
    lv1.setAdapter(adapter);

}

并将此方法添加到适配器（MyCustomnBaseAdapter类）代码中

public void setListItems(ArrayList<SearchResult> newList) {
     searchArrayList = newList;
     notifyDataSetChanged();
}

Answer 2

onPostExecute（）发生在主UI线程上。看起来您仍在使用该方法进行大量工作，这些工作应该在UI线程外完成，即处理响应、迭代JSON对象等。在doInBackground（）中执行这些操作，并让其返回结果列表，因此onPostExecute需要做的唯一一件事就是将新项传递给列表适配器。

此外，不要使用与适配器持有的ArrayList相同的ArrayList。如果出于某种原因，适配器发现数据已更改，而您没有调用通知DataSetChanged（），它可能会崩溃（或至少显示奇怪的行为）。在Async任务中创建一个新的ArrayList，然后将其放入适配器并从onPostExecute调用：

public void setListItems(ArrayList<SearchResult> newList) {
    searchArrayList = newList;
    notifyDataSetChanged();
}