android - 更新 ListView 中的进度条

Question

我有一个场景，在我的聊天应用程序中我想发送照片，照片发送需要时间。我附上了一个进度条(水平)来显示在我的应用程序中发送照片的进度。但是我无法更新进度条，因为它是自定义 ListView 的项目。

这是我设置进度条进度的异步任务，但我无法获取它。

 class SendPhotoToFriend extends AsyncTask<String, String, String>{

        String receiver,path = "";

        public SendPhotoToFriend(String path,String receiver) {
            // TODO Auto-generated constructor stub

            this.path = path;
            this.receiver = receiver;

        }


        @Override
        protected String doInBackground(String... arg0) {
            // TODO Auto-generated method stub

            ServiceDiscoveryManager sdm = ServiceDiscoveryManager
            .getInstanceFor(connection);

            if (sdm == null)
                sdm = new ServiceDiscoveryManager(connection);

            sdm.addFeature("http://jabber.org/protocol/disco#info");
            sdm.addFeature("jabber:iq:privacy");

            // Create the file transfer manager
            FileTransferManager manager = new FileTransferManager(
                    connection);
            FileTransferNegotiator.setServiceEnabled(connection, true);

            // Create the outgoing file transfer
            OutgoingFileTransfer transfer = manager
            .createOutgoingFileTransfer(receiver + "/Smack");

            System.out.println("Receiver of the file is "+receiver+"/smack");

            Log.i("transfere file", "outgoingfiletransfer is created");

            try {
                long total = 0;

                OutgoingFileTransfer.setResponseTimeout(30000);
                transfer.sendFile(new File(path), "Description");
                Log.i("transfere file", "sending file");
                while (!transfer.isDone()) {
                    //Thread.sleep(1000);

                    total+=transfer.getProgress();

                    publishProgress(""+(int)((total*100)/transfer.getFileSize()));

                    Log.i("transfere file", "sending file status "
                            + transfer.getStatus() + "progress: "
                            + transfer.getProgress());
                    if (transfer.getStatus() == org.jivesoftware.smackx.filetransfer.FileTransfer.Status.error) {
                        Log.i("transfere file", "Errorrr isss: "
                                + transfer.getError()+transfer.getPeer());
                        transfer.cancel();
                        break;
                    }
                }

            } catch (XMPPException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

            Log.i("transfere file", "sending file done");

            return null;
        }

        @Override
        protected void onProgressUpdate(final String... values) {
            // TODO Auto-generated method stub
            super.onProgressUpdate(values);


            LayoutInflater inflater = (LayoutInflater)getBaseContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
            final View view =inflater.inflate(R.layout.user_chat_send_chat, null); 
            ProgressBar p_Bar = (ProgressBar)view.findViewById(R.id.progress_bar_image);
            p_Bar.setProgress(Integer.parseInt(values[0]));

            customAdapter1.notifyDataSetChanged();



        }

        @Override
        protected void onPostExecute(String result) {
            // TODO Auto-generated method stub
            super.onPostExecute(result);
        }
    }

进度条是自定义 ListView 的 View ，我想在运行时更新。

谢谢

Answer 1

您正在 onProgress 回调中膨胀 ProgressBar。这是绝对错误的。 ProgressBar 应该在您的 AsyncTask 启动(膨胀和添加)之前添加到 View 中，然后将其转换为在您的 AsyncTask 构造函数中可见。您还应该在 AsyncTask 中存储对 ProgressBar 的引用(或以其他方式在非静态内部类的范围内)。

最后你的 AsyncTask 应该看起来像这样(假设 ProgressBar 已经附加到 View ):

class SendPhotoToFriend extends AsyncTask<String, String, String> {

    String receiver,path = "";

    ProgressBar progress;

    public SendPhotoToFriend(String path, String receiver, ProgressBar progress) {
        this.path = path;
        this.receiver = receiver;
        this.progress = progress;
        this.progress.setVisibility(View.Visible); 
    }


    @Override
    protected String doInBackground(String... arg0) {
        // You're application logic...
        // ...
        publishProgress((int)((total*100)/transfer.getFileSize()));
        // ...
    }

    @Override
    protected void onProgressUpdate(final Integer... values) {
        this.progress.setProgress(values[0]); 
    }
}

此外，您不需要(也不应该)在 onProgres-Callback 中调用 adapter.notifiyDataSetChanged()。