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我正在使用 AsyncTask 来更新水平进度对话框。没有错误。我唯一想不通的是 ProgressDialog 仅在后台工作后出现。

也就是说，单击按钮时（依次执行以下操作：）

    //within concerned OnClick Function of my main class:
    ASYNC_TEST GH=new ASYNC_TEST(this,"something","something","url", "booga");
    String response=GH.execute().get();

按钮键保持按下很长时间（HTTP POST 很慢），然后突然出现进度对话框不超过一秒钟，一次完成 100% 并消失。

我正在粘贴我的代码：

下面是扩展 AsyncTask 的类，它处理 HTTP Post 操作并且应该更新进度条。

    import android.app.ProgressDialog;
    import android.os.AsyncTask;
    import android.content.Context;
    import android.util.Log;

    public class ASYNC_TEST extends AsyncTask<Void, Integer, String> {

    private String result = "";
    private int ProgressStatus;
    String username, password, THE_URL, YouSure;

    private ProgressDialog pdb;

    public ASYNC_TEST(Context ConT, String username, String password,String THE_URL, String YouSure) 
    {
        Log.d("LOG_TAG", "Constructor");

        this.username = username;
        this.password = password;
        this.THE_URL = THE_URL;
        this.YouSure = YouSure;

        pdb = new ProgressDialog(ConT);
    }

    @Override
    protected void onPreExecute() 
    {

        pdb.setCancelable(true);
        pdb.setMessage("Logging In. Hold On a Sec...");
        pdb.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
        pdb.setProgress(0);
        pdb.setMax(100);
        pdb.show();

        Log.d("LOG_TAG", "Pre-Execute");
        super.onPreExecute();
    }

    @Override
    protected void onPostExecute(String res) 
    {

        Log.d("LOG_TAG", "Post-Execute");
        pdb.dismiss();
        super.onPostExecute(res);
    }

    @Override
    protected void onProgressUpdate(Integer... progress) 
    {

        Log.d("LOG_TAG", "Progress Update: " + progress[0]);
        pdb.setProgress(progress[0]);
        super.onProgressUpdate();
    }

    @Override
    protected String doInBackground(Void... smt) 
    {
        Log.d("LOG_TAG", "doInBackground: ");

        try {

            ProgressStatus = 0;
            publishProgress(0);

            //Stuff

            ProgressStatus = 10;
            publishProgress(10);

            // More Stuff (HTTP POST)

            ProgressStatus = 20;
            publishProgress(10);

            //....Finally...

            ProgressStatus = 100;
            publishProgress(100);


        catch (Exception e) 
        {
            e.printStackTrace();
        }

        return "";

    }
    }

日志数据：

    05-18 15:19:52.773: D/LOG_TAG(1596): Constructor
    05-18 15:19:52.822: D/LOG_TAG(1596): Pre-Execute
    05-18 15:19:52.832: D/LOG_TAG(1596): doInBackground: 
    05-18 15:19:53.482: D/dalvikvm(1596): GC freed 13648 objects / 583400 bytes in 77ms
    05-18 15:19:53.502: D/OpenSSLSessionImpl(1596): Freeing OpenSSL session
    05-18 15:19:53.982: D/dalvikvm(1596): GC freed 17495 objects / 885728 bytes in 77ms
    05-18 15:19:54.292: D/dalvikvm(1596): GC freed 10363 objects / 441600 bytes in 71ms
    05-18 15:19:54.982: D/dalvikvm(1596): GC freed 6564 objects / 298808 bytes in 71ms
    05-18 15:19:55.132: I/global(1596): Default buffer size used in BufferedReader constructor. It would be better to be explicit if an 8k-char buffer is required.
    05-18 15:19:55.212: D/dalvikvm(1596): GC freed 843 objects / 85392 bytes in 65ms
    05-18 15:19:55.212: I/dalvikvm-heap(1596): Grow heap (frag case) to 4.120MB for 22148-byte allocation
    05-18 15:19:55.282: D/dalvikvm(1596): GC freed 1 objects / 14776 bytes in 68ms
    05-18 15:19:56.012: I/global(1596): Default buffer size used in BufferedReader constructor. It would be better to be explicit if an 8k-char buffer is required.
    05-18 15:19:56.092: D/dalvikvm(1596): GC freed 1758 objects / 193224 bytes in 67ms
    05-18 15:19:56.172: D/dalvikvm(1596): GC freed 391 objects / 44792 bytes in 67ms
    05-18 15:19:56.252: D/dalvikvm(1596): GC freed 411 objects / 62120 bytes in 66ms
    05-18 15:19:56.252: I/dalvikvm-heap(1596): Grow heap (frag case) to 4.194MB for 54142-byte allocation
    05-18 15:19:56.322: D/dalvikvm(1596): GC freed 1 objects / 36104 bytes in 69ms
    05-18 15:19:56.413: D/dalvikvm(1596): GC freed 955 objects / 67536 bytes in 70ms
    05-18 15:19:56.413: I/dalvikvm-heap(1596): Grow heap (frag case) to 4.237MB for 81208-byte allocation
    05-18 15:19:56.483: D/dalvikvm(1596): GC freed 1 objects / 54152 bytes in 69ms
    05-18 15:19:56.852: I/global(1596): Default buffer size used in BufferedReader constructor. It would be better to be explicit if an 8k-char buffer is required.
    05-18 15:19:56.942: D/dalvikvm(1596): GC freed 1317 objects / 241880 bytes in 71ms
    05-18 15:19:57.112: D/LOG_TAG(1596): Progress Update: 0
    05-18 15:19:57.112: D/LOG_TAG(1596): Progress Update: 10
    05-18 15:19:57.122: D/LOG_TAG(1596): Progress Update: 20
    05-18 15:19:57.122: D/LOG_TAG(1596): Progress Update: 30
    05-18 15:19:57.122: D/LOG_TAG(1596): Progress Update: 40
    05-18 15:19:57.133: D/LOG_TAG(1596): Progress Update: 50
    05-18 15:19:57.133: D/LOG_TAG(1596): Progress Update: 70
    05-18 15:19:57.133: D/LOG_TAG(1596): Progress Update: 90
    05-18 15:19:57.133: D/LOG_TAG(1596): Progress Update: 100
    05-18 15:19:57.133: D/LOG_TAG(1596): Post-Execute
    05-18 15:19:57.513: W/InputManagerService(51): Window already focused, ignoring focus gain of: com.android.internal.view.IInputMethodClient$Stub$Proxy@44c5f5a0
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1 回答 1

1

Seems like the delay is due to get() method in String response=GH.execute().get();. It puts wait on the execution till the AsyncTask is completed.

As per Javadoc:

get(): Waits if necessary for the computation to complete, and then retrieves its result.

I think you should simply call GH.execute(); to execute your AsyncTask wihtout affecting UI thread by putting it on hold.

于 2012-05-18T10:29:48.490 回答