未显示进度对话框

Question

我有这段代码片段，这段代码的问题是当我单击“完成”按钮时 进度对话框未显示。请帮忙

public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.send);


        done = (Button)findViewById(R.id.sendbut);

        done.setOnClickListener(new OnClickListener() {             

            public void onClick(View v) {

                 showProgressDialog();
                 query_str = getString();
                         startUploading();
            }
        });          
 }

 public void showProgressDialog(){
     GlobalClass.printLine("Showing progress dialog"); 
     progressDialog = new ProgressDialog(Send.this);
     progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
     progressDialog.setMessage("Sending...");
     progressDialog.setCancelable(false);
     progressDialog.show();  
     // Start lengthy operation in a background thread
     new Thread(new Runnable() {
         public void run() {
                 // Update the progress bar
                 mHandler.post(new Runnable() {
                     public void run() {
                         progressDialog.setProgress(mProgressStatus);
                         Toast.makeText(getApplicationContext(), "Herererererer",Toast.LENGTH_LONG).show();
                         if(mProgressStatus == 100){                                             
                             Toast.makeText(getApplicationContext(), "Done",Toast.LENGTH_LONG).show();
                             progressDialog.dismiss();
                         }
                     }
                 });                                 
             }
     }).start(); 
 }

Answer 1

您是否尝试过使用AsyncTask？

这是文档： http://developer.android.com/reference/android/ os/AsyncTask.html

您可能想用 AsyncTask 替换线程。

Answer 2

您应该使用 AsyncTask，它也称为无痛线程。

现在，要在后台处理时显示进度条，下面是一个示例：

    // ASync Task Begin to perform 
 private class performBackgroundTask extends Async Task < Void, Void, Void >  
 {
    private ProgressDialog Dialog = new ProgressDialog( this);

    protected void onPreExecute() 
    {
           // here you have place code which you want to show in UI thread like progressbar or dialog or any layout . 
           Dialog.setMessage(" please wait...");
           Dialog.show();
    }

    protected Void doInBackground(Void... params) 
    {
       // write here the code to download  or to perform any background task.
   return null;
  }

  protected void onPostExecute(Void unused) {
     Dialog.dismiss();  // here we have to dismiss the progress dialog 
   // To display fetched data in textview, imageview, or any

  }

 }

Answer 3

@Hari ..

我认为您正在从startUploading()内部调用另一个函数，这就是ProgressDialog不显示的原因。尝试在 XML 中创建进度条并将所有函数写入按钮单击内。如果这是一个递归函数，请更改您的逻辑以在按钮单击本身内调用它。

Answer 4

Paresh Mayani 上面发布的答案将不起作用，因为您无法

new ProgressDialog(this)

在 AsyncTask 中使用。 “this”需要是一个上下文。