Android进度条未显示

Question

private Handler handler = new Handler()
{
    @Override
    public void handleMessage(Message msg)
    {
        removeDialog(0);
        switch (msg.what)
        {
            case SUCCESS:
                Log.i("LoginActivity", "Got inputstream");
                final InputStream is = (InputStream)msg.obj;
                if (is != null)
                {
                    //TODO: examine the input stream, etc...
                }
                break;
            case FAILURE:
                Log.i("LoginActivity", "Login failed");
                //TODO: Failure handling
                break;
            default:
                break;
        }
    }
};

@Override
protected Dialog onCreateDialog(int id)
{
    switch (id)
    {
        case 0:
        {
            dialog = new ProgressDialog(this);
            dialog.setMessage("Please wait...");
            dialog.setIndeterminate(true);
            dialog.setCancelable(true);
            return dialog;
        }
    }
    return null;
}

public void loginRequest(String name,String password)
{   
    showDialog(0);
    loginThread thread = new loginThread(serverURL, name, password,getMyIMENumber(), handler);
    thread.start();
}

.

public class loginThread extends Thread {

String name;
String password;
InputStream is;
String Url;
String ime;

private final Handler handler;

   public loginThread(String Url,String name,String password,String ime,final Handler handler) {
       this.name = name;
       this.Url = Url;
       this.password = password;
       this.ime = ime;
       this.handler = handler;         
   }


   public void run() {
          try{
                  HttpClient httpClient = new DefaultHttpClient();
                  String loginURL = Url+"member/login";
                  HttpPost httppost = new HttpPost(loginURL);
                  HttpParams httpParameters = new BasicHttpParams();
                  List<NameValuePair> pairs = new ArrayList<NameValuePair>();
                  if(name.contentEquals(""))
                  {
                      pairs.add(new BasicNameValuePair("ime", ime));
                  }
                  else
                  {
                      pairs.add(new BasicNameValuePair("userName", name));
                      pairs.add(new BasicNameValuePair("password", password));                            
                  }                  


                  int timeoutConnection = 3000;
                  HttpConnectionParams.setConnectionTimeout(httpParameters, timeoutConnection);
                  // Set the default socket timeout (SO_TIMEOUT) 
                  // in milliseconds which is the timeout for waiting for data.
                  httppost.setEntity(new UrlEncodedFormEntity(pairs));
                  HttpResponse response = httpClient.execute(httppost);                           
                  HttpEntity entity = response.getEntity();
                  final InputStream is = entity.getContent();

                  Message message = new Message();
                  message.obj = is;
                  message.what = server.SUCCESS;
                  handler.sendMessage(message);
          }catch(Exception e){  
              Log.e("log_tag", "Error in http connection " + e.toString(), e);
              handler.sendEmptyMessage(server.FAILURE);
          }           

   }

}

进度对话框没有显示我做错了什么！！请帮帮我..

..

//编译自DexFile.java (版本1.5 : 49.0，超级位)公共最终类dalvik.system.DexFile {

//方法描述符#8 (Ljava/io/File;)V //堆栈: 3，本地:2个公共文件(java.io.File DexFile)抛出java.io.IOException；0 aload_0此1调用特殊java.lang.Object() 1 4新java.lang.RuntimeException 2 7 dup 8 LDC3 10调用特殊java.lang.RuntimeException(java.lang.String) 4 13行线号: pc: 0，line: 4局部变量表: pc: 0，pc: 14 local:此索引:0类型: dalvik.system.DexFile pc: 0，pc: 14 local:文件索引:1类型: java.io.File

//方法描述符#18 (Ljava/lang/String;)V //栈: 3，本地:2个公共DexFile(java.lang.String fileName)抛出java.io.IOException；0 aload_0此1调用特殊java.lang.Object() 1 4新索引2 7 dup 8 LDC3 10调用特殊java.lang.RuntimeException( java.lang.String ) 4 13行线路编号: pc: 0，line: 5局部变量表: pc: 0，pc: 14 local:此索引:0类型: dalvik.system.DexFile pc: 0，pc: 14 local: fileName index: 1类型:java.lang.String

//方法描述符#22 (Ljava/lang/String;Ljava/lang/String;I)Ldalvik/system/DexFile；//堆栈: 3，本地变量:3公共静态标志loadDex(java.lang.String sourcePathName，java.lang.String outputPathName，int dalvik.system.DexFile )抛出java.io.IOException；0新java.lang.RuntimeException 2 3 dup 4 LDC3 6调用特殊java.lang.RuntimeException( java.lang.String ) 4 9行线路编号: pc: 0，line: 6局部变量表: pc: 0，pc: 10 local: sourcePathName index: 0类型: java.lang.String pc: 0，pc: 10 local: outputPathName index: 1类型:java.lang.String pc: 0pc: 10 local:标志索引:2类型: int

//方法描述符#28 ()Ljava/lang/String；//栈: 3，本地变量:1公共java.lang.String getName()；0新索引2 3 dup 4 ldc 3 6调用特殊java.lang.RuntimeException(java.lang.String) 4 9行线号: pc: 0，line: 7局部变量表: pc: 0，pc: 10 local: this index: 0 java.lang.RuntimeException :0 java.lang.RuntimeException: dalvik.system.DexFile

//方法描述符#30 ()V //堆栈: 3，局部变量:1 public void close()抛出java.io.IOException；0新索引2 3 dup 4 ldc 3 6 invokespecial java.lang.RuntimeException(java.lang.String) 4 9 athrow行号: pc: 0，line: 8局部变量表: pc: 0，pc: 10 local: this index: 0 java.lang.RuntimeException :0 type: dalvik.system.DexFile

//方法描述符#32 (Ljava/lang/String;Ljava/lang/ClassLoader;)Ljava/lang/Class；//堆栈: 3，本地变量:3公共java.lang.Class loadClass(java.lang.String name，java.lang.ClassLoader loader)；0新的java.lang.RuntimeException 2 3 dup 4 LDC3 6调用特殊java.lang.RuntimeException( java.lang.String ) 4 9行线路编号: pc: 0，line: 9局部变量表: pc: 0，pc: 10 local:此索引:0类型: dalvik.system.DexFile pc: 0，pc: 10 local:名称索引:1类型:java.lang.String pc: 0，pc: 10 local: local:2类型: java.lang.ClassLoader

//方法描述符#37 ()Ljava/util/枚举；//签名：()Ljava/util/枚举；//堆栈: 3，本地:1个公共java.util.Enumeration条目()；0新java.lang.RuntimeException 2 3 dup 4 ldc 3 6调用特殊java.lang.RuntimeException(java.lang.String) 4 9行线路编号: pc: 0，line: 10局部变量表: pc: 0，pc: 10 local:此索引:0类型: dalvik.system.DexFile

//方法描述符#30 ()V // Stack: 3，Locals: 1 protected void finalize()抛出java.io.IOException；0 new java.lang.RuntimeException 2 3 dup 4 ldc 3 6 invokespecial java.lang.RuntimeException(java.lang.String) 4 9 athrow行号: pc: 0，line: 11局部变量表: pc: 0，pc: 10 local: this index: 0类型: dalvik.system.DexFile

//方法描述符#42 (Ljava/lang/String;)Z公共静态本机布尔isDexOptNeeded(java.lang.String arg0)抛出java.io.FileNotFoundException，java.io.IOException；}

Answer 1

你立即从你的线程中检索InputStream，很可能它仍然是空的，或者有它的初始值，还没有得到http响应。这样，您的进度对话框最多显示几毫秒。

在调用thread.start()之后结束您的loginRequest，如果您使用Handler获得了UI线程的结果或任何异常，则从线程的run方法中进行通信。在处理程序的handleMessage中检查loginRequest的结果(结果输入流应直接传递给处理程序，而不是从线程中检索它)，并删除进度对话框。

以下是如何使用线程实现所需功能的更新示例：

在下面的代码中，您的main activity被引用为LoginActivity (因为我不知道您的类名)，所以您应该将其更改为您拥有loginRequest方法的java activity类的名称。

从您的主活动中删除showProgressDialog()方法，并放入：

public static final int FAILURE = 0;
public static final int SUCCESS = 1;
private ProgressDialog dialog;

private Handler handler = new Handler()
{
    @Override
    public void handleMessage(Message msg)
    {
        removeDialog(0);
        switch (msg.what)
        {
            case SUCCESS:
                Log.i("LoginActivity", "Got inputstream");
                final InputStream is = (InputStream)msg.obj;
                if (is != null)
                {
                    //TODO: examine the input stream, etc...
                }
                break;
            case FAILURE:
                Log.i("LoginActivity", "Login failed");
                //TODO: Failure handling
                break;
            default:
                break;
        }
    }
};

@Override
protected Dialog onCreateDialog(int id)
{
    switch (id)
    {
        case 0:
        {
            dialog = new ProgressDialog(this);
            dialog.setMessage("Please wait...");
            dialog.setIndeterminate(true);
            dialog.setCancelable(true);
            return dialog;
        }
    }
    return null;
}

public void loginRequest(String name, String password)
{
    showDialog(0);
    LoginThread thread = new LoginThread(serverURL, name, password, 
        getMyIMENumber(), handler);
    thread.start();
}

注意，loginRequest方法已经改变了！

您的LoginThread类也是如此：

public class LoginThread extends Thread
{

    private final String name;
    private final String password;
    private final String url;
    private final String ime;
    private final Handler handler;

    public LoginThread(String Url, String name, String password, 
        String ime, final Handler handler)
    {
        this.name = name;
        this.url = Url;
        this.password = password;
        this.ime = ime;
        this.handler = handler;
    }

    public void run()
    {
        try
        {
            HttpClient httpClient = new DefaultHttpClient();
            String loginURL = url + "member/login";
            HttpPost httppost = new HttpPost(loginURL);
            HttpParams httpParameters = new BasicHttpParams();
            List<NameValuePair> pairs = new ArrayList<NameValuePair>();
            if (name.contentEquals(""))
            {
                pairs.add(new BasicNameValuePair("ime", ime));
            }
            else
            {
                pairs.add(new BasicNameValuePair("userName", name));
                pairs.add(new BasicNameValuePair("password", password));
            }

            int timeoutConnection = 3000;
            HttpConnectionParams.setConnectionTimeout(httpParameters, 
                timeoutConnection);
            // Set the default socket timeout (SO_TIMEOUT)
            // in milliseconds which is the timeout for waiting for data.
            httppost.setEntity(new UrlEncodedFormEntity(pairs));
            HttpResponse response = httpClient.execute(httppost);
            HttpEntity entity = response.getEntity();
            final InputStream is = entity.getContent();

            Message message = new Message();
            message.obj = is;
            message.what = LoginActivity.SUCCESS;
            handler.sendMessage(message);
        }
        catch (Exception e)
        {
            Log.e("log_tag", "Error in http connection " + e.toString(), e);
            handler.sendEmptyMessage(LoginActivity.FAILURE);
        }
    }
}

现在，您的LoginThread实例有了一个Handler类型的新成员。它是通过构造函数参数初始化的(与其他参数一样)，因此可以将其声明为final。

此处理程序将通知您的UI线程(主活动)，如果它从http响应中获得了输入流，或者由于某种原因而失败。

完成Handler实现，让它做您需要的事情。

我希望代码能把这种方法讲清楚一点。

Answer 2

不要调用thread.run()，而要调用thread.start()。

run()在同一线程上调用函数run()。start()将在新线程中调用它。当前，GUI线程被阻塞，因为它执行本应在后台线程中完成的操作。

您可以通过以下方式调用线程：

Thread thread = new Thread(new loginThread(serverURL, name, password,getMyIMENumber()));
thread.start();

或者让你的loginThread 扩展线程，而不是实现Runnable。

Answer 3

除非您调用进度对话框的show方法，否则它不会显示。

do this in your showProgressDialog method -- mDialog.show();