与AsyncTask的进度对话框 [英] progress dialog with asynctask
问题描述
我有3类和类称为WebServiceCleint类扩展的AsyncTask
和 doInBackgrnd()
即时消息传递网址和IM从web服务获取数据。但即时调用这个从叫VerifyTeacherId另一个类的方法。现在我该怎么让进度对话框???我应该在哪里写pg.show和pg.dismiss。???
公共类WebServiceClient此类扩展的AsyncTask<字符串,太虚,字符串>
{
私有静态最后弦乐BASE_PATH =http://www.gdaschools.in/;
受保护的静态最后弦乐SLASH =/;
私人ProgressDialog对话框;
私人活动的活动;
公共WebServiceClient此类(活动活动){
this.activity =活动;
this.dialog =新ProgressDialog(活动);
}
@覆盖
在preExecute保护无效(){
this.dialog.setMessage(进度开始);
this.dialog.show();
}
@覆盖
保护字符串doInBackground(字符串... PARAMS){
StringBuffer的SB =新的StringBuffer();
sb.append(BASE_PATH);
sb.append(PARAMS [0]);
HTT pretriever retrieveResponse =新HTT pretriever();
retrieveResponse.retrieve(sb.toString());
返回retrieveResponse.getResponseXml();
}
@覆盖
保护无效onPostExecute(字符串结果){
如果(this.dialog.isShowing()){
this.dialog.dismiss();
}
}
}
和IM的地方调用它是在另一个名为类中的方法 SelectOptionActivity
。该方法是
公共无效verifyTeacherId(查看视图)
{
teacherIdString = TeacherId.getText()的toString()修剪()。
clientThread =新WebServiceClient此类(SelectOptionActivity.this);
clientThread.execute(教师/+ teacherIdString);
尝试
{
XML字符串= clientThread.get();
DocumentBuilderFactory的FACTORY1 = DocumentBuilderFactory.newInstance();
factory1.setNamespaceAware(真正的);
尝试
{
DocumentBuilder的建设者= factory1.newDocumentBuilder();
文档的文档= builder.parse(新的InputSource(新StringReader(XML)));
元根= doc.getDocumentElement();
如果(文件!= NULL)
{
NodeList的NL = doc.getElementsByTagName(EMPID);
如果(nl.getLength()大于0)
{
节点node = nl.item(0);
responseTeacherId = node.getTextContent();
}
节点列表N2 = doc.getElementsByTagName(empName);
如果(n2.getLength()大于0)
{
节点node = n2.item(0);
responseTeacherName = node.getTextContent();
}
}
Toast.makeText(getBaseContext(),+ responseTeacherId,10).show();
}
赶上(例外五)
{
e.printStackTrace();
}
}赶上(InterruptedException异常E){
// TODO自动生成的catch块
e.printStackTrace();
}赶上(为ExecutionException E){
// TODO自动生成的catch块
e.printStackTrace();
}
现在得到的错误,如
十二月5日至8日:10:10.834:D / AndroidRuntime(524):关闭虚拟机
十二月5日至八号:10:10.834:W / dalvikvm(524):主题ID = 1:螺纹退出与未捕获的异常(组= 0x40014760)
十二月5日至八号:10:10.872:E / AndroidRuntime(524):致命异常:主要
十二月5日至八号:10:10.872:E / AndroidRuntime(524):java.lang.RuntimeException的:无法实例活动ComponentInfo {com.GDAProj / com.GDAProj.SelectOptionActivity}:显示java.lang.NullPointerException
十二月5日至八号:10:10.872:E / AndroidRuntime(524):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1739)
十二月5日至八号:10:10.872:E / AndroidRuntime(524):在android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1831)
十二月5日至八号:10:10.872:E / AndroidRuntime(524):在android.app.ActivityThread.access $ 500(ActivityThread.java:122)
十二月5日至八号:10:10.872:E / AndroidRuntime(524):在android.app.ActivityThread $ H.handleMessage(ActivityThread.java:1024)
十二月5日至八号:10:10.872:E / AndroidRuntime(524):在android.os.Handler.dispatchMessage(Handler.java:99)
十二月5日至八号:10:10.872:E / AndroidRuntime(524):在android.os.Looper.loop(Looper.java:132)
十二月5日至八号:10:10.872:E / AndroidRuntime(524):在android.app.ActivityThread.main(ActivityThread.java:4123)
十二月5日至八号:10:10.872:E / AndroidRuntime(524):在java.lang.reflect.Method.invokeNative(本机方法)
十二月5日至八号:10:10.872:E / AndroidRuntime(524):在java.lang.reflect.Method.invoke(Method.java:491)
十二月5日至八号:10:10.872:E / AndroidRuntime(524):在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:841)
十二月5日至八号:10:10.872:E / AndroidRuntime(524):在com.android.internal.os.ZygoteInit.main(ZygoteInit.java:599)
十二月5日至八号:10:10.872:E / AndroidRuntime(524):在dalvik.system.NativeStart.main(本机方法)
十二月5日至八号:10:10.872:E / AndroidRuntime(524):由:显示java.lang.NullPointerException
十二月5日至八号:10:10.872:E / AndroidRuntime(524):在android.content.ContextWrapper.getApplicationInfo(ContextWrapper.java:132)
十二月5日至八号:10:10.872:E / AndroidRuntime(524):在android.view.ContextThemeWrapper.getTheme(ContextThemeWrapper.java:65)
十二月5日至八号:10:10.872:E / AndroidRuntime(524):在android.app.AlertDialog.resolveDialogTheme(AlertDialog.java:120)
十二月5日至八号:10:10.872:E / AndroidRuntime(524):在android.app.AlertDialog< INIT>(AlertDialog.java:80)
十二月5日至八号:10:10.872:E / AndroidRuntime(524):在android.app.ProgressDialog< INIT>(ProgressDialog.java:76)
。12月5日至八日:10:10.872:E / AndroidRuntime(524):在com.GDAProj.WebServiceClient< INIT>(WebServiceClient.java:20)
十二月5日至八号:10:10.872:E / AndroidRuntime(524):在com.GDAProj.SelectOptionActivity< INIT>(SelectOptionActivity.java:70)
十二月5日至八号:10:10.872:E / AndroidRuntime(524):在java.lang.Class.newInstanceImpl(本机方法)
十二月5日至八号:10:10.872:E / AndroidRuntime(524):在java.lang.Class.newInstance(Class.java:1301)
十二月5日至八号:10:10.872:E / AndroidRuntime(524):在android.app.Instrumentation.newActivity(Instrumentation.java:1022)
十二月5日至八号:10:10.872:E / AndroidRuntime(524):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1730)
十二月5日至八号:10:10.872:E / AndroidRuntime(524):11 ...更多
在$ P你当前活动的AsyncTask 类和使用方面显示进度对话框中的的合格范围内$ pExecute()
并驳回 onPostExecute()
公共类WebServiceClient此类扩展的AsyncTask<字符串,太虚,字符串>
{
私有静态最后弦乐BASE_PATH =http://www.gdaschools.in;
受保护的静态最后弦乐SLASH =/;
私人ProgressDialog对话框;
私人活动的活动;
公共WebServiceClient此类(活动活动){
this.activity =活动;
this.dialog =新ProgressDialog(活动);
}
@覆盖
在preExecute保护无效(){
this.dialog.setMessage(进度开始);
this.dialog.show();
}
@覆盖
保护无效onPostExecute(最终布尔成功){
如果(this.dialog.isShowing()){
this.dialog.dismiss();
}
。
。
。
code是唯一的理解。
i have 3 classes and the class called WebServiceCleint class is extending Asynctask
and in doInBackgrnd()
i m passing url and i m getting data from webservice. but i m calling this from another class's method called VerifyTeacherId. Now how can i show progress dialog??? where should i write the pg.show and pg.dismiss.???
public class WebServiceClient extends AsyncTask<String, Void, String>
{
private static final String base_path = "http://www.gdaschools.in/";
protected static final String SLASH = "/";
private ProgressDialog dialog;
private Activity activity;
public WebServiceClient(Activity activity) {
this.activity = activity;
this.dialog = new ProgressDialog(activity);
}
@Override
protected void onPreExecute() {
this.dialog.setMessage("Progress start");
this.dialog.show();
}
@Override
protected String doInBackground(String... params) {
StringBuffer sb = new StringBuffer();
sb.append(base_path);
sb.append(params[0]);
HttpRetriever retrieveResponse = new HttpRetriever();
retrieveResponse.retrieve(sb.toString());
return retrieveResponse.getResponseXml();
}
@Override
protected void onPostExecute(String result) {
if (this.dialog.isShowing()) {
this.dialog.dismiss();
}
}
}
And the method where i m calling is it in another class named SelectOptionActivity
. The method is
public void verifyTeacherId(View view)
{
teacherIdString = TeacherId.getText().toString().trim();
clientThread = new WebServiceClient(SelectOptionActivity.this);
clientThread.execute("teacher/" + teacherIdString);
try
{
String xml = clientThread.get();
DocumentBuilderFactory factory1 = DocumentBuilderFactory.newInstance();
factory1.setNamespaceAware(true);
try
{
DocumentBuilder builder = factory1.newDocumentBuilder();
Document doc =builder.parse(new InputSource(new StringReader(xml)));
Element root = doc.getDocumentElement();
if (doc != null)
{
NodeList nl = doc.getElementsByTagName("empId");
if (nl.getLength() > 0)
{
Node node = nl.item(0);
responseTeacherId = node.getTextContent();
}
NodeList n2=doc.getElementsByTagName("empName");
if (n2.getLength() > 0)
{
Node node = n2.item(0);
responseTeacherName = node.getTextContent();
}
}
Toast.makeText(getBaseContext(),""+responseTeacherId,10).show();
}
catch(Exception e)
{
e.printStackTrace();
}
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ExecutionException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Now getting error like
05-08 12:10:10.834: D/AndroidRuntime(524): Shutting down VM
05-08 12:10:10.834: W/dalvikvm(524): threadid=1: thread exiting with uncaught exception (group=0x40014760)
05-08 12:10:10.872: E/AndroidRuntime(524): FATAL EXCEPTION: main
05-08 12:10:10.872: E/AndroidRuntime(524): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.GDAProj/com.GDAProj.SelectOptionActivity}: java.lang.NullPointerException
05-08 12:10:10.872: E/AndroidRuntime(524): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1739)
05-08 12:10:10.872: E/AndroidRuntime(524): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1831)
05-08 12:10:10.872: E/AndroidRuntime(524): at android.app.ActivityThread.access$500(ActivityThread.java:122)
05-08 12:10:10.872: E/AndroidRuntime(524): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1024)
05-08 12:10:10.872: E/AndroidRuntime(524): at android.os.Handler.dispatchMessage(Handler.java:99)
05-08 12:10:10.872: E/AndroidRuntime(524): at android.os.Looper.loop(Looper.java:132)
05-08 12:10:10.872: E/AndroidRuntime(524): at android.app.ActivityThread.main(ActivityThread.java:4123)
05-08 12:10:10.872: E/AndroidRuntime(524): at java.lang.reflect.Method.invokeNative(Native Method)
05-08 12:10:10.872: E/AndroidRuntime(524): at java.lang.reflect.Method.invoke(Method.java:491)
05-08 12:10:10.872: E/AndroidRuntime(524): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:841)
05-08 12:10:10.872: E/AndroidRuntime(524): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:599)
05-08 12:10:10.872: E/AndroidRuntime(524): at dalvik.system.NativeStart.main(Native Method)
05-08 12:10:10.872: E/AndroidRuntime(524): Caused by: java.lang.NullPointerException
05-08 12:10:10.872: E/AndroidRuntime(524): at android.content.ContextWrapper.getApplicationInfo(ContextWrapper.java:132)
05-08 12:10:10.872: E/AndroidRuntime(524): at android.view.ContextThemeWrapper.getTheme(ContextThemeWrapper.java:65)
05-08 12:10:10.872: E/AndroidRuntime(524): at android.app.AlertDialog.resolveDialogTheme(AlertDialog.java:120)
05-08 12:10:10.872: E/AndroidRuntime(524): at android.app.AlertDialog.<init>(AlertDialog.java:80)
05-08 12:10:10.872: E/AndroidRuntime(524): at android.app.ProgressDialog.<init>(ProgressDialog.java:76)
05-08 12:10:10.872: E/AndroidRuntime(524): at com.GDAProj.WebServiceClient.<init>(WebServiceClient.java:20)
05-08 12:10:10.872: E/AndroidRuntime(524): at com.GDAProj.SelectOptionActivity.<init>(SelectOptionActivity.java:70)
05-08 12:10:10.872: E/AndroidRuntime(524): at java.lang.Class.newInstanceImpl(Native Method)
05-08 12:10:10.872: E/AndroidRuntime(524): at java.lang.Class.newInstance(Class.java:1301)
05-08 12:10:10.872: E/AndroidRuntime(524): at android.app.Instrumentation.newActivity(Instrumentation.java:1022)
05-08 12:10:10.872: E/AndroidRuntime(524): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1730)
05-08 12:10:10.872: E/AndroidRuntime(524): ... 11 more
Pass context of your current activity to AsyncTask class and using that context show progress dialog in onPreExecute()
and dismiss it onPostExecute()
public class WebServiceClient extends AsyncTask<String, Void, String>
{
private static final String base_path = "http://www.gdaschools.in";
protected static final String SLASH = "/";
private ProgressDialog dialog;
private Activity activity;
public WebServiceClient(Activity activity) {
this.activity = activity;
this.dialog = new ProgressDialog(activity);
}
@Override
protected void onPreExecute() {
this.dialog.setMessage("Progress start");
this.dialog.show();
}
@Override
protected void onPostExecute(final Boolean success) {
if (this.dialog.isShowing()) {
this.dialog.dismiss();
}
.
.
.
Code is only for your understanding..
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