android - 如何在列表 fragment 中使用 AsyncTask 实现进度条？

Question

我想在加载列表之前显示进度条，如下图所示。我的类(class)用 AsyncTask 扩展了 SherlockListFragment。我看了很多，但没有得到实现 progressbar 的合适信息。任何人都可以帮助我如何实现如下图所示的进度条。

提前致谢。

图片 1

下面是我的课

public class Residential extends SherlockListFragment {

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle saved) {

    View view = inflater.inflate(R.layout.residential_list,container, false);
    resListviewId = (ListView)view.findViewById(android.R.id.list);
    projectList = new ArrayList<HashMap<String,String>>();

    new LoadProjects().execute();

    return view;
}

public void onStart() {
    super.onStart();

}

//inner class for network operation
private class LoadProjects extends AsyncTask<String, String, String> {

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
    }

    @Override
    protected String doInBackground(String... params) {
        return null;
    }

    @Override
    protected void onPostExecute(String result) {

        ListAdapter projAdapter = new SimpleAdapter(getSherlockActivity(),
                projectList, R.layout.residential_list_item, 
                new String[] {PROJ_ID,PROJ_NAME}, new int[] 
                        {R.id.projectId,R.id.projectName});
        //updating the UI
        setListAdapter(projAdapter);
    }
}
}

下面是progressbar.xml

    <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/projectLinearLayout"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal" 
    android:gravity="center_horizontal"
    android:padding="10dp"
    android:visibility="gone">

    <ProgressBar
        android:id="@+id/projectprogressBar"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_vertical" />

    <TextView 
        android:id="@+id/projectProgressTxtvw"
        android:text="@string/Loading"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>

</LinearLayout>

Answer 1

试试这个。它可能对您有用。

public class Residential extends SherlockListFragment 
{

public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle saved) 
{
View view = inflater.inflate(R.layout.residential_list,container, false);
resListviewId = (ListView)view.findViewById(android.R.id.list);
projectList = new ArrayList<HashMap<String,String>>();

new LoadProjects().execute();

return view;
}
public void onStart() {
super.onStart();

}
private class LoadProjects extends AsyncTask<String, String, String> {

@Override
protected void onPreExecute() {
   showLoader("Loading...");
    super.onPreExecute();
}

@Override
protected String doInBackground(String... params) {
    return null;
}

@Override
protected void onPostExecute(String result) {

           hideLoader();
    ListAdapter projAdapter = new SimpleAdapter(getSherlockActivity(),
            projectList, R.layout.residential_list_item, 
            new String[] {PROJ_ID,PROJ_NAME}, new int[] 
                    {R.id.projectId,R.id.projectName});
    //updating the UI
    setListAdapter(projAdapter);
}
}
public void showLoader(final String msg)
{
runOnUiThread(new Runnable() 
{ 
@Override
public void run() 
    {
if(dialog == null)
    dialog = new Dialog(this, R.style.Theme_Dialog_Translucent);
dialog.setContentView(R.layout.loading);
dialog.setCancelable(true);
dialog.show();
ImageView imgeView = (ImageView) dialog.findViewById(R.id.imgeView);
TextView tvLoading = (TextView)dialog.findViewById(R.id.tvLoading);
if(msg.length() > 0)
    tvLoading.setText(msg);
imgeView.setBackgroundResource(R.anim.frame);
animationDrawable = (AnimationDrawable) imgeView.getBackground();
imgeView.post(new Runnable()
{
 @Override
 public void run() 
 {
   if(animationDrawable != null)
    animationDrawable.start();
 }
});
 }
 });
 }
protected void hideLoader()
{
    runOnUiThread(new Runnable() 
    {
        @Override
        public void run()
        {
            if(dialog != null && dialog.isShowing())
                dialog.dismiss();
        }
    });
}
}

框架.xml:

<animation-list xmlns:android="http://schemas.android.com/apk/res/android" >
<item android:drawable="@drawable/loader1" android:duration="50"></item>
<item android:drawable="@drawable/loader2" android:duration="50"></item>
<item android:drawable="@drawable/loader3" android:duration="50"></item>
<item android:drawable="@drawable/loader4" android:duration="50"></item>
<item android:drawable="@drawable/loader5" android:duration="50"></item>
<item android:drawable="@drawable/loader6" android:duration="50"></item>
<item android:drawable="@drawable/loader7" android:duration="50"></item>
<item android:drawable="@drawable/loader8" android:duration="50"></item>
<item android:drawable="@drawable/loader9" android:duration="50"></item>
<item android:drawable="@drawable/loader10" android:duration="50"></item>
<item android:drawable="@drawable/loader11" android:duration="50"></item>
<item android:drawable="@drawable/loader12" android:duration="50"></item>
</animation-list>

加载.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/llPopup"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#000"
android:gravity="center"
android:orientation="vertical"
android:padding="20dp" >
<ImageView
android:id="@+id/imgeViews"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<TextView
android:id="@+id/tvLoading"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:singleLine="true"
android:text="Loading..."
android:textColor="#FFFFFF"
android:textSize="18dp" />
</LinearLayout>