这是我的活动...我怎样才能在后台执行test（）函数，这样我才能在执行test（）之前显示一些东西？是否可以在显示布局后动态加载内容???请帮帮我...........
public class viewstoryActivity extends Activity {
LinearLayout layout1;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.list);
/** Create a new layout to display the view */
//ScrollView sv = (ScrollView)findViewById(R.id.sv);
layout1 =(LinearLayout)findViewById(R.id.LinearLayout);
test();
}
public void test(){
try{
LinearLayout layout[];
LinearLayout layout2[];
LinearLayout layout3[];
TextView name[];
TextView desc[];
TextView viewCount[];
ImageView website[];
ImageView star[];
TextView category[];
//ImageButton img[];
URL url = new URL("http://gdata.youtube.com/feeds/api/videos?start-index=1&max-results=25&vq=itsaperfectstory&orderby=relevance");
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document doc = db.parse(new InputSource(url.openStream()));
//doc.getDocumentElement().normalize();
NodeList nodeList = doc.getElementsByTagName("entry");
/** Assign textview array lenght by arraylist size */
layout= new LinearLayout[nodeList.getLength()];
layout2= new LinearLayout[nodeList.getLength()];
layout3= new LinearLayout[nodeList.getLength()];
name = new TextView[nodeList.getLength()];
desc = new TextView[nodeList.getLength()];
viewCount = new TextView[nodeList.getLength()];
website = new ImageView[nodeList.getLength()];
star = new ImageView[nodeList.getLength()];
category = new TextView[nodeList.getLength()];
//img = new ImageButton[nodeList.getLength()];
for (int i = 0; i < nodeList.getLength(); i++) {
Node node = nodeList.item(i);
layout[i]= new LinearLayout(this);
layout[i].setOrientation(LinearLayout.HORIZONTAL);
layout[i].setBackgroundResource(R.anim.bg);
layout[i].setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT,150));
layout2[i]= new LinearLayout(this);
layout2[i].setOrientation(LinearLayout.VERTICAL);
layout2[i].setLayoutParams(new LayoutParams(400,150));
layout3[i]= new LinearLayout(this);
layout3[i].setOrientation(LinearLayout.VERTICAL);
layout3[i].setLayoutParams(new LayoutParams(150,150));
name[i] = new TextView(this);
desc[i] = new TextView(this);
viewCount[i]=new TextView(this);
website[i] = new ImageView(this);
star[i]=new ImageView(this);
category[i] = new TextView(this);
//img[i] = new ImageButton(this);
//img[i].setBackgroundResource(R.anim.button);
//img[i].setLayoutParams(new LayoutParams(74,35));
name[i].setPadding(10, 20,0,0);
name[i].setTextSize(16);
Element fstElmnt = (Element) node;
NodeList nameList = fstElmnt.getElementsByTagName("title");
Element nameElement = (Element) nameList.item(0);
nameList = nameElement.getChildNodes();
name[i].setText(((Node) nameList.item(0)).getNodeValue());
name[i].setLines(1);
NodeList websiteList = fstElmnt.getElementsByTagName("media:content");
Element websiteElement = (Element) websiteList.item(0);
websiteList = websiteElement.getChildNodes();
final String url1=websiteElement.getAttribute("url");
NodeList websiteList1 = fstElmnt.getElementsByTagName("media:thumbnail");
Element websiteElement1 = (Element) websiteList1.item(0);
String test=websiteElement1.getAttribute("url");
NodeList descitem = fstElmnt.getElementsByTagName("content");
Element descElement = (Element) descitem.item(0);
nameList = descElement.getChildNodes();
desc[i].setText(((Node) nameList.item(0)).getNodeValue());
desc[i].setLines(1);
desc[i].setTextColor(Color.DKGRAY);
desc[i].setPadding(10,8,0,0);
NodeList gditem = fstElmnt.getElementsByTagName("yt:statistics");
Element gdElement = (Element) gditem.item(0);
String view1=gdElement.getAttribute("viewCount");
viewCount[i].setText(view1+" views");
viewCount[i].setPadding(10,8,0,0);
Bitmap bm = null; URL aURL = new URL(test); URLConnection conn = aURL.openConnection(); conn.connect();
InputStream is = conn.getInputStream(); BufferedInputStream bis = new BufferedInputStream(is);
bm = BitmapFactory.decodeStream(bis); bis.close(); is.close(); // TODO: handle exception
website[i].setImageBitmap(bm);
website[i].setPadding(30, 20, 0, 0);
layout3[i].addView(website[i]);
layout2[i].addView(name[i]);
layout2[i].addView(desc[i]);
layout2[i].addView(viewCount[i]);
NodeList staringitem = fstElmnt.getElementsByTagName("gd:rating");
if ((staringitem==null)||(staringitem.getLength()==0)) {
star[i].setImageResource(R.drawable.star0);
layout2[i].addView(star[i]);
}
else
{
Element starElement = (Element) staringitem.item(0);
String stars = starElement.getAttribute("average");
double d=Double.parseDouble(stars);
DecimalFormat decimalFormat=new DecimalFormat("#");
stars=decimalFormat.format(d);
if (stars.contentEquals("1")) {
star[i].setImageResource(R.drawable.star1);
layout2[i].addView(star[i]);
}
else if (stars.contentEquals("2")) {
star[i].setImageResource(R.drawable.star2);
layout2[i].addView(star[i]);
}
else if (stars.contentEquals("3")) {
star[i].setImageResource(R.drawable.star3);
layout2[i].addView(star[i]);
}
else if (stars.contentEquals("4")) {
star[i].setImageResource(R.drawable.star4);
layout2[i].addView(star[i]);
}
else if (stars.contentEquals("5")) {
star[i].setImageResource(R.drawable.star5);
layout2[i].addView(star[i]);
}
else if (stars.contentEquals("0")) {
star[i].setImageResource(R.drawable.star0);
layout2[i].addView(star[i]);
}
}
layout[i].addView(layout3[i]);
layout[i].addView(layout2[i]);
//layout.addView(category[i]);
//layout[i].addView(img[i]);
((LinearLayout)layout1).addView(layout[i]);
layout[i].setOnClickListener(new OnClickListener() {
public void onClick(View v) {
/*Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(url1));
startActivity(intent);*/
Bundle bundle = new Bundle();
// add data to bundle
bundle.putString("url", url1);
Intent intent=new Intent(viewstoryActivity.this , VidActivity.class);
intent.putExtras(bundle);
startActivityForResult(intent, 0);
overridePendingTransition (R.anim.right_slide_out, R.anim.right_slide_out);
}
});
}
}
catch (Exception e) {
System.out.println("XML Pasing Excpetion = " + e);
}
/** Set the layout view to display */
// ((ScrollView) sv).addView(layout1);
//setContentView(sv);
}
}
答案 0 :(得分：2)
使用AsyncTask进行后台操作。
答案 1 :(得分：1)
创建一个将AsyncTask扩展为
private class DownloadTask extends AsyncTask<String, Void, String> {
@Override
protected String doInBackground(String... urls) {
test();
return "";
}
@Override
protected void onPostExecute(String result) {
}
}
在oncreate中，您可以执行test()
DownloadTask task = new DownloadTask();
task.execute();
答案 2 :(得分：0)
创建子类：
public class LoadData extends AsyncTask<Void, Void, Void>
{
ProgressDialog progressDialog;
//declare other objects as per your need
@Override
protected void onPreExecute()
{
progressDialog= ProgressDialog.show(YourActivity.this, "Progress Dialog Title Text","Process Description Text", true);
//do initialization of required objects objects here
};
@Override
protected Void doInBackground(Void... params)
{
test();
//do other operation as required
return null;
}
@Override
protected void onPostExecute(Void result)
{
super.onPostExecute(result);
progressDialog.dismiss();
};
}
现在，无论何时需要加载数据，都可以创建对象，并使用它：
...
LoadData ld=new LoadData();
ld.execute();
...
使用它将为您提供一个在后台运行活动的progess对话框，并且在完成操作之前不允许用户执行任何操作。您可以根据您的要求在onPreExecute（）中设置自定义标题文本和说明文字。