Question

我正在尝试从xml获取图像和文本...但我希望这个进展发生在后台，所以我试图使用一个线程，我可以将我的数据放入一些数组，然后我可以设置我的带有此数组的imageView和textView。当我运行时，我看到在线程中程序工作正常获取数据并放入数组...但在setText和setImageBitmap，我看到那些数组是空的？！怎么会发生？

我基本上遵循本教程从Xml获取数据：http://p-xr.com/android-tutorial-how-to-parseread-xml-data-into-android-listview/

这是我的代码：

 public class mainPage {

HashMap<Integer, String> desc;
HashMap<Integer, Bitmap> bitMap;
ScrollView scroll;
View app, temp;
static int j = 0;
static View first;
static NodeList nodes;
static TextView textView, textView1, textView2;
static ImageView img, image1, image2;
LinearLayout parent;
HashMap<Integer, View> others;
Runnable get;

public mainPage() {

    this.app = MainActivity.app;
    this.scroll = (ScrollView) app.findViewById(R.id.mainPage_scroll);
    this.parent = new LinearLayout(scroll.getContext());

    parent.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT,
            LayoutParams.FILL_PARENT));
    parent.setOrientation(LinearLayout.VERTICAL);
    scroll.addView(parent);

    LayoutInflater inflater = LayoutInflater.from(parent.getContext());

    others = new HashMap<Integer, View>();

    // add first item to main page
    first = inflater.inflate(R.layout.main_page_first_item, null);
    parent.addView(first);
    others.put(0, first);

    for (int i = 2; i < 10; i++) {
        temp = inflater.inflate(R.layout.main_page_item, null);
        others.put(i, temp);
        parent.addView(temp);
    }

}

public void setPage() {

    // take datas from XML
    String xml = XMLfunctions.getXML();
    Document doc = XMLfunctions.XMLfromString(xml);

    // which datas need to be taken, by tag
    nodes = doc.getElementsByTagName("image");

    desc = new HashMap<Integer, String>();
    bitMap = new HashMap<Integer, Bitmap>();

    new Thread(new Runnable() {
        public void run() {
            for (j = 0; j < 20; j++) {
                if (j != 1) {
                    Element e = (Element) nodes.item(j);
                    desc.put(j, XMLfunctions.getValue(e, "description"));
                    Log.d("try", desc.get(j));
                    Log.d("tryy",
                            XMLfunctions.getValue(e, "description"));
                    bitMap.put(j, XMLfunctions.getContactPhoto(XMLfunctions
                            .getValue(e, "path")));
                }
            }
        }
    }).start();

    // add the first item to main page
    textView = (TextView) (others.get(0)).findViewById(R.id.text);
    img = (ImageView) (others.get(0)).findViewById(R.id.image);
    Log.d("first", desc.get(0) + desc.get(0));
    if (textView != null)
        textView.setText(desc.get(0));
    if (img != null)
        img.setImageBitmap(bitMap.get(0));

    // add the rest of items to main page
    for (j = 2; j < 10; j++) {
        if (j % 2 == 0) {
            textView1 = (TextView) (others.get(j)).findViewById(R.id.text1);
            image1 = (ImageView) (others.get(j)).findViewById(R.id.image1);
            Log.d("others", j + ": " + desc.get(j) + desc.get(j));
            if (textView1 != null)
                textView1.setText(desc.get(j));
            if (image1 != null)
                image1.setImageBitmap(bitMap.get(j));
        } else {
            textView2 = (TextView) (others.get(j - 1))
                    .findViewById(R.id.text2);
            image2 = (ImageView) (others.get(j - 1))
                    .findViewById(R.id.image2);
            Log.d("others", j + ": " + desc.get(j) + desc.get(j));
            if (textView2 != null)
                textView2.setText(desc.get(j));

            if (image2 != null)
                image2.setImageBitmap(bitMap.get(j));
        }
    }

}

  }

最后在mainActivity上，我正在使用这些代码来达到这个级别，我不确定这是否有必要，但我也给予了。

 mainPage fillMain = new mainPage();
 fillMain.setPage();

Answer 1

AsyncTask是您想要使用的

Answer 2

查看此示例：http://www.vogella.de/articles/AndroidPerformance/article.html

两个方法在线程任务之前和之后触发，因此您应该能够使用它来获取数据。 onPostExecute方法之后的doInBackground会触发实际工作; onPostExecute获取doInBackground返回的任何内容......

从线程中的xml获取数据？

2 个答案: