成佩涛编程之路——android之jquery使用（二）

异步网络：1. 添加权限：<uses-permission android:name="android.permission.INTERNET" />2. 支持的类型JSONObjectJSONArrayString (HTML, XML)XmlDom (XML parsing)XmlPullParser (Large XML files)byte arrayUser defined custom type (Transformer)Bitmap3. 以Json数据为例，注意，红色部分是随你请求的数据类型一起改变String url = "http://www.google.com/uds/GnewsSearch?q=Obama&v=1.0";aq.ajax(url, JSONObject.class, new AjaxCallback<JSONObject>() {@Overridepublic void callback(String url, JSONObject json, AjaxStatus status) {if(json != null){//successful ajax call, show status code and json contentToast.makeText(aq.getContext(), status.getCode() + ":" + json.toString(), Toast.LENGTH_LONG).show();}else{//ajax error, show error codeToast.makeText(aq.getContext(), "Error:" + status.getCode(), Toast.LENGTH_LONG).show();}}});上面的形式也可以写成下面一样，他们是无条件对等public void asyncJson(){//perform a Google search in just a few lines of codeString url = "http://www.google.com/uds/GnewsSearch?q=Obama&v=1.0";aq.ajax(url, JSONObject.class, this, "jsonCallback");}public void jsonCallback(String url, JSONObject json, AjaxStatus status){if(json != null){//successful ajax call}else{//ajax error}}再举一个使用AQuery的XmlDom解析xml的例子，如果XML过大，使用XMLPullParserpublic void xml_ajax(){String url = "https://picasaweb.google.com/data/feed/base/featured?max-results=8";aq.ajax(url, XmlDom.class, this, "picasaCb");}public void picasaCb(String url, XmlDom xml, AjaxStatus status){// 返回一系列为entry的结点,并把其add进listList<XmlDom> entries = xml.tags("entry");List<String> titles = new ArrayList<String>();String imageUrl = null;for(XmlDom entry: entries){titles.add(entry.text("title")); //循环把第一个结点为title的文本放进titleimageUrl = entry.tag("content", "type", "image/jpeg").attr("src");//把第一个结点为content,属性为type,属性值为image/jpeg的src属性值赋予给imageUri}aq.id(R.id.image).image(imageUrl);}4. 如果你想指定保存文件的位置，使用download方法

String url = "https://picasaweb.google.com/data/feed/base/featured?max-results=16";

File ext = Environment.getExternalStorageDirectory();
File target = new File(ext, "aquery/myfolder/photos.xml");

aq.progress(R.id.progress).download(url, target, new AjaxCallback<File>(){

public void callback(String url, File file, AjaxStatus status) {

if(file != null){
showResult("File:" + file.length() + ":" + file, status);
}else{
showResult("Failed", status);
}
}
});

5. 自定义类型（文档例子是gson数据使用对象解析），详细见文档6. 使用Http Post （Multiple）private void aync_multipart(){

String url = "https://graph.facebook.com/me/photos";

Map<String, Object> params = new HashMap<String, Object>();
params.put("message", "Message");

//Simply put a byte[] to the params, AQuery will detect it and treat it as a multi-part post
byte[] data = getImageData();
params.put("source", data);

//Alternatively, put a File or InputStream instead of byte[]
//File file = getImageFile();
//params.put("source", file);

AQuery aq = new AQuery(getApplicationContext());
aq.auth(handle).ajax(url, params, JSONObject.class, this, "photoCb");

}

7. 使用ajax是很容易达到缓存的String url = "http://www.google.com";

// 返回最近15分钟内的缓存副本,如果expire为-1,内容将会立即更新且缓存
long expire = 15 * 60 * 1000;

aq.ajax(url, String.class, expire, new AjaxCallback<String>() {

@Override
public void callback(String url, String html, AjaxStatus status) {
showResult(html);
}

});

8. 使缓存无效

public void callback(String url, JSONObject json, AjaxStatus status) {

if(json != null){
if("1".equals(json.optString("status"))){
//do something
}else{
// 不缓存
status.invalidate();
}
}
}

9. 同步调用：如果ajax调用是在新开的线程,sync方法能够阻塞线程,直到ajax调用完毕,如果sync方法用在主线程将会引起Exception

String url = "http://www.google.com/uds/GnewsSearch?q=Obama&v=1.0";

AjaxCallback<JSONObject> cb = new AjaxCallback<JSONObject>();
cb.url(url).type(JSONObject.class);

aq.sync(cb);

JSONObject jo = cb.getResult();
AjaxStatus status = cb.getStatus();

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