本文介绍了在gridview的延迟加载的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
这是GridView控件的获取图像的JSON。我成功地用它。但是，当我从服务器获取它有大量的图片，这意味着从服务器中的所有图像。我想，一旦负载12幅。
如何限制图像加载多少？
请帮我简单，因为我瞎用延迟加载。如果下面没有没有足够的code。这里充满源 http://pastie.org/5583485
在此网址，50是一个数字图像加载的，我可以用这个值任何我想要限制图像的数量。但我只是可以加载一次的时间，所以我不能加载它了。这个网址提供的图像路径为JSON。
字符串URL = "http://xxx.xxx.xxx/card/all/50/0/?token=57LzEsmBeykLbDCD04wTgK9WWV2XjJY0XBdqVU0HQvjIdu5EtTWOT1IQ1AYNwxt6Q5bG6FG73uvzLQSDGAIezwc8VcopEp0s63uzbdVgLSfts0TLmuVDOgyfn4lX";
的AsyncTask的doInBackground
公共类DownloadJSONFileAsync扩展的AsyncTask＆LT;字符串，太虚，太虚＆GT; {
在preExecute保护无效（）{
super.on preExecute（）;
的ShowDialog（DIALOG_DOWNLOAD_JSON_PROGRESS）;
}
@覆盖
保护无效doInBackground（字符串... PARAMS）{
字符串URL = "http://rest.mcolle.com/card/all/50/0/?token=57LzEsmBeykLbDCD04wTgK9WWV2XjJY0XBdqVU0HQvjIdu5EtTWOT1IQ1AYNwxt6Q5bG6FG73uvzLQSDGAIezwc8VcopEp0s63uzbdVgLSfts0TLmuVDOgyfn4lX";
JSONArray数据= NULL;
尝试 {
的JSONObject的JSONObject =新的JSONObject（getJSONUrl（URL））;
MyArrList =新的ArrayList＆LT; HashMap的＆LT;字符串，对象＆gt;＆GT;（）;
HashMap的＆LT;字符串，对象＆gt;地图;
数据= jsonObject.getJSONArray（数据）;
的for（int i = 0; I＆LT; data.length（）;我++）{
JSONObject的C = data.getJSONObject（我）;
图=新的HashMap＆LT;字符串，对象＆gt;（）;
//缩略图获取ImageBitmap到对象
map.put（cardimage，（串）c.getString（cardimage））;
map.put（ImageThumBitmap，（位图）loadBitmap（c.getString（cardimage）））;
map.put（类别ID（串）c.getString（类别ID））;
MyArrList.add（图）
}
}赶上（JSONException E）{
// TODO自动生成的catch块
e.printStackTrace（）;
}
返回null;
}
保护无效onPostExecute（作废不用）{
ShowAllContent（）; //当完成显示内容
dismissDialog（DIALOG_DOWNLOAD_JSON_PROGRESS）;
removeDialog（DIALOG_DOWNLOAD_JSON_PROGRESS）;
}
ImageAdpater其中i显示图片
公共类ImageAdapter扩展了BaseAdapter {
私人上下文的背景下;
私人的ArrayList＆LT; HashMap的＆LT;字符串，对象＆gt;＆GT; myArr，该=新的ArrayList＆LT; HashMap的＆LT;字符串，对象＆gt;＆GT;（）;
公共ImageAdapter（上下文C，ArrayList的＆LT; HashMap的＆LT;字符串，对象＆gt;＆GT; myArrList）{
上下文= C;
myArr，该= myArrList;
}
公众诠释getCount将（）{
返回MyArr.size（）;
}
公共对象的getItem（INT位置）{
返回的位置;
}
众长getItemId（INT位置）{
返回的位置;
}
公共查看getView（INT位置，查看convertView，ViewGroup中父）{
ViewHolder viewHolder;
viewHolder =新ViewHolder（）;
LayoutInflater充气=（LayoutInflater）context.getSystemService（Context.LAYOUT_INFLATER_SERVICE）;
如果（convertView == NULL）{
convertView = inflater.inflate（R.layout.grid_item，NULL）;
}
viewHolder.categoryCard =（ImageView的）convertView.findViewById（R.id.category_card）;
viewHolder.categoryCard.setImageResource（R.drawable.card_etc）;
viewHolder.imageView =（ImageView的）convertView.findViewById（R.id.imageView1）;
尝试 {
viewHolder.imageView.setImageBitmap（（位图）MyArr.get（位置）获得（ImageThumBitmap））;
}赶上（例外五）{
viewHolder.imageView.setImageResource（android.R.drawable.ic_menu_report_image）;
}
返回convertView;
}
}
解决方案
您可以使用通用的图像加载器，
https://github.com/nostra13/Android-Universal-Image-Loader
this is gridview that get image from json. I successfully with it. But when I get it from server it has a lot of images, that mean all images from server. I want to once load is 12 images.
How can I limit number of images to load?
Please help me briefly because I blind with lazy loading. If the code below not not enough. here is full source http://pastie.org/5583485
in this url, 50 is a number of image to load, i can limit number of image by this value whatever i want. but i just can load once time, so i can't load it more. this url provide image path as json.
String url = "http://xxx.xxx.xxx/card/all/50/0/?token=57LzEsmBeykLbDCD04wTgK9WWV2XjJY0XBdqVU0HQvjIdu5EtTWOT1IQ1AYNwxt6Q5bG6FG73uvzLQSDGAIezwc8VcopEp0s63uzbdVgLSfts0TLmuVDOgyfn4lX";
doInBackground of asynctask
public class DownloadJSONFileAsync extends AsyncTask<String, Void, Void> {
protected void onPreExecute() {
super.onPreExecute();
showDialog(DIALOG_DOWNLOAD_JSON_PROGRESS);
}
@Override
protected Void doInBackground(String... params) {
String url = "http://rest.mcolle.com/card/all/50/0/?token=57LzEsmBeykLbDCD04wTgK9WWV2XjJY0XBdqVU0HQvjIdu5EtTWOT1IQ1AYNwxt6Q5bG6FG73uvzLQSDGAIezwc8VcopEp0s63uzbdVgLSfts0TLmuVDOgyfn4lX";
JSONArray data = null;
try {
JSONObject jsonObject = new JSONObject(getJSONUrl(url));
MyArrList = new ArrayList<HashMap<String, Object>>();
HashMap<String, Object> map;
data = jsonObject.getJSONArray("data");
for (int i = 0; i < data.length(); i++) {
JSONObject c = data.getJSONObject(i);
map = new HashMap<String, Object>();
// Thumbnail Get ImageBitmap To Object
map.put("cardimage", (String) c.getString("cardimage"));
map.put("ImageThumBitmap",(Bitmap) loadBitmap(c.getString("cardimage")));
map.put("categoryid", (String) c.getString("categoryid"));
MyArrList.add(map);
}
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
protected void onPostExecute(Void unused) {
ShowAllContent(); // When Finish Show Content
dismissDialog(DIALOG_DOWNLOAD_JSON_PROGRESS);
removeDialog(DIALOG_DOWNLOAD_JSON_PROGRESS);
}
ImageAdpater where i show image
public class ImageAdapter extends BaseAdapter {
private Context context;
private ArrayList<HashMap<String, Object>> MyArr = new ArrayList<HashMap<String, Object>>();
public ImageAdapter(Context c, ArrayList<HashMap<String, Object>> myArrList) {
context = c;
MyArr = myArrList;
}
public int getCount() {
return MyArr.size();
}
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder viewHolder;
viewHolder = new ViewHolder();
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
if (convertView == null) {
convertView = inflater.inflate(R.layout.grid_item, null);
}
viewHolder.categoryCard = (ImageView) convertView.findViewById(R.id.category_card);
viewHolder.categoryCard.setImageResource(R.drawable.card_etc);
viewHolder.imageView = (ImageView) convertView.findViewById(R.id.imageView1);
try {
viewHolder.imageView.setImageBitmap((Bitmap) MyArr.get(position).get("ImageThumBitmap"));
} catch (Exception e) {
viewHolder.imageView.setImageResource(android.R.drawable.ic_menu_report_image);
}
return convertView;
}
}
解决方案
you can use universal image loader ,
https://github.com/nostra13/Android-Universal-Image-Loader
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