Java 要转换ArrayList<;HashMap<;字符串,对象>&燃气轮机;串
我阅读并创建了具有gridview的应用程序,该gridview从json获取图像。但是我的应用程序加载太慢了,所以我想使用通用图像加载器,但它在ImageAdapeter类中使用的通用图像加载器中的函数是这样的Java 要转换ArrayList<;HashMap<;字符串,对象>&燃气轮机;串,java,android,string,arraylist,universal-image-loader,Java,Android,String,Arraylist,Universal Image Loader,我阅读并创建了具有gridview的应用程序,该gridview从json获取图像。但是我的应用程序加载太慢了,所以我想使用通用图像加载器,但它在ImageAdapeter类中使用的通用图像加载器中的函数是这样的 imageLoader.displayImage(imageUrls[position],imageView,选项)或用于公式 imageLoader.displayImage(字符串、imageView、选项) 所以我没有字符串来完成这个公式。我可以创建对象arr来存储Arrayli
imageLoader.displayImage(imageUrls[position],imageView,选项)代码>或用于公式
imageLoader.displayImage(字符串、imageView、选项)代码>
所以我没有字符串来完成这个公式。我可以创建对象arr
来存储Arraylist
如何将ArrayList
转换为字符串或任何更改代码的方法
请确认或建议或推荐我,因为你可以。易读
下面是我的ImageAdapter。它工作得很好,但是很慢
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);
//==================== change area
Object arr = new ArrayList<HashMap<String, Object>>(); // make objec arr to store arraylist
arr = MyArr.get(position).get("categoryid");
if (arr.equals("1")) {
viewHolder.categoryCard.setImageResource(R.drawable.card_eat);
viewHolder.imageView = (ImageView) convertView.findViewById(R.id.imageView1);
} else {
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;
}
}
// Download JSON in Background
public class DownloadJSONFileAsync extends AsyncTask<String, Void, Void> {
String token = getIntent().getExtras().getString("token1");
protected void onPreExecute() {
super.onPreExecute();
showDialog(DIALOG_DOWNLOAD_JSON_PROGRESS);
}
@Override
protected Void doInBackground(String... params) {
String url = "http://xxx.xxx.xxx/card/all/20/0/?token="+token;
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);
}
}
在您的下载jsonfileasync类中
您尚未下载JSON。因此,变量JSONArray data
将始终为空
在第33行
无需使用新的ArrayList
您需要访问存储在下载JSonfileasync类
中的ArrayList。在下面查找更新的代码
public class DownloadJSONFileAsync extends AsyncTask<String, Void, Void> {
String token = getIntent().getExtras().getString("token1");
JSONObject response = null;
protected void onPreExecute() {
super.onPreExecute();
showDialog(DIALOG_DOWNLOAD_JSON_PROGRESS);
}
@Override
protected Void doInBackground(String... params) {
String url = "http://xxx.xxx.xxx/card/all/20/0/?token="+token;
JSONArray response = //YOUR JSON ARRAY AFTER DOWNLOADING;
return null;
}
protected void onPostExecute(Void unused) {
ShowAllContent(JSONArray); // When Finish Show Content and send the Response JSONARRAY and display the content on the GridView
dismissDialog(DIALOG_DOWNLOAD_JSON_PROGRESS);
removeDialog(DIALOG_DOWNLOAD_JSON_PROGRESS);
}}
在您的下载jsonfileasync类中
您尚未下载JSON。因此,变量JSONArray data
将始终为空
在第33行
无需使用新的ArrayList
您需要访问存储在下载JSonfileasync类
中的ArrayList。在下面查找更新的代码
public class DownloadJSONFileAsync extends AsyncTask<String, Void, Void> {
String token = getIntent().getExtras().getString("token1");
JSONObject response = null;
protected void onPreExecute() {
super.onPreExecute();
showDialog(DIALOG_DOWNLOAD_JSON_PROGRESS);
}
@Override
protected Void doInBackground(String... params) {
String url = "http://xxx.xxx.xxx/card/all/20/0/?token="+token;
JSONArray response = //YOUR JSON ARRAY AFTER DOWNLOADING;
return null;
}
protected void onPostExecute(Void unused) {
ShowAllContent(JSONArray); // When Finish Show Content and send the Response JSONARRAY and display the content on the GridView
dismissDialog(DIALOG_DOWNLOAD_JSON_PROGRESS);
removeDialog(DIALOG_DOWNLOAD_JSON_PROGRESS);
}}
如果要保留ArrayList
,必须通过以下方式创建一个新的字符串[]
:
String[] urls = new String[MyArrList.size()];
for(int i=0; i<MyArrList.size(); i++){
urls[i] = MyArrList.get(i).get("cardimage");
}
String[]url=新字符串[MyArrList.size()];
对于(int i=0;i如果要保留ArrayList
,则必须通过以下方式创建一个新的字符串[]
:
String[] urls = new String[MyArrList.size()];
for(int i=0; i<MyArrList.size(); i++){
urls[i] = MyArrList.get(i).get("cardimage");
}
String[]url=新字符串[MyArrList.size()];
对于(inti=0;i1)您拥有ArrayList
,对吗?2)每个HashMap是否都包含图像URL?它的内容如下MyArr.get(position).get(“categoryid”)
1)您拥有ArrayList
,对吗?2) 是否每个HashMap都包含图像URL?它包含如下内容MyArr.get(position.get(“categoryid”)
我无法将JSONArray添加到ShowAllContent。请看。请帮我更改一下。我无法将JSONArray添加到ShowAllContent。请看。请帮我修改一下,我怎样才能修改所有的代码呢。我非常想改变它。我想更快地改进它。如何更改所有这些代码。我非常想改变它。我想更快地改进它。
String[] urls = new String[MyArrList.size()];
for(int i=0; i<MyArrList.size(); i++){
urls[i] = MyArrList.get(i).get("cardimage");
}