我有Listview用于显示JSON数据。我获得了pdf标题但我无法使用JSON webservices获得pdf标题图像。在日志中，整个数据显示在arraylist中。我使用hashmap概念在Listview上设置JSON数据。以下是我的源代码。
// Default url
private static String url = "http://.....";
// JSON Node names
public static final String TAG_DOCUMENT = "docs";
public static final String TAG_TITLE = "name";
public static final String TAG_IMAGEPATH = "imagepath";
ArrayList<HashMap<String, String>> documentList = new ArrayList<HashMap<String,String>>();
Button mPdf_list_btn_more;
ListView lv;
JSONArray document = null;
ProgressDialog pDialog;
// flag for Internet connection status
Boolean isInternetPresent = false;
ConnectionDetector cd;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Remove Titlebar
this.requestWindowFeature(Window.FEATURE_NO_TITLE);
// Remove Notificationbar
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_HIDDEN);
setContentView(R.layout.pdf_list);
if (android.os.Build.VERSION.SDK_INT > 9) {
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
}
mPdf_list_btn_more = (Button)findViewById(R.id.mPdf_list_btn_more);
mPdf_list_btn_more.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Intent i = new Intent(PDF_List.this,Info_Screen.class);
startActivity(i);
}
});
lv = (ListView)findViewById(R.id.listView1);
ServiceHandler sh = new ServiceHandler();
cd = new ConnectionDetector(getApplicationContext());
// new GetPDF().execute();
new GetPDFNew().execute();
}
public void ListViewData() {
/* ServiceHandler sh = new ServiceHandler();
// Making a request to url and getting response
String jsonStr = sh.makeServiceCall(url, ServiceHandler.GET);
Log.d("Response: ", "> " + jsonStr);
if (jsonStr != null) {
try {
JSONObject jsonObj = new JSONObject(jsonStr);
// Getting JSON Array node
document = jsonObj.getJSONArray(TAG_DOCUMENT);
// looping through All Contacts
for (int i = 0; i < document.length(); i++) {
JSONObject c = document.getJSONObject(i);
String name = c.getString(TAG_TITLE);
String image_path = c.getString(TAG_IMAGEPATH);
Log.i("Name:--->", name);
Log.i("Image_Path--->",image_path);
// tmp hashmap for single contact
HashMap<String, String> doc = new HashMap<String, String>();
doc.put(TAG_TITLE,name);
doc.put(TAG_IMAGEPATH, image_path);
documentList.add(doc);
Log.i("ArrayList for documentList ","-->"+ documentList);
Log.i("TAG IMAGEPATH IN ListviewData", TAG_IMAGEPATH);
Log.i("TAG TITLE IN ListviewData", TAG_TITLE);
String[] from = {TAG_IMAGEPATH,TAG_TITLE};
final int[] to = {R.id.mImageview_pdf,R.id.mtextview_title};
SimpleAdapter adapter = new SimpleAdapter(PDF_List.this, documentList, R.layout.list_item, from, to);
lv.setAdapter(adapter);
}
}
catch(JSONException e){
}
}
else {
Log.e("ServiceHandler", "Couldn't get any data from the url");
}*/
Log.i("TAG IMAGEPATH IN ListviewData", TAG_IMAGEPATH);
Log.i("TAG TITLE IN ListviewData", TAG_TITLE);
String[] from = {TAG_IMAGEPATH,TAG_TITLE};
final int[] to = {R.id.mImageview_pdf,R.id.mtextview_title};
SimpleAdapter adapter = new SimpleAdapter(PDF_List.this, documentList, R.layout.list_item, from, to);
lv.setAdapter(adapter);
lv.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> arg0, View arg1,
int position, long arg3) {
// TODO Auto-generated method stub
Object position1 = lv.getItemAtPosition(position);
System.out.println(position1+"-->:item postion");
for (HashMap<String, String> map : documentList)
for (Entry<String, String> mapEntry : map.entrySet())
{
String key = mapEntry.getKey();
String value = mapEntry.getValue();
// Log.i("arraylist key-->",key);
// Log.i("arraylist value-->",value);
// Log.i("cccc","->>"+documentList.get(position).get(key).valueOf(pathforurl+file_path));
}
}
});
}
private class GetPDF extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(PDF_List.this);
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
// get Internet status
isInternetPresent = cd.isConnectingToInternet();
// check for Internet status
if (isInternetPresent) {
// Internet Connection is Present
// make HTTP requests
// showAlertDialog(MainActivity.this, "Internet Connection",
// "You have internet connection", true);
} else {
// Internet connection is not present
// Ask user to connect to Internet
showAlertDialog(PDF_List.this, "No Internet Connection",
"You don't have internet connection.", false);
pDialog.dismiss();
}
}
@Override
protected Void doInBackground(Void... arg0) {
// TODO Auto-generated method stub
ServiceHandler sh = new ServiceHandler();
// Making a request to url and getting response
String jsonStr = sh.makeServiceCall(url, ServiceHandler.GET);
Log.d("Response: ", "> " + jsonStr);
if (jsonStr != null) {
try {
JSONObject jsonObj = new JSONObject(jsonStr);
// Getting JSON Array node
document = jsonObj.getJSONArray(TAG_DOCUMENT);
// looping through All Contacts
for (int i = 0; i < document.length(); i++) {
JSONObject c = document.getJSONObject(i);
String name = c.getString(TAG_TITLE);
String image_path = c.getString(TAG_IMAGEPATH);
Log.i("Name:--->", name);
Log.i("Image_Path--->",image_path);
// tmp hashmap for single contact
HashMap<String, String> doc = new HashMap<String, String>();
doc.put(TAG_TITLE,name);
doc.put(TAG_IMAGEPATH, image_path);
documentList.add(doc);
Log.i("ArrayList for documentList ","-->"+ documentList);
}
}
catch(JSONException e){
}
}
else {
Log.e("ServiceHandler", "Couldn't get any data from the url");
}
return null;
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
// Dismiss the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
/**
* Updating parsed JSON data into ListView
* */
ListViewData();
}
}
private class GetPDFNew extends AsyncTask<String, Void, Bitmap> {
@Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(PDF_List.this);
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
// get Internet status
isInternetPresent = cd.isConnectingToInternet();
// check for Internet status
if (isInternetPresent) {
// Internet Connection is Present
// make HTTP requests
// showAlertDialog(MainActivity.this, "Internet Connection",
// "You have internet connection", true);
} else {
// Internet connection is not present
// Ask user to connect to Internet
showAlertDialog(PDF_List.this, "No Internet Connection",
"You don't have internet connection.", false);
pDialog.dismiss();
}
}
@Override
protected void onPostExecute(Bitmap result) {
super.onPostExecute(result);
// Dismiss the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
/**
* Updating parsed JSON data into ListView
* */
ListViewData();
}
@Override
protected Bitmap doInBackground(String... params) {
// TODO Auto-generated method stub
ServiceHandler sh = new ServiceHandler();
// Making a request to url and getting response
String jsonStr = sh.makeServiceCall(url, ServiceHandler.GET);
Log.d("Response: ", "> " + jsonStr);
if (jsonStr != null) {
try {
JSONObject jsonObj = new JSONObject(jsonStr);
// Getting JSON Array node
document = jsonObj.getJSONArray(TAG_DOCUMENT);
// looping through All Contacts
for (int i = 0; i < document.length(); i++) {
JSONObject c = document.getJSONObject(i);
String name = c.getString(TAG_TITLE);
String image_path = c.getString(TAG_IMAGEPATH);
Log.i("Name:--->", name);
Log.i("Image_Path--->",image_path);
// tmp hashmap for single contact
HashMap<String, String> doc = new HashMap<String, String>();
doc.put(TAG_TITLE,name);
doc.put(TAG_IMAGEPATH, image_path);
documentList.add(doc);
Log.i("ArrayList for documentList ","-->"+ documentList);
}
}
catch(JSONException e){
}
}
return null;
}
}
@SuppressWarnings("deprecation")
public void showAlertDialog(Context context, String title, String message, Boolean status) {
AlertDialog alertDialog = new AlertDialog.Builder(context).create();
// Setting Dialog Title
alertDialog.setTitle(title);
// Setting Dialog Message
alertDialog.setMessage(message);
// Setting alert dialog icon
alertDialog.setIcon((status) ? R.drawable.ic_launcher : R.drawable.ic_launcher);
// Setting OK Button
alertDialog.setButton("OK", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
}
});
}
答案 0 :(得分：0)
您可以使用名为Picasso
的简单库来实现此目的最准确的方式，它可以处理所有内容，例如缓存维护，离线渲染以及从网络和磁盘加载图像
<强> 1。大多数情况下，如果在批量图像的情况下无法正确处理，则可能会出现名为bitmap size exceeds vm budget的异常
所以我建议你选择通用图片加载库或Picasso
public static void loadNetworkThumNail(final Context context, final ImageView imageview, final String Url) {
Picasso.with(context).load(Url.trim()).resize(98, 98).placeholder(R.drawable.default_image).into(imageview);
}