我正在通过网址查看JSON数据。 JSON数组中有许多JSON对象，其中一个是jpeg图像。
我想将该图片发送到Android应用中的列表视图。
现在我将图像JSON对象链接到我的Java文件中的私有静态最终String TAG。但是，我意识到我必须解码图像，否则我将收到以下错误：无法解码流：java.io.FileNotFoundException和resolveUri在错误的位图uri上失败。
我正在进行长期不断的搜索，以了解如何解码JSON jpeg图像，通过查看本网站上的帖子进行了大量此类研究，因此请不要将其标记为重复的问题。
public class JSONBuilderActivity extends ListActivity {
private ProgressDialog pDialog;
//URL to get JSON
private static String url = "";
//JSON Node names
private static final String TAG_CARS = "cars"; //root
private static final String TAG_CARID = "CarID";
private static final String TAG_CARVIN = "CarVIN";
private static final String TAG_IMG= "CarMainImage";
JSONArray carid = null; //Initializes JSON array
static String response = null;
//Hashmap for ListView
ArrayList<HashMap<String, Object>>caridList;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ListView lv = getListView();
//Listview on item click listener
lv.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
//Gets values from selected ListItem
String cars = ((TextView) view.findViewById(R.id.cars)).getText().toString();
String car_id = ((TextView) view.findViewById(R.id.car_id)).getText().toString();
String car_vin = ((TextView) view.findViewById(R.id.car_vin)).getText().toString();
String model_img = ((ImageView) view.findViewById(R.id.model_img)).getTag().toString();
Intent in = new Intent(JSONBuilderActivity.this, MainActivity.class);
//Sends data to MainActivity
in.putExtra("TAG_CARS", cars);
in.putExtra("TAG_CARID", car_id);
in.putExtra("TAG_CarVin", car_vin);
in.putExtra("TAG_IMG", model_img);
startActivity(in);
}
});
//Calls async task to get json
new GetCars().execute();
}
public class ServiceHandler {
public final static int GET = 1;
public final static int POST = 2;
public ServiceHandler() {
}
/**
* Makes service call
* @url - url to make request
* @method - http request method
* */
public String makeServiceCall(String url, int method) {
return this.makeServiceCall(url, method, null);
}
/**
* Makes service call
* @url - url to make request
* @method - http request method
* @params - http request params
* */
public String makeServiceCall(String url, int method,ArrayList<NameValuePair> params) {
try {
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpEntity httpEntity = null;
HttpResponse httpResponse = null;
//Checks http request method type
if (method == POST) {
HttpPost httpPost = new HttpPost(url);
//Adds post params
if (params != null) {
httpPost.setEntity(new UrlEncodedFormEntity(params));
}
httpResponse = httpClient.execute(httpPost);
} else if (method == GET) {
//Appends params to url
if (params != null) {
String paramString = URLEncodedUtils.format(params, "utf-8");
url += "?" + paramString;
}
HttpGet httpGet = new HttpGet(url);
httpResponse = httpClient.execute(httpGet);
}
httpEntity = httpResponse.getEntity();
response = EntityUtils.toString(httpEntity);
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return response;
}
}
/*
* Async task class to get json by making HTTP call
*/
private class GetCars extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
caridList = new ArrayList<HashMap<String, Object>>();
//Shows progress dialog
pDialog = new ProgressDialog(JSONBuilderActivity.this);
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
}
@Override
protected Void doInBackground(Void... arg0) {
//Creates service handler class instance
ServiceHandler sh = new ServiceHandler();
//Makes a request to url and getting response
String jsonStr = sh.makeServiceCall(url, ServiceHandler.GET);
//Prints the json response in the log
Log.d("GetCars response: ", "> " + jsonStr);
if (jsonStr != null) {
try {
Log.d("try", "in the try");
JSONObject jsonObj = new JSONObject(jsonStr);
Log.d("jsonObject", "new json Object");
//Gets JSON Array node
carid = jsonObj.getJSONArray(TAG_CARS);
Log.d("json array", "user point array");
int len = carid.length();
Log.d("len", "get array length");
for (int i = 0; i < carid.length(); i++) {
JSONObject c = carid.getJSONObject(i);
String car_id = c.getString(TAG_CARID);
Log.d("car_id", car_id);
String car_vin = c.getString(TAG_CARVIN);
Log.d("car_vin", car_vin);
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeResource(getResources(), R.id.model_img, options);
int imageHeight = options.outHeight;
int imageWidth = options.outWidth;
String imageType = options.outMimeType;
// byte[] byteArray = Base64.decode(jsonObj.getString(TAG_IMG), Base64.DEFAULT) ;
//Bitmap bmp1 = BitmapFactory.decodeByteArray(byteArray, 0, byteArray.length);
//String model_img = c.getString(TAG_IMG);
//Log.d("model_img", model_img);
//Hashmap for single match
HashMap<String, Object> matchGetCars = new HashMap<String, Object>();
//Adds each child node to HashMap key => value
matchGetCars.put(TAG_CARID, car_id);
matchGetCars.put(TAG_CARVIN, car_vin);
matchGetCars.put(TAG_IMG, ); //idk
caridList.add(matchGetCars);
}
} catch (JSONException e) {
e.printStackTrace();
}
} else {
Log.e("ServiceHandler", "Couldn't get any data from the url");
}
return null;
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
//Dismisses the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
/**
* Updates parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(JSONBuilderActivity.this, caridList, R.layout.list_item,
new String[]{TAG_CARID, TAG_CARVIN, TAG_IMG}, new int[]{R.id.car_id, R.id.car_vin, R.id.model_img});
setListAdapter(adapter);
Log.v("List parsed", caridList.toString());
}
}
因此，非常感谢任何有关如何解码JSON jpeg图像的建议。谢谢。
}
更新
public Uri getImageUri(Context inContext, Bitmap inImage){
ByteArrayOutputStream bytes = new ByteArrayOutputStream();
inImage.compress(Bitmap.CompressFormat.JPEG, 100, bytes);
String path = MediaStore.Images.Media.insertImage(inContext.getContentResolver(), inImage, "CarMainImage", null);
return Uri.parse(path);
}
public void saveBmpToFile(File filename, Bitmap bmp){
FileOutputStream out = null;
try {
out = new FileOutputStream(filename);
bmp.compress(Bitmap.CompressFormat.PNG, 100, out); // bmp is your Bitmap instance
// PNG is a lossless format, the compression factor (100) is ignored
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
if (out != null) {
out.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
//------------------------
public boolean renameFileExtension(String source, String newExtension)
{
String target;
String currentExtension = getFileExtension(source);
if (currentExtension.equals(""))
{
target = source + "." + newExtension;
}
else
{
target = source.replaceFirst(Pattern.quote("." +
currentExtension) + "$", Matcher.quoteReplacement("." + newExtension));
}
return new File(source).renameTo(new File(target));
}
//---------------------------------------------------
public String getFileExtension(String f)
{
String ext = "";
int i = f.lastIndexOf('.');
if (i > 0 && i < f.length() - 1)
{
ext = f.substring(i + 1);
}
return ext;
}
/*
* Async task class to get json by making HTTP call
*/
private class GetCars extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
caridList = new ArrayList<HashMap<String, Object>>();
//Shows progress dialog
pDialog = new ProgressDialog(JSONBuilderActivity.this);
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
}
@Override
protected Void doInBackground(Void... arg0) {
//Creates service handler class instance
ServiceHandler sh = new ServiceHandler();
//Makes a request to url and getting response
String jsonStr = sh.makeServiceCall(url, ServiceHandler.GET);
//Prints the json response in the log
Log.d("GetCars response: ", "> " + jsonStr);
if (jsonStr != null) {
try {
Log.d("try", "in the try");
JSONObject jsonObj = new JSONObject(jsonStr);
Log.d("jsonObject", "new json Object");
//Gets JSON Array node
carid = jsonObj.getJSONArray(TAG_CARS);
Log.d("json array", "user point array");
int len = carid.length();
Log.d("len", "get array length");
for (int i = 0; i < carid.length(); i++) {
JSONObject c = carid.getJSONObject(i);
String car_id = c.getString(TAG_CARID);
Log.d("car_id", car_id);
String car_vin = c.getString(TAG_CARVIN);
Log.d("car_vin", car_vin);
String model_img=c.getString(TAG_IMG);
// byte[] byteArray = Base64.decode(jsonObj.getString(TAG_IMG), Base64.DEFAULT) ;
//Bitmap bmp1 = BitmapFactory.decodeByteArray(byteArray, 0, byteArray.length);
// String model_img = c.getString(TAG_IMG);
//Log.d("model_img", model_img);
//Hashmap for single match
HashMap<String, Object> matchGetCars = new HashMap<String, Object>();
//Adds each child node to HashMap key => value
matchGetCars.put(TAG_CARID, car_id);
matchGetCars.put(TAG_CARVIN, car_vin);
matchGetCars.put(TAG_IMG, model_img);
caridList.add(matchGetCars);
}
} catch (JSONException e) {
e.printStackTrace();
}
} else {
Log.e("ServiceHandler", "Couldn't get any data from the url");
}
return null;
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
//Dismisses the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
/**
* Updates parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(JSONBuilderActivity.this, caridList, R.layout.list_item,
new String[]{TAG_CARID, TAG_CARVIN, TAG_IMG}, new int[]{R.id.car_id, R.id.car_vin, R.id.model_img});
setListAdapter(adapter);
Log.v("List parsed", caridList.toString());
}
}
logcat的：
V/List parsed﹕ [{CarMainImage=/images/image.php?w=200&i
Unable to decode stream: java.io.FileNotFoundException: /images/image.php?w=200....
unable to resolveUri failed on bad bitmap uri: /images/image.php?w=200....
我不明白为什么解析后的列表被正确记录，然后弹出错误列表。但是，URL中的JSON jpeg没有像log cat中的jpeg那样完全格式化，因为JSON中的jpeg看起来像：/ images/image.php？w = 200 ...而logcat中的jpeg看起来像：/ images /image.php?200 ..所以不同的是..谁可以详细说明，如果这可能是为什么显示错误消息和/或提供修复错误的建议？ 我非常愿意研究并反复去理解你的建议。感谢。
答案 0 :(得分：0)
任何BitmapFactory方法适合您吗？有一对可以采用字节数组并为您提供Bitmap。然后，您可以非常轻松地将Bitmap放入ImageView。
答案 1 :(得分：0)
我建议使用Picasso
因为您只需要在适配器的getView（）函数内提供图像url和imageView。从下载图像从url到位图转换并设置为图像视图的所有工作都将由Picasso处理。
例如：Picasso.with(context).load(url).into(view/*Your image view*/);
答案 2 :(得分：0)
without thinking I will post you some conversion code:
**this is a place holder.**
required understanding:
Bitmap
Uri Provides an object representation of a "uniform resource identifier"
URL (Universal resourse loacator) reference (an address) to a resource on the Internet.
file extensions. *.png *.jpg
this will be up-dated when my brain is not without sleep ;O)
more to come as I think , my brain hurts:
//------------------------
public Uri getImageUri(Context inContext, Bitmap inImage)
{
ByteArrayOutputStream bytes = new ByteArrayOutputStream();
inImage.compress(Bitmap.CompressFormat.JPEG, 100, bytes);
String path = Images.Media.insertImage(inContext.getContentResolver(), inImage, "Title", null);
return Uri.parse(path);
}
public void saveBmpToFile(File filename, Bitmap bmp)
{
FileOutputStream out = null;
try {
out = new FileOutputStream(filename);
bmp.compress(Bitmap.CompressFormat.PNG, 100, out); // bmp is your Bitmap instance
// PNG is a lossless format, the compression factor (100) is ignored
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
if (out != null) {
out.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
//------------------------
public static boolean renameFileExtension(String source, String newExtension)
{
String target;
String currentExtension = getFileExtension(source);
if (currentExtension.equals(""))
{
target = source + "." + newExtension;
}
else
{
target = source.replaceFirst(Pattern.quote("." +
currentExtension) + "$", Matcher.quoteReplacement("." + newExtension));
}
return new File(source).renameTo(new File(target));
}
//---------------------------------------------------
public static String getFileExtension(String f)
{
String ext = "";
int i = f.lastIndexOf('.');
if (i > 0 && i < f.length() - 1)
{
ext = f.substring(i + 1);
}
return ext;
}
//-----------------------