我得到以下错误:
Error parsing to json on getJarrayFromString(); org.json.JSONException: Value result of type java.lang.String cannot be converted to JSONArray
public String getJsonFromUrl(String url){
// to initialise the objects
InputStream is = null;
String result = "";
//making HTTP POST request
try {
HttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
HttpResponse response = httpClient.execute(httpPost);
HttpEntity entity = response.getEntity();
is = entity.getContent();
}catch(Exception e){
Log.e(DEBUG, "Error getJsonFromUrl: " + e.toString());
}
// Converting to String
try{
BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while((line = reader.readLine()) != null){
sb.append(line + "'n");
}
is.close();
result=sb.toString();
}catch(Exception e){
Log.e(DEBUG, "Error converting the response to string getJsonFromUrl: " + e.toString());
}
return result;
}
/**
* To convert the string recieved into json object
* result refers to the string that will be converted
* @return will return the json array
*/
public JSONArray getJarrayFromString(String result){
// Parsing string to JSON Array
try{
jarray = new JSONArray("result"); <---- Error is here
}catch(JSONException e){
Log.e(DEBUG, "Error parsing to json on getJarrayFromString(); " + e.toString());
}
return jarray;
}
和我的Java活动如下:
public void onTaskCompleted(String result) {
try {
if(result!=""){
// the remote php link
// converting the response into json array
Log.i(DEBUG, result);
jarray = utils.getJarrayFromString(result);
// number of rows in total for a query
int mysqlSize = (jarray.getJSONObject(0).getInt("numRows"));
Log.i(DEBUG, "From " + from + " to " + mysqlSize);
// to check if all the rows are parsed from the mysql
if(from <= mysqlSize){
int rows;
// to check if there is 0
if(jarray.length()>0){
Log.i(DEBUG, "From " + from + " to " + Math.floor(mysqlSize/nr)*nr);
if(from+5<=Math.floor(mysqlSize/nr)*nr){
rows = jarray.length();
}else{
rows = mysqlSize%nr+1;
Utils.IS_ENDED_PRODUCT_LIST = true;
}
ArrayList<String> list = new ArrayList<String>();
for(int i=1; i<rows; i++){
JSONObject row = jarray.getJSONObject(i);
bid.add(row.getInt("bid"));
bTitle.add(row.getString("bTitle"));
bCode.add(row.getString("bCode"));
bPrice.add(row.getString("bPrice") + "£");
bDescription.add(row.getString("bDescription"));
bModule.add(row.getString("bModule"));
bImage.add(Utils.PATH + row.getString("bImage"));
list.add(row.getString("bImage"));
// to check if an id already exists in the db or to create one if doesn't exist
if(!db.hasIDBooks(row.getInt("bid"))) db.createRowOnBooks(row.getInt("bid"), row.getString("bTitle"), row.getString("bCode"), row.getString("bPrice"), row.getString("bDescription"), row.getString("bModule"), Utils.PATH + row.getString("bImage"), row.getString("bSpecialOffer"), row.getInt("bSpecialDiscount"), row.getString("bDateAdded"));
Log.i(DEBUG, row.getString("bDescription"));
}
new DownloadImages(list, bAdapter).execute();
}
}
postParameters.removeAll(postParameters);
}else{
Utils.IS_ENDED_PRODUCT_LIST = true;
if(rlLoading.isShown()){
rlLoading.startAnimation(fadeOut());
rlLoading.setVisibility(View.INVISIBLE);
}
}
} catch (Exception e) {
Log.e(DEBUG, "Error at fillProductList(): " + e.toString());
}
}
});
task.execute();
}else{
// if internet connectio is not available
// then, rows will be fetched from the local sqllite database stored on the android phone
if(db.size(justdealsDatabase.TABLE_BOOKS) > 0){
Cursor cursor = db.getBooksRows(justdealsDatabase.TABLE_BOOKS);
cursor.moveToFirst();
while(!cursor.isAfterLast()){
bid.add(cursor.getInt(cursor.getColumnIndex(justdealsDatabase.KEY_BID)));
bTitle.add(cursor.getString(cursor.getColumnIndex(justdealsDatabase.KEY_BTITLE)));
bCode.add(cursor.getString(cursor.getColumnIndex(justdealsDatabase.KEY_BCODE)));
bPrice.add(cursor.getString(cursor.getColumnIndex(justdealsDatabase.KEY_BPRICE))+ "£");
bDescription.add(cursor.getString(cursor.getColumnIndex(justdealsDatabase.KEY_BDESCRIPTION)));
bModule.add(cursor.getString(cursor.getColumnIndex(justdealsDatabase.KEY_BMODULE)));
bImage.add(cursor.getString(cursor.getColumnIndex(justdealsDatabase.KEY_BIMAGE)));
cursor.moveToNext();
}
bAdapter.notifyDataSetChanged();
Utils.IS_ENDED_PRODUCT_LIST = true;
}
}
}
<?php
include("MysqlConnection.php");
header('Content-Type: application/json');
$from = $_POST["from"];
$nr = $_POST["nr"];
// those variables are for search
$title = $_POST["title"];
$code = $_POST["code"];
$price = $_POST["price"];
$module = $_POST["module"];
$order = $_POST["order"];
$by = $_POST["by"];
$sql = "SET CHARACTER SET utf8";
$db->query($sql);
// if those 2 var are set then we order the query after them
if(isset($order) && isset($by)){
$sql .= " ORDER BY `$order` $by LIMIT $from, $nr";
}else{
$sql .= "LIMIT $from, $nr";
}
$query = $db->query($sql);
$rows = array();
$rows[] = array("numRows"=>$db->numRows($query));
if($db->numRows($query)!=0){
while($row = mysql_fetch_assoc($query)) {
$rows[] = $row;
}
echo(json_encode($rows));
}
}
$db->closeConnection();
?>
目前我对这个问题进行了广泛的研究，但还没有找到一个具体的解决方案。
我读过一些帖子，可能是字符串声明不使用双引号。这是否意味着存储在SQL文件中的值(例如。书的名字，价格等)需要双引号而不是单引号?
如果我在JSONLint中运行上述代码，我会得到以下错误:
Parse error on line 1:
^
Expecting '{', '['
我尝试使用("{结果}")而不是{结果)或("结果")，但这给了我更多的错误。我是如此接近得到这整个应用程序的工作，但唯一的问题是将result字符串转换成一个有效的JSON数组。
任何想法和建议都将是非常感谢的。
JARRAY= NEW JSONARRAY (RESULT);03-06 21:17:31.387: D/AndroidRuntime(818): Shutting down VM
03-06 21:17:31.387: W/dalvikvm(818): threadid=1: thread exiting with uncaught exception (group=0x40014760)
03-06 21:17:31.417: E/AndroidRuntime(818): FATAL EXCEPTION: main
03-06 21:17:31.417: E/AndroidRuntime(818): java.lang.NullPointerException
03-06 21:17:31.417: E/AndroidRuntime(818): at com.fokrul.justdeals.ActivityTab$ProductsAdapter.getView(ActivityTab.java:1565)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.widget.AbsListView.obtainView(AbsListView.java:1970)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.widget.ListView.makeAndAddView(ListView.java:1756)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.widget.ListView.fillDown(ListView.java:656)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.widget.ListView.fillFromTop(ListView.java:716)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.widget.ListView.layoutChildren(ListView.java:1595)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.widget.AbsListView.onLayout(AbsListView.java:1800)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.view.View.layout(View.java:9581)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.view.ViewGroup.layout(ViewGroup.java:3877)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.widget.RelativeLayout.onLayout(RelativeLayout.java:912)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.view.View.layout(View.java:9581)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.view.ViewGroup.layout(ViewGroup.java:3877)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.widget.FrameLayout.onLayout(FrameLayout.java:400)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.view.View.layout(View.java:9581)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.view.ViewGroup.layout(ViewGroup.java:3877)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1542)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1403)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.widget.LinearLayout.onLayout(LinearLayout.java:1314)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.view.View.layout(View.java:9581)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.view.ViewGroup.layout(ViewGroup.java:3877)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.widget.FrameLayout.onLayout(FrameLayout.java:400)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.view.View.layout(View.java:9581)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.view.ViewGroup.layout(ViewGroup.java:3877)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.widget.RelativeLayout.onLayout(RelativeLayout.java:912)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.view.View.layout(View.java:9581)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.view.ViewGroup.layout(ViewGroup.java:3877)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.widget.FrameLayout.onLayout(FrameLayout.java:400)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.view.View.layout(View.java:9581)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.view.ViewGroup.layout(ViewGroup.java:3877)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1542)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1403)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.widget.LinearLayout.onLayout(LinearLayout.java:1314)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.view.View.layout(View.java:9581)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.view.ViewGroup.layout(ViewGroup.java:3877)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.widget.FrameLayout.onLayout(FrameLayout.java:400)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.view.View.layout(View.java:9581)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.view.ViewGroup.layout(ViewGroup.java:3877)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.view.ViewRoot.performTraversals(ViewRoot.java:1282)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.view.ViewRoot.handleMessage(ViewRoot.java:2040)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.os.Handler.dispatchMessage(Handler.java:99)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.os.Looper.loop(Looper.java:132)
03-06 21:17:31.417: E/AndroidRuntime(818): at android.app.ActivityThread.main(ActivityThread.java:4123)
03-06 21:17:31.417: E/AndroidRuntime(818): at java.lang.reflect.Method.invokeNative(Native Method)
03-06 21:17:31.417: E/AndroidRuntime(818): at java.lang.reflect.Method.invoke(Method.java:491)
03-06 21:17:31.417: E/AndroidRuntime(818): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:841)
03-06 21:17:31.417: E/AndroidRuntime(818): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:599)
03-06 21:17:31.417: E/AndroidRuntime(818): at dalvik.system.NativeStart.main(Native Method)
这部分
jarray = new JSONArray("result");
当然应该读作
jarray = new JSONArray(result);
，但我想你已经试过了。从解析器错误判断，我假设结果不包含有效的JSON字符串。如果它应该表示一个数组，它必须是这样的(最简单的形式):
["abc", "def", "ghi"]
当涉及到单引号或双引号时，一些JSON解析器很挑剔。但在你的情况下，问题似乎在于括号。您可以使用调试器进入getJarrayFromString并检查结果的值是什么，进入getJarrayFromString或者至少将原始值打印到控制台?