Sorry for the length, but I've been stuck on this for a while.
I'm trying to read Google Places API from an Android app, I've written similar code in Eclipse and it runs successfully, however when I changed it for Android it breaks:
public constructor(double lat, double lng, int maxPrice, double distance) throws Exception {
responseBuilder = new StringBuilder();
//Format the params
query = String.format("type=%s&maxprice=%s&opennow=%s&key=%s&location=%s&radius=%s",
URLEncoder.encode(type,charset),
URLEncoder.encode(String.valueOf(maxPrice),charset),
URLEncoder.encode(opennow,charset),
URLEncoder.encode(apiKey,charset),
URLEncoder.encode(lat + "," + lng,charset),
URLEncoder.encode(String.valueOf(distance),charset));
Thread thread = new Thread(new Runnable() {
@Override
public void run() {
try {
//Create a connection with the website
HttpURLConnection connection = (HttpURLConnection) new URL(url + "?" + query).openConnection();
//Set the requrest property
connection.setRequestProperty("Accept-Charset", charset);
//Get the response
InputStream response = connection.getInputStream();
//Scan the response
Scanner responseScanner = new Scanner(response);
while(responseScanner.hasNextLine()) {
responseBuilder.append(responseScanner.nextLine());
}
responseScanner.close();
obj = new JSONObject(responseBuilder.toString());
//arr is a global variable
arr = obj.getJSONArray("results");
setRandNumber();
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
When I try to access an element (even the first) in arr,
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'int org.json.JSONArray.length()' on a null object reference
at com.example.turtl.project.picker.ispopulated(picker.java:72)
at com.example.turtl.project.MainActivity.getRestaurant(MainActivity.java:67)
at java.lang.reflect.Method.invoke(Native Method)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
at android.view.View.performClick(View.java:5610)
at android.view.View$PerformClick.run(View.java:22260)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6077)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
Application terminated.
This is the offending function:
public void getResult(View view) throws Exception {
EditText priceText = (EditText) findViewById(R.id.maxPrice);
EditText mileText = (EditText) findViewById(R.id.searchSize);
if (criteriaIsNull(priceText, mileText)) {
showAlert("Invalid Fields", "Please set a max price and a distance to search");
} else {
miles = Integer.parseInt(mileText.getText().toString());
double meters = milesToMeters(miles);
maxPrice = Integer.parseInt(priceText.getText().toString());
if ((miles != previousMiles || maxPrice != previousMaxPrice) && !criteriaIsNull(priceText, mileText)) {
previousMaxPrice = maxPrice;
previousMiles = miles;
picker = new picker(loc.getLatitude(), loc.getLongitude(), maxPrice, meters);
if (picker.ispopulated()){
//This line specifically
showAlert(picker.getResultName(), picker.getResultAddress());
} else {
wait(1000);
}
} else {
picker.getNewPlace();
showAlert(picker.getResultName(), picker.getResultAddress());
}
}
}
This is a function I wrote to check if the array was being populated, it also crashes since it calls a method of arr:
public boolean ispopulated() {
return (arr.length()>0);
}
I checked if the call was coming too fast and the array wasn't given time to populate, but I had it wait 10 seconds, and 100 seconds and still the code crashed when it reached that line. I used URLConnection when I was originally writing the code, but changed to HTTPURLConnection when it didn't work and I read some other questions.
Is this a valid way to perform an API call for a JSON response in Android? Is there a better way I should be using? I'm new to Android development so I'm not familiar with its best practices. Any help is appreciated.
