java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Object android.content.Context.getSystemService(java.lang.String)' on a null object reference #19
Description
Hi
I have problem using this package
I wrote exactly your sample but when i try it, i got this:
java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Object android.content.Context.getSystemService(java.lang.String)' on a null object reference
Complete log:
:
I/flutter (24775): DataReceived: 0%
I/flutter (24775): DataReceived: 2%
I/flutter (24775): DataReceived: 4%
I/flutter (24775): DataReceived: 6%
I/flutter (24775): DataReceived: 7%
I/flutter (24775): DataReceived: 9%
I/flutter (24775): DataReceived: 11%
I/flutter (24775): DataReceived: 13%
I/flutter (24775): DataReceived: 15%
I/flutter (24775): DataReceived: 16%
I/flutter (24775): DataReceived: 18%
I/flutter (24775): DataReceived: 20%
I/flutter (24775): DataReceived: 22%
I/flutter (24775): DataReceived: 24%
I/flutter (24775): DataReceived: 25%
I/flutter (24775): DataReceived: 27%
I/flutter (24775): DataReceived: 29%
I/flutter (24775): DataReceived: 31%
I/flutter (24775): DataReceived: 33%
I/flutter (24775): DataReceived: 34%
I/flutter (24775): DataReceived: 36%
I/flutter (24775): DataReceived: 38%
I/flutter (24775): DataReceived: 40%
I/flutter (24775): DataReceived: 41%
I/flutter (24775): DataReceived: 43%
I/flutter (24775): DataReceived: 45%
I/flutter (24775): DataReceived: 47%
I/flutter (24775): DataReceived: 49%
I/flutter (24775): DataReceived: 51%
I/flutter (24775): DataReceived: 52%
I/flutter (24775): DataReceived: 54%
I/flutter (24775): DataReceived: 56%
I/flutter (24775): DataReceived: 58%
I/flutter (24775): DataReceived: 60%
I/flutter (24775): DataReceived: 61%
I/flutter (24775): DataReceived: 63%
I/flutter (24775): DataReceived: 65%
I/flutter (24775): DataReceived: 67%
I/flutter (24775): DataReceived: 69%
I/flutter (24775): DataReceived: 70%
I/flutter (24775): DataReceived: 72%
I/flutter (24775): DataReceived: 78%
I/flutter (24775): DataReceived: 83%
I/flutter (24775): DataReceived: 83%
I/flutter (24775): DataReceived: 85%
I/flutter (24775): DataReceived: 90%
I/flutter (24775): DataReceived: 96%
I/flutter (24775): DataReceived: 100%
I/flutter (24775): java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Object android.content.Context.getSystemService(java.lang.String)' on a null object reference
I/flutter (24775): Task Done
My code:
FlatButton(
color: Colors.black45,
textColor: Colors.white,
onPressed: () {
progressString = Wallpaper.ImageDownloadProgress(
widget.imageUrl);
progressString.listen((data) {
setState(() {
res = data;
downloading = true;
});
print("DataReceived: " + data);
}, onDone: () async {
home = await Wallpaper.bothScreen(imageName: widget.imageUrl,);
print(home);
setState(() {
downloading = false;
home = home;
});
print("Task Done");
}, onError: (error) {
setState(() {
downloading = false;
});
print("Some Error");
});
}