JSON 파일을 읽고 해당 콘텐츠를 표시하는 앱을 만들려고합니다.
JSON 파일은 다음과 같습니다.
"Jett": {
"name":
"Jett",
"info":
"From Korea comes Jett, an agile fighter who prioritizes movement over everything. Her abilities include a teleportation-based dash and an updraft that lets her reach higher ledges. She also has a smokebomb ability to hinder sightlines and a powerful Bladestorm ultimate that deals moderate-to-heavy damage and remains accurate even while she's moving [1]. Jett is one of the few Agents with a passive ability. Holding the jump key while in the air will allow Jett to slow her descent. Jett's Ultimate allows her to wield several throwing knives that deal moderate damage and kill on headshots. Getting a kill replenishes your daggers and you can choose to throw them one at a time or throw all remaining daggers in a short-ranged burst.",
"ability 1":{
"name" : "Cloudburst",
"type" : "Basic",
"cost" : "100",
"duration" : "7 Secs",
"health" : "N/A",
"description" : "Instantly throw a projectile that expands into a brief vision cloud on impact with a surface. Hold the ability key to curve the cloud in the direction of your crosshair."
},
"ability 2" : {
"name" : "Updraft",
"type" : "Basic",
"cost" : "100",
"duration" : "N/A",
"health" :"N/A",
"description" : "Instantly propel Jett high into the air."
},
"ability 3" : {
"name" : "Tailwind",
"type" : "Signature",
"cost" : "None",
"duration" : "N/A",
"health" :"N/A",
"description" : "Instantly propel in the direction she is moving. If Jett is standing still, she will propel forward."
},
"ability 4" : {
"name" : "Bladestorm",
"type" : "Ultimate",
"cost" : "6 Ult Points",
"duration" : "N/A",
"health" :"N/A",
"description" : "Equip a set of 5 highly accurate throwing knives. Fire to throw a single knife. Alternative Fire to throw all remaining daggers at once. Restocks upon killing an enemy."
}
},
"Breach": {
"name": "Breach",
"info":
"Breach fires powerful, targeted kinetic blasts to aggressively clear a path through enemy ground. The damage and disruption he inflicts ensures no fight is ever fair. Breach's main gimmick is the ability to use all of his abilities through the geometry of the map,whether it is through walls, roofs, or terrain. This ability set rewards experienced players for knowing the maps well. His abilities also seem to reward an aggressive playstyle despite most of his abilities being crowd-control based.",
"ability 1":{
"name" : "Aftershock",
"type" : "Basic",
"cost" : "100",
"duration" : "N/A",
"health" : "N/A",
"description" : "Equip a fusion charge. Fire the charge to set a slow-acting burst through the wall. The burst does heavy damage to anyone caught in its area."
},
"ability 2" : {
"name" : "Flashpoint",
"type" : "Basic",
"cost" : "200",
"duration" : "2 Secs",
"health" :"N/A",
"description" : " Equip a blinding charge. Fire the charge to set a fast-acting burst through the wall. The charge detonates to blind all players looking at it."
},
"ability 3" : {
"name" : "Fault Line",
"type" : "Signature",
"cost" : "None",
"duration" : "N/A",
"health" :"N/A",
"description" : "Equip a seismic blast. Hold Fire to increase the distance. Release to set off the quake, dazing all players in its zone and in a line up to the zone."
},
"ability 4" : {
"name" : "Rolling Thunder",
"type" : "Ultimate",
"cost" : "7 Ult Points",
"duration" : "N/A",
"health" :"N/A",
"description" : "Equip a seismic charge. Fire to send a cascading quake through all terrain in a large cone. The quake dazes and knocks up anyone caught in it."
}
}
클래스는 다음 코드를 사용하여 CharacterPageConstructor라는 다른 클래스로 전달되는 'characterName'이라는 문자열을 보유합니다.
onTap: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => CharacterPageConstructor(characterName)));
},
CharacterPageConstructor는이 characterName을 매개 변수로 사용하여 Json 파일에서 이름을 검색합니다. 내가 읽는 데 사용한 코드는 다음과 같습니다.
class CharacterPageConstructor extends StatelessWidget {
final String characterName;
CharacterPageConstructor(this.characterName);
String jsonData;
Future<String> _read() async {
try {
final File file = File('assets/data/character_data.json');
jsonData = await file.readAsString();
} catch (e) {
print("Couldn't read file");
}
return jsonData;
}
Widget build(BuildContext context) {
Map<String, dynamic> characterData = jsonDecode(jsonData);
var name = characterData[characterName]['name'];
var info = characterData[characterName]['info'];
return Scaffold(
backgroundColor: Color.fromARGB(255, 15, 23, 34),
body: Container(
margin: EdgeInsets.all(20),
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(5.0),
color: Color.fromARGB(175, 252, 70, 82),
),
child: Row(
children: [ Text(name),
Text(info)
그러나 결국 다음 오류가 발생합니다.
The following NoSuchMethodError was thrown building CharacterPageConstructor(dirty):
The getter 'length' was called on null.
Receiver: null
Tried calling: length
The relevant error-causing widget was
CharacterPageConstructor
lib\characterBox.dart:40
When the exception was thrown, this was the stack
#0 Object.noSuchMethod (dart:core-patch/object_patch.dart:51:5)
#1 _parseJson (dart:convert-patch/convert_patch.dart:39:28)
#2 JsonDecoder.convert (dart:convert/json.dart:505:36)
#3 JsonCodec.decode (dart:convert/json.dart:156:41)
#4 jsonDecode (dart:convert/json.dart:96:10)
...
오류 lib\characterBox.dart:40는 다음 줄을 나타냅니다.
builder: (context) => CharacterPageConstructor(characterName)));
final File file = File('assets/data/character_data.json');
jsonData = await file.readAsString();
로 변경:
String data = await rootBundle.loadString('assets/data/character_data.json');
jsonData = json.decode(data);
print(jsonData);
또는
final file = File('assets/data/character_data.json');
String data = await file.readAsString();
jsonData = json.decode(data);
print(jsonData);
이 기사는 인터넷에서 수집됩니다. 재 인쇄 할 때 출처를 알려주십시오.
침해가 발생한 경우 연락 주시기 바랍니다[email protected] 삭제
몇 마디 만하겠습니다