Question

我在viewController中有一个 usernameTextField ，在其中输入用户名和带有以下代码的按钮 searchTapped ：

@IBAction func searchTapped(_ sender: UIButton) {
        guard let username = usernameTextField.text, username != "" else {
            displayWarningLabel(withText: "Information is incorrect")
            return
        }

        guard let gitUrl = URL(string: "https://api.github.com/users/\(username)/gists") else { return }
        URLSession.shared.dataTask(with: gitUrl) { (data, response, error) in

            guard let data = data else { return }
            guard error == nil else { return }
            do {
                let gitData = try JSONDecoder().decode([Gists].self, from: data)
                DispatchQueue.main.async {
                    self.gists = gitData
                }
            } catch let error {
                print(error)
            }
            }.resume()

        performSegue(withIdentifier: "GistsSegue", sender: nil)
    }

从json获取数据后，我想将数据保存到此方法之外的数组要点中，但这不会发生。

 var gists = [Gists]()

可能是什么问题？

以防万一，这是我解析json的模型：

struct Gists: Codable {
    var description: String?
    var files: [String: DetailGist]
}

struct DetailGist: Codable {
    var filename: String?
    var raw_url: String?
}

Answer 1

public class AtdListAdapter extends RecyclerView.Adapter<AtdListAdapter.ViewHolder> { private List<String> atd ; private Context context; String str; private DatabaseReference demo; public AtdListAdapter(List<String> atd, Context context) { this.atd = atd; this.context = context; } @Override public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { LayoutInflater inflater = LayoutInflater.from(context); View view = inflater.inflate(R.layout.atdliststaff,null); return new ViewHolder(view); } @Override public void onBindViewHolder(ViewHolder holder, int position) { str = atd.get(position); holder.name.setText(str); } @Override public int getItemCount() { return atd.size(); } public class ViewHolder extends RecyclerView.ViewHolder{ private DatabaseReference demo; private TextView name; private RadioButton rb1,rb2; private RadioGroup rg; public ViewHolder(View itemView) { super(itemView); name = itemView.findViewById(R.id.name); rg = itemView.findViewById(R.id.rg); rb1 = itemView.findViewById(R.id.rb1); rb2 = itemView.findViewById(R.id.rb2); if(rb1.isSelected()) { demo = FirebaseDatabase.getInstance().getReference().child("IDS").child("AtdList").child("1").child("1").child(str).child("status"); demo.setValue("Present"); Toast.makeText(context, "updated by Present", Toast.LENGTH_SHORT).show(); } else if(rb2.isSelected()) { demo = FirebaseDatabase.getInstance().getReference().child("IDS").child("AtdList").child("1").child("1").child(str).child("status"); demo.setValue("Absent"); Toast.makeText(context, "Updated by Absent", Toast.LENGTH_SHORT).show(); } } } }正在被调用，但是在您调用self.gists = gitData之后很久才被调用。这就是异步数据访问的本质。

只需将您的performSegue呼叫移到设置performSegue之后。

self.gists

SWIFT可解码数据传输

1 个答案: