在textView中打印json文件

Question

这里是我的json文件：settings.json（在资产文件夹中：]

{
  "settings": [
    {
      "level": "upper"
    }
  ]
}

我在Android Studio中工作。我从json文件在TextView中打印高位单词，但是这不起作用，我的应用程序崩溃了。有想法吗？我在Java文件中的代码：

public class MainActivity extends AppCompatActivity {
    ArrayList<String> level = new ArrayList<>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        try {

            JSONObject obj = new JSONObject(loadJSONFromAsset());

            JSONArray userArray = obj.getJSONArray("settings");

            for (int i = 0; i < userArray.length(); i++) {

                JSONObject userDetail = userArray.getJSONObject(i);

                level.add(userDetail.getString("level"));
            }
            } catch(JSONException e){
                e.printStackTrace();

            }
        TextView textView = (TextView) findViewById(R.id.textView);

        textView.setText(level.get(0));

        setContentView(R.layout.activity_main);
    }
    public String loadJSONFromAsset() {
        String json = null;
        try {
            InputStream is = getAssets().open("settings.json");

            int size = is.available();

            byte[] buffer = new byte[size];

            is.read(buffer);

            is.close();

            json = new String(buffer, "UTF-8");


        } catch (IOException ex) {
            ex.printStackTrace();
            return null;
        }
        return json;
    }

谢谢。Android，json，源代码...

Answer 1

我希望这对您有用，

像这样编写onCreate()方法，

 @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        try {

            JSONObject obj = new JSONObject(loadJSONFromAsset());
            JSONArray userArray = obj.getJSONArray("settings");
            for (int i = 0; i < userArray.length(); i++) {
                JSONObject userDetail = userArray.getJSONObject(i);
                level.add(userDetail.getString("level"));
            }
            } catch(JSONException e){
                e.printStackTrace();

            }
        TextView textView = (TextView) findViewById(R.id.textView);

        textView.setText(level.get(0));
    }

首先设置setContentView()方法，然后初始化您的文本视图。在您的代码中，在初始化布局之前，您将访问文本视图。

Answer 2

以及为什么else在if函数中起作用？该级别的记录更高。如果不正确，为什么呢？

protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
        try {
            // get JSONObject from JSON file
            JSONObject obj = new JSONObject(loadJSONFromAsset());
            // fetch JSONArray named users
            JSONArray userArray = obj.getJSONArray("settings");
            // implement for loop for getting users list data
            for (int i = 0; i < userArray.length(); i++) {
                // create a JSONObject for fetching single user data
                JSONObject userDetail = userArray.getJSONObject(i);
                // fetch email and name and store it in arraylist
                level.add(userDetail.getString("level"));
            }
            } catch(JSONException e){
                e.printStackTrace();

            }
        TextView textView = (TextView) findViewById(R.id.textView);

        if (level.get(0) == "upper") {
            textView.setText(level.get(0));
        } else {

        }