Java 如何将其他类的列表项放入数组，然后在textview中设置文本

如何将MainActivity java类中mylistofquestion（第2行）的值放入slideadapter java类中的字符串titleqw（第7行）

所以我可以将它从slideadapter java文件中的数组（buttom的第7行）传递到TextView到settext

主要活动：

public class MainActivity extends AppCompatActivity {
    public List<String> mylistofquestion = new ArrayList<>();
    public List<String> mylistofanswer = new ArrayList<>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ViewPager viewPager = (ViewPager) findViewById(R.id.viewpager);
        slideadapter slideadapter = new slideadapter(this);
        viewPager.setAdapter(slideadapter);


        myjsonrequest();


    }

    //requesting for data
    public void myjsonrequest() {
        //url to make request
        String Url = "https://learncodeonline.in/api/android/datastructure.json";

        JsonObjectRequest myjsonObjectRequest = new JsonObjectRequest(Request.Method.GET, Url, null,
                new Response.Listener<JSONObject>() {
                    @Override
                    public void onResponse(JSONObject response) {
                        Log.i("response", "is " + response);

                        try {

                            JSONArray jsonArrayofmine = response.getJSONArray("questions");


                            Log.i("jsonarray", "is " + jsonArrayofmine);


                            for (int i = 0; i < jsonArrayofmine.length(); i++) {
                                //taking quesstion and answer
                                JSONObject jsonObjectinarray = jsonArrayofmine.getJSONObject(i);

                                String question = jsonObjectinarray.getString("question");
                                String answer = jsonObjectinarray.getString("Answer");

                                mylistofquestion.add(i, question);
                                mylistofanswer.add(i, answer);


                            }
                            Log.i("mylistofquestion", "is " + mylistofquestion);
                            Log.i("mylistofanswer", "is " + mylistofanswer);


                            for (int i1 = 0; i1 < mylistofquestion.size(); i1++) {

                                Log.i("Value of element " + i1, mylistofquestion.get(i1));

                            }

                        } catch (JSONException e) {
                            e.printStackTrace();
                        }


                    }
                }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                //show snackbar
            }
        }

        );
        MySingleton.getInstance(getApplicationContext()).addToRequestque(myjsonObjectRequest);


    }
}

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在上面这一行中，我想得到txttitle中的arraylist项，您可以尝试将slideadapter放置在Mainactivity.class中，它实际上应该是“slideadapter”。我想你还需要和其他人一起工作。

第1步：从主活动中删除这两行

  slideadapter slideadapter = new slideadapter(this);
  viewPager.setAdapter(slideadapter);

步骤2：在方法myjsonrequest（如下所示）中的for循环之后粘贴这两行，并进行一些修改

   slideadapter slideadapter = new slideadapter(this,mylistofquestion,mylistofanswer);
   viewPager.setAdapter(slideadapter);

步骤3：在slideadapter中将构造函数更改为

public slideadapter(Context context, List<String> mylistofquestion, List<String> mylistofanswer) {
    this.context = context;
    this.mylistofquestion = mylistofquestion;
    this.mylistofanswer = mylistofanswer;
}

下面是一个新的

txttitle.setText(mylistofquestion.get(position));

---

错误：在步骤3java.lang.IndexOutOfBoundsException中找不到符号变量mylistofquestion异常：索引：0，大小：0位于java.util.ArrayList.get（ArrayList.java:437），位于kvadityaaz.forhitesh.com.datastructurepreparation.slideadapter.InstanceItem（slideadapter.java:122），位于android.support.v4.view.ViewPager.addNewItem（ViewPager.java:1004）在slidedapter中上下文之后；添加这两行->列出mylistofquestion；列出mylistofanswer；

txttitle.setText(titleqw[position]);

txttitle.setText(mylistofquestion.get(position));