Android arrayadapter 不能正常工作

Question

我不知道我做錯了什么。 我是新手。 我需要創建一個與兩個 EditText(number) 和一個按鈕交互的自定義​​列表。 當用戶單擊按鈕時，它會生成一個從第一個數字到最后一個數字的列表，並檢查列表中單擊的數字是否為素數...但我在這部分出現錯誤：ListView listMod;

            listMod = (ListView) findViewById(R.id.listMod);

            List<Integer> lista = new ArrayList<>();
            for (int i = first; i <= last; i++) {
                listMod.add(i);
            }

            ArrayAdapter<Integer> arrayAdapter = new ArrayAdapter<Integer>(
                    this,
                    android.R.layout.simple_list_item_2,
                    lista);

            listMod.setAdapter(arrayAdapter);

所以我不明白問題是什么。 我也在另一個活動中使用了此代碼。 我還將發布整個活動：包 com.example.andre.thelist;

            import android.app.AlertDialog;
            import android.content.DialogInterface;
            import android.os.Bundle;
            import android.support.design.widget.FloatingActionButton;
            import android.support.design.widget.Snackbar;
            import android.support.v7.app.AppCompatActivity;
            import android.support.v7.widget.Toolbar;
            import android.view.View;
            import android.widget.AdapterView;
            import android.widget.ArrayAdapter;
            import android.widget.Button;
            import android.widget.EditText;
            import android.widget.ListView;
            import android.widget.Toast;

            import java.util.ArrayList;
            import java.util.List;

            public class TheList extends AppCompatActivity {


                @Override
                protected void onCreate(Bundle savedInstanceState) {
                    super.onCreate(savedInstanceState);
                    setContentView(R.layout.activity_the_list);
                    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
                    setSupportActionBar(toolbar);


                    FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
                    fab.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View view) {
                            Snackbar.make(view, "Maybe I can use this", Snackbar.LENGTH_LONG)
                            .setAction("Action", null).show();
                        }
                    });



                    Button btn = (Button)findViewById(R.id.gen);

                    btn.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            EditText firstn = (EditText) findViewById(R.id.firstn);
                            EditText lastn = (EditText) findViewById(R.id.lastn);
                            String firstnString = firstn.getText().toString();
                            String lastnString = lastn.getText().toString();

                            if(firstnString.isEmpty() == true || lastnString.isEmpty() == true ) {
                                Integer first = 1;
                                Integer last = 100;
                                Toast.makeText(getApplicationContext(),"Verranno usate le cifre di esempio 1 e 100", Toast.LENGTH_SHORT).show();
                            }
                            final Integer first = Integer.parseInt(firstnString);
                            final Integer last = Integer.parseInt(lastnString);

                            ListView listMod;

                            listMod = (ListView) findViewById(R.id.listMod);

                            List<Integer> lista = new ArrayList<>();
                            for (int i = first; i <= last; i++) {
                                lista.add(i);
                            }

                            ArrayAdapter<Integer> arrayAdapter = new ArrayAdapter<Integer>(
                                this,
                                android.R.layout.simple_list_item_2,
                                lista);

                            listMod.setAdapter(arrayAdapter);

                            listMod.setOnItemClickListener(new AdapterView.OnItemClickListener() {
                                @Override
                                public void onItemClick(AdapterView<?> adattatore, final View componente, int pos, long id) {
                                    final Integer numero = (Integer) adattatore.getItemAtPosition(pos);

                                    //creo il ciclo di controllo valori
                                    if (numero > 0) {
                                        boolean isPrime = true;
                                        for (int i = 2; i <= numero / 2; i++) {
                                            if (numero % i == 0) {
                                                isPrime = false;
                                                break;
                                            }
                                        }
                                        if (isPrime) {
                                            AlertDialog alertDialog = new AlertDialog.Builder(TheList.this).create();
                                            alertDialog.setTitle("Yeah numero primo");
                                            alertDialog.setMessage("Il numero " + numero + " è un numero primo!");
                                            alertDialog.show();
                                        } else {
                                            Toast.makeText(getApplicationContext(), "Il numero " + numero + " non è un numero primo", Toast.LENGTH_SHORT).show();
                                        }
                                    }
                                }
                            });
            }

            });

            }

感謝您的任何幫助

好的，我已經修改了該行（真是失態），但現在控制台向我顯示了其他錯誤，例如：

 Error:(70, 54) error: no suitable constructor found for ArrayAdapter(<anonymous OnClickListener>,int,List<Integer>)
constructor ArrayAdapter.ArrayAdapter(Context,int,int,List<Integer>) is not applicable
(actual and formal argument lists differ in length)
constructor ArrayAdapter.ArrayAdapter(Context,int,List<Integer>) is not applicable
(actual argument <anonymous OnClickListener> cannot be converted to Context by method invocation conversion)
constructor ArrayAdapter.ArrayAdapter(Context,int,int,Integer[]) is not applicable
 (actual and formal argument lists differ in length)
constructor ArrayAdapter.ArrayAdapter(Context,int,Integer[]) is not applicable
(actual argument <anonymous OnClickListener> cannot be converted to Context by method invocation conversion)
 constructor ArrayAdapter.ArrayAdapter(Context,int,int) is not applicable
(actual argument <anonymous OnClickListener> cannot be converted to Context by method invocation conversion)
constructor ArrayAdapter.ArrayAdapter(Context,int) is not applicable
(actual and formal argument lists differ in length)

和

Error:(75, 22) error: cannot find symbol method setAdapter(ArrayAdapter<Integer>)

還

 Error:(77, 22) error: cannot find symbol method setOnItemClickListener(<anonymous OnItemClickListener>)

Answer 1

這里：

for (int i = first; i <= last; i++) { 
   listMod.add(i);
}

listMod.add(i); 行導致問題，因為listMod是ListView對象，而您正試圖在其上調用add方法..

使用lista這是ArrayList用於添加的物品中ArrayList其傳遞作為數據源適配器：

for (int i = first; i <= last; i++) { 
   lista.add(i);
}

如更新日志：

錯誤：(77, 22) 錯誤：找不到符號方法 setOnItemClickListener()

問題是由於將this作為 ArrayAdapter.create 適配器對象中的第一個參數傳遞為：

ArrayAdapter<Integer> arrayAdapter = new ArrayAdapter<Integer>(
                                TheList.this,
                                android.R.layout.simple_list_item_2,
                                lista);