无法在ArrayAdapter中解析构造函数

Question

public class MainActivity extends AppCompatActivity
    implements NavigationView.OnNavigationItemSelectedListener {
EditText myeditText1;
EditText myeditText2;
Button myButton;
Double myfirstET1;
Double myfirstET2;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);
    myeditText1 = (EditText) findViewById(R.id.editText1);
    myeditText2 = (EditText) findViewById(R.id.editText2);
    myButton = (Button) findViewById(R.id.buttonID);
    final TextView myTextView = (TextView) findViewById(R.id.textView2);

    myButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            myfirstET1 = Double.parseDouble(myeditText1.getText().toString());
            myfirstET2 = Double.parseDouble(myeditText2.getText().toString());
            final ListView mListView = (ListView) findViewById(R.id.mList);
            if ((myeditText1.getText().length() > 0) && (myeditText2.getText().length() > 0)) {
                double oper1 = Double.parseDouble(myeditText1.getText().toString());
                double oper2 = Double.parseDouble(myeditText2.getText().toString());
                double result = oper1 / oper2;
                myTextView.setText(Double.toString(result));

                Double myyList[] = {oper1, oper2 + 1, oper2 + 1};
                ListAdapter myAdapter = new ArrayAdapter<Double>(this, android.R.layout.simple_list_item_1, myyList);
                mListView.setAdapter(myAdapter);
            }
        }
    });

创建listView并将适配器设置为其时，我会在listAdapter中遇到错误。如何修复它或简单的替代方案是什么？我希望我的Moto对我编写的代码很清楚。

所有建议都是心脏赞赏的。

Answer 1

您需要在匿名类中使用MainActivity.this而不是this，将此实际的活动上下文称为

 ListAdapter myAdapter = new ArrayAdapter<Double>(MainActivity.this, android.R.layout.simple_list_item_1, myyList);
 //                                             ^^^^^^^^^^^^^^^^^^

，还提到类型并使用ArrayAdapter不是ListAdapter

 ArrayAdapter<Double> myAdapter = new ArrayAdapter<>(MainActivity.this...);
 //         ^^^^^^^ 

Answer 2

您应该使用类似的东西

ArrayAdapter<Double> myAdapter = new ArrayAdapter<Double>(this, android.R.layout.simple_list_item_1, myyList);

Answer 3

您可以使用

ListAdapter myAdapter = new ArrayAdapter<>(MainActivity.this, 
android.R.layout.simple_list_item_1, myyList);
mListView.setAdapter(myAdapter);

或

ListAdapter myAdapter = new ArrayAdapter<Double>(MainActivity.this, 
android.R.layout.simple_list_item_1, myyList);
                mListView.setAdapter(myAdapter);

，但请确保使用MainActivity。这是