android - 类型参数 t 具有不兼容的上界 View 和 ListView

Question

初始化 ListView 时出现错误 findViewById(R.id.listview)

error: incompatible types: no unique maximal instance exists for type variable T with upper bounds ListView,View where T is a type-variable: T extends View declared in method findViewById(int)

public class ListView extends AppCompatActivity {
    ListView listview;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_list_view);

        listview = findViewById(R.id.listview);

    }
}

Answer 1

将您的 Activity 名称重命名为 ListView 为 ListViewActivity。

因为当你在声明 ListView listview; 时，listview 变成了 Activity 类型。