Question

当我将其放在onCreate其工作台上时，我想使用数组创建listview。

String nama [] = {"Olala","bolabola","yolooo","fighter"};

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

但是当我将其放在onCreate下方时，“ nama”无法读取我的数组

public class MainActivity extends AppCompatActivity {





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

    String nama [] = {"Olala","bolabola","yolooo","fighter"};


    ListView listView = (ListView)findViewById(R.id.ListView);
    CostumAdapter costumAdapter = new CostumAdapter();
    listView.setAdapter(costumAdapter);

}
public class CostumAdapter extends BaseAdapter{
    @Override
    public int getCount() {
        return nama.length;
    }

    @Override
    public Object getItem(int position) {
        return null;
    }

    @Override
    public long getItemId(int position) {
        return 0;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        convertView = getLayoutInflater().inflate(R.layout.arablayout,null);

        TextView textViewName = (TextView)convertView.findViewById(R.id.textview);

        textViewName.setText(nama[position]);



        return convertView;
    }

}
}

无法解析符号纳马我必须这样做，因为此后我将创建spannableString 有什么建议吗？

Answer 1

您应该为customView类创建一个构造函数，该构造函数包括一个参数以使数组通过：-

public class MainActivity extends AppCompatActivity {

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

        String nama [] = {"Olala","bolabola","yolooo","fighter"};

        ListView listView = (ListView)findViewById(R.id.ListView);
        CostumAdapter costumAdapter = new CostumAdapter(nama);
        listView.setAdapter(costumAdapter);

}

public class CostumAdapter extends BaseAdapter{

    String[] nama;

    public CostumAdapter(String[] nama){
        this.nama = nama;
    }

    @Override
    public int getCount() {
        return nama.length;
    }

    @Override
    public Object getItem(int position) {
        return null;
    }

    @Override
    public long getItemId(int position) {
        return 0;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        convertView = getLayoutInflater().inflate(R.layout.arablayout,null);

        TextView textViewName = (TextView)convertView.findViewById(R.id.textview);

        textViewName.setText(nama[position]);



        return convertView;
    }

}
}

Answer 2

您必须声明一个函数，该函数可以更新适配器类中的数据，可以在onCreate方法中初始化列表，或者是否需要，然后调用该函数来更新适配器的数据。

这是一个例子：

public class MyActivity extends AppCompactActivity {

    List<String> myList = new ArrayList<String>();

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

        myList.add("firstString");
        myList.add("secondString");
        myList.add("thirdString");
        myList.add("fourthString");

        ListView listView = (ListView)findViewById(R.id.ListView);
        CostumAdapter costumAdapter = new CostumAdapter();
        customAdapter.updateList(myList);
        listView.setAdapter(costumAdapter);
    }

    public class CostumAdapter extends BaseAdapter{

        private List<String> myList = new ArrayList();

        public void updateList(List<String> newList) {
            this.myList = newList;
            notifyDataSetChanged();
        }

        @Override
        public int getCount() {
            return myList.length;
        }

        @Override
        public Object getItem(int position) {
            return null;
        }

        @Override
        public long getItemId(int position) {
            return 0;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            convertView = getLayoutInflater().inflate(R.layout.arablayout,null);

            TextView textViewName = (TextView)convertView.findViewById(R.id.textview);

            textViewName.setText(myList.get(position));

            return convertView;
        }

    }
}

无法在Costum适配器中访问onCreate下面的数组

2 个答案: