Question

我一直在使用Android Studio自学Java / XML，并希望得到一些帮助。我正在尝试创建一个购物清单应用程序，我遇到了在数组中命名字符串数组的问题。我设置了一个ArrayList，但我想用字符串数组填充ArrayList。当我尝试添加字符串输入（来自用户）时，我收到一条错误消息：

列表中的
add（java.lang.String []）无法应用
to（java.lang.String）

这是我的代码：

public class ShoppingLists extends AppCompatActivity {

    /* Create ArrayList (from List) and Adapter for the ListView */
    List<String[]> shoppingLists = null;
    ArrayAdapter<String> adapter = null;
    ListView lv = null;

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

        /* Create main array */
        shoppingLists = new ArrayList<>();

        /* Set view style with adapter */
        adapter = new ArrayAdapter(this, android.R.layout.simple_list_item_1, shoppingLists);
        lv = (ListView) findViewById(R.id.shoppingListView);
        lv.setAdapter(adapter);
    }

    /* Create a menu. */
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.shopping_menu, menu);
        return true;
    }

    /* Create actions for menu button presses */
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        /* Determine which menu button is pressed */
        switch (item.getItemId()) {
            case R.id.action_add:
                /* Create an alert dialog for user input */
                AlertDialog.Builder builder = new AlertDialog.Builder(this);
                builder.setTitle(getString(R.string.add_list));
                final EditText input= new EditText(this);
                builder.setView(input);

                /* If 'OK' is pressed, enter user input as new object into shoppingLists array */
                builder.setPositiveButton(getString(R.string.ok_button), new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        /* Convert user input to string and add it to list */
                        shoppingLists.add(input.getText().toString());
                        /* Update adapter with new object to make visible */
                        lv.setAdapter(adapter);
                    }
                });
                builder.setNegativeButton(getString(R.string.cancel_button), new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        /* Exit dialog box without adding new object */
                        dialog.cancel();
                    }
                });
                builder.show();
                return true;
        }
        return super.onOptionsItemSelected(item);
    }
}

此处的错误标有：

shoppingLists.add(input.getText().toString());

我有一种感觉，我错过了一些简单的东西，但我无法理解。

预先感谢您的协助！

Answer 1

List<String[]> shoppingLists = null;它应该是

List<String> shoppingLists = null;

Answer 2

有两种解决方案

1 - 将List<String[]> shoppingLists = null;更改为List<String> shoppingLists = null;

2 - 首先将输入文本添加到字符串数组中，然后将该字符串数组添加到列表中，如下所示：String[] strArray = {input.getText().toString()}; shoppingLists.add(strArray);

Java getText（）。toString（）用于命名String数组

2 个答案: