Question

我想在textView中显示所选项目时，从我实施的微调器的下拉列表中选择AdapterView.OnItemSelectedListener但是当我选择项目时，null/empty总是@Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); spinner = (Spinner) findViewById(R.id.spinner); spinner.setAdapter(new CustomAdapter(MainActivity.this, Languages)); btn.setOnClickListener(this); spinner.setOnItemSelectedListener(this); } @Override public void onItemSelected(AdapterView<?> parent, View view, int position, long id) { item = (String)parent.getItemAtPosition(position); Toast.makeText(MainActivity.this, item.toString(), Toast.LENGTH_SHORT).show(); } @Override public void onNothingSelected(AdapterView<?> parent) { }这是我的代码：

enum CustomCellIdentifiers
{
    static let cellForCountry = "cellForCountry"
    static let cellForCity = "cellForCity"
    static let cellForStoreType = "cellForStoreType"
}

Answer 1

SO答案来源：https://stackoverflow.com/a/49301966/5461982

我知道这是一个老问题了，但是如果遇到其他任何人，请确保检查您为Spinner设置的适配器的自定义实现会覆盖getItem方法：

@Override
public Object getItem(int position) {
    return spinnerItems.get(position);
}

默认情况下，在实现自定义BaseAdapter时需要重写此方法，但默认返回类型为null。确保将返回类型修改为return spinnerItems.get(position)。

希望这会有所帮助，我花了大约30分钟的时间尝试解决此问题！

Answer 2

试试这个，

String selected_item = spinner.getSelectedItem().toString();

Answer 3

只需从String Array中检索值：

@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
    final String item = Languages[position];
    Toast.makeText(MainActivity.this, item, Toast.LENGTH_SHORT).show();
}

Answer 4

试试这个

spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
        @Override
        public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
            sSelectedItem = arr_spiner.get(spinner.getSelectedItemPosition())
                    .getName();
            txtSpinnerValue.setText(sSelectedItem);
        }
        @Override
        public void onNothingSelected(AdapterView<?> parent) {
        }
    });

https://stackoverflow.com/questions/45159011/spinner-item-is-not-visible-data-is-coming-from-server-android/45161202#45161202

Answer 5

试一下

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

    spinner = (Spinner) findViewById(R.id.spinner);
    spinner.setAdapter(new CustomAdapter(MainActivity.this, Languages));

    btn.setOnClickListener(this);
    spinner.setOnItemSelectedListener(this);

}

@Override
public void onItemSelected(AdapterView<?> parent, 
                        View view, int position, long id) {

    //item = (String)parent.getItemAtPosition(position);
      item = (String) spinner.getSelectedItem().toString(); //Here is the Change

        Toast.makeText(MainActivity.this, item.toString(),
                Toast.LENGTH_SHORT).show();
}

@Override
public void onNothingSelected(AdapterView<?> parent) {
}

此处的更改为

来自

item = (String)parent.getItemAtPosition(position);

要

item = (String) spinner.getSelectedItem().toString();

Spinner：getItemAtPosition（position）返回null / empty

5 个答案: