我使用这个 java 代码来编写 Android RPN 计算器。现在我正处于单击微调器设置显示的小数位数的阶段。不幸的是,名为 onItemselected 的 Toast 函数不起作用,我认为这意味着该函数未被调用。有什么想法吗?
谢谢!
public class MainActivity extends AppCompatActivity implements View.OnClickListener, AdapterView.OnItemSelectedListener {
TextView stackedit0;
LinkedList<Double> fifo = new LinkedList<Double>();
int stack = 0;
int initialized = -1;
double m;
private Spinner spinner;
private static final List<String> paths = new ArrayList<String>();
public void create_string() {
for (int i=0; i<=1047; i++){
paths.add(String.valueOf(i));
}
}
public void onItemSelected(AdapterView<?> parent, View v, int position, long id) {
Toast.makeText(this, parent.getItemAtPosition(position).toString(), Toast.LENGTH_LONG).show();
}
public void onNothingSelected(AdapterView<?> parent) {
// TODO Auto-generated method stub
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
spinner = (Spinner)findViewById(R.id.spinner);
ArrayAdapter<String>adapter = new ArrayAdapter<String>(MainActivity.this,
android.R.layout.simple_spinner_item,paths);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(adapter);
spinner.setOnItemSelectedListener(this);
create_string();
...
}
<Spinner
android:id="@+id/spinner"
android:layout_width="52dp"
android:layout_height="19dp"
android:layout_gravity="center_vertical"
android:layout_marginLeft="4dp"
android:layout_marginRight="4dp"
android:background="#66000000"
android:text="AC"
android:textColor="#FFFFFF"
android:spinnerMode="dropdown"/>
最佳答案
当您在适配器初始化后填充列表时,您可以调用
adapter.notifyDataSetChanged();
填充列表后,即在 create_string() 方法之后或填充列表后初始化适配器。
关于java - 为什么 Spinner 不触发 onItemselected?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/58682816/