我有一个包含单选按钮的自定义对话框，但是当我添加 oncheckedchangelistener 时，我的应用程序崩溃了。可能是什么问题呢？
提前致谢！：D
这是我的代码：
GridViewAdapter adapter = new GridViewAdapter(alcoholType.this, images,names);
gridView.setAdapter(adapter);
gridView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
final Dialog dialog = new Dialog(context);
dialog.setContentView(R.layout.alcoholdialog);
dialog.setTitle("ORDER " + names.get(position));
radioQuantity = (RadioGroup) findViewById(R.id.radioQuantity);
quantity1 = (RadioButton) findViewById(R.id.quantity1);
quantity2 = (RadioButton) findViewById(R.id.quantity2);
radioQuantity.clearCheck();
radioQuantity.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(RadioGroup group, int checkedId) {
}
});
dialog.show();
}
});
这是错误跟踪：
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.gin.ordering, PID: 22005
java.lang.NullPointerException: Attempt to invoke …我正在使用SQLITE来存储,检索和删除购物车中添加的值.并为自定义列表视图中的每一行添加了删除按钮.
因此,当用户点击特定行上的删除按钮时,它也将删除表中的数据.
我的问题是,当用户删除购物车中的所有内容时,如何检查列表视图是否为空？
有人能指出我应该做什么或使用什么？提前致谢!:d
这是我的购物车类:
//CART LISTVIEW
private ArrayList<String> orderid;
private ArrayList<String> orderName;
private ArrayList<String> orderSize;
private ArrayList<String> orderQuantity;
private cartDatabaseHelper db;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_cart);
db = new cartDatabaseHelper(this);
//CART LISTVIEW
orderid = new ArrayList<>();
orderName = new ArrayList<>();
orderSize = new ArrayList<>();
orderQuantity = new ArrayList<>();
TextView textEmpty = (TextView) findViewById(R.id.textEmpty);
Button btnCheckout = (Button) findViewById(R.id.btnCheckout);
ListView listView = (ListView) findViewById(R.id.listView);
//ListView listView1 = (ListView) findViewById(R.id.emptyView);
final ListCartAdapter adapter = new ListCartAdapter(cart.this, orderid, orderName, …