Java ArrayList add在android中不起作用
这是我的密码。OnOltuud是一个ArrayList。我获取Firebase数据,然后添加Onoltuud arrayList。但是arrayList大小为0。注意从Firebase传入的数据。帮帮我Java ArrayList add在android中不起作用,java,android,firebase,firebase-realtime-database,Java,Android,Firebase,Firebase Realtime Database,这是我的密码。OnOltuud是一个ArrayList。我获取Firebase数据,然后添加Onoltuud arrayList。但是arrayList大小为0。注意从Firebase传入的数据。帮帮我 public class OnooltActivity2 extends AppCompatActivity implements View.OnClickListener { ArrayList<String> onooltuud = new ArrayList<Strin
public class OnooltActivity2 extends AppCompatActivity implements View.OnClickListener {
ArrayList<String> onooltuud = new ArrayList<String>();`
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.onoolt_activity_2);
save = (Button) findViewById(R.id.save);
database = FirebaseDatabase.getInstance();
ref = database.getReference("db").child("davaa").child(String.valueOf(davaaniiNo) + "-iinDavaa");
Query query = ref.orderByChild("onooltDugaar");
query.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
int temp = (int) dataSnapshot.getChildrenCount();
Log.i("count", String.valueOf(temp));
for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
Log.i("snapshot", snapshot.getValue().toString());
Onoolt onoolt = snapshot.getValue(Onoolt.class);
onoolts.add(onoolt.getOnooltDugaar());
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
Toast.makeText(OnooltActivity2.this, "Датаг уншиж чадсангүй: " + databaseError.getCode(), Toast.LENGTH_SHORT).show();
}
});
Log.i("testSize:", String.valueOf(onoolts.size()));
这是我的代码onolts add not working它说您的Arraylist对象onoltuud的大小为0=0,因为您从未向它添加任何内容。您这样声明了ArrayList:
ArrayList<String> onooltuud = new ArrayList<String>();
名称不对应:onoltuud与onolts
删除此行:
onoolts.add(onoolt.getOnooltDugaar());
并把这一行:
onooltuud.add(onoolt.getOnooltDugaar());
在哪里添加到onoltuud?您的数组称为onoltuud,而不是onolts.addonolt.getonoltdugar;放置onoltuud.addonolt.getonoltdugar;您只需登录错误place@LieForBananas::也许你应该添加解决方案提示作为答案!我不认为OP能够理解你的建议,如果没有更结构化的响应。@Barns你是对的,我将添加更多细节作为回答:@Barns,希望如此!:
onooltuud.add(onoolt.getOnooltDugaar());