我正在访问marraylist服务变量，尽管它是由Firebase中的数据初始化的，但是在marraylist中返回空的Activity却是通过从Firebase数据库获取数据在服务数组中初始化此变量的并在敬酒中，我从Firebase获取数据到marraylist，但是当我尝试访问活动中的变量时，它返回的是空ArrayList。
绑定到服务的我的班级是
public class ProfileList extends AppCompatActivity
implements View.OnClickListener {
private FirebaseAuth mAuth;
Dialog Mydialog;
private FirebaseAuth.AuthStateListener authStateListener;
public DatabaseReference db;
public String userid;
FirebaseUser firebaseUser;
public String iamlog="hy";
List<String> listSt;
String snapdata,log;
ArrayList<String> m1arraylist = new ArrayList <String>();
RecyclerView recyclerView;
public ProfileService myservice;
Intent intent;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.profilelist);
db = FirebaseDatabase.getInstance().getReference().child("users");
recyclerView = (RecyclerView) findViewById(R.id.recyclerview);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
Button button2 = (Button) findViewById(R.id.button2);
mAuth = FirebaseAuth.getInstance();
userid = mAuth.getCurrentUser().getUid();
db = db.child(userid);
Uri uri = Uri.parse(String.valueOf(db));
Log.e(iamlog,String.valueOf(uri));
Intent Profileserviceint = new Intent(this, ProfileService.class);
Profileserviceint.putExtra("dbrefuri",String.valueOf(uri));
bindService(Profileserviceint, connection, Context.BIND_AUTO_CREATE);
}
ServiceConnection connection = new ServiceConnection() {
@Override
public void onServiceConnected(ComponentName name, IBinder service) {
Localservice localservice = (Localservice) service;
myservice=localservice.getservice();
m1arraylist=myservice.getdata();
recyclerView.setAdapter(new ProgramingAdapter(ProfileList.this,localservice.getservice().marraylist));
Log.e(iamlog,"Profile calss "+ String.valueOf(localservice.getservice().marraylist));
}
@Override
public void onServiceDisconnected(ComponentName name) {
}
};
我的服务等级是
public class ProfileService extends Service {
public DatabaseReference db;
Intent intent;
public String iamlog="hy";
String dbref;
public ArrayList<String> marraylist = new ArrayList<>() ;
public IBinder mbinder = new Localservice();
/**
* Creates an IntentService. Invoked by your subclass's constructor.
*
* Used to name the worker thread, important only for debugging.
*/
@Nullable
@Override
public IBinder onBind(Intent intent) {
dbref =intent.getStringExtra("dbrefuri");
return mbinder;
}
/**
* Creates an IntentService. Invoked by your subclass's constructor.
*
*/
public class Localservice extends Binder
{
public ProfileService getservice()
{
return ProfileService.this;
}
}
public ArrayList<String> getdata()
{
db= FirebaseDatabase.getInstance().getReferenceFromUrl(dbref);
db.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot dataSnapshot2 : dataSnapshot.getChildren())
{
marraylist.add(dataSnapshot2.getKey());
}
Toast toast = Toast.makeText(ProfileService.this ,String.valueOf(marraylist),Toast.LENGTH_LONG);
toast.show();
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
return marraylist;
}
}
答案 0 :(得分：0)
致电时 getData（） 它启动数据获取，但是获取尚未完成。 返回的ArrayList尚无任何项目。 一旦在内部获取数据
onDataChange(DataSnapshot dataSnapshot)
数据已添加到列表中。 RecyclerView没有看到此更改。
您需要致电
notifyDataSetChanged()
一旦数据被加载。 将您的代码更改为类似这样的内容
public class ProfileService extends Service {
public DatabaseReference db;
Intent intent;
public String iamlog="hy";
String dbref;
WeakReference<ProfileServiceCallback> profileServiceCallBackRef;
public ArrayList<String> marraylist = new ArrayList<>() ;
public IBinder mbinder = new Localservice();
/**
* Creates an IntentService. Invoked by your subclass's constructor.
*
* Used to name the worker thread, important only for debugging.
*/
@Nullable
@Override
public IBinder onBind(Intent intent) {
dbref =intent.getStringExtra("dbrefuri");
return mbinder;
}
/**
* Creates an IntentService. Invoked by your subclass's constructor.
*
*/
public class Localservice extends Binder
{
public ProfileService getservice()
{
return ProfileService.this;
}
public void setCallback(ProfileServiceCallBack callback){
profileServiceCallbackRef = new WeakReference<ProfileServiceCallBack>(callback);
}
}
public static interface ProfileServiceCallBack {
public void onDataChanged(List<String> data);
}
public void getdata()
{
db= FirebaseDatabase.getInstance().getReferenceFromUrl(dbref);
db.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot dataSnapshot2 : dataSnapshot.getChildren())
{
marraylist.add(dataSnapshot2.getKey());
}
Toast toast = Toast.makeText(ProfileService.this ,String.valueOf(marraylist),Toast.LENGTH_LONG);
toast.show();
if(profileServiceCallbackRef != null){
ProfileServiceCallback callback = profileServiceCallbackRef.get();
if(callback != null){
profileServiceCallback.onDataChanged(mArrayList);
}
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
}
活动
public class ProfileList extends AppCompatActivity
implements View.OnClickListener,ProfileServiceCallback {
private FirebaseAuth mAuth;
Dialog Mydialog;
private FirebaseAuth.AuthStateListener authStateListener;
public DatabaseReference db;
public String userid;
FirebaseUser firebaseUser;
public String iamlog="hy";
List<String> listSt;
String snapdata,log;
ArrayList<String> m1arraylist = new ArrayList <String>();
RecyclerView recyclerView;
public ProfileService myservice;
ProgramingAdapter programmingAdapter;
Intent intent;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.profilelist);
db = FirebaseDatabase.getInstance().getReference().child("users");
recyclerView = (RecyclerView) findViewById(R.id.recyclerview);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
programmingAdapter = new ProgrammingAdapter();
recyclerView.setAdapter(programmingAdapter);
recyclerView.setAdapter();
Button button2 = (Button) findViewById(R.id.button2);
mAuth = FirebaseAuth.getInstance();
userid = mAuth.getCurrentUser().getUid();
db = db.child(userid);
Uri uri = Uri.parse(String.valueOf(db));
Log.e(iamlog,String.valueOf(uri));
Intent Profileserviceint = new Intent(this, ProfileService.class);
Profileserviceint.putExtra("dbrefuri",String.valueOf(uri));
bindService(Profileserviceint, connection, Context.BIND_AUTO_CREATE);
}
@Override
public void onDataChanged(List<String> data){
programmingAdapter.setData(data);
programmingAdapter.notifyDatasetChanged();
}
ServiceConnection connection = new ServiceConnection() {
@Override
public void onServiceConnected(ComponentName name, IBinder service) {
Localservice localservice = (Localservice) service;
myservice=localservice.getservice();
myservice.getdata(ProfileList.this);
myservice.setCallback();
Log.e(iamlog,"Profile calss "+ String.valueOf(localservice.getservice().marraylist));
}
@Override
public void onServiceDisconnected(ComponentName name) {
}
};
您需要在ProgrammingAdapter中添加一个方法
setData(List<String> data){
this.data = data;
notifyDatasetChanged();
}