FirebaseUI数据库和身份验证

Question

我正在尝试制作一个适配器，它将显示给listview实时数据库内容。

带适配器返回null得身份验证：

private void prepareRequests() {
    auth.addAuthStateListener(new FirebaseAuth.AuthStateListener() {
        @Override
        public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
            user = firebaseAuth.getCurrentUser();
            if (user == null) {
                startActivity(new Intent(MainActivity.this, OnStart.class));
                finish();
            } else {
                databaseRef = database.getReference("requests").child(user.getUid());
            }
        }
    });
    FirebaseListAdapter<Request> requestAdapter;
    try {
        requestAdapter = new FirebaseListAdapter<Request>(
                this,
                Request.class,
                android.R.layout.two_line_list_item,
                databaseRef) {
            @Override
            protected void populateView(View v, Request model, int position) {
                ((TextView) v.findViewById(R.id.requestName)).setText(model.getRequestName());
                ((TextView) v.findViewById(R.id.handled)).setText(model.getHandled());
            }
        };

    } catch (NullPointerException e){
        Request request = new Request("Make new request here!", "false", "no one", "None", 0, 0, "No Message");
        databaseRef.child("Request").setValue(request);
        requestAdapter = new FirebaseListAdapter<Request>(
                this,
                Request.class,
                android.R.layout.two_line_list_item,
                databaseRef
        ) {
            @Override
            protected void populateView(View v, Request model, int position) {
                ((TextView) v.findViewById(R.id.requestName)).setText(model.getRequestName());
                ((TextView) v.findViewById(R.id.handled)).setText(model.getHandled());
            }
        };
    }

    ListView listView = (ListView) findViewById(R.id.list_of_req);
    listView.setAdapter(requestAdapter);
}

类：

public class Request {
    private String requestname;
    private String handled;
    private String type;
    private String handler;
    private String message;
    private double lat;
    private double longt;

    public Request() {
    }

    public Request(String requestname, String handled, String handler, String type, double lat, double longt, String message) {
        this.requestname = requestname;
        this.handled = handled;
        this.lat = lat;
        this.longt = longt;
        this.type = type;
        this.handler = handler;
        this.message = message;
    }

    public String getRequestName(){
        return requestname;
    }

    public void setRequestName(String requestname){
        this.requestname = requestname;
    }

    public double getLat () {
        return lat;
    }

    public void setLat(double lat) {
        this.lat = lat;
    }

    public double getLongt() {
        return longt;
    }

    public void setLongt(double longt) {
        this.longt = longt;
    }

    public String getHandled() {
        return handled;
    }

    public void setHandled(String handled){
        this.handled = handled;
    }

    public String getType(){
        return type;
    }

    public void setType (String type) {
        this.type = type;
    }

    public String getHandler() {
        return handler;
    }

    public void setHandler(String handler){
        this.handler = handler;
    }

    public String getMessage(){
        return message;
    }

    public void setMessage(String message){
        this.message = message;
    }
}

请求布局：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:id="@+id/requestName"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textColor="@color/colorPrimary"
        android:textSize="18sp" />

    <TextView
        android:id="@+id/handled"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textColor="@color/colorPrimaryDark"
        android:textSize="16sp" />
</LinearLayout>

Answer 1

我发现了问题，Android是异步的，这意味着它不需要等待身份验证状态监听器，而是直接跳入数据库分析。

我所要做的就是将数据库和列表适配器放在侦听器内部。