在Firebase数据库中读取和写入数据
问题描述:
注意: - 由于英语不是我的母语,所以对不起我的英语很糟糕,因为我已经使用谷歌翻译器。在Firebase数据库中读取和写入数据
我正在开发一个android地图应用程序,其中用户可以找到他们朋友的当前位置并存储当前位置我正在使用FireBase实时数据库。因此,当用户点击查找按钮时,他们朋友的当前位置将以其用户名位于地图上。
但我无法解决一个问题,当我试图从Firebase中获取用户数据时。它没有以正确的方式反映出来。数据被反映在2条不同的线在日志中:
- 第1行: - 纬度&经度为0.0但电子邮件是显示并在
- 第2行: - 纬度&经度被正确地反映,但电子邮件是空
我不知道如何在一行中得到两个。我在谷歌上搜索了很多,但失败了。请帮助我了解如何以正确的方式完成。
下面是我的代码和android studio屏幕截图。
MainActivity.java
findfriend.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
startActivity(new Intent(MainActivity.this, MapsActivity.class));
}
});
final TextView tname;
tname = (TextView) findViewById(R.id.textview);
ref = FirebaseDatabase.getInstance().getReferenceFromUrl("https://ffinder-b4617.firebaseio.com/Email");
mReferece2 = ref.child("email");
mReferece2 = ref.child("location");
proceed.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
ref.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot dataSnapshot1: dataSnapshot.getChildren()){
UserInformation details = dataSnapshot1.getValue(UserInformation.class);
String email = details.email;
Double lat = details.latitude;
Double lon = details.longitude;
tname.setText(lat+" "+'\n'+lon+'\n'+email);
System.out.println("-->"+ lat+" " + lon+" "+ email);
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
});
}
MapsActivity.java
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
Firebase.setAndroidContext(this);
if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
checkLocationPermission();
}
//Check if Google Play Services Available or not
if (!CheckGooglePlayServices()) {
Log.d("onCreate", "Finishing test case since Google Play Services are not available");
finish();
} else {
Log.d("onCreate", "Google Play Services available.");
}
auth = FirebaseAuth.getInstance();
// Obtain the SupportMapFragment and get notified when the map is ready to be used.
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
FirebaseDatabase.getInstance().getReference().child("Location");
}
@Override
public void onLocationChanged(Location location) {
Log.d("onLocationChanged", "entered");
mLastLocation = location;
DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
dateFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
Date date = new Date();
mLastUpdateTime = ((dateFormat.format(date).toString()));
saveToFirebase();
if (mCurrLocationMarker != null) {
mCurrLocationMarker.remove();
}
latitude = location.getLatitude();
longitude = location.getLongitude();
LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
MarkerOptions markerOptions = new MarkerOptions();
markerOptions.position(latLng);
markerOptions.draggable(true);
markerOptions.title("Current Position");
markerOptions.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_MAGENTA));
mCurrLocationMarker = mMap.addMarker(markerOptions);
mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
mMap.animateCamera(CameraUpdateFactory.zoomTo(11));
Toast.makeText(MapsActivity.this,"Your Current Location", Toast.LENGTH_LONG).show();
//stop location updates
if (mGoogleApiClient != null) {
LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
Log.d("onLocationChanged", "Removing Location Updates");
}
}
public void saveToFirebase() {
Firebase firebase = new Firebase("https://ffinder-b4617.firebaseio.com").child("Email").child("location");
Map mLoactions = new HashMap();
mLoactions.put("timestamp",mLastUpdateTime);
mLoactions.put("latitude", mLastLocation.getLatitude());
mLoactions.put("longitude", mLastLocation.getLongitude());
firebase.setValue(mLoactions);
}
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
}
public static final int MY_PERMISSIONS_REQUEST_LOCATION = 99;
public boolean checkLocationPermission(){
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
!= PackageManager.PERMISSION_GRANTED) {
// Asking user if explanation is needed
if (ActivityCompat.shouldShowRequestPermissionRationale(this,
Manifest.permission.ACCESS_FINE_LOCATION)) {
ActivityCompat.requestPermissions(this,
new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
MY_PERMISSIONS_REQUEST_LOCATION);
} else {
// No explanation needed, we can request the permission.
ActivityCompat.requestPermissions(this,
new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
MY_PERMISSIONS_REQUEST_LOCATION);
}
return false;
} else {
return true;
}
}
@Override
public void onRequestPermissionsResult(int requestCode,
String permissions[], int[] grantResults) {
switch (requestCode) {
case MY_PERMISSIONS_REQUEST_LOCATION: {
// If request is cancelled, the result arrays are empty.
if (grantResults.length > 0
&& grantResults[0] == PackageManager.PERMISSION_GRANTED) {
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
if (mGoogleApiClient == null) {
buildGoogleApiClient();
}
mMap.setMyLocationEnabled(true);
}
} else {
// Permission denied, Disable the functionality that depends on this permission.
Toast.makeText(this, "permission denied", Toast.LENGTH_LONG).show();
}
return;
}
}
}
@Override
public boolean onMarkerClick(Marker marker) {
marker.setDraggable(true);
return false;
}
@Override
public void onMarkerDragStart(Marker marker) {}
@Override
public void onMarkerDrag(Marker marker) {}
@Override
public void onMarkerDragEnd(Marker marker) {
end_latitude = marker.getPosition().latitude;
end_longitude = marker.getPosition().longitude;
Log.d("end_lat",""+end_latitude);
Log.d("end_lng",""+end_longitude);
}
}
Login.class
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
Firebase.setAndroidContext(this);
auth = FirebaseAuth.getInstance();
if (auth.getCurrentUser() != null){
startActivity(new Intent(LoginActivity.this, MainActivity.class));
finish();
}
setContentView(R.layout.activity_login);
inputEmail = (EditText) findViewById(R.id.email);
inputPassword = (EditText) findViewById(R.id.password);
progressBar = (ProgressBar) findViewById(R.id.progressBar);
btnSignup = (Button) findViewById(R.id.btn_signup);
btnLogin = (Button) findViewById(R.id.btn_login);
btnReset = (Button) findViewById(R.id.btn_reset_password);
auth = FirebaseAuth.getInstance();
btnSignup.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
startActivity(new Intent(LoginActivity.this, SignupActivity.class));
}
});
btnReset.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
startActivity(new Intent(LoginActivity.this, ResetPasswordActivity.class));
}
});
btnLogin.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String email = inputEmail.getText().toString();
final String password = inputPassword.getText().toString();
if (TextUtils.isEmpty(email)) {
Toast.makeText(getApplicationContext(), "Enter email address!", Toast.LENGTH_SHORT).show();
return;
}
if (TextUtils.isEmpty(password)) {
Toast.makeText(getApplicationContext(), "Enter password!", Toast.LENGTH_SHORT).show();
return;
}
progressBar.setVisibility(View.VISIBLE);
//authenticate user
auth.signInWithEmailAndPassword(email, password)
.addOnCompleteListener(LoginActivity.this, new OnCompleteListener<AuthResult>() {
@Override
public void onComplete(@NonNull Task<AuthResult> task) {
progressBar.setVisibility(View.GONE);
if (!task.isSuccessful()) {
// there was an error
if (password.length() < 6) {
inputPassword.setError(getString(R.string.minimum_password));
} else {
Toast.makeText(LoginActivity.this, getString(R.string.auth_failed), Toast.LENGTH_LONG).show();
}
} else {
Intent intent = new Intent(LoginActivity.this, MainActivity.class);
startActivity(intent);
finish();
}
}
});
}
});
}
public void userLoginInfo(){
String email = inputEmail.getText().toString();
mDatabase = FirebaseDatabase.getInstance().getReference().child("Email").push();
String userId = mDatabase.child("email").getKey();
mDatabase.child(userId).setValue(email);
}
}
个UserInformation.class
public class UserInformation {
public String email;
public double latitude;
public double longitude;
public UserInformation() {
}
public UserInformation(String email, double latitude, double longitude) {
this.email = email;
this.latitude = latitude;
this.longitude = longitude;
}
public String getEmail() {
return email;
}
public double getLatitude() {
return latitude;
}
public double getLongitude() {
return longitude;
}
}
答
你userLoginInfo()
方法使用push()
来在数据库中创建一个唯一的密钥存储的电子邮件地址,并您的saveToFirebase()
方法不同地存储纬度/经度值,这意味着数据在不同的地方结束。
这将有利于充分利用你的UserInformation
对象的标准化数据库,并使用DatabaseReference#setValue(Object)
和DataSnapshot#getValue(Class<CT>)
来存储和检索数据。所以,当你要存储用户的位置,你这样做:
public void saveToFirebase() {
DatabaseReference ref = FirebaseDatabase.getInstance().getReference().child("Email").push();
String email = FirebaseAuth.getInstance().getCurrentUser().getEmail();
UserInformation userInformation = new UserInformation(email, mLastLocation.getLatitude(), mLastLocation.getLongitude());
ref.setValue(userInformation);
}
然后,再取回这些细节,您可以使用您现有的ValueEventListener
了一些调整:
DatabaseReference ref = FirebaseDatabase.getInstance().getReference().child("Email");
ref.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot child : dataSnapshot.getChildren()){
UserInformation details = child.getValue(UserInformation.class);
System.out.println("-->" + details.getLatitude() +" " + details.getLongitude() +" "+ details.getEmail());
}
}
@Override
public void onCancelled(DatabaseError databaseError) {}
});
我希望我”我已经正确理解您的要求,请让我知道我是否遗漏了任何东西。
感谢您的回复,它帮助我组织单亲“电子邮件”下的数据,但现在我没有在Firebase中获取用户的登录电子邮件。 –
它是未来像这样如下: - 。 ffinder-b4617 电子邮件 邮件: “电子邮件” 纬度:31.5037501 经度:74.3502436 –
你可以用'FirebaseAuth.getInstance()getCurrentUser()getEmail( )'以获得当前用户的电子邮件地址,因此您可以在'saveToFirebase()'方法中使用它。这会起作用吗? – Grimthorr