【发布时间】：2019-07-21 07:10:53
【问题描述】：
我正在尝试通过 MainActivity 将一个自动更新文本，它是从 fragment_map 到 fragment_clocking 的纬度和经度信息，但是我在 fragment_clocking 中获得的值返回为 null，Logcat 中没有错误。
我正在尝试使用 bundle 来传递值，但我不确定在哪里以及如何声明和调用 bundle，因为我有一个底部导航视图。
MainActivity.java
public class MainActivity extends AppCompatActivity {
TextView latitude;
TextView longitude;
Bundle bundle = new Bundle();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
BottomNavigationView bottomNav = findViewById(R.id.nav_view);
bottomNav.setOnNavigationItemSelectedListener(navListener);
latitude = findViewById(R.id.id_latitude);
longitude = findViewById(R.id.id_longitude);
bundle.putString("latitudeInfo", String.valueOf(latitude));
bundle.putString("longitudeInfo", String.valueOf(longitude));
getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, new MapFragment()).commit();
}
private BottomNavigationView.OnNavigationItemSelectedListener navListener
= new BottomNavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
Fragment selectedFragment = null;
switch (item.getItemId()) {
case R.id.navigation_map:
selectedFragment = new MapFragment();
selectedFragment.setArguments(bundle);
break;
case R.id.navigation_clocking:
selectedFragment = new ClockingFragment();
selectedFragment.setArguments(bundle);
break;
}
getSupportFragmentManager()
.beginTransaction()
.replace(R.id.fragment_container, selectedFragment)
.commit();
return true;
}
};
}
MapFragment.java
public class MapFragment extends Fragment implements GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener, LocationListener, OnMapReadyCallback {
TextView latitude;
TextView longitude;
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_map, null);
latitude = rootView.findViewById(R.id.id_latitude);
longitude = rootView.findViewById(R.id.id_longitude);
SupportMapFragment mapFragment = (SupportMapFragment) getChildFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
return rootView;
}
@Override
public void onLocationChanged(Location location) {
latitude.setText("Longitude: "+ location.getLongitude());
longitude.setText("Latitude: "+ location.getLatitude());
}
@Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
mGoogleApiClient = new GoogleApiClient.Builder(getActivity())
.addApi(LocationServices.API)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.build();
mGoogleApiClient.connect();
}
}
ClockingFragment.java
public class ClockingFragment extends Fragment implements LocationListener {
TextView latitude, longitude;
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_clocking, null);
latitude = rootView.findViewById(R.id.id_latitudeLocation);
longitude = rootView.findViewById(R.id.id_longitudeLocation);
Bundle bundle = getArguments();
if(bundle != null){
String latitudetest = bundle.getString("latitudeInfo");
String longitudetest = bundle.getString("longitudeInfo");
latitude.setText(latitudetest);
longitude.setText(longitudetest);
}
return rootView;
}
activity_main.xml
<FrameLayout
android:id="@+id/fragment_container"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_above="@+id/nav_view"/>
<com.google.android.material.bottomnavigation.BottomNavigationView
android:id="@+id/nav_view"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:background="?android:attr/windowBackground"
app:menu="@menu/bottom_nav_menu" />
fragment_clocking.xml
<FrameLayout
android:id="@+id/fragment_clocking"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
<TextView
android:id="@+id/id_latitudeLocation"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_marginStart="20dp"
android:layout_marginLeft="20dp"
android:layout_marginTop="20dp"
android:text="TEST PLACEHOLDER"
android:textSize="30sp" />
<TextView
android:id="@+id/id_longitudeLocation"
android:layout_below="@+id/id_latitudeLocation"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="20dp"
android:layout_marginLeft="20dp"
android:text="TEST PLACEHOLDER"
android:textSize="30sp"/>
fragment_map.xml
<FrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/fragment_map" />
<fragment
xmlns:map="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/map"
android:name="com.google.android.gms.maps.SupportMapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MapsActivity" />
<TextView
android:id="@+id/id_latitude"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="20dp"
android:layout_marginLeft="20dp"
android:textSize="30sp" />
<TextView
android:id="@+id/id_longitude"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="30dp"
android:layout_below="@+id/id_latitude"
android:layout_marginStart="20dp"
android:layout_marginLeft="20dp"
android:textSize="30sp" />
预期结果：FragmentMap.java 中的经纬度值通过 MainActivity.java 并显示在 FragmentClocking.java 中
【问题讨论】：
-
您在创建
Activity时将纬度和经度值放在Bundle中。我不清楚这些数据应该来自哪里。您希望从哪里获得经度和纬度？请解释
标签： java android android-fragments android-activity bottomnavigationview