Android 片段NullPointerException中的MapFragment
我试图在另一个带有include标记的片段中显示mapfragment，当我执行项目时，我得到了Android 片段NullPointerException中的MapFragment,android,android-fragments,navigation-drawer,google-maps-android-api-2,Android,Android Fragments,Navigation Drawer,Google Maps Android Api 2,我试图在另一个带有include标记的片段中显示mapfragment，当我执行项目时，我得到了NullPointerException，有人能告诉我我做错了什么吗？代码如下： 主要抽屉类别： public class DrawerPrincipal extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener,FragmentoPrincipalUsuario.OnFra
NullPointerExceptionpublic class DrawerPrincipal extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener,FragmentoPrincipalUsuario.OnFragmentInteractionListener {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_drawer_principal);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
//cargar fragment principal usuario
Fragment fragmento= null;
fragmento = new FragmentoPrincipalUsuario();
getSupportFragmentManager().beginTransaction()
.replace(R.id.content_main, fragmento)
.commit();
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
//fragmento del chofer
/*
Fragment fragmento= null;
fragmento = new FragmentoPrincipalChofer();
getSupportFragmentManager().beginTransaction()
.replace(R.id.content_main, fragmento)
.commit();*/
}
@Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.pantalla_principal_usuario, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
if (id == R.id.cuenta) {
Fragment fragmento= null;
fragmento = new OpcionDrawerUsuario();
getSupportFragmentManager().beginTransaction()
.replace(R.id.content_main, fragmento)
.commit();
} else if (id == R.id.historial_viajes) {
Fragment fragmento= null;
fragmento = new FragmentoViajesAcumulados();
getSupportFragmentManager().beginTransaction()
.replace(R.id.content_main, fragmento)
.commit();
} else if (id == R.id.contacto) {
String emailAdress[] = {"gastondelacruz@gmail.com"};
Intent email= new Intent(Intent.ACTION_SEND);
email.putExtra(Intent.EXTRA_EMAIL,emailAdress);
email.putExtra(Intent.EXTRA_SUBJECT,"Pon aqui el motivo de tu mail");
email.setType("text/plain");
email.putExtra(Intent.EXTRA_TEXT,"Su mensaje");
startActivity(email);
} else if (id == R.id.compartir) {
String texto="https://www.google.com.ar/?gfe_rd=cr&ei=9JuBVvmcGanX8gejsK_4CA&gws_rd=ssl";
Intent intento= new Intent();
intento.setAction(Intent.ACTION_SEND);
intento.putExtra(Intent.EXTRA_TEXT, texto);
intento.setType("text/plain");
startActivity(intento);
} else if (id == R.id.version) {
String prueba="aceptar";
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("prueba") //
.setMessage("Esta es una prueba todavia no poseo el numero de version del producto") //
.setPositiveButton(prueba, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
// TODO
dialog.dismiss();
}
}); //
builder.show();
} else if (id == R.id.salir) {
finish();
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
@Override
public void onFragmentInteraction(Uri uri) {
}
}
public class DrawerPrincipal extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener,FragmentoPrincipalUsuario.OnFragmentInteractionListener {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_drawer_principal);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
//cargar fragment principal usuario
Fragment fragmento= null;
fragmento = new FragmentoPrincipalUsuario();
getSupportFragmentManager().beginTransaction()
.replace(R.id.content_main, fragmento)
.commit();
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
//fragmento del chofer
/*
Fragment fragmento= null;
fragmento = new FragmentoPrincipalChofer();
getSupportFragmentManager().beginTransaction()
.replace(R.id.content_main, fragmento)
.commit();*/
}
@Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.pantalla_principal_usuario, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
if (id == R.id.cuenta) {
Fragment fragmento= null;
fragmento = new OpcionDrawerUsuario();
getSupportFragmentManager().beginTransaction()
.replace(R.id.content_main, fragmento)
.commit();
} else if (id == R.id.historial_viajes) {
Fragment fragmento= null;
fragmento = new FragmentoViajesAcumulados();
getSupportFragmentManager().beginTransaction()
.replace(R.id.content_main, fragmento)
.commit();
} else if (id == R.id.contacto) {
String emailAdress[] = {"gastondelacruz@gmail.com"};
Intent email= new Intent(Intent.ACTION_SEND);
email.putExtra(Intent.EXTRA_EMAIL,emailAdress);
email.putExtra(Intent.EXTRA_SUBJECT,"Pon aqui el motivo de tu mail");
email.setType("text/plain");
email.putExtra(Intent.EXTRA_TEXT,"Su mensaje");
startActivity(email);
} else if (id == R.id.compartir) {
String texto="https://www.google.com.ar/?gfe_rd=cr&ei=9JuBVvmcGanX8gejsK_4CA&gws_rd=ssl";
Intent intento= new Intent();
intento.setAction(Intent.ACTION_SEND);
intento.putExtra(Intent.EXTRA_TEXT, texto);
intento.setType("text/plain");
startActivity(intento);
} else if (id == R.id.version) {
String prueba="aceptar";
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("prueba") //
.setMessage("Esta es una prueba todavia no poseo el numero de version del producto") //
.setPositiveButton(prueba, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
// TODO
dialog.dismiss();
}
}); //
builder.show();
} else if (id == R.id.salir) {
finish();
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
@Override
public void onFragmentInteraction(Uri uri) {
}
}
public class MapaPrincipal extends FragmentActivity implements OnMapReadyCallback {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.mapa_principal);
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
}
@Override
public void onMapReady(GoogleMap map) {
// Add a marker in Sydney, Australia, and move the camera.
LatLng sydney = new LatLng(-34, 151);
map.addMarker(new MarkerOptions().position(sydney).title("Marker in Sydney"));
map.moveCamera(CameraUpdateFactory.newLatLng(sydney));
}
}
public class DrawerPrincipal extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener,FragmentoPrincipalUsuario.OnFragmentInteractionListener {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_drawer_principal);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
//cargar fragment principal usuario
Fragment fragmento= null;
fragmento = new FragmentoPrincipalUsuario();
getSupportFragmentManager().beginTransaction()
.replace(R.id.content_main, fragmento)
.commit();
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
//fragmento del chofer
/*
Fragment fragmento= null;
fragmento = new FragmentoPrincipalChofer();
getSupportFragmentManager().beginTransaction()
.replace(R.id.content_main, fragmento)
.commit();*/
}
@Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.pantalla_principal_usuario, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
if (id == R.id.cuenta) {
Fragment fragmento= null;
fragmento = new OpcionDrawerUsuario();
getSupportFragmentManager().beginTransaction()
.replace(R.id.content_main, fragmento)
.commit();
} else if (id == R.id.historial_viajes) {
Fragment fragmento= null;
fragmento = new FragmentoViajesAcumulados();
getSupportFragmentManager().beginTransaction()
.replace(R.id.content_main, fragmento)
.commit();
} else if (id == R.id.contacto) {
String emailAdress[] = {"gastondelacruz@gmail.com"};
Intent email= new Intent(Intent.ACTION_SEND);
email.putExtra(Intent.EXTRA_EMAIL,emailAdress);
email.putExtra(Intent.EXTRA_SUBJECT,"Pon aqui el motivo de tu mail");
email.setType("text/plain");
email.putExtra(Intent.EXTRA_TEXT,"Su mensaje");
startActivity(email);
} else if (id == R.id.compartir) {
String texto="https://www.google.com.ar/?gfe_rd=cr&ei=9JuBVvmcGanX8gejsK_4CA&gws_rd=ssl";
Intent intento= new Intent();
intento.setAction(Intent.ACTION_SEND);
intento.putExtra(Intent.EXTRA_TEXT, texto);
intento.setType("text/plain");
startActivity(intento);
} else if (id == R.id.version) {
String prueba="aceptar";
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("prueba") //
.setMessage("Esta es una prueba todavia no poseo el numero de version del producto") //
.setPositiveButton(prueba, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
// TODO
dialog.dismiss();
}
}); //
builder.show();
} else if (id == R.id.salir) {
finish();
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
@Override
public void onFragmentInteraction(Uri uri) {
}
}
public class MapaPrincipal extends FragmentActivity implements OnMapReadyCallback {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.mapa_principal);
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
}
@Override
public void onMapReady(GoogleMap map) {
// Add a marker in Sydney, Australia, and move the camera.
LatLng sydney = new LatLng(-34, 151);
map.addMarker(new MarkerOptions().position(sydney).title("Marker in Sydney"));
map.moveCamera(CameraUpdateFactory.newLatLng(sydney));
}
}
<fragment xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/map"
tools:context=".MapsActivity"
android:name="com.google.android.gms.maps.SupportMapFragment" />
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".FragmentoPrincipalUsuario">
<!-- TODO: Update blank fragment layout -->
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal|top">
<include layout="@layout/mapa_principal"/>
</LinearLayout>
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="149dp"
android:layout_gravity="center_horizontal|bottom">
<Button
android:layout_width="117dp"
android:layout_height="wrap_content"
android:text="pedir taxi"
android:id="@+id/pedirTaxi"
android:layout_gravity="center_horizontal" />
</LinearLayout>
</FrameLayout>
您的问题在于：
Fragment fragmento= null;
OnCreateFragment fragmento;
如果仍然存在问题，请告诉我将其声明为类变量，无需将其初始化为null， java会自动做到这一点：
Fragment fragmento;
Fragment fragmento= null;
getSupportFragmentManager().beginTransaction()
.add(R.id.content_main, fragmento)
.commit();
请将您的stacktrace发布到npe