java - Android 无法找到显式 Activity 类

Question

Android - 无法找到显式 Activity 类如果您转到 map ，应用程序将关闭其余的都有效

错误:

01-03 08:13:38.684 16073-16073/? E/AndroidRuntime: FATAL EXCEPTION: main
   Process: driesc.bocholtapp, PID: 16073
   java.lang.NullPointerException
       at com.google.a.a.ae.a(Unknown Source)
       at com.google.maps.api.android.lib6.e.do.<init>(Unknown Source)
       at com.google.maps.api.android.lib6.e.dn.a(Unknown Source)
       at com.google.maps.api.android.lib6.e.ag.<init>(Unknown Source)
       at com.google.maps.api.android.lib6.e.ev.a(Unknown Source)
       at com.google.android.gms.maps.internal.j.onTransact(SourceFile:167)
       at android.os.Binder.transact(Binder.java:361)
       at com.google.android.gms.maps.internal.IGoogleMapDelegate$zza$zza.addMarker(Unknown Source)
       at com.google.android.gms.maps.GoogleMap.addMarker(Unknown Source)
       at driesc.bocholtapp.Bocholt.onMapReady(Bocholt.java:45)
       at com.google.android.gms.maps.SupportMapFragment$zza$1.zza(Unknown Source)
       at com.google.android.gms.maps.internal.zzm$zza.onTransact(Unknown Source)
       at android.os.Binder.transact(Binder.java:361)
       at com.google.android.gms.maps.internal.be.a(SourceFile:82)
       at com.google.maps.api.android.lib6.e.fb.run(Unknown Source)
       at android.os.Handler.handleCallback(Handler.java:733)
       at android.os.Handler.dispatchMessage(Handler.java:95)
       at android.os.Looper.loop(Looper.java:136)
       at android.app.ActivityThread.main(ActivityThread.java:5135)
       at java.lang.reflect.Method.invokeNative(Native Method)
       at java.lang.reflect.Method.invoke(Method.java:515)
       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:606)
       at dalvik.system.NativeStart.main(Native Method)    

博霍尔特

public class Bocholt extends FragmentActivity implements OnMapReadyCallback {

    private GoogleMap mMap;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_bocholt);
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
    }


    /**
     * Manipulates the map once available.
     * This callback is triggered when the map is ready to be used.
     * This is where we can add markers or lines, add listeners or move the camera. In this case,
     * we just add a marker near Sydney, Australia.
     * If Google Play services is not installed on the device, the user will be prompted to install
     * it inside the SupportMapFragment. This method will only be triggered once the user has
     * installed Google Play services and returned to the app.
     */
    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;

        LatLng Bocholt = new LatLng(51.172339, 5.579252);
        mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(Bocholt, 15));

        LatLng DeWatermolen = new LatLng(51.153935, 5.558743);
        mMap.addMarker(new MarkerOptions().position(DeWatermolen).title("De Watermolen").snippet("").icon(BitmapDescriptorFactory.fromResource(R.drawable.dewatermolen)));

        LatLng DeVoorsteLuysmolen = new LatLng(51.184088, 5.629534);
        mMap.addMarker(new MarkerOptions().position(DeVoorsteLuysmolen).title("De Voorste Luysmolen").snippet("").icon(BitmapDescriptorFactory.fromResource(R.drawable.deluysmolen)));

        LatLng ToerismeBocholt = new LatLng(51.173664, 5.579505);
        mMap.addMarker(new MarkerOptions().position(ToerismeBocholt).title("Toerisme Bocholt").snippet(""));

        LatLng Smeetshof = new LatLng(51.198714, 5.633185);
        mMap.addMarker(new MarkerOptions().position(Smeetshof).title("Smeetshof").snippet("").icon(BitmapDescriptorFactory.fromResource(R.drawable.smeetshof)));

        LatLng DePriool = new LatLng(51.174403, 5.580748);
        mMap.addMarker(new MarkerOptions().position(DePriool).title("De Priool").snippet("").icon(BitmapDescriptorFactory.fromResource(R.drawable.depriool)));
    }
}

博霍尔特首页

public class BocholtHome extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_bocholt_home);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Coming Soon", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });

        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);
    }

    @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.bocholt_home, 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.nav_camera) {
            // Handle the camera action
        } else if (id == R.id.nav_gallery) {
            Intent intent1= new Intent(this,Bocholt.class);
            startActivity(intent1 );

        } else if (id == R.id.nav_slideshow) {

        } else if (id == R.id.nav_manage) {

        } else if (id == R.id.nav_share) {

        } else if (id == R.id.nav_send) {

        }

        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        drawer.closeDrawer(GravityCompat.START);
        return true;
    }

AndroidManiest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="driesc.bocholtapp">



<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<uses-permission android:name="android.permission.INTERNET"/>

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">

        <meta-data
            android:name="com.google.android.geo.API_KEY"
            android:value="****************************" />

        <activity
            android:name=".BocholtHome"
            android:label="@string/app_name"
            android:theme="@style/AppTheme.NoActionBar">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name=".Bocholt"
            android:label="@string/app_name">
        </activity>
    </application>

</manifest>

Answer 1

使用权限

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<uses-permission android:name="android.permission.INTERNET"/>

在 list 中，例如

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="driesc.bocholtapp">

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<uses-permission android:name="android.permission.INTERNET"/>

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">

    <meta-data
        android:name="com.google.android.geo.API_KEY"
        android:value="AIzaSyBb-nHMIsIvBoQjRBMtInY6kTAiToQBLrU" />

    <activity
        android:name=".BocholtHome"
        android:label="@string/app_name"
        android:theme="@style/AppTheme.NoActionBar">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity
        android:name=".Bocholt"
        android:label="@string/app_name">
    </activity>
</application>