無法從導航抽屜中調用活動

Question

我們有一個導航抽屜，我們要從中調用包含Google地圖的活動。 這是MapsActivity.java的代碼

package com.sahayatra.samyatra;

import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.view.View;
import android.widget.Button;

import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback
{

    private GoogleMap mMap;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);
        Button btn=(Button)findViewById(R.id.offer_a_ride);
        btn.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View v) {
                startActivity(new Intent(MapsActivity.this,ToFromO9Activity.class));
            }
        });
        Button btn1=(Button)findViewById(R.id.find_a_ride);
        btn1.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View v) {
                startActivity(new Intent(MapsActivity.this,ToFromF10Activity.class));
            }
        });
        // Obtain the SupportMapFragment and get notified when the map is ready to be used.
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(MapsActivity.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;
        // Add a marker in Sydney and move the camera
        LatLng sydney = new LatLng(-34, 151);
        mMap.addMarker(new MarkerOptions().position(sydney).title("Marker in Sydney"));
        mMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));
    }
}

Main8Navigation.java的代碼：-

package com.sahayatra.samyatra;

import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.MenuItem;

public class Main8navigation extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener{
    DrawerLayout drawer;
    Toolbar toolbar;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main8navigation);
        toolbar=findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        drawer=findViewById(R.id.drawer_layout);
        NavigationView navigationView=findViewById(R.id.nav_view);
        navigationView.setNavigationItemSelectedListener(this );
        ActionBarDrawerToggle toggle=new ActionBarDrawerToggle(this,drawer,toolbar,R.string.navigation_drawer_open,R.string.navigation_drawer_close);
        drawer.addDrawerListener(toggle);
        toggle.syncState();
        getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,new HomeFragment()).commit();
        navigationView.setCheckedItem(R.id.nav_home);

    }

    @Override
    public boolean onNavigationItemSelected(@NonNull MenuItem item) {
        switch (item.getItemId())
        {
            case R.id.nav_myaccount:
                getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,new MyAccountFragment()).commit();

                break;
            case R.id.nav_fav:
                getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,new FavouritesFragment()).commit();

                break;
            case R.id.nav_block:
                getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,new BlockFragment()).commit();

                break;
            case R.id.nav_home:
               getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,new HomeFragment()).commit();


                break;
        }
        drawer.closeDrawer(GravityCompat.START);
        return true;
    }

這是我們要在其中調用MapsActivity.java的HomeFragment.java：

package com.sahayatra.samyatra;

import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class HomeFragment extends Fragment {
    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState)
    {
        ((MapsActivity)getActivity()).onCreate(savedInstanceState);
        return inflater.inflate(R.layout.fragment_home,container,false);

    }
}

這是導航抽屜的xml文件：-

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/drawer_layout"
    android:fitsSystemWindows="true"
    tools:context=".Main8navigation"
    tools:openDrawer="start"
    >

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="@color/white"
        android:elevation="4dp"
        android:theme="@style/ThemeOverlay.AppCompat.ActionBar"
        app:popupTheme="@style/ThemeOverlay.AppCompat.Dark"
        />

    <FrameLayout
        android:id="@+id/fragment_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

    </FrameLayout>
</LinearLayout>
    <android.support.design.widget.NavigationView
        android:id="@+id/nav_view"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        app:headerLayout="@layout/nav_header"
        app:menu="@menu/drawer_menu">

    </android.support.design.widget.NavigationView>


</android.support.v4.widget.DrawerLayout>

這是MapsActivity的xml文件：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/white"
    android:orientation="vertical">


    <FrameLayout
        android:layout_width="350dp"
        android:layout_height="300dp"
        android:layout_marginStart="18dp"
        android:layout_marginEnd="18dp"
        android:layout_marginTop="100dp">

        <fragment
            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="com.sample.sishin.maplocation.MapsActivity" />
        <LinearLayout
            android:id="@+id/locationMarker"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:layout_marginBottom="30dp"
            android:gravity="center"
            android:orientation="vertical" >
            <ImageView
                android:id="@+id/imageMarker"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                />
        </LinearLayout>



    </FrameLayout>
    <Button
        android:id="@+id/offer_a_ride"
        android:layout_width="150dp"
        android:layout_height="80dp"
        android:layout_marginBottom="1dp"
        android:layout_marginTop="480dp"
        android:layout_marginEnd="200dp"
        android:layout_marginLeft="8dp"
        android:layout_marginRight="8dp"
        android:layout_marginStart="20dp"
        android:text="OFFER A RIDE"
        android:textColor="@color/white"
        android:background="@drawable/mybutton"
        />
    <Button
        android:id="@+id/find_a_ride"
        android:layout_width="200dp"
        android:layout_height="80dp"
        android:layout_marginBottom="1dp"
        android:layout_marginTop="480dp"
        android:layout_marginEnd="20dp"
        android:layout_marginLeft="8dp"
        android:layout_marginRight="8dp"
        android:layout_marginStart="220dp"
        android:text="FIND A RIDE"
        android:textColor="@color/white"
        android:background="@drawable/mybutton"
      />
</RelativeLayout>

這是AndroidManifest：-

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

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

    <!--
         The ACCESS_COARSE/FINE_LOCATION permissions are not required to use
         Google Maps Android API v2, but you must specify either coarse or fine
         location permissions for the 'MyLocation' functionality. 
    -->
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.WAKE_LOCK" />
    <uses-permission android:name="android.permission.READ_PHONE_STATE" />

    <uses-feature android:name="android.hardware.location.gps" />

    <uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme.NoTitleBar">
        <activity
            android:name=".MainActivity"
            android:label="Samyatra">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name=".Main3Activity" />
        <activity android:name=".LogoActivity" />
        <activity android:name=".Main2Activity" />
        <activity android:name=".Main1Activity" />
        <activity android:name=".Main4Activity" />
        <activity android:name=".Main5Activity" />
        <activity android:name=".Main6Activity" />
        <activity android:name=".Main7Activity" />
        <activity
            android:name="com.theartofdev.edmodo.cropper.CropImageActivity"
            android:screenOrientation="portrait" />
        <!--
             The API key for Google Maps-based APIs is defined as a string resource.
             (See the file "res/values/google_maps_api.xml").
             Note that the API key is linked to the encryption key used to sign the APK.
             You need a different API key for each encryption key, including the release key that is used to
             sign the APK for publishing.
             You can define the keys for the debug and release targets in src/debug/ and src/release/. 
        -->
        <meta-data
            android:name="com.google.android.geo.API_KEY"
            android:value="AIzaSyD1bUfbDXswczR-DtXfgig2acAdERY6WQg" />

        <activity
            android:name=".MapsActivity"
            android:label="@string/title_activity_maps"
       />
        <activity android:name=".Main8navigation" />

        <service
            android:name="com.amazonaws.mobileconnectors.s3.transferutility.TransferService"
            android:enabled="true" />

        <activity android:name=".MyAcc9Activity" />
        <activity android:name=".ToFromO9Activity" />
        <activity android:name=".ToFromF10Activity"></activity>
    </application>

</manifest>

Answer 1

您應該使用startActivity啟動Activity，而不是通過手動調用該Activity的onCreate方法來啟動。

因此，在您的情況下，在HomeFragment.java ，添加以下代碼行：

startActivity(new Intent(getActivity(), MapsActivity.class));

並刪除該行：

((MapsActivity)getActivity()).onCreate(savedInstanceState)