Java 启动新活动时，获取不是封闭类错误

首先，我是android和java的新手

我有一个使用facebook登录的MainActivity，然后我希望OnSuccess启动一个Map.Activity类，但它不会，它说该类不是封闭的。我不知道它是什么意思，我也没有足够的知识将它与其他已回答的问题联系起来

我的两个班级是这样的

MainActivity.java

package com.example.nan.spymap;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;

import com.facebook.CallbackManager;
import com.facebook.FacebookCallback;
import com.facebook.FacebookException;
import com.facebook.FacebookSdk;
import com.facebook.login.LoginResult;
import com.facebook.login.widget.LoginButton;

public class MainActivity extends Activity {

    private CallbackManager callbackManager;

    private TextView info;
    private LoginButton loginButton;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        FacebookSdk.sdkInitialize(getApplicationContext());
        callbackManager = CallbackManager.Factory.create();

        setContentView(R.layout.activity_main);



        setContentView(R.layout.activity_main);
        info = (TextView)findViewById(R.id.info);
        loginButton = (LoginButton)findViewById(R.id.login_button);

        loginButton.registerCallback(callbackManager, new FacebookCallback<LoginResult>() {
            @Override
            public void onSuccess(LoginResult loginResult) {
                startActivity(new Intent(MapActivity.this, MapActivity.class));

            }

            @Override
            public void onCancel() {
                info.setText("Login attempt cancelled.");
            }

            @Override
            public void onError(FacebookException e) {
                info.setText("Login attempt failed.");
            }
        });

    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        callbackManager.onActivityResult(requestCode, resultCode, data);
    }
}

package com.example.nan.spymap;

import android.support.v4.app.FragmentActivity;
import android.os.Bundle;

import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.MapFragment;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.UiSettings;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.Marker;
import com.google.android.gms.maps.model.MarkerOptions;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
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 MapActivity extends FragmentActivity implements OnMapReadyCallback {

    private GoogleMap mMap; // Might be null if Google Play services APK is not available.
    private MapFragment mMapFragment;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);
        setUpMapIfNeeded();

       /* MapFragment mapFragment = (MapFragment) getFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
    */}

    @Override
    protected void onResume() {
        super.onResume();
        setUpMapIfNeeded();
    }
    @Override
    public void onMapReady(GoogleMap map) {
        // Add a marker in Sydney, Australia, and move the camera.
        map.addMarker(new MarkerOptions()
                .position(new LatLng(10, 10))
                .title("Hello world").draggable(true));
        mMap.setMyLocationEnabled(true); // false to disable
    }
    /**
     * Sets up the map if it is possible to do so (i.e., the Google Play services APK is correctly
     * installed) and the map has not already been instantiated.. This will ensure that we only ever
     * call {@link #setUpMap()} once when {@link #mMap} is not null.
     * <p/>
     * If it isn't installed {@link SupportMapFragment} (and
     * {@link com.google.android.gms.maps.MapView MapView}) will show a prompt for the user to
     * install/update the Google Play services APK on their device.
     * <p/>
     * A user can return to this FragmentActivity after following the prompt and correctly
     * installing/updating/enabling the Google Play services. Since the FragmentActivity may not
     * have been completely destroyed during this process (it is likely that it would only be
     * stopped or paused), {@link #onCreate(Bundle)} may not be called again so we should call this
     * method in {@link #onResume()} to guarantee that it will be called.
     */
    private void setUpMapIfNeeded() {
        // Do a null check to confirm that we have not already instantiated the map.
        if (mMap == null) {
            // Try to obtain the map from the SupportMapFragment.
            mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
                    .getMap();
            // Check if we were successful in obtaining the map.
            if (mMap != null) {
                setUpMap();
            }
        }
    }

    /**
     * This is where we can add markers or lines, add listeners or move the camera. In this case, we
     * just add a marker near Africa.
     * <p/>
     * This should only be called once and when we are sure that {@link #mMap} is not null.
     */
    private void setUpMap() {
        mMap.addMarker(new MarkerOptions().position(new LatLng(0, 0)).title("Marker"));
    }
}

package com.example.nan.spymap；
导入android.app.Activity；
导入android.content.Intent；
导入android.os.Bundle；
导入android.view.Menu；
导入android.view.MenuItem；
导入android.widget.TextView；
导入com.facebook.CallbackManager；
导入com.facebook.facebook回调；
导入com.facebook.facebook异常；
导入com.facebook.FacebookSdk；
导入com.facebook.login.LoginResult；
导入com.facebook.login.widget.LoginButton；
公共类MainActivity扩展了活动{
私人CallbackManager CallbackManager；
私有文本视图信息；
私人登录按钮登录按钮；
@凌驾
创建时受保护的void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
sdkinInitialize（getApplicationContext（））；
callbackManager=callbackManager.Factory.create（）；
setContentView（R.layout.activity_main）；
setContentView（R.layout.activity_main）；
info=（TextView）findViewById（R.id.info）；
loginButton=（loginButton）findviewbyd（R.id.login_按钮）；
registerCallback（callbackManager，newfacebookcallback（））{
@凌驾
成功时公共无效（LoginResult LoginResult）{
startActivity（新意图（MapActivity.this、MapActivity.class））；
}
@凌驾
公开作废{
info.setText（“登录尝试已取消”）；
}
@凌驾
公共无效onError（FaceBook例外e）{
info.setText（“登录尝试失败”）；
}
});
}
@凌驾
受保护的void onActivityResult（int请求代码、int结果代码、意图数据）{
callbackManager.onActivityResult（请求代码、结果代码、数据）；
}
}

以及MapActivity.java

package com.example.nan.spymap;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;

import com.facebook.CallbackManager;
import com.facebook.FacebookCallback;
import com.facebook.FacebookException;
import com.facebook.FacebookSdk;
import com.facebook.login.LoginResult;
import com.facebook.login.widget.LoginButton;

public class MainActivity extends Activity {

    private CallbackManager callbackManager;

    private TextView info;
    private LoginButton loginButton;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        FacebookSdk.sdkInitialize(getApplicationContext());
        callbackManager = CallbackManager.Factory.create();

        setContentView(R.layout.activity_main);



        setContentView(R.layout.activity_main);
        info = (TextView)findViewById(R.id.info);
        loginButton = (LoginButton)findViewById(R.id.login_button);

        loginButton.registerCallback(callbackManager, new FacebookCallback<LoginResult>() {
            @Override
            public void onSuccess(LoginResult loginResult) {
                startActivity(new Intent(MapActivity.this, MapActivity.class));

            }

            @Override
            public void onCancel() {
                info.setText("Login attempt cancelled.");
            }

            @Override
            public void onError(FacebookException e) {
                info.setText("Login attempt failed.");
            }
        });

    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        callbackManager.onActivityResult(requestCode, resultCode, data);
    }
}

package com.example.nan.spymap;

import android.support.v4.app.FragmentActivity;
import android.os.Bundle;

import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.MapFragment;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.UiSettings;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.Marker;
import com.google.android.gms.maps.model.MarkerOptions;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
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 MapActivity extends FragmentActivity implements OnMapReadyCallback {

    private GoogleMap mMap; // Might be null if Google Play services APK is not available.
    private MapFragment mMapFragment;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);
        setUpMapIfNeeded();

       /* MapFragment mapFragment = (MapFragment) getFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
    */}

    @Override
    protected void onResume() {
        super.onResume();
        setUpMapIfNeeded();
    }
    @Override
    public void onMapReady(GoogleMap map) {
        // Add a marker in Sydney, Australia, and move the camera.
        map.addMarker(new MarkerOptions()
                .position(new LatLng(10, 10))
                .title("Hello world").draggable(true));
        mMap.setMyLocationEnabled(true); // false to disable
    }
    /**
     * Sets up the map if it is possible to do so (i.e., the Google Play services APK is correctly
     * installed) and the map has not already been instantiated.. This will ensure that we only ever
     * call {@link #setUpMap()} once when {@link #mMap} is not null.
     * <p/>
     * If it isn't installed {@link SupportMapFragment} (and
     * {@link com.google.android.gms.maps.MapView MapView}) will show a prompt for the user to
     * install/update the Google Play services APK on their device.
     * <p/>
     * A user can return to this FragmentActivity after following the prompt and correctly
     * installing/updating/enabling the Google Play services. Since the FragmentActivity may not
     * have been completely destroyed during this process (it is likely that it would only be
     * stopped or paused), {@link #onCreate(Bundle)} may not be called again so we should call this
     * method in {@link #onResume()} to guarantee that it will be called.
     */
    private void setUpMapIfNeeded() {
        // Do a null check to confirm that we have not already instantiated the map.
        if (mMap == null) {
            // Try to obtain the map from the SupportMapFragment.
            mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
                    .getMap();
            // Check if we were successful in obtaining the map.
            if (mMap != null) {
                setUpMap();
            }
        }
    }

    /**
     * This is where we can add markers or lines, add listeners or move the camera. In this case, we
     * just add a marker near Africa.
     * <p/>
     * This should only be called once and when we are sure that {@link #mMap} is not null.
     */
    private void setUpMap() {
        mMap.addMarker(new MarkerOptions().position(new LatLng(0, 0)).title("Marker"));
    }
}

package com.example.nan.spymap；
导入android.support.v4.app.FragmentActivity；
导入android.os.Bundle；
导入com.google.android.gms.maps.GoogleMap；
导入com.google.android.gms.maps.MapFragment；
导入com.google.android.gms.maps.SupportMapFragment；
导入com.google.android.gms.maps.UiSettings；
导入com.google.android.gms.maps.model.LatLng；
导入com.google.android.gms.maps.model.Marker；
导入com.google.android.gms.maps.model.MarkerOptions；
导入android.os.Bundle；
导入android.support.v4.app.FragmentActivity；
导入com.google.android.gms.maps.CameraUpdateFactory；
导入com.google.android.gms.maps.GoogleMap；
导入com.google.android.gms.maps.OnMapReadyCallback；
导入com.google.android.gms.maps.SupportMapFragment；
导入com.google.android.gms.maps.model.LatLng；
导入com.google.android.gms.maps.model.MarkerOptions；
公共类MapActivity扩展了FragmentActivity在MapReadyCallback上的实现{
私有GoogleMap mMap；//如果Google Play services APK不可用，则可能为空。
私人地图碎片；
@凌驾
创建时受保护的void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
setContentView（R.layout.activity_映射）；
setupmapifneed（）；
/*MapFragment MapFragment=（MapFragment）getFragmentManager（）
.findFragmentById（R.id.map）；
getMapAsync（这个）；
*/}
@凌驾
受保护的void onResume（）{
super.onResume（）；
setupmapifneed（）；
}
@凌驾
已于4月1日公开作废（谷歌地图）{
//在澳大利亚悉尼添加一个标记，然后移动相机。
addMarker（新的MarkerOptions（）
.位置（新车床（10,10））
.title（“Hello world”）.draggable（真实））；
mMap.setMyLocationEnabled（true）；//false禁用
}
/**
*如果可能的话，设置地图（例如，Google Play services APK已正确启动）
*已安装）并且映射尚未实例化。这将确保
*当{@link#mMap}不为null时，调用{@link#setUpMap（）}一次。
*

*如果未安装{@link SupportMapFragment}（和
*{@link com.google.android.gms.maps.MapView MapView}）将提示用户
*在其设备上安装/更新Google Play services APK。
*

*用户可以按照提示正确返回此FragmentActivity
*安装/更新/启用Google Play服务。因为碎片活动可能不会
*在这一过程中被完全破坏（很可能
*停止或暂停），{@link#onCreate（Bundle）}可能不会被再次调用，因此我们应该调用它
*方法来保证将调用它。
*/
私有void setUpMapIfNeeded（）{
//执行空检查以确认尚未实例化映射。
如果（mMap==null）{
//尝试从SupportMapFragment获取映射。
mMap=（（SupportMapFragment）getSupportFragmentManager（）.findFragmentById（R.id.map））
.getMap（）；
//检查我们是否成功获得地图。
如果（mMap！=null）{
setUpMap（）；
}
}
}
/**
*在这里，我们可以添加标记或线条、添加侦听器或移动摄影机
*在非洲附近加一个标记。
*

*当我们确定{@link#mMap}不是null时，应该只调用一次。
*/
私有void setUpMap（）{
mMap.addMarker（新标记选项（）.position（新板条（0，0））.title（“标记”）