java - Android - 将类 X 的实例从 Activity A 发送到 Activity B

Question

我试图从我的 Mainactivity 将我的 Connection 类发送到我的 Mapsactivity，这样我就可以在我的 Mapsactivity 的 Connection 类中使用方法。

由于某种原因，我在启动 Mapsactivity 时遇到此错误，

java.lang.RuntimeException: Parcelable 遇到IOException 写入可序列化对象

我不太确定问题出在哪里，我的 Connection 类已经实现了 Serializable，我也让我的 Mainactivity 实现了 Serializable 以查看它是否会修复但没有成功。

我的应用程序应该让人们连接到一个服务器，他们可以在服务器上发送他们的位置，并从其他连接的人那里接收位置，并将坐标放在他们的 map 上。我已经删除了与此问题无关的代码，因此可以阅读的代码更少。我相信我已经获得了所有必要的代码，如果还不够，我可以发布整个类(class)。提前致谢

主要 Activity 类

public class MainActivity extends FragmentActivity{
private Connection connection;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    initialize();
    setListeners();
}

public void initialize() {
    connection = new Connection("xxx.xxx.xxx.x",xxxx);
    btnShowMap = (Button)findViewById(R.id.btnShowMap);
    Log.w(null, "Initialized");
}

public void startMap() {
    Intent intent = new Intent(this, MapsActivity.class);
    intent.putExtra("class", connection);
    startActivity(intent);
}

public void setListeners() {
    btnShowMap.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            btnShowMap.setOnClickListener(new View.OnClickListener() {
                public void onClick(View v) {
                    startMap();
                }
            });
        }
    });
}

连接类

    public class Connection implements Serializable{
private InetAddress address;
private int port;
private String ip, groupName, myName, total, membersInfo, id, fName;
private Socket socket;
private InputStream is;
private DataInputStream dis;
private OutputStream os;
private DataOutputStream dos;
private boolean connected = false;
private double latitude, longitude, fLong ,fLat;
private String name;
private double Longi, Lati;

public Connection(String ip, int port){
    this.ip = ip;
    this.port = port;
}

public void listenToServer() {
    Thread thread = new Thread(new ListenToServer());
    thread.start();
}

private class ListenToServer implements Runnable {
    public void run() {
        Log.w(null,"Listening to server");
        try {
            String locations = new String(dis.readUTF());
            if(locations == null) {
                Log.e(null,"EMPTY");
            }
            if(locations != null) {
                JSONObject friends = new JSONObject(locations);
                JSONArray jsonArray = friends.getJSONArray("location");
                JSONObject transaction;
                for (int i = 0; i < jsonArray.length(); i++) {
                    transaction = jsonArray.getJSONObject(i);
                    fName = transaction.getString("member");
                    fLong = transaction.getDouble("longitude");
                    fLat = transaction.getDouble("latitude");
                }
            }
            if (locations == null) {
                dis.close();
            }
        }
        catch (JSONException e) {
            e.printStackTrace();
        }
        catch (IOException e) {
            e.printStackTrace();
        }
    }
}

MapsActivity 类

public class MapsActivity extends FragmentActivity {

private GoogleMap mMap; // Might be null if Google Play services APK is not available.
private LocationManager locationManager;
private LocationListener locationListener;
private double latitude, longitude, flat, flong;
private String friendName;
private boolean addMarker = false;
private Connection connection;
private Button btnAddMyMarker, btnAddFriendMarker;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_maps);
    initialize();
    setListener();
}

public void initialize() {
    btnAddMyMarker = (Button)findViewById(R.id.btnAddMyMarker);
    btnAddMyMarker.setEnabled(false);
    btnAddFriendMarker = (Button)findViewById(R.id.btnAddFriendMarker);
    connection = (Connection) getIntent().getSerializableExtra("class");
    mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
            .getMap();
    locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
    locationListener = new LocList();

}

public void setListener() {
    btnAddMyMarker.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            addMyMarker();
        }
    });

    btnAddFriendMarker.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            connection.listenToServer();
        }
    });
}


public void addMyMarker() {
    mMap.addMarker(new MarkerOptions().position(new LatLng(latitude, longitude)).title("My position"));
}

private class LocList implements LocationListener {
    @Override
    public void onLocationChanged(Location location) {
        latitude = location.getLatitude();
        longitude = location.getLongitude();
        if(addMarker == false && longitude != 0 && latitude != 0) {
            btnAddMyMarker.setEnabled(true);
        }
        connection.sendLocation(latitude, longitude);
    }

    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {

    }

    @Override
    public void onProviderEnabled(String provider) {

    }

    @Override
    public void onProviderDisabled(String provider) {

    }
}

Answer 1

您将无法在 Activity 之间传递 Connection，因为其中的大部分内容无法序列化或转换为 Parcel。值得注意的是，以下都不支持任一操作:

private InputStream is;
private DataInputStream dis;
private OutputStream os;
private DataOutputStream dos;

或者:

• 这应该是一项服务，特别是如果工作应该独立于任何 UI 完成，或者

• 这需要是单例，或者

• 没有单独的 Activity ，而是一个 Activity 有多个 fragment ，或者

• 将所有与连接相关的工作隔离到一个 Activity 中