將可序列化對象傳遞給片段時發生「空對象引用」錯誤

Question

我一直在研究這個問題並嘗試幾個小時。我已經在這篇文章後採取瞭如何傳遞參數到一個片段的例子： Send data from activity to fragment in android

我想從活動傳遞一個自定義對象，到一個片段。我選擇使用，以實現序列化和傳遞對象：

bundle.putSerializable("key", Serializable). 

，我發現了錯誤

java.lang.NullPointerException:嘗試在空對象引用調用虛方法java.io.Serializable android.os.Bundle.getSerializable(java.lang.String)

當我試圖設置我的對象等於從活動傳入的參數。

這裏是我的對象

public class Player implements Serializable { 

    int attack; 
    private int tempAttack; 
    int defense; 
    private int tempDefense; 
    int pop; 
    int level; 
    String t1Evo; 
    String t2Evo; 
    String t3Evo; 

    public Player() { 
     attack = 0; 
     tempAttack = 0; 
     defense = 0; 
     tempDefense = 0; 
     pop = 20; 
     level = 1; 
     t1Evo = null; 
     t2Evo = null; 
     t3Evo = null; 
    } 
} 

那麼這裏就是我的活動從我傳遞，我最終想通過我的對象的所有四個，但是我現在我試圖得到至少一個順利通過。

public class GameScreen extends FragmentActivity { 

// Anytime you need to grab data from the players, 
// this screen will hold them. 

    private Player player1; 
    private Player player2; 
    private Player player3; 
    private Player player4; 


    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     requestWindowFeature(Window.FEATURE_NO_TITLE); 
     setContentView(R.layout.activity_game_screen); 

     // Instantiate the player objects 
     player1 = new Player(); 
     player2 = new Player(); 
     player3 = new Player(); 
     player4 = new Player(); 

     // put the objects to send to our fragment in a bundle 
     PlayerInformation newFragment = new PlayerInformation(); 
     Bundle args = new Bundle(); 
     args.putSerializable("Player1", player1); 
     newFragment.setArguments(args); 

     // start transaction 
     FragmentTransaction transaction = getSupportFragmentManager().beginTransaction(); 

     // Replace whatever is in the fragment_player_information view with this fragment, 
     transaction.add(R.id.playerInformation, newFragment); 
     transaction.commit(); 
    } 
} 

然後其拋出空指針異常的片段，我曾表示與線「 - >」 包com.cs246.spencer.naturalselection;

import android.app.Activity; 

import android.content.Context; 
import android.content.Intent; 
import android.net.Uri; 
import android.os.Bundle; 
import android.support.v4.app.Fragment; 
import android.support.v4.app.FragmentActivity; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.TextView; 

import java.io.Serializable; 


/** 
* Fragment that displays the Player information on GameScreen 
*/ 
public class PlayerInformation extends Fragment { 
    Context context; 
    Player player1; 
    Player player2; 
    Player player3; 
    Player player4; 

    public PlayerInformation(){ 
     this.context=context; 
    } 
    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
         Bundle savedInstanceState) { 
     // grab the objects passed from GameScreen 
     Bundle args = getArguments(); 
    --> player1 = (Player) args.getSerializable("Player1"); 
     player1 = (Player) getArguments().getSerializable("Player1"); 

     // Inflate the layout for this fragment 
     return inflater.inflate(R.layout.fragment_player_information, container, false); 
    } 

    public void Update() { 
     TextView player1Pop = (TextView) ((Activity)context).findViewById(R.id.player1Pop); 
     player1Pop.setText(player1.pop); 
    } 
} 

Answer 1

試試這個

player1 = (Player)getActivity().getIntent().getSerializableExtra("Player1");