的Android清單NullPointerException異常

Question

我有這樣一段代碼，它是造成NullPointerException異常

private List<Player> playerList; 
private List<String> playerName; 

Bundle b = getIntent().getExtras(); 
this.currentGame = b.getParcelable("created_tournament"); 
playerList = currentGame.getPlayers(); 
for (int i = 0; i < playerList.size(); i ++) { 
    this.playerName.add(this.playerList.get(i).getName()); 
    Log.d(TAG, "Input was not a number!" + this.playerList.get(i).getName()); 
}   

與playerList從Parcelable對象採取List<Player>和playerName是List<String>。

從理論上講，應該this.playerName.add(this.playerList.get(i).getName());因爲Log.d(TAG, "Input was not a number!" + this.playerList.get(i).getName());作品能正常工作，而不會造成任何異常

任何想法？

Answer 1

該playerName列表中未初始化，並且您調用它的方法add而它的null。

變化是：

private List<String> playerName; 

到：

private List<String> playerName = new ArrayList<String>();