我不明白我的代码有什么问题。我在 myAddressUniqueness 中遇到错误。不知道为什么。在我尝试使用字符串数据类型但得到相同的错误之前。它说的是 java.null 异常。

ArrayList<String>  myAddressUniqueness = null; 
    String name = "hello"; 
 
    if (indexBody < 0 || !cursor.moveToFirst()) 
        return; 
 
    smsList.clear(); 
 
    do { 
        // int cursorPostion = cursor.getPosition(); 
 
        String address; 
        String msgStr = cursor.getString(indexBody); 
        String senderNumber = cursor.getString(indexAddr); 
        Log.d("Name : ", senderNumber); 
        // String name = cursor.getString(cursor 
        // .getColumnIndex(PhoneLookup.DISPLAY_NAME)); 
        // Log.d("Name : ",name); 
 
        if (name != null) { 
            address = name; 
        } else { 
            address = senderNumber; 
        } 
        Log.d("Address: ", address); 
        flag = 1; 
        //Log.e("Number: ", addressUniqueness.length + ""); 
 
        for (j = 0; j < myAddressUniqueness.size(); j++) { 
            if (myAddressUniqueness.contains(address)) { 
                flag = 0; 
                break; 
            } 
 
        } 
 
        if (flag == 1) { 
            myAddressUniqueness.add(new String(address)); 
            i++; 
 
            String str = "Sender: " + address + "\n"; 
            smsList.add(str); 
 
        } 
 
        // TODO Auto-generated catch block 
 
    } while (cursor.moveToNext()); 

请您参考如下方法:

将您的声明更改为

ArrayList<String> myAddressUniqueness = new ArrayList<String>();

您已将其初始化为 null .这将实例化它，然后您可以向它添加数据。