ActivityA Bundle传值到一个有内部类的AcivityB的取值问题

Question

Activity只有一个按钮带值“a”、“b”、“c”跳转到ActivityB
ActivityB的代码

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_activity_b);
        recive();
        setArray();
    }

```//接收Bundle
    private void recive() {
        Bundle bundle = getIntent().getExtras();
        if (bundle != null) {
            A = bundle.getString("a", "");
            B = bundle.getString("b", "");
            C = bundle.getString("c", "");
            Set<String> set = bundle.keySet();
            for (String value : set) {
                mMap.put(value, bundle.getString(value, ""));
            }
            Log.e("Tag", "--->>>>" + A + "----->>" + B + "----->>>>" + C);
            Log.e("TagMap", "--->>>>" + mMap.toString());
        }
    }


```class Util {
        String a;
        String b;
        String c;

        public Util(String a, String b, String c) {
            this.a = a;
            this.b = b;
            this.c = c;
        }

        public Map<String, Object> getMap() {
            Map<String, Object> map = new HashMap<>();
            map.put("title", a);
            map.put("value", b);
            map.put("type", c);
            return map;
        }
    }

    class Util2 {
        String a;
        String b;
        String c;

        public Util2(String a, String b, String c) {
            this.a = a;
            this.b = b;
            this.c = c;
        }

        public Map<String, Object> getMap2() {
            Map<String, Object> map = new HashMap<>();
            map.put("title", mMap.get(a));
            map.put("value", mMap.get(b));
            map.put("type", mMap.get(c));
            return map;
        }
    }

    public Util u[] = {
            new Util(A, B, C),
            new Util(A, B, C),
            new Util(A, B, C),
            new Util(A, B, C),
    };
    public Util2 u2[] = {
            new Util2("a", "b", "c"),
            new Util2("a", "b", "c"),
            new Util2("a", "b", "c"),
            new Util2("a", "b", "c"),
    };

    private void setArray() {
        for (Util a : u) {
            Log.e("tagUtil", "--->>>" + a.getMap().get("title") + "--->>>" + a.getMap().get("value") + "--->>>" + a.getMap().get("type"));
        }
        for (Util2 b : u2) {
            Log.e("tagUtil2", "--->>>" + b.getMap2().get("title") + "--->>>" + b.getMap2().get("value") + "--->>>" + b.getMap2().get("type"));
        }
    }

        打印的Log
04-05 10:50:23.413  14371-14371/com.project.xzj.testbundle E/Tag﹕ --->>>>a----->>b----->>>>c
04-05 10:50:23.413  14371-14371/com.project.xzj.testbundle E/TagMap﹕ --->>>>{b=b, c=c, a=a}
04-05 10:50:23.413  14371-14371/com.project.xzj.testbundle E/tagUtil﹕ --->>>--->>>null--->>>null
04-05 10:50:23.413  14371-14371/com.project.xzj.testbundle E/tagUtil﹕ --->>>--->>>null--->>>null
04-05 10:50:23.413  14371-14371/com.project.xzj.testbundle E/tagUtil﹕ --->>>--->>>null--->>>null
04-05 10:50:23.413  14371-14371/com.project.xzj.testbundle E/tagUtil﹕ --->>>--->>>null--->>>null
04-05 10:50:23.413  14371-14371/com.project.xzj.testbundle E/tagUtil2﹕ --->>>a--->>>b--->>>c
04-05 10:50:23.413  14371-14371/com.project.xzj.testbundle E/tagUtil2﹕ --->>>a--->>>b--->>>c
04-05 10:50:23.413  14371-14371/com.project.xzj.testbundle E/tagUtil2﹕ --->>>a--->>>b--->>>c
04-05 10:50:23.413  14371-14371/com.project.xzj.testbundle E/tagUtil2﹕ --->>>a--->>>b--->>>c

我想问题的是 为什util的值取成员变量A 、B、C的为空，而用map取值的Util2则有值？

Answer 1

请问您的A,B,C有默认值吗？