Question

我在MainActivity中创建了多个片段。我使用Switch case调用片段。每次创建新实例时。如何维护相同的实例？这里是我的代码：

Fragment fragment = null;
    switch (position) {
    case 0:
        fragment = new Fragment1();
        break;
    case 1:
        fragment = new Fragment2();
        break;
    case 2:
        fragment = new Fragment3();
        break;
    case 3:
        fragment = new Fragment4();
        break;
    case 4:
        fragment = new Fragment5();
        break;
    }

    FragmentManager fragmentManager = getFragmentManager();
    fragmentManager.beginTransaction().replace(R.id.content_frame, fragment).commit();

Answer 1

而不是

Fragment fragment = null;

fragment = new Fragment1()
fragment = new Fragment2()

将片段存储在单独的变量中：

Fragment fragment1 = null;
Fragment fragment2 = null;

fragment1 = new Fragment1()
fragment2 = new Fragment2()

...

并且仅在变量为null

时才创建新对象

如何维护片段的实例

1 个答案: