在 Android 中完成父活动和当前活动 [英] Finish parent and current activity in Android

问题描述

我有 3 个活动.活动 A 导致活动 B，活动 B 又可以返回活动 A 或启动活动 C.但是，如果我在活动 C 中按回，应用程序应该关闭.

I have 3 activities. Activity A which leads to activity B, which in turn can go back to activity A or start activity C. However, if I press back in activity C the app should close.

总结:

• 活动 A 开始活动 B
• 在活动 B 上按返回应该会导致 A
• 活动 B 开始活动 C
• 在活动 C 上按返回应关闭应用

• Activity A starts activity B
• Pressing Back on activity B should lead to A
• Activity B starts activity C
• Pressing Back on activity C should close the app

我应该如何从活动 B 转到活动 C?这段代码目前在最后一行给了我一个 NullPointerException:

How should I go from activity B to C? This code currently gives me a NullPointerException on the last line:

Intent intent=new Intent(ActivityB.this, ActivityC.class);
startActivity(intent);
ActivityB.this.finish();
ActivityB.this.getParent().finish();

如果我切换最后两行，我也会得到一个空指针.

If I switch the last two lines I also get a null pointer.

推荐答案

我不知道这是否可行，但你可以试试:

I don't know if this will work, but you could try it:

• 从活动 A，使用 startActivityForResult()

在Activity B中，当用户触发Activity C时，启动Activity C.

In Activity B, when the user triggers Activity C, start activity C.

startActivity() 立即返回，所以

• 设置一个结果，通知A也完成，

• set a result that will inform A to finish as well,

在 B 中调用 finish().

当 A 收到 B 的结果时，A 也会对自身调用 finish().

When A receives that result from B, A calls finish() on itself as well.

否则，您可以将 Activity C 设置为自己的应用程序，然后在启动第二个应用程序后关闭第一个应用程序(使用 A 和 B).

Failing that, you could make Activity C into its own app and then close the first app (with A & B) after it starts the second.

附言在您前进的过程中考虑 Falmarri 的评论！
祝你好运.

P.S. Take Falmarri's comment into consideration as you move forward!
Good luck.

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