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浏览多个活动

[英]Navigating through multiple activities

原文 2010-10-12 07:45:38 1 3 android/ android-activity/ state

I have 2 Activities A and B . 我有2个活动A和B。 Now these are my objectives. 现在这些是我的目标。

When I'm in B and if I press the Home button, the state of the Activity should be saved. 当我在B中并且如果按“ 主页”按钮时，应保存“活动”的状态。 (No problem with this.) （这没问题。）
When I start B from A after step 1 a new instance of B should be created (ie) Previous state should be discarded. 当我在第1步之后从A开始B时，应创建B的新实例（即，应该放弃先前的状态）。

But in Step 2 the state of B still prevails. 但是在步骤2中，状态B仍然有效。 How do I accomplish my objective? 我如何实现我的目标？

3 个解决方案

I think one possible solution woudl be to pass some extra information inside the starting Intent, when you start Activity B from A (like a boolean value). 我认为一种可行的解决方案是，当您从A启动Activity B时，在启动Intent内传递一些额外的信息（如布尔值）。 And in the "onStart()" of B, you check if you can find this extra info in the intent (you get it with getIntent()). 然后在B的“ onStart（）”中，检查是否可以在意图中找到此额外信息（您可以通过getIntent（）获得它）。 If it's not present, that means you do reload the activity's previous state. 如果不存在，则表示您确实要重新加载活动的先前状态。 If it is, then you don't reload it. 如果是这样，则您无需重新加载它。

refer this url 参考这个网址

Android; Android； How can I initialise state in one activity, then have another refresh that? 如何在一个活动中初始化状态，然后进行另一次刷新？

You don't even need to send a boolean like Scythe suggested. 您甚至不需要发送像Scythe建议的布尔值。 The Bundle savedInstanceState will be null in onCreate for Activity B if Activity A just started it, whereas it will be non-null if you are coming back from a saved state. 如果活动A刚刚开始，则在活动B的onCreate Bundle savedInstanceState将为null，而如果您从已保存状态返回，则该Bundle savedInstanceState将为非null。