I have a text field which indicates date selected by the user.Also i have provided a button for the user to change the currect date. The problem i am facing is as follows.
1。在“Oncape ”方法中,我已经将文本字段设定为当前日期。当活动创建时,它将显示当前日期。
这一切都工作正常..
但当我旋转设备时, 创建中的设备再次被调用, 文本字段被更改为当前设备。 我希望文本字段能保留被选中的用户 。
有办法阻止吗?
屏幕旋转杀死了您的活动, 并导致整个生命周期重新启动 。 发生这种情况时, 在 Create 上仍然可以访问开始活动的原始意图, 某些部件可能保留部分状态( 例如 编辑文本), 但很多动态活动数据将会丢失 。 为了防止这种情况, 请使用 < code> sonSaveInstance State 方法 。 这将允许您在旋转杀死屏幕之前将任何重要数据成员放入捆绑中 。 此捆绑随后将传送到您在 Create 上的参数 < code> saveedInstance State. 这里是此上的 dev文档 :
在您的情况下, 您会想要通过将日期值作为额外附加值放入捆绑来保存您的日期值。 然后, 在 Create 上, 请检查保存的 Instance State 是否为无效, 表明它包含您的日期并相应处理它。 另外, 请确定如果您在活动生命周期中稍后为此文本设定默认值, 它不会破坏您检索的日期 。
您需要在旋转前保存变量。 我认为最好的选择是使用应用程序类作为保存变量的位置, 并在 Pause () 函数中执行 。
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