设备的旋转之后恢复更改的菜单状态 [英] Restore changed menu state after rotation of a device

问题描述

我正在写的应用程序，它具有与按钮和图像的菜单。我preSS从录制单曲为停止录制按钮变为按钮和标签。问题是，当我转动我的设备，带有按钮活动得到由操作系统杀害。所以，我明白，我要救我的数据之前，它在的onSaveInstanceState 方法被杀，然后在我的的onCreate 方法。事情是这样的：

I'm writing an application, which has a menu with buttons and an image. I press the button and label of the button changes from "Record track" to "Stop recording". The issue is when I rotate my device, the activity with buttons gets killed by the OS. So, I understood that I have to save my data before it's get killed in onSaveInstanceState method and then restore it in my onCreate method. Something like this:

@Override
public void onSaveInstanceState(final Bundle saveInstanceState) {
    saveInstanceState.putSerializable("image", image);
    saveInstanceState.putSerializable("buttonState", isRecording);

}

和

if (savedInstanceState != null) {                                
    isRecording = savedInstanceState.getBoolean("buttonState");  

    if (menu != null) {                                          
        MenuItem recordButton = menu.getItem(R.id.track);

        if (!isRecording) {
            recordButton.setTitle(R.string.rec_track_label);     
        } else {
            recordButton.setTitle(R.string.stop_rec_track_label);
        }
    }                                                            

    Image = (Image)savedInstanceState.getSerializable("image");

} 

虽然它完美地恢复我的形象，我仍然有菜单的问题：由于某种原因，它总是保持为零，所以它永远不会改变我的按钮的标签，尽管它应该重新每次活动开始时，我把它保存在我的活动的私有对象：

And while it perfectly restores my image, I still have issues with the menu: for some reason it always stays "null", so it will never change label of my button despite that it should be recreated every time, when Activity starts and I save it in a private object of my Activity:

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    new MenuInflater(this).inflate(R.menu.actions, menu);
    this.menu = menu;
    return (super.onCreateOptionsMenu(menu));
}

任何想法，我究竟做错了什么？谢谢你。

Any ideas what am I doing wrong? Thanks.

推荐答案

您应该将你的菜单！= NULL 块成<一个href=\"http://developer.android.com/reference/android/app/Activity.html#on$p$ppareOptionsMenu%28android.view.Menu%29\"相对=nofollow>在prepareOptionsMenu ：

public boolean onPrepareOptionsMenu(Menu menu)
{
    MenuItem recordButton = menu.findItem(R.id.track);

    if (isRecording) {
        recordButton.setTitle(R.string.rec_track_label);     
    } else {
        recordButton.setTitle(R.string.stop_rec_track_label);
    }
}

作为被显示给用户的菜单的前此方法是直接调用

As this method is called directly before the menu is being shown to the user.

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