Android：如何永久设置可见性

Question

这不是“如何设置可见性”问题的重复。

我有一个活动 1 和一个活动 2，当我开始活动 2 时，我在侦听器中设置了从 Gone 到 Visible 的布局并且它可以工作，我的问题是，当我返回活动 1 并返回活动 2 时，布局的可见性又回到了 Gone。如何让布局在离开时保持可见？

Activity2.java：

@Override
 public void onClick(View v) {

        if (FirstLayout.getVisibility() == View.INVISIBLE) {
            FirstLayout.setVisibility(View.VISIBLE);
         }
}

Activity2.xml：

 <LinearLayout
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:visibility="invisible"
      android:id="@+id/oneLayout"
      android:animateLayoutChanges="true"
      android:orientation="vertical">

      <!-- one Button -->
      <!-- one TextView -->   

  </LinearLayout>

Answer 1

如上面 cmets 中所说，在您的 Activity2.java 中：

SharedPreferences sharedPreferences;

在Activity2的onCreate方法中：

 sharedPreferences=getPreferences(Context.MODE_PRIVATE);
 FirstLayout.setVisibility(sharedPreferences.getBoolean("visibility",false)); 

然后：

 @Override
    public void onClick(View v) {
    if (FirstLayout.getVisibility() == View.INVISIBLE) {
        FirstLayout.setVisibility(View.VISIBLE);
        SharedPreferences.Editor editor=sharedPreferences.edit();
        editor.putBoolean("visibility",true).commit();
     }
}

Answer 2

您可以通过以下方法保存上一个状态

boolean mState = false;
final String STATE_VISIBILITY = "state-visibility";

// somewhere in the code assign a value to mState 
// i.e. mState = false (if GONE default) and mState = true (if VISIBLE)

@Override
public void onSaveInstanceState(Bundle savedInstanceState) {
    // Save the user's current game state
    savedInstanceState.putBoolean(STATE_VISIBILITY, mState);

    // Always call the superclass so it can save the view hierarchy state
    super.onSaveInstanceState(savedInstanceState);
}

然后恢复

@Override
public void onRestoreInstanceState(Bundle savedInstanceState) {
    // Always call the superclass so it can restore the view hierarchy
    super.onRestoreInstanceState(savedInstanceState);

    // Restore state members from saved instance
    mState = savedInstanceState.Boolean(STATE_VISIBILITY);
    view.setVisibility(mState?View.VISIBLE:View.GONE);

    }

更多关于http://developer.android.com/training/basics/activity-lifecycle/recreating.html