在不使用 savedInstanceState 的情况下保存动态添加的 LinearLayouts？

Question

我有一个布局，只需按一下按钮，我就可以在其中动态添加自定义视图。这些布局扩展了 LinearLayout，每个布局都有自己独特的 Action 对象。

但是，如果再次调用 onCreate，当用户离开或旋转屏幕时，视图将会消失。我想将这些自定义 ActionHolder 视图保留在那里。更糟糕的是，ActionHolder 对象包含敏感信息。 Action 对象本身存储一个实时计时器（即使应用程序关闭，它也应该继续计时），以及其他信息。

根据下面的答案，我做了以下操作，但无济于事。这是我目前所拥有的：

public class ActionHolder extends LinearLayout implements Serializable {

   /**
    * 
    */
   private static final long serialVersionUID = 2271402255369440088L;
   private Action action;
   private String timer;
   public static final int ACTION_TITLE = 0, ACTION_TIMER = 1,
         PAUSEANDPLAY_BTN = 2, FINISH_BTN = 3;



   public ActionHolder(Context context) {
      super(context);
   }



   public ActionHolder(Context context, AttributeSet attr) {
      super(context, attr);
   }



   public ActionHolder(Context context, AttributeSet attr, int defStyle) {
      super(context, attr, defStyle);
   }



   public void initiate(Action input) {
      // int hashedID = input.getActionName().hashCode();
      // if (hashedID < 0)
      // hashedID *= -1;
      // this.setId(hashedID);
      this.setOrientation(LinearLayout.VERTICAL);
      this.setLayoutParams(new LinearLayout.LayoutParams(
            LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT));
      action = input;
      LayoutInflater inflater = LayoutInflater.from(getContext());
      View view = inflater.inflate(R.layout.action_holder_layout, this, true);

      TextView actionTitle = (TextView) view
            .findViewById(com.tonimiko.mochi_bean.R.id.action_holder_title);
      actionTitle.setText(action.getActionName());
      actionTitle.setId(ActionHolder.ACTION_TITLE);

      TextView actionTimer = (TextView) view
            .findViewById(R.id.action_holder_timer);
      actionTimer.setId(ActionHolder.ACTION_TIMER);

      Button pauseBtn = (Button) view
            .findViewById(com.tonimiko.mochi_bean.R.id.pause_and_play_timer_btn);
      pauseBtn.setId(ActionHolder.PAUSEANDPLAY_BTN);

      Button finishBtn = (Button) view
            .findViewById(com.tonimiko.mochi_bean.R.id.finish_activity_button);
      finishBtn.setId(ActionHolder.FINISH_BTN);

      action.setActivityStartTime();
   }



   public Action finishAction() {
      action.setActivityStopTime();
      return action;
   }



   @Override
   protected void onLayout(boolean changed, int l, int t, int r, int b) {
      super.onLayout(changed, l, t, r, b);
   }



   public String toString() {
      return "Action stored: " + action.getActionName();
   }



   @Override
   public boolean equals(Object other) {
      ActionHolder otherObj = (ActionHolder) other;
      if (this.action.getActionName().toUpperCase()
            .equals(otherObj.action.getActionName().toUpperCase()))
         return true;
      return false;
   }



   @Override
   public int hashCode() {
      return action.getActionName().hashCode();
   }



   @Override
   protected Parcelable onSaveInstanceState() {
      Parcelable superState = super.onSaveInstanceState();
      Bundle data = new Bundle();
      data.putString("Timer", timer);
      data.putSerializable("Action", action);
      Log.e("debug", "View onSaveInstanceState called!"); // TODO
      Parcelable test = new ActionHolderSavedState(superState, data);
      if(test==null)
         Log.e("debug", "NULL PARCELABLE"); // TODO
      return new ActionHolderSavedState(superState, data);
   }



   @Override
   protected void onRestoreInstanceState(Parcelable state) {
      Log.e("debug", "View onRestore called!");
      if (state instanceof ActionHolderSavedState) {
         final ActionHolderSavedState savedState = (ActionHolderSavedState) state;
         this.action = savedState.getAction();
         this.timer = savedState.getTimer();
         // this.initiate(action);
         super.onRestoreInstanceState(savedState.getSuperState());
         Log.e("debug", "View onRestoreInstanceState finished"); // TODO
      }
   }

   static class ActionHolderSavedState extends BaseSavedState {

      private Action storedAction;
      private String storedTimer;



      public ActionHolderSavedState(Parcelable superState, Bundle data) {
         super(superState);
         storedTimer = data.getString("Timer");
         storedAction = (Action) data.getSerializable("Action");
      }



      private ActionHolderSavedState(Parcel in) {
         super(in);
         storedTimer = in.readString();
         storedAction = in.readParcelable(ActionHolder.class.getClassLoader());
      }



      public Action getAction() {
         return storedAction;
      }



      public String getTimer() {
         return storedTimer;
      }



      @Override
      public void writeToParcel(final Parcel out, final int flags) {
         super.writeToParcel(out, flags);
         out.writeString(storedTimer);
         out.writeSerializable(storedAction);
      }

      // required field that makes Parcelables from a Parcel
      public static final Parcelable.Creator<ActionHolderSavedState> CREATOR = new Parcelable.Creator<ActionHolderSavedState>() {

         public ActionHolderSavedState createFromParcel(final Parcel in) {
            return new ActionHolderSavedState(in);
         }



         public ActionHolderSavedState[] newArray(int size) {
            return new ActionHolderSavedState[size];
         }
      };
   }
}

我做错了什么吗？我已经花了将近 4 天的时间。

Answer 1

我的情况与您的情况非常相似，例如，自定义视图被动态添加到屏幕上，并且需要在 Activity 被操作系统终止并稍后重新创建时保存状态。

我在自定义视图上覆盖 onSaveInstanceState。它需要返回一个Parcelable 对象。关键是创建一个自定义类来扩展BaseSavedState 并将您的数据存储到Parcelable 中。它看起来有点像这样：

@Override
protected Parcelable onSaveInstanceState() {
    final Parcelable state = super.onSaveInstanceState();
    return new ContainerLayoutSavedState(state, data);
}

@Override
protected void onRestoreInstanceState(final Parcelable state) {
    if (state instanceof ContainerLayoutSavedState) {
        final ContainerLayoutSavedState savedState = (ContainerLayoutSavedState)state;
        this.data = savedState.getData();
        super.onRestoreInstanceState(savedState.getSuperState());
    }
}

public static class ContainerLayoutSavedState extends BaseSavedState {
    private String data;

    ContainerLayoutSavedState(final Parcelable superState, final String data) {
        super(superState);
        // Here in this constructor you inject whatever you want to get saved into the Parcelable object. In this contrived example, we're just saving a string called data.
        this.data = data;
    }


    private ContainerLayoutSavedState(final Parcel in) {
        super(in);

        data = in.readString();
    }

    public String getData()
        return data;
    }

    @Override
    public void writeToParcel(final Parcel out, final int flags) {
        super.writeToParcel(out, flags);

        out.writeString(data);
    }

    // required field that makes Parcelables from a Parcel
    public static final Parcelable.Creator<ContainerLayoutSavedState> CREATOR = new Parcelable.Creator<ContainerLayoutSavedState>() {
        @Override
        public ContainerLayoutSavedState createFromParcel(final Parcel in) {
            return new ContainerLayoutSavedState(in);
        }

        @Override
        public ContainerLayoutSavedState[] newArray(final int size) {
            return new ContainerLayoutSavedState[size];
        }
    };
} }

此外，不要忘记为您动态添加的视图设置 ID，以便在您返回时将它们重新添加到视图树中。