Android实现返回键操作思路

  /**   * 返回键处理   */  @Override  public boolean onKeyDown(int keyCode, KeyEvent event) {    if(keyCode==KeyEvent.KEYCODE_BACK){      boolean result=MiddleManager.getInstance().goBack();      if(!result){        Toast.makeText(MainActivity.this, "是否退出应用", 1).show();      }      return false;    }    return super.onKeyDown(keyCode, event);  }

  //操作历史栈  private LinkedList<String> HISTORY=new LinkedList<String>();  /**   * 处理返回键   * @return    */  public boolean goBack() {    //如果为空会抛异常    if(HISTORY.size()>0){      if(HISTORY.size()==1){        return false;      }            HISTORY.removeFirst();      if(HISTORY.size()>0){        String key=HISTORY.getFirst();        BaseView targetView=VIEWCACHE.get(key);        mainContainer.removeAllViews();        View child=targetView.getView();        mainContainer.addView(child);        child.startAnimation(AnimationUtils.loadAnimation(mainContainer.getContext(), R.anim.left_to_right));        currentView=targetView;        return true;      }    }    return false;  }

  /**   * 加载界面   */  public void loadView(Class<? extends BaseView> baseViewClass) {    BaseView baseView=null;    //判断是否存在    String key=baseViewClass.getSimpleName();    if(VIEWCACHE.containsKey(key)){      baseView=VIEWCACHE.get(key);    }else{      try {        Constructor<? extends BaseView> constructor;        constructor = baseViewClass.getConstructor(Context.class);        baseView=constructor.newInstance(mainContainer.getContext());      } catch (Exception e) {        e.printStackTrace();      }      VIEWCACHE.put(key, baseView);    }    mainContainer.removeAllViews();    View child=baseView.getView();    mainContainer.addView(child);    child.startAnimation(AnimationUtils.loadAnimation(mainContainer.getContext(), R.anim.left_to_right));    currentView=baseView;    //放入栈    HISTORY.addFirst(key);  }