Android开发中返回键功能的实现

/**
* 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 HISTORY=new LinkedList();
/**
* 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);
}