标题是阿里电话面试的问题，一直以为自己很清楚MVC模式，结果被问到时，这M、V、C这几者之间的关系都搞不清楚了，最主要是，没法将MVC和Android中各个组件对应起来，所以，面试肯定挂了，不过面试也是学习的一种方式，可以知道大公司看中什么，以及自己还有哪些知识漏洞，例如这次面试就学到了很多东西。
大家也可以在看下面的内容之前，也想想能否把MVC及与Android各个组件的对应关系讲清楚，看是否还有和我一样对MVC一知半解的。
如果写的有问题的地方，欢迎讨论。转载请注明出处：http://www.cnblogs.com/John-Chen/p/4458823.html
学习MVC模式中读了很多别人总结的文章，有几篇不错，推荐给大家：
前端之Android入门(3):MVC模式：
http://isux.tencent.com/learn-android-from-zero-session3.html
http://isux.tencent.com/learn-android-from-zero-session4.html
http://isux.tencent.com/learn-android-from-zero-session5-html.html
The Activity Revisited:
http://www.therealjoshua.com/2012/07/android-architecture-part-10-the-activity-revisited/
谈谈UI架构设计的演化：
http://www.cnblogs.com/winter-cn/p/4285171.html
MVC，MVP 和 MVVM 的图示：
http://www.ruanyifeng.com/blog/2015/02/mvcmvp_mvvm.html
关于另一种框架模式MVP的实践：
http://www.imooc.com/wenda/detail/216700
搞清楚MVC以及与Android各个组件的对应关系之后，再看自己项目中的某些实现，其实很多地方已经是遵循MVC的思想在实现，只是在设计和实现时，没想到框架模式，只是根据以前的经验，以及一些基本的设计思想在做，所以被问到MVC模式时，也没想到项目中有用到的地方。我觉得不管你自己了不了解什么框架模式以及设计模式，最主要的是得想办法做到解耦以及提升应用的稳定性。
下面以项目中得一个实现来介绍Android中的MVC框架模式：
项目中有一个记录轨迹的功能，记录有几种状态：记录、暂停、停止：
、
接下来我把轨迹控制部分的逻辑提取出来，简单介绍下这部分的MVC设计思想。
demo源码地址：https://github.com/John-Chen/BlogSamples/tree/master/MVCDemo
View实现：
public class TrackCtrlView implements View.OnClickListener{
// ------------------------ Constants ------------------------
// ------------------------- Fields --------------------------
private ImageView btnStartTrack, btnStopTrack, btnPauseTrack;
private TrackCtrlViewListener listener;
private TrackRecordInfo trackRecordInfo;
// ----------------------- Constructors ----------------------
public TrackCtrlView(Activity activity, TrackCtrlViewListener listener){
this.listener = listener;
btnStartTrack = (ImageView) activity.findViewById(R.id.btnStartTrack);
btnStopTrack = (ImageView) activity.findViewById(R.id.btnStopTrack);
btnPauseTrack = (ImageView) activity.findViewById(R.id.btnPauseTrack);
btnStartTrack.setOnClickListener(this);
btnStopTrack.setOnClickListener(this);
btnPauseTrack.setOnClickListener(this);
btnPauseTrack.setOnClickListener(this);
}
// -------- Methods for/from SuperClass/Interfaces -----------
/**
* 将用户请求通知Controller
*/
@Override
public void onClick(View v) {
switch(v.getId()){
case R.id.btnStartTrack:
if(listener != null){
listener.trackStatusRequest(TrackRecordStatus.Recording);
}
break;
case R.id.btnStopTrack:
if(listener != null){
listener.trackStatusRequest(TrackRecordStatus.Stoped);
}
break;
case R.id.btnPauseTrack:
if(listener != null){
if(trackRecordInfo.status == TrackRecordStatus.Paused){
listener.trackStatusRequest(TrackRecordStatus.Recording);
}else{
listener.trackStatusRequest(TrackRecordStatus.Paused);
}
}
break;
default:
break;
}
}
// --------------------- Methods public ----------------------
// --------------------- Methods private ---------------------
private void refreshView(){
TrackRecordStatus trackStatus = trackRecordInfo == null ?
TrackRecordStatus.Stoped : trackRecordInfo.status;
if (trackStatus == TrackRecordStatus.Recording) {
btnStartTrack.setVisibility(View.GONE);
btnPauseTrack.setVisibility(View.VISIBLE);
btnStopTrack.setVisibility(View.VISIBLE);
btnPauseTrack.setImageResource(R.drawable.btn_track_ctrl_pause);
} else if (trackStatus == TrackRecordStatus.Paused) {
btnStartTrack.setVisibility(View.GONE);
btnPauseTrack.setVisibility(View.VISIBLE);
btnStopTrack.setVisibility(View.VISIBLE);
btnPauseTrack.setImageResource(R.drawable.btn_track_ctrl_resume);
} else {
// TrackRecordStatus.Stoped
btnStartTrack.setVisibility(View.VISIBLE);
btnPauseTrack.setVisibility(View.GONE);
btnStopTrack.setVisibility(View.GONE);
}
}
// --------------------- Getter & Setter -----------------
public void setTrackRecordInfo(@Nullable TrackRecordInfo trackRecordInfo) {
this.trackRecordInfo = trackRecordInfo;
refreshView();
}
// --------------- Inner and Anonymous Classes ---------------
public interface TrackCtrlViewListener{
/**
* 用户点击按钮
*/
public void trackStatusRequest(@Nullable TrackRecordStatus newStatus);
}
// --------------------- logical fragments -----------------
}
Model实现：
public class TrackRecordInfo {
// ------------------------ Constants ------------------------
// ------------------------- Fields --------------------------
private static final Gson gson = new Gson();
/**
* 应该是保存轨迹数据库id，此demo中数据库操作不实现，暂时trackId一直为0
*/
public int trackId;
public TrackRecordStatus status;
// ----------------------- Constructors ----------------------
public TrackRecordInfo(int trackId, TrackRecordStatus status) {
this.trackId = trackId;
this.status = status;
}
// -------- Methods for/from SuperClass/Interfaces -----------
// --------------------- Methods public ----------------------
@NonNull
public static TrackRecordInfo loadTrackRecordInfo(@NonNull Context context){
String pref = SpUtil.getString(context, SpUtil.KEY_TRACK_RECORD_INFO, "");
if(!TextUtils.isEmpty(pref)){
return gson.fromJson(pref, TrackRecordInfo.class);
}
return null;
}
public static void changeTrackRecordInfo(@NonNull Context context, @Nullable TrackRecordInfo info){
SpUtil.saveString(context,
SpUtil.KEY_TRACK_RECORD_INFO,
info == null ? "" : gson.toJson(info));
//model通过消息总线，通知View刷新
EventBus.getDefault().post(new EventTrackRecordInfoChanged(info));
}
// --------------------- Methods private ---------------------
// --------------------- Getter & Setter -----------------
// --------------- Inner and Anonymous Classes ---------------
// --------------------- logical fragments -----------------
}
Controller实现：
public class MainActivity extends ActionBarActivity implements TrackCtrlView.TrackCtrlViewListener{
private TrackCtrlView trackCtrlView;
private TrackRecordInfo trackRecordInfo;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
trackCtrlView = new TrackCtrlView(this, this);
EventBus.getDefault().register(this);
trackRecordInfo = TrackRecordInfo.loadTrackRecordInfo(this);
trackCtrlView.setTrackRecordInfo(trackRecordInfo);
}
@Override
protected void onDestroy() {
super.onDestroy();
EventBus.getDefault().unregister(this);
}
@Override
public void trackStatusRequest(@Nullable TrackRecordStatus newStatus) {
if(newStatus == TrackRecordStatus.Recording){
int trackId = 0; //在数据库创建一条轨迹，并获取到数据库id
trackRecordInfo = new TrackRecordInfo(trackId, TrackRecordStatus.Recording);
}else if (newStatus == TrackRecordStatus.Paused) {
if(trackRecordInfo != null){
trackRecordInfo.status = newStatus;
}
} else {
trackRecordInfo = null;
}
TrackRecordInfo.changeTrackRecordInfo(this, trackRecordInfo);
}
public void onEventMainThread(EventTrackRecordInfoChanged event){
trackRecordInfo = event.info;
trackCtrlView.setTrackRecordInfo(trackRecordInfo);
}
}
比较晚了，明天下班再继续整理...
时间： 2024-02-20 08:47:14