MVP学习
最近接触了MVP，觉得比较有意思，之前学习了mvc，感觉MVP对于解耦方面不比mvc差，更重要的一点，感觉MVP比mvc在处理逻辑啥上面更清晰，把逻辑、界面、数据分离的更彻底，值得学习与研究一下。
下面是从一个开源项目学习与总结过来的基础知识：
MVpView:View个基础类。
public interface MvpView {
}
Mvppresenter：Presenter的基础类，控制的MvpView的子类，比如activity实现的MvpView,可以调用attachview 将veiw引用。
public interface Mvppresenter<V extends MvpView> {
public void attachView(V view);
public void detachView();
}
public class MvpBasepresenter<V extends MvpView> implements Mvppresenter<V>{
private WeakReference<V> reference;
@Override
public void attachView(V view) {
if(view==null)
throw new NullPointerException("view can not be null when in attachview() in MvpBasepresenter");
else
{
if(reference==null)
reference=new WeakReference<V>(view);
}
}
@Override
public void detachView() {
if(reference!=null)
reference.clear();
}
public V getMvpView()
{
if(reference!=null&&reference.get()!=null)
return reference.get();
else throw new NullPointerException("have you ever called attachview() in MvpBasepresenter");
}
public Boolean isAttach()
{
return reference!=null&&reference.get()!=null;
}
}
BasemvpDelegateCallback 用于对获取MvpView、创建以及获取presenter:
public interface BasemvpDelegateCallback <P extends Mvppresenter,V extends MvpView>{
public void setPresenter();
public P getPresenter();
public P createPresenter();
public V getMvpView();
}
MvpInternalDelegate 用于控制presenter与MvpView:
public class MvpInternalDelegate<P extends Mvppresenter, V extends MvpView> {
BasemvpDelegateCallback<P, V> callback;
public MvpInternalDelegate(BasemvpDelegateCallback<P, V> callback)
{
this.callback = callback;
}
public P creatPresneter() {
P p=callback.getPresenter();
if (p== null)
p=callback.createPresenter();
if(p==null)
throw new NullPointerException("callback.createPresenter() is null in MvpInternalDelegate");
return p;
}
public void attachView() {
callback.getPresenter().attachView(callback.getMvpView());
}
public void detacthView() {
callback.getPresenter().detachView();
}
}
接下来是如何使用，以activity为例：
1.创建一个ActyvityDelegate，与activity生命周期一致，目的是为了通过activity的生命周期去控制是否要attachView：
public interface ActyvityDelegate {
public void onCreate();
public void onPause();
public void onResume();
public void onStop();
public void onDestroy();
}
2.创建一个ActivityMvpDelegateCallback，为了面向接口编程，解耦性好：
public interface ActivityMvpDelegateCallback<P extends Mvppresenter,V extends MvpView>
extends BasemvpDelegateCallback<P,V> {
}
3.创建一个ActivityDelegateImp，实现了ActyvityDelegate，在生命周期里控制presenter与MvpView：
public class ActivityDelegateImp<P extends Mvppresenter,V extends MvpView> implements ActyvityDelegate {
private BasemvpDelegateCallback<P,V> basemvpDelegateCallback;
private MvpInternalDelegate<P,V> mvpInternalDelegate;
public ActivityDelegateImp(BasemvpDelegateCallback<P,V> basemvpDelegateCallback) {//传入BasemvpDelegateCallback 去控制presenter
if(basemvpDelegateCallback==null)
throw new NullPointerException("the basemvpDelegateCallback in ActivityDelegateImpn is null");
this.basemvpDelegateCallback=basemvpDelegateCallback;
mvpInternalDelegate=new MvpInternalDelegate<P,V>(this.basemvpDelegateCallback);
}
@Override
public void onCreate() {
mvpInternalDelegate.creatPresneter();
mvpInternalDelegate.attachView();
}
@Override
public void onPause() {
}
@Override
public void onResume() {
}
@Override
public void onStop() {
}
@Override
public void onDestroy() {
mvpInternalDelegate.detacthView();
}
}
4.创建MvpActivity 的抽象类，实现了ActivityMvpDelegateCallback，然后创建一个BasemvpDelegateCallback:
public abstract class MvpActivity<P extends Mvppresenter, V extends MvpView> extends Activity implements
ActivityMvpDelegateCallback<P, V>, MvpView {
private ActyvityDelegate mActyvityDelegate;
private P mPresenter;
public MvpActivity() {
super();
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mActyvityDelegate = new ActivityDelegateImp<P, V>(this);
mActyvityDelegate.onCreate();
}
@Override
protected void onResume() {
super.onResume();
mActyvityDelegate.onResume();
}
@Override
protected void onPause() {
super.onPause();
mActyvityDelegate.onPause();
}
@Override
protected void onStop() {
super.onStop();
mActyvityDelegate.onStop();
}
@Override
protected void onDestroy() {
super.onDestroy();
mActyvityDelegate.onDestroy();
}
@Override
public void setPresenter() {
}
protected abstract P CreatePresenter();//暴露一个创建的方法用于创建presenter
@Override
public P createPresenter()//这个方法由MvpInternalDelegate 调用<span style="font-family: Arial, Helvetica, sans-serif;">BasemvpDelegateCallback 来创建presenter</span>
{
mPresenter=CreatePresenter();
return mPresenter;
}
@Override
public P getPresenter() {//
return mPresenter;
}
@Override
public V getMvpView() {
return (V) this;
}
}
5.创建MyMvpActivity，继承了MvpActivity,创建了必要的presenter、Mvpview,以及加载了相应的布局:
public class MyMvpActivity extends MvpActivity<MyActivityPresenter, ActivityMvpView> implements ActivityMvpView {
protected RelativeLayout mLoadinglayout;
protected RelativeLayout mMsglayout;
protected TextView mMsgtextview;
public MyMvpActivity() {
super();
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.mymvp_activity_layout);
findview();
}
private void findview() {
mLoadinglayout = (RelativeLayout) findViewById(R.id.my_mvpactovity_loadinglayout);
mMsglayout = (RelativeLayout) findViewById(R.id.my_mvpactovity_errormsglayout);
mMsgtextview = (TextView) findViewById(R.id.my_mvpactovity_errormsg_textview);
}
@Override
public void showLoading() {
mLoadinglayout.setVisibility(View.VISIBLE);
mMsglayout.setVisibility(View.GONE);
}
@Override
public void showContent() {
}
@Override
public void showerror() {
mLoadinglayout.setVisibility(View.GONE);
mMsglayout.setVisibility(View.VISIBLE);
}
@Override
public void setdata() {
}
@Override
protected MyActivityPresenter CreatePresenter() {
return new MyActivityPresenter();
}
}
明显，ActivityMvpView是MvpView的子类：
public interface ActivityMvpView extends MvpView{
public void showLoading();
public void showContent();
public void showerror();
public void setdata();
}
MyActivityPresenter是MvpBasepresenter的子类：
public class MyActivityPresenter extends MvpBasepresenter<ActivityMvpView> {
public MyActivityPresenter() {
super();
}
public void setdata() {
getMvpView().showerror();
}
public void showdata() {
getMvpView().showLoading();
}
}