Mvp实战心得(二)---Base基类的封装

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转载请标明出处：http://www.jianshu.com/p/651146bd0688本文出自:Jlanglang
基类:
在开发中有着很重要的地位,基类设计封装的好,不管是对app的性能,还是对开发的效率都有着很重要的作用
基类可以简单几个字概况,一个良好的父类.
结构:
不管你的app是多个acitivity,还是1个activity+n个fragment,还是多个acitivity多个fragment.
始终都是用的acitivity和fragment.
根据项目的不同,基类不可能完全相同,但很多还是可以通用的.
抽取:
既然是mvp,那么不管是acitivity还是fragment.都归于v既然是v,那么就应该有相对应的presenter,view那么基类应该有:BaseActivityViewBaseFragmentViewBaseViewBasePresenter
具体代码:
BaseActivity
public abstract class BaseActivity<T extends BasePresenter> extends AppCompatActivity implements BaseActivityView {    protected T mPresenter;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        //创建Presenter        mPresenter = initPresenter();        //类似fragment的绑定.拿到引用        mPresenter.onAttch(this);        //初始化acitivity,        onCreateActivity(savedInstanceState);        //初始化Presenter        mPresenter.onCreate();    }    @Override    public void onSaveInstanceState(Bundle outState) {        super.onSaveInstanceState(outState);        mPresenter.onSaveInstanceState(outState);    }    @Override    protected void onDestroy() {        mPresenter.onDestroy();         mPresenter.onDetach();        super.onDestroy();    }    @Override    public BaseActivity getActivity() {        return this;    }    /**     * 创建prensenter     * @return <T extends BasePresenter> 必须是BasePresenter的子类     */    protected abstract T initPresenter();    /**     * 子类必须实现,并初始化Activity,比如setContentView()     */    protected abstract void onCreateActivity(Bundle savedInstanceState);    @Override    public void isNightMode(boolean isNight) {    }}
BaseFragment
稍微复杂一点.
public abstract class BaseFragment<T extends BasePresenter> extends Fragment implements BaseFragmentView {    protected T mPresenter;    protected Context mContext;//activity的上下文对象    protected Bundle mBundle;    @Override    public void onSaveInstanceState(Bundle outState) {        super.onSaveInstanceState(outState);        if (mBundle != null) {            outState.putBundle("bundle", mBundle);        }    }    /**     * 绑定activity     *     * @param context     */    @Override    public void onAttach(Context context) {        super.onAttach(context);        mContext = context;    }    /**     * 运行在onAttach之后     * 可以接受别人传递过来的参数,实例化对象.     *     * @param savedInstanceState     */    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        //获取bundle,并保存起来        if (savedInstanceState != null) {            mBundle = savedInstanceState.getBundle("bundle");        } else {            mBundle = getArguments() == null ? new Bundle() : getArguments();        }        //创建presenter        mPresenter = initPresenter();    }    /**     * 运行在onCreate之后     * 生成view视图     */    @Nullable    @Override    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {        return initView(inflater, container, savedInstanceState);    }    /**     * 运行在onCreateView之后     * 加载数据     */    @Override    public void onActivityCreated(@Nullable Bundle savedInstanceState) {        super.onActivityCreated(savedInstanceState);        //由于fragment生命周期比较复杂,所以Presenter在onCreateView创建视图之后再进行绑定,不然会报空指针异常        mPresenter.onAttch(this);        mPresenter.onCreate();    }    @Override    public void onDestroyView() {        mPresenter.onDestroy();        super.onDestroyView();    }    @Override    public void onDetach() {        mPresenter.onDetach();        super.onDestroyView();    }    /**     * 跳转fragment     *     * @param tofragment     */    @Override    public void startFragment(Fragment tofragment) {        startFragment(tofragment, null);    }    /**     * @param tofragment 跳转的fragment     * @param tag        fragment的标签     */    @Override    public void startFragment(Fragment tofragment, String tag) {        FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();        fragmentTransaction.hide(this).add(android.R.id.content, tofragment, tag);        fragmentTransaction.addToBackStack(tag);        fragmentTransaction.commitAllowingStateLoss();    }    /**     * 类似Activity的OnBackgress     * fragment进行回退     */    public void onBack() {        getFragmentManager().popBackStack();    }    /**     * 初始化Fragment应有的视图     *     * @return     */    public abstract View initView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState);    /**     * 创建prensenter     *     * @return <T extends BasePresenter> 必须是BasePresenter的子类     */    public abstract T initPresenter();    @Override    public Context getContext() {        return mContext;    }    @Override    public Bundle getBundle() {        return mBundle;    }    @Override    public BaseFragment getFragment() {        return this;    }}
再看看BaseView
public interface BaseView {    /**     * 切换夜间模式     * @param isNight 是否切换为夜间模式     */    void isNightMode(boolean isNight);}
BaseView得想好做什么事,必须是你的项目里所有view都有的共性
不仅是acitivity和fragment,还有控件
-----------------------------------------------------------------------------------------------------
关键的BasePresenter来了
/** * @author jlanglang  2016/11/11 15:10 */public abstract class BasePresenter<T extends BaseView> {   protected T mView;    /**     * 绑定View     */    public void onAttch(T view) {        this.mView = view;    }    /**     * 做初始化的操作,需要在V的视图初始化完成之后才能调用     * presenter进行初始化.     */    public abstract void onCreate();    /**     * 在这里结束异步操作    */    public void onDestroy(){    }    /**     * 在V销毁的时候调用,解除绑定    */    public void onDetach() {         mView = null;    }    /**    * 容易被回收掉时保存数据    */    public abstract void onSaveInstanceState(Bundle outState);}
看看Acitivity的使用:
//创建的时候写好泛型实现好抽象方法就行,多么简单.public class MainActivity extends BaseActivity<MainActivityPresenterImpl> implements MainActivityContract.View {    @Override    protected MainActivityPresenterImpl initPresenter() {        return new MainActivityPresenterImpl();    }    @Override    protected void onCreateActivity(Bundle savedInstanceState) {        setContentView(R.layout.activity_main);    }}
最后是对应的MainActivityPresenterImpl以及MainActivityContract
public class MainActivityPresenterImpl extends BasePresenter<MainActivityContract.View> implements MainActivityContract.Presenter {    @Override    public void onCreate() {    }    @Override    public void onSaveInstanceState(Bundle outState) {    }}
public class MainActivityContract {    public interface View extends BaseActivityView {    }    public interface Presenter{    }    public interface Model {    }}
总结:
对于BasePresenter一开始我是写成接口形式的,
后来使用过程中,发现很麻烦,每次绑定View,释放View都需要重复造轮子.
仔细想想,抽象类更合适,
每个Presenter继承BasePresenter,实现Contract中的接口为其补充
最后会发现,view和presenter的结构一样.基类作为复用,接口作为补充.


作者：Jlanglang
链接：http://www.jianshu.com/p/651146bd0688
來源：简书
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