如何优化Androd App启动速度

public class ExampleUtils {
    private static HeavyObject sHeavyObject = HeavyObject.newInstance(); //比较耗时的初始化
    ...
    public static void useHeavyObject() {
        sHeavyObject.doSomething();
    }

    /**
     * 
     * 启动过程中需要用到的方法
     */
    public static void methodUseWhenStartUp() {
      ...
    }
    ...
}

public class ExampleUtils {
    private static HeavyObject sHeavyObject;
    ...
    public static void useHeavyObject() {
        if (sHeavyObject == null) {
            sHeavyObject = HeavyObject.newInstance(); //比较耗时的初始化
        }
        sHeavyObject.doSomething();
    }

    /**
     * 
     * 启动过程中需要用到的方法
     */
    public static void methodUseWhenStartUp() {
      ...
    }
    ...
}

<com.example.ad.h5Ad.ui.H5AdWebView
    android:id="@+id/ad_web"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:visibility="gone" />

<ViewStub
    android:id="@+id/ad_web_stub"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout="@layout/h5_ad_layout"/>

<com.example.ad.h5Ad.ui.H5AdWebView
    android:id="@+id/ad_web"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:visibility="gone" />

...
    private void setupView() {
        ...  
        mAdWebViewStub = (ViewStub) findViewById(R.id.ad_web_stub);
        mAdWebViewStub.setOnInflateListener(new ViewStub.OnInflateListener() {
            @Override
            public void onInflate(ViewStub stub, View inflated) {
                isAdWebStubInflated = true;
            }
        });
        ...
    }

    /**
     * 显示H5交互广告
     */
    private void showWebAd() {
        ...
        if (!isAdWebStubInflated) {
            View h5AdLayout = mAdWebViewStub.inflate();
            mAdWebView = (H5AdWebView) h5AdLayout.findViewById(R.id.ad_web);
        }
        ...
    }

/**
 * 使用继承方式实现的懒加载Fragment基类
 */
public abstract class InheritedFakeFragment extends Fragment {
    protected FrameLayout rootContainer;
    private boolean isLazyViewCreated = false;
    private LayoutInflater inflater;
    private Bundle savedInstanceState;

    @Nullable
    @Override
    public final View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        this.inflater = inflater;
        this.savedInstanceState = savedInstanceState;
        rootContainer = new FrameLayout(getContext().getApplicationContext());
        rootContainer.setLayoutParams(new FrameLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));
        return rootContainer;
    }

    @Override
    public final void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
    }

    @Override
    public void setUserVisibleHint(boolean isVisibleToUser) {
        super.setUserVisibleHint(isVisibleToUser);
        if (isVisibleToUser && !isLazyViewCreated && inflater != null) {
            View view = onLazyCreateView(inflater, rootContainer, savedInstanceState);
            rootContainer.addView(view);
            isLazyViewCreated = true;
            onLazyViewCreated(rootContainer, savedInstanceState);
        }
    }

    /**
     * 获取真实的fragment是否已经初始化view
     *
     * @return 已经初始化view返回true，否则返回false
     */
    @SuppressWarnings("unused")
    public boolean isLazyViewCreated() {
        return isLazyViewCreated;
    }

    @Override
    public void onDestroyView() {
        super.onDestroyView();
        isLazyViewCreated = false;
    }

    /**
     * 用于替代真实Fragment的onCreateView，在真正获取到用户焦点后才会调用
     *
     * @param inflater           - The LayoutInflater object that can be used to inflate any views in the fragment,
     * @param container          - If non-null, this is the parent view that the fragment's UI should be attached to. The fragment should not add the view itself, but this can be used to generate the LayoutParams of the view.
     * @param savedInstanceState - If non-null, this fragment is being re-constructed from a previous saved state as given here.
     * @return Return the View for the fragment's UI, or null.
     */
    protected abstract View onLazyCreateView(LayoutInflater inflater, ViewGroup container, @Nullable Bundle savedInstanceState);

    /**
     * 用来代替真实Fragment的onViewCreated，在真正获得用户焦点并且{@link #onLazyViewCreated(View, Bundle)}
     *
     * @param view               - The View returned by onCreateView(LayoutInflater, ViewGroup, Bundle).
     * @param savedInstanceState - If non-null, this fragment is being re-constructed from a previous saved state as given here.
     */
    protected abstract void onLazyViewCreated(View view, @Nullable Bundle savedInstanceState);

}

/**
 * 使用代理方式实现的懒加载Fragment基类
 */
public class ProxyFakeFragment extends Fragment {
    private static final String REAL_FRAGMENT_NAME = "realFragmentName";

    private String realFragmentName;

    private Fragment realFragment;

    private LayoutInflater inflater;
    private boolean isRealFragmentAdded = false;
    private boolean isCurrentVisiable = false;


    public ProxyFakeFragment() {
        // Required empty public constructor
    }

    /**
     * Use this factory method to create a new instance of
     * this fragment using the provided parameters.
     *
     * @param realFragmentName 需要替换的真实fragment.
     * @return A new instance of fragment FakeFragment.
     */
    @SuppressWarnings("unused")
    public static ProxyFakeFragment newInstance(String realFragmentName) {
        ProxyFakeFragment fragment = new ProxyFakeFragment();
        Bundle args = new Bundle();
        args.putString(REAL_FRAGMENT_NAME, realFragmentName);
        fragment.setArguments(args);
        return fragment;
    }

    /**
     * Use this factory method to create a new instance of
     * this fragment using the provided parameters.
     *
     * @param realFragmentName 需要替换的真实fragment.
     * @param bundle           放入真实fragment 需要的bundle
     * @return A new instance of fragment FakeFragment.
     */
    @SuppressWarnings("unused")
    public static ProxyFakeFragment newInstance(String realFragmentName, Bundle bundle) {
        ProxyFakeFragment fragment = new ProxyFakeFragment();
        Bundle args = new Bundle();
        args.putString(REAL_FRAGMENT_NAME, realFragmentName);
        if (bundle != null) {
            args.putAll(bundle);
        }
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (TextUtils.isEmpty(realFragmentName) && getArguments() != null) {
            realFragmentName = getArguments().getString(REAL_FRAGMENT_NAME);
        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        this.inflater = inflater;
        View view = inflater.inflate(R.layout.fragment_fake, container, false);
        setUserVisibleHint(isCurrentVisiable);
        return view;
    }

    @Override
    public void setUserVisibleHint(boolean isVisibleToUser) {
        super.setUserVisibleHint(isVisibleToUser);
        isCurrentVisiable = isVisibleToUser;
        if (TextUtils.isEmpty(realFragmentName) && getArguments() != null) {
            realFragmentName = getArguments().getString(REAL_FRAGMENT_NAME);
        }
        if (!TextUtils.isEmpty(realFragmentName) && isVisibleToUser &&
                !isRealFragmentAdded) {
            getRealFragment();
            if (inflater != null) {
                addRealFragment();
            }
        }
        if (isRealFragmentAdded) {
            realFragment.setUserVisibleHint(isVisibleToUser);
        }
    }

    /**
     * 获取对应的真正的fragment实体
     *
     * @return 真正的fragment实体
     */
    public Fragment getRealFragment() {
        if (TextUtils.isEmpty(realFragmentName) && getArguments() != null) {
            realFragmentName = getArguments().getString(REAL_FRAGMENT_NAME);
        }
        if (!TextUtils.isEmpty(realFragmentName) && realFragment == null) {
            try {
                realFragment = (Fragment) Class.forName(realFragmentName).newInstance();
                realFragment.setArguments(getArguments());
                return realFragment;
            } catch (Exception e) {
                e.printStackTrace();
                return null;
            }
        } else if (realFragment != null) {
            return realFragment;
        } else {
            return null;
        }
    }

    private void addRealFragment() {
        if (realFragment != null) {
            getChildFragmentManager()
                    .beginTransaction()
                    .add(R.id.fake_fragment_container, realFragment)
                    .commit();
            getChildFragmentManager().executePendingTransactions();
            isRealFragmentAdded = true;
        }
    }

    @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        if (TextUtils.isEmpty(realFragmentName) && getArguments() != null) {
            realFragmentName = getArguments().getString(REAL_FRAGMENT_NAME);
        }
    }
}

Bundle bundle = new Bundle();
bundle.putString(OriginFragment.FRAGMENT_MSG, "ProxyLazyFragment");
bundle.putInt(OriginFragment.FRAGMENT_POS, position);
return ProxyFakeFragment.newInstance(OriginFragment.class.getName(), bundle);

public static class MessageEvent { /* Additional fields if needed */ }

@Subscribe(threadMode = ThreadMode.MAIN)  
public void onMessageEvent(MessageEvent event) {/* Do something */};

 @Override
 public void onStart() {
     super.onStart();
     EventBus.getDefault().register(this);
 }

 @Override
 public void onStop() {
     super.onStop();
     EventBus.getDefault().unregister(this);
 }

 EventBus.getDefault().post(new MessageEvent());

<activity
    android:name=".activity.DictSplashActivity"
    android:theme="@style/MyLightTheme.NoActionBar.FullScreen">
    <intent-filter>
        <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.DEFAULT" />
        <category android:name="android.intent.category.LAUNCHER" />
    </intent-filter>
</activity>

<style name="MyLightTheme.NoActionBar.FullScreen" parent="MyLightTheme.NoActionBar">
    <item name="android:windowBackground">@drawable/bg_launcher</item>
    <item name="android:windowFullscreen">true</item>
</style>

<?xml version="1.0" encoding="utf-8"?><!--
  ~ @(#)bg_launcher.xml, 2017-02-06.
  ~
  ~ Copyright 2014 Yodao, Inc. All rights reserved.
  ~ YODAO PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
  -->

<layer-list xmlns:android="http://schemas.android.com/apk/res/android"
    android:opacity="opaque">
    <!-- The background color, preferably the same as your normal theme -->
    <item>
        <shape android:shape="rectangle">
            <solid android:color="@color/background_grey"/>
            <size android:height="640dp" android:width="360dp"/>
        </shape>
    </item>
    <!-- Your product logo - 144dp color version of your app icon -->
    <item>
        <bitmap
            android:gravity="bottom|center"
            android:src="@drawable/splash_bottom" />
    </item>
</layer-list>