View的inflate过程最耗时，一个包含5个子view的也要耗时30ms左右。

有多少种Context

    Activity.getApplicationContext();   返回进程Context
    Activity.getBaseContext();  返回ContextImpl实例
    View.getContext();  对应Activity，Activity是对ContextImpl的代理

从ActivityTrhead中Application的Context

Context
ActivityTrhead
Context appContext = createBaseContextForActivity(r, activity); ---- ContextImpl

public class ContextWrapper extends Context
protected void attachBaseContext(Context base)
public class ContextThemeWrapper extends ContextWrapper
public class Activity extends ContextThemeWrapper
final void attach(Context context, ActivityThread aThread,) 对 ContextImpl 做了一次代理
mWindow = new PhoneWindow(this, window);
public PhoneWindow(Context context, Window preservedWindow)

getBaseContext() 获取的是 ContextImpl ,而 ViewGroup中获取Context是容器对应的Activity

PhoneWindow 是对 进程级别的Window的代理

如何进程级别复用View

inflate的过程执行对主线程的检测

E/AndroidRuntime: FATAL EXCEPTION: Thread-3
                  Process: com.pitaya.loadjar, PID: 11903
                  android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
                      at android.view.ViewRootImpl.checkThread(ViewRootImpl.java:6891)
                      at android.view.ViewRootImpl.requestLayout(ViewRootImpl.java:1048)
                      at android.view.View.requestLayout(View.java:19781)
                      at android.view.View.requestLayout(View.java:19781)
                      at android.view.View.requestLayout(View.java:19781)
                      at android.view.View.requestLayout(View.java:19781)
                      at android.view.View.requestLayout(View.java:19781)
                      at android.view.ViewGroup.removeAllViews(ViewGroup.java:4857)
                      at android.support.v7.app.AppCompatDelegateImplV9.setContentView(AppCompatDelegateImplV9.java:278)
                      at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:145)
                      at com.pitaya.loadjar.MainActivity$1.run(MainActivity.java:55)
                      at java.lang.Thread.run(Thread.java:761)


    void checkThread() {
        if (mThread != Thread.currentThread()) {
            throw new CalledFromWrongThreadException(
                    "Only the original thread that created a view hierarchy can touch its views.");
        }
    }

已经关联了parent

同一个View被添加两次，存在 『已经有parent了报错』

01-23 07:41:27.736 5167-5184/? D/zxx: 187ms 耗时
01-23 06:18:56.392 15787-16013/com.pitaya.loadjar D/zxx: 0ms 耗时
反射的方式 清除 parent 

/AndroidRuntime: FATAL EXCEPTION: main
                 Process: com.pitaya.loadjar, PID: 2452
                 java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first.
                     at android.view.ViewGroup.addViewInner(ViewGroup.java:4417)
                     at android.view.ViewGroup.addView(ViewGroup.java:4258)
                     at android.view.ViewGroup.addView(ViewGroup.java:4198)
                     at android.view.ViewGroup.addView(ViewGroup.java:4171)
                     at android.support.v7.app.AppCompatDelegateImplV9.setContentView(AppCompatDelegateImplV9.java:279)
                     at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:145)
                     at com.pitaya.loadjar.MainActivity$1$1.run(MainActivity.java:53)
                     at android.os.Handler.handleCallback(Handler.java:751)
                     at android.os.Handler.dispatchMessage(Handler.java:95)
                     at android.os.Looper.loop(Looper.java:154)
                     at android.app.ActivityThread.main(ActivityThread.java:6119)
                     at java.lang.reflect.Method.invoke(Native Method)
                     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
                     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)

已经关联了Context

发射的方式 替换为 ApplicationContext，解决内存泄漏的问题，复用时才重新加入当前ActivityContext。

    private void clearContext(View root) {
        long old = System.currentTimeMillis();
        processInjectContext(getApplicationContext(), root);
        Log.d("zxx", (System.currentTimeMillis() - old) + "ms 耗时 clearContext过程");
    }
    
    private void processInjectContext(Context context, View root) {
        if (!(root instanceof ViewGroup)) {
            injectContext(context, root);
            return;
        }

        if (root instanceof ViewGroup) {
            ViewGroup viewGroupRoot = (ViewGroup) root;
            for (int i = 0; i < viewGroupRoot.getChildCount(); i++) {
                clearContext(viewGroupRoot.getChildAt(i));
            }
            injectContext(context, viewGroupRoot);
        }
    }

    private void injectContext(Context context, View view) {
        try {
            Field mParent = View.class.getDeclaredField("mContext");
            mParent.setAccessible(true);
            mParent.set(view, context);
        } catch (NoSuchFieldException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        }
    }