从源码中看到，在创建实例前，会先从一个静态Map中获取缓存，
Constructor<? extends View> constructor = sConstructorMap.get(name);
缓存的是Constructor对象，目的是用于创建实例，这里要注意sConstructorMap是静态的，并且通过Constructor创建的实例，是使用和Constructor对象同一个ClassLoader来创建的，换句话说，在同一个进程中，同一个自定义View对象，是无法用不同ClassLoader加载的，如果想解决这个问题，就不要让系统使用createView()接口创建View，做法就是自定义Factory或Factory2来自行创建View。
继续往下看，如果缓存里没有，则创建View的Class对象clazz，并缓存到sConstructorMap中，
if (constructor == null) {
// Class not found in the cache, see if it's real, and try to add it
clazz = mContext.getClassLoader().loadClass(
prefix != null ? (prefix + name) : name).asSubclass(View.class);
if (mFilter != null && clazz != null) {
boolean allowed = mFilter.onLoadClass(clazz);
if (!allowed) {
failNotAllowed(name, prefix, attrs);
}
}
constructor = clazz.getConstructor(mConstructorSignature);
sConstructorMap.put(name, constructor);
}
然后就是newInstance了，至此这个View便从xml中变成了java对象，我们继续返回到inflate函数中，看看这个View返回之后做了什么，
......
// Temp is the root view that was found in the xml
View temp;
if (TAG_1995.equals(name)) {
temp = new BlinkLayout(mContext, attrs);
} else {
temp = createViewFromTag(root, name, attrs);
}
ViewGroup.LayoutParams params = null;
if (root != null) {
// Create layout params that match root, if supplied
params = root.generateLayoutParams(attrs);
if (!attachToRoot) {
// Set the layout params for temp if we are not
// attaching. (If we are, we use addView, below)
temp.setLayoutParams(params);
}
}
// Inflate all children under temp
rInflate(parser, temp, attrs, true);
// We are supposed to attach all the views we found (int temp)
// to root. Do that now.
if (root != null && attachToRoot) {
root.addView(temp, params);
}
// Decide whether to return the root that was passed in or the
// top view found in xml.
if (root == null || !attachToRoot) {
result = temp;
}
......
return result;
