onAttachedToWindow()在整个Activity生命周期的位置
参考Google上的一张比较详细的Activity生命周期图:
onAttachedToWindow()调用时机
onAttachedToWindow()方法的调用是在ViewRootImpl的performTraversals()方法:
private void performTraversals() {
...//其他代码
host.dispatchAttachedToWindow(mAttachInfo, 0); //final View host = mView; host就是DecorView,
...//其他代码
performMeasure(childWidthMeasureSpec, childHeightMeasureSpec);
...//其他代码
performLayout(lp, mWidth, mHeight);
...//其他代码
performDraw();
...//其他代码
}
1.ViewRootImpl.performTraversals() 调用了DecorView.dispatchAttachedToWindow()
2.DecorView没有重写dispatchAttachedToWindow()方法,所以这里会调用父类ViewGroup的dispatchAttachedToWindow()方法
3.ViewGroup的dispatchAttachedToWindow()方法会调用View.onAttachedToWindow()方法
4.DecorView重写了onAttachedToWindow()方法,所以调用DecorView.onAttachedToWindow()
5.DecorView的onAttachedToWindow()方法会获取其所在Window的Window.Callback,而这个Window.Callback就是Window所在的Activity(Activity实现了Window.Callback接口),所以DecorView.onAttachedToWindow() 会回调Activity的onAttachedToWindow() 方法。
// DecorView.java
@Override
protected void onAttachedToWindow() {
super.onAttachedToWindow();
final Window.Callback cb = mWindow.getCallback();
if (cb != null && !mWindow.isDestroyed() && mFeatureId < 0) {
cb.onAttachedToWindow();
}
...//其他代码
}
参考:
onAttachedToWindow()在整个Activity生命周期的位置及使用
https://www.androidos.net.cn/android/9.0.0_r8/xref/frameworks/base/core/java/android/view/ViewRootImpl.java
https://www.androidos.net.cn/android/9.0.0_r8/xref/frameworks/base/core/java/com/android/internal/policy/DecorView.java