Androdアプリ開発におけるネストスクロール問題と向き合うの説明用途

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1. AndroidView時代のコードと比較 NestedWebViewの実装(簡略化する) class NestedWebView (...) : WebView, NestedScrollingChild { private val mChildHelper = NestedScrollingChildHelper(this) override fun onTouchEvent(...): Boolean {...} override fun setNestedScrollingEnabled(...) {...} override fun isNestedScrollingEnabled(...): Boolean {...} override fun startNestedScroll(...): Boolean {...} override fun stopNestedScroll(...) {...} override fun hasNestedScrollingParent(...): Boolean {...} override fun dispatchNestedScroll(...): Boolean {...} override fun dispatchNestedPreScroll(...): Boolean {...} override fun dispatchNestedFling(...): Boolean {... override fun dispatchNestedPreFling(...): Boolean {...} }
2. AndroidView時代のコードと比較 NestedScrollingChildを実装する class NestedWebView (...) : WebView, NestedScrollingChild { private val mChildHelper = NestedScrollingChildHelper(this) override fun onTouchEvent(...): Boolean {...} override fun setNestedScrollingEnabled(...) {...} override fun isNestedScrollingEnabled(...): Boolean {...} override fun startNestedScroll(...): Boolean {...} override fun stopNestedScroll(...) {...} override fun hasNestedScrollingParent(...): Boolean {...} override fun dispatchNestedScroll(...): Boolean {...} override fun dispatchNestedPreScroll(...): Boolean {...} override fun dispatchNestedFling(...): Boolean {... override fun dispatchNestedPreFling(...): Boolean {...} }
3. AndroidView時代のコードと比較 NestedScrollingChildHelperを介してイベントを送る class NestedWebView (...) : WebView, NestedScrollingChild { private val mChildHelper = NestedScrollingChildHelper(this) override fun onTouchEvent(...): Boolean {...} override fun setNestedScrollingEnabled(...) {...} override fun isNestedScrollingEnabled(...): Boolean {...} override fun startNestedScroll(...): Boolean {...} override fun stopNestedScroll(...) {...} override fun hasNestedScrollingParent(...): Boolean {...} override fun dispatchNestedScroll(...): Boolean {...} override fun dispatchNestedPreScroll(...): Boolean {...} override fun dispatchNestedFling(...): Boolean {... override fun dispatchNestedPreFling(...): Boolean {...} }
4. AndroidView時代のコードと比較 ACTION_DOWNでネストスクロールを開始する class NestedWebView (...) : WebView, NestedScrollingChild { private val mChildHelper = NestedScrollingChildHelper(this) override fun onTouchEvent(...): Boolean {...} override fun setNestedScrollingEnabled(...) {...} override fun isNestedScrollingEnabled(...): Boolean {...} override fun startNestedScroll(...): Boolean {...} override fun stopNestedScroll(...) {...} override fun hasNestedScrollingParent(...): Boolean {...} override fun dispatchNestedScroll(...): Boolean {...} override fun dispatchNestedPreScroll(...): Boolean {...} override fun dispatchNestedFling(...): Boolean {... override fun dispatchNestedPreFling(...): Boolean {...} }
5. AndroidView時代のコードと比較 ネストスクロールを有効化 / 確認 class NestedWebView (...) : WebView, NestedScrollingChild { private val mChildHelper = NestedScrollingChildHelper(this) override fun onTouchEvent(...): Boolean {...} override fun setNestedScrollingEnabled(...) {...} override fun isNestedScrollingEnabled(...): Boolean {...} override fun startNestedScroll(...): Boolean {...} override fun stopNestedScroll(...) {...} override fun hasNestedScrollingParent(...): Boolean {...} override fun dispatchNestedScroll(...): Boolean {...} override fun dispatchNestedPreScroll(...): Boolean {...} override fun dispatchNestedFling(...): Boolean {... override fun dispatchNestedPreFling(...): Boolean {...} }
6. AndroidView時代のコードと比較 NestedScrollConnectionと同様にスクロール量を送る class NestedWebView (...) : WebView, NestedScrollingChild { private val mChildHelper = NestedScrollingChildHelper(this) override fun onTouchEvent(...): Boolean {...} override fun setNestedScrollingEnabled(...) {...} override fun isNestedScrollingEnabled(...): Boolean {...} override fun startNestedScroll(...): Boolean {...} override fun stopNestedScroll(...) {...} override fun hasNestedScrollingParent(...): Boolean {...} override fun dispatchNestedScroll(...): Boolean {...} override fun dispatchNestedPreScroll(...): Boolean {...} override fun dispatchNestedFling(...): Boolean {... override fun dispatchNestedPreFling(...): Boolean {...} }
7. AndroidView時代のコードと比較 ACTION_UP / ACTION_CANCELでスクロールを終了する class NestedWebView (...) : WebView, NestedScrollingChild { private val mChildHelper = NestedScrollingChildHelper(this) override fun onTouchEvent(...): Boolean {...} override fun setNestedScrollingEnabled(...) {...} override fun isNestedScrollingEnabled(...): Boolean {...} override fun startNestedScroll(...): Boolean {...} override fun stopNestedScroll(...) {...} override fun hasNestedScrollingParent(...): Boolean {...} override fun dispatchNestedScroll(...): Boolean {...} override fun dispatchNestedPreScroll(...): Boolean {...} override fun dispatchNestedFling(...): Boolean {... override fun dispatchNestedPreFling(...): Boolean {...} }