NestScrollView中的控件即使设置match_parent属性也不会充满的问题

ScrollView的fillViewPort属性 【NestScrollView中的控件即使设置match_parent属性也不会充满的问题】在ScrollView的源码的onMeasure中,专门针对fillViewPort这个属性做了特殊的处理

protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); if (!mFillViewport) { return; }final int heightMode = MeasureSpec.getMode(heightMeasureSpec); if (heightMode == MeasureSpec.UNSPECIFIED) { return; }if (getChildCount() > 0) { final View child = getChildAt(0); final int widthPadding; final int heightPadding; final int targetSdkVersion = getContext().getApplicationInfo().targetSdkVersion; final FrameLayout.LayoutParams lp = (LayoutParams) child.getLayoutParams(); if (targetSdkVersion >= VERSION_CODES.M) { widthPadding = mPaddingLeft + mPaddingRight + lp.leftMargin + lp.rightMargin; heightPadding = mPaddingTop + mPaddingBottom + lp.topMargin + lp.bottomMargin; } else { widthPadding = mPaddingLeft + mPaddingRight; heightPadding = mPaddingTop + mPaddingBottom; }final int desiredHeight = getMeasuredHeight() - heightPadding; if (child.getMeasuredHeight() < desiredHeight) { final int childWidthMeasureSpec = getChildMeasureSpec( widthMeasureSpec, widthPadding, lp.width); final int childHeightMeasureSpec = MeasureSpec.makeMeasureSpec( desiredHeight, MeasureSpec.EXACTLY); child.measure(childWidthMeasureSpec, childHeightMeasureSpec); } } }

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