RecycleView滚动监听

实测可用方法:

mRecyclerView.addOnScrollListener(newRecyclerView.OnScrollListener() {

privateinttotalDy =0;

@Override

publicvoidonScrolled(RecyclerView recyclerView,intdx,intdy) {

totalDy -= dy;

}

});

使用场景: 对RecycleView滚动距离进行监听,动态改变 ActionBar透明度 ,完成渐变标题栏

RecycleView 实现渐变标题栏

具体实现代码:

viewHolder.getRecyclerView().setOnScrollListener(newRecyclerView.OnScrollListener() {

@Override

public voidonScrollStateChanged(RecyclerView recyclerView, intnewState) {

super.onScrollStateChanged(recyclerView,newState);

}

@Override

public voidonScrolled(RecyclerView recyclerView, intdx, intdy) {

/*计算透明度算法说明: if条件,450是规定在高度0-450之间进行变动 alpha不透明时值为255 ,值越小越透增加if else判断,提高稳定性*/

d-= dy;

if(d<450) {

floatscale = (float) (-d) /450;

if(scale >1) {

scale =1;

}

floatalpha = (255* scale);

Log.i("--->>>","onScrolled:dy "+ dy +"---d总距离"+d+"--透明度"+ alpha);

//只是layout背景透明(仿知乎滑动效果)55c1f5 Color.argb((int) alpha, 0xfd, 0x91, 0x5b)

viewHolder.getBarLinearLayout().setBackgroundColor(Color.argb((int) alpha,0x55,0xc1,0xf5));

}else{

Log.i("--->>>","onScrolled:dy距离大于450");

viewHolder.getBarLinearLayout().setBackgroundColor(Color.argb(255,0x55,0xc1,0xf5));

}

}

});