自定义view-MaterialDesign自定义behavior

首先看效果图

接下来看我们的布局文件
代码如下

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.mvvm.md.Main2Activity">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/rc_main"
        app:layout_scrollFlags="scroll|enterAlways|snap"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>
    <!--app:layout_behavior="@string/appbar_scrolling_view_behavior"-->

    <android.support.design.widget.FloatingActionButton
        app:layout_anchor="@id/rc_main"
        app:layout_behavior="com.mvvm.md.ABbehavior"
        app:layout_anchorGravity="bottom|right"
        android:layout_width="wrap_content"
        android:layout_margin="30dp"
        android:layout_height="wrap_content"/>
</android.support.design.widget.CoordinatorLayout>

这里我们需要注意以下几点
1. app:layout_behavior=”com.mvvm.md.ABbehavior”是我们自定义的behavior路径
2. 我们的recyclerview要定义如下属性 app:layout_scrollFlags=”scroll|enterAlways|snap”
3. 我们要控制的FloatingActionButton以及RecyclerView要是CoordinatorLayout的子view不能为子view的子view也就是说这两个布局只能是CoordinatorLayout的儿子

接下来是我们在Activity中的调用逻辑
代码如下

final List<String> items = new ArrayList<>();
        for (int i = 0; i < 50; i++) {
            items.add("-----" + i + "-----");
        }
        RecyclerView rc_main = (RecyclerView) findViewById(R.id.rc_main);
        rc_main.setLayoutManager(new LinearLayoutManager(Main2Activity.this, LinearLayoutManager.VERTICAL, false));
        rc_main.setAdapter(new RecyclerView.Adapter() {
            @Override
            public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
                return new MyViewHolder(View.inflate(Main2Activity.this, R.layout.item_vg, null));
            }

            @Override
            public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
                ((TextView) holder.itemView.findViewById(R.id.tv_content)).setText(items.get(position));
            }

            @Override
            public int getItemCount() {
                return items.size();
            }
        });



class MyViewHolder extends RecyclerView.ViewHolder {

        public MyViewHolder(View itemView) {
            super(itemView);
        }
    }

代码很简单只是给recyclerview设置了适配器并没有做别的事情

接下来使我们的自定义的behavior
代码也很简单如下

public class ABbehavior extends FloatingActionButton.Behavior {
    boolean isOut = false;//是否滑出界面
    boolean isAnimEnd = true;//动画是否结束

    public ABbehavior(Context context, AttributeSet attrs) {
        super();
    }

    @Override
    public boolean onStartNestedScroll(CoordinatorLayout coordinatorLayout, FloatingActionButton child, View directTargetChild, View target, int nestedScrollAxes) {
        return nestedScrollAxes == ViewCompat.SCROLL_AXIS_VERTICAL;
    }

    @Override
    public void onNestedScroll(CoordinatorLayout coordinatorLayout, FloatingActionButton child, View target, int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed) {
        Log.e("---------", dyConsumed + "");
        if (dyConsumed > 0) {//手指向上滑动按钮向下滑动
            if (!isOut && isAnimEnd) {
                int dy = child.getMeasuredHeight() + ((CoordinatorLayout.LayoutParams) child.getLayoutParams()).bottomMargin;
                child.animate().translationY(dy)
                        .setListener(new Animator.AnimatorListener() {
                            @Override
                            public void onAnimationStart(Animator animation) {
                                isAnimEnd = false;
                            }

                            @Override
                            public void onAnimationEnd(Animator animation) {
                                isAnimEnd = true;
                            }

                            @Override
                            public void onAnimationCancel(Animator animation) {

                            }

                            @Override
                            public void onAnimationRepeat(Animator animation) {

                            }
                        })
                        .setDuration(500).start();
                isOut = true;
            }
        } else {
            if (isOut && isAnimEnd) {
                child.animate().translationY(0).setListener(new Animator.AnimatorListener() {
                    @Override
                    public void onAnimationStart(Animator animation) {
                        isAnimEnd = false;
                    }

                    @Override
                    public void onAnimationEnd(Animator animation) {
                        isAnimEnd = true;
                    }

                    @Override
                    public void onAnimationCancel(Animator animation) {

                    }

                    @Override
                    public void onAnimationRepeat(Animator animation) {

                    }
                }).setDuration(500).start();
                isOut = false;
            }

        }

        super.onNestedScroll(coordinatorLayout, child, target, dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed);
    }
}