Android实现炫酷的视觉差效果

<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=".MainActivity">
    <android.support.design.widget.AppBarLayout        android:id="@+id/appbar"        android:layout_width="match_parent"        android:layout_height="wrap_content">        <android.support.design.widget.CollapsingToolbarLayout            android:layout_width="match_parent"            app:contentScrim="@color/colorPrimary"            app:expandedTitleMarginStart="15dp"            app:collapsedTitleTextAppearance="@style/ToolbarTextStyle" //设置收缩时的标题样式            app:expandedTitleTextAppearance="@style/CollapseexpandedTextStyle" //设置展开时的标题样式            app:layout_scrollFlags="scroll|exitUntilCollapsed" //这个属性使得CollapsingToolbarLayout在滑动的时候显示隐藏            android:layout_height="wrap_content">            <ImageView                android:layout_width="match_parent"                android:src="@mipmap/bg"                android:scaleType="fitXY"                app:layout_collapseMode="parallax" //这个属性使得ImageView在CollapsingToolbarLayout展开的时候显示                android:layout_height="200dp" />            <android.support.v7.widget.Toolbar                android:layout_width="match_parent"                android:id="@+id/toolbar"                app:layout_collapseMode="pin" //这个属性使得Toolbar在CollapsingToolbarLayout收缩的时候显示                android:layout_height="50dp">            android.support.v7.widget.Toolbar>        android.support.design.widget.CollapsingToolbarLayout>    android.support.design.widget.AppBarLayout>    <android.support.v7.widget.RecyclerView        android:layout_width="match_parent"        android:id="@+id/recycle"        app:layout_behavior="@string/appbar_scrolling_view_behavior" //这个属性是让控件在AppBarLayout下边        android:layout_height="match_parent">
    android.support.v7.widget.RecyclerView>    <android.support.design.widget.FloatingActionButton        android:layout_width="wrap_content"        android:src="@drawable/ic_logo"        app:layout_anchor="@id/appbar" //这个属性是让FloatingActionButton以AppBarLayout为锚点，同时这也是使FloatingActionButton实现显示隐藏的关键        app:layout_anchorGravity="bottom|end" //在AppBarLayout的右下方        app:borderWidth="0dp"        app:rippleColor="#E23B74"        app:elevation="6dp"        app:pressedTranslationZ="12dp"        android:clickable="true"        android:layout_marginRight="10dp"        android:layout_height="wrap_content" />android.support.design.widget.CoordinatorLayout>

public class MainActivity extends AppCompatActivity {    Toolbar toolbar;    RecyclerView recyclerView;    AppBarLayout appBarLayout;    private BaseQuickAdapter baseQuickAdapter;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        toolbar=findViewById(R.id.toolbar);        appBarLayout=findViewById(R.id.appbar);        toolbar.setTitle("我是标题");        setSupportActionBar(toolbar);//        设置条目（可以省略）========================        recyclerView=findViewById(R.id.recycle);        recyclerView.setLayoutManager(new LinearLayoutManager(this));        final ArrayList strings = new ArrayList<>();        for(int x=0;x<10;x++){            strings.add("我是条目"+x);        }        baseQuickAdapter = new BaseQuickAdapter(R.layout.item, strings) {            @Override            protected void convert(BaseViewHolder helper, String item) {                helper.setText(R.id.tv_title, item);            }        };        baseQuickAdapter.openLoadAnimation(BaseQuickAdapter.SLIDEIN_LEFT);        baseQuickAdapter.setOnItemChildClickListener(new BaseQuickAdapter.OnItemChildClickListener() {            @Override            public void onItemChildClick(BaseQuickAdapter adapter, View view, int position) {
            }        });        recyclerView.setAdapter(baseQuickAdapter);//        ==================================================        appBarLayout.addOnOffsetChangedListener(new AppBarStateChangeListener() {            @Override            public void onStateChanged(AppBarLayout appBarLayout, State state) {                if( state == State.EXPANDED ) {                    //展开状态                    toolbar.setNavigationIcon(R.drawable.ic_backfour);                }else if(state == State.COLLAPSED){                    //折叠状态                    toolbar.setNavigationIcon(R.drawable.ic_back);                }else {                    //中间状态                    toolbar.setNavigationIcon(R.drawable.ic_back);                }            }        });
    }    private abstract static class AppBarStateChangeListener implements AppBarLayout.OnOffsetChangedListener {        public enum State {            EXPANDED,            COLLAPSED,            IDLE        }
        private State mCurrentState = State.IDLE;        @Override        public final void onOffsetChanged(AppBarLayout appBarLayout, int i) {            if (i == 0) {                if (mCurrentState != State.EXPANDED) {                    onStateChanged(appBarLayout, State.EXPANDED);                }                mCurrentState = State.EXPANDED;            } else if (Math.abs(i) >= appBarLayout.getTotalScrollRange()) {                if (mCurrentState != State.COLLAPSED) {                    onStateChanged(appBarLayout, State.COLLAPSED);                }                mCurrentState = State.COLLAPSED;            } else {                if (mCurrentState != State.IDLE) {                    onStateChanged(appBarLayout, State.IDLE);                }                mCurrentState = State.IDLE;            }        }        public abstract void onStateChanged(AppBarLayout appBarLayout, State state);    }  }