CoordinatorLayout-带图片伸缩工具栏

步骤一：

在build.gilde中添加以下代码

dependencies {
    compile fileTree(dir: ‘libs‘, include: [‘*.jar‘])
    compile ‘com.android.support:appcompat-v7:22.2.0‘
    compile ‘com.android.support:design:22.2.0‘
    compile ‘com.android.support:cardview-v7:22.2.0‘
}

步骤二：

布局文件：

<?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"
    android:id="@+id/main_content"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true">

    <!--第一部分：伸缩工具栏-->
    <android.support.design.widget.AppBarLayout
        android:id="@+id/appbar"
        android:layout_width="match_parent"
        android:layout_height="@dimen/detail_backdrop_height"
        android:fitsSystemWindows="true"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

        <android.support.design.widget.CollapsingToolbarLayout
            android:id="@+id/collapsing_toolbar"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:fitsSystemWindows="true"
            app:contentScrim="?attr/colorPrimary"
            app:expandedTitleMarginEnd="64dp"
            app:expandedTitleMarginStart="48dp"
            app:layout_scrollFlags="scroll|exitUntilCollapsed">

            <ImageView
                android:id="@+id/backdrop"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:fitsSystemWindows="true"
                android:scaleType="centerCrop"
                android:src="@drawable/cheese_2"
                app:layout_collapseMode="parallax" />

            <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                app:layout_collapseMode="pin"
                app:popupTheme="@style/ThemeOverlay.AppCompat.Light" />

        </android.support.design.widget.CollapsingToolbarLayout>

    </android.support.design.widget.AppBarLayout>

    <!--第二部分：主要内容，NestedScrollView和ScrollView基本功能一致，只不过NestedScrollView可以兼容新的控件-->
    <android.support.v4.widget.NestedScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical"
            android:paddingTop="24dp">

            <!--卡片布局-->
            <android.support.v7.widget.CardView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_margin="@dimen/card_margin">

                <LinearLayout
                    style="@style/Widget.CardContent"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content">

                    <TextView
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:text="Info"
                        android:textAppearance="@style/TextAppearance.AppCompat.Title" />

                    <TextView
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:text="@string/cheese_ipsum" />

                </LinearLayout>

            </android.support.v7.widget.CardView>

            <android.support.v7.widget.CardView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginBottom="@dimen/card_margin"
                android:layout_marginLeft="@dimen/card_margin"
                android:layout_marginRight="@dimen/card_margin">

                <LinearLayout
                    style="@style/Widget.CardContent"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content">

                    <TextView
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:text="Friends"
                        android:textAppearance="@style/TextAppearance.AppCompat.Title" />

                    <TextView
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:text="@string/cheese_ipsum" />

                </LinearLayout>

            </android.support.v7.widget.CardView>

            <android.support.v7.widget.CardView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginBottom="@dimen/card_margin"
                android:layout_marginLeft="@dimen/card_margin"
                android:layout_marginRight="@dimen/card_margin">

                <LinearLayout
                    style="@style/Widget.CardContent"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content">

                    <TextView
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:text="Related"
                        android:textAppearance="@style/TextAppearance.AppCompat.Title" />

                    <TextView
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:text="@string/cheese_ipsum" />

                </LinearLayout>

            </android.support.v7.widget.CardView>

        </LinearLayout>

    </android.support.v4.widget.NestedScrollView>

    <!--第三部分：漂浮按钮-->
    <android.support.design.widget.FloatingActionButton
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="@dimen/fab_margin"
        android:clickable="true"
        android:src="@drawable/ic_discuss"
        app:layout_anchor="@id/appbar"
        app:layout_anchorGravity="bottom|right|end" />
</android.support.design.widget.CoordinatorLayout>

步骤三：

主页面代码：

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        //给页面设置工具栏
        final Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);

        //设置工具栏标题
        CollapsingToolbarLayout collapsingToolbar = (CollapsingToolbarLayout) findViewById(R.id.collapsing_toolbar);
        collapsingToolbar.setTitle("cheeseName");

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}

小结：

伸缩工具栏的代码结构：

<android.support.design.widget.AppBarLayout
        android:layout_height="192dp"
        android:layout_width="match_parent">
    <android.support.design.widget.CollapsingToolbarLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:layout_scrollFlags="scroll|exitUntilCollapsed">
        <android.support.v7.widget.Toolbar
                android:layout_height="?attr/actionBarSize"
                android:layout_width="match_parent"
                app:layout_collapseMode="pin"/>
        </android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>

节选自android开发博客