Android Support V7官方Demo概览（三）

2016-05-31

状态：未完成

本文介绍了Support V7中Card View、Drawer layout、GridLayout、Palette、RecyclerView、AsyncListUtil、GridLayoutManager、ItemTouchHelper、LinearLayoutManager、SortedList和RecyclerView配合使用、Staggered Grid Layout Manager等组件的使用。

Card View

演示了CardView的用法。
xml文件

<RelativeLayout android:layout_width="fill_parent"
    android:layout_height="match_parent">
    <android.support.v7.widget.CardView
            android:id="@+id/card_view"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            card_view:cardElevation="10dp"
            android:clickable="true"
            android:layout_margin="8dp">
        <TextView
                android:id="@+id/info_text"
                android:text="@string/card_view"
                android:textColor="@android:color/black"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" />
    </android.support.v7.widget.CardView>
    <TextView android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:text="@string/card_view_sample_text"
              android:textColor="@android:color/black"
              android:layout_toRightOf="@id/card_view"
              android:layout_alignTop="@id/card_view"/>
</RelativeLayout>

Drawer layout

这个例子说明了一个Android support library中基于Material design准则的drawer组件的DrawerLayout控件结合Toolbar的常见用法。

DrawerLayout应该放在view层级的顶层，把它放在action bar的下面content views的上面。主内容大小都应该match_parent。每个drawer应该定义合理的宽度和match_parent的高度。在你的布局中Drawer views应该放在content view的后面为了保持合适顺序。

当一个navigation (left) drawer呈现时，主activity应该检测action bar的向上功能的按下作为一个打开和关闭navigation drawer的信号。drawer中的Items应该放到其中一个类别。

View switches（开关）。一个View switch依据同样基本的策略作为一个list或tab导航，view switch不会创建导航历史。这个模式应该只用于一个task的根activity，对于进入到更深导航层级的Activity留下一些向上导航的形式。
Selective Up。drawer允许用户选择一个交替parent对于向上导航。这允许用户随意跳到跨应用程序的导航层级。
使用TaskStackBuilder替换当前任务

右面的drawers应该用于actions，而不是导航。这个依据Action Bar建立的模型导航应该在左边actions在右边。action应该操作执行窗口的当前内容，例如使能或禁止当前内容顶部的数据覆盖。

当drawer是打开的，它是在应用的toolbar之上。在Android 5.0及以上版本drawer扩展为全屏的高度，包括后面的系统状态条。

先来看下布局文件：

<!--
    A DrawerLayout is indended to be used as the top-level content view
    using match_parent for both width and height to consume the full space available.
    See https://www.google.com/design/spec/patterns/navigation-drawer.html#navigation-drawer-specs
    for the full spec of a drawer in Material design.
-->
<android.support.v4.widget.DrawerLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true">
    <!-- As the main content view, the view below consumes the entire
         space available using match_parent in both dimensions. Note that
         this child does not specify android:layout_gravity attribute. -->
    <LinearLayout
        android:id="@+id/content"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">
        <!-- This will be set as the support action bar of the activity at runtime.
             It needs to be a dynamic runtime call for correct vertical layering of
             the drawer and the toolbar. -->
        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize" />

        <ScrollView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:scrollbarStyle="outsideOverlay">
            <TextView
                android:id="@+id/content_text"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:text="@string/drawer_layout_summary"
                android:textAppearance="?android:attr/textAppearanceMedium"
                android:padding="16dp"/>
        </ScrollView>
    </LinearLayout>

    <!-- android:layout_gravity="start" tells DrawerLayout to treat
         this as a sliding drawer on the starting side, which is
         left for left-to-right locales. The drawer is given arbitrary
         initial width and extends the full height of the container. A
         solid background is used for contrast with the content view.
         android:fitsSystemWindows="true" tells the system to have
         DrawerLayout span the full height of the screen, including the
         system status bar on Lollipop+ versions of the plaform. The actual
         width of drawer will be determined at runtime based on the screen
         size according to the Material spec. -->
    <ListView
            android:id="@+id/start_drawer"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:layout_gravity="start"
            android:background="#333333"
            android:fitsSystemWindows="true"/>

    <!-- android:layout_gravity="end" tells DrawerLayout to treat
         this as a sliding drawer on the ending side, which is
         right for left-to-right locales. The drawer is given arbitrary
         initial width and extends the full height of the container. A
         solid background is used for contrast with the content view.
         The actual width of drawer will be determined at runtime based on
         the screen size according to the Material spec. -->
    <FrameLayout
            android:id="@+id/end_drawer"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:layout_gravity="end"
            android:background="#808080"/>
</android.support.v4.widget.DrawerLayout>

可以看到示例使用DrawerLayout作为内容的父布局，宽高都为match_parent，第一个子布局LinearLayout作为内容布局，宽高也高match_parent，其中包含一个Toolbar和一个ScrollView；紧随其后的控件是一个ListView作侧滑抽屉，注意layout_gravity属性为“start”，这个属性会告诉DrawerLayout这是一个开始位置的侧滑抽屉，android:fitsSystemWindows=”true”属性告诉系统伸展为屏幕的高度，在5.0+的系统上包含状态栏。它的实际宽度根据Material规范在运行时基于屏幕大小决定。最后的FrameLayout则是从右滑出的抽屉。

GridLayout Simple Form

演示了使用GridLayout构建简单的表格。

<android.support.v7.widget.GridLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@drawable/blue"
    android:padding="10dip"
    app:columnCount="4"
    >
    <TextView
        android:text="@string/grid_layout_1_instructions"
    />
    <EditText
        app:layout_gravity="fill_horizontal"
        app:layout_column="0"
        app:layout_columnSpan="4"
    />
    <Button
        android:text="@string/grid_layout_1_cancel"
        app:layout_column="2"
    />
    <Button
        android:text="@string/grid_layout_1_ok"
        android:layout_marginLeft="10dip"
    />
</android.support.v7.widget.GridLayout>

GridLayout Form(XML)

一个表格，说明了GridLayout API从XML的使用。

<android.support.v7.widget.GridLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:useDefaultMargins="true"
    app:alignmentMode="alignBounds"
    app:columnOrderPreserved="false"
    app:columnCount="4"
    >
    <TextView
        android:text="Email setup"
        android:textSize="32dip"
        app:layout_columnSpan="4"
        app:layout_gravity="center_horizontal"
    />
    <TextView
        android:text="You can configure email in a few simple steps:"
        android:textSize="16dip"
        app:layout_columnSpan="4"
        app:layout_gravity="left"
    />
    <TextView
        android:text="Email address:"
        app:layout_gravity="right"
    />
    <EditText
        android:ems="10"
    />
    <TextView
        android:text="Password:"
        app:layout_column="0"
        app:layout_gravity="right"
    />
    <EditText
        android:ems="8"
    />
    <Button
        android:text="Manual setup"
        app:layout_row="5"
        app:layout_column="3"
    />
    <Button
        android:text="Next"
        app:layout_column="3"
        app:layout_gravity="fill_horizontal"
    />
</android.support.v7.widget.GridLayout>

GridLayout Form(Java)

一个表格，说明GridLayout API的使用。我们演示了行/列保持顺序属性的使用，当需要的时候允许行或列越过其它的元素。
右下角的两个按钮需要和其它UI元素分离。这个可以通过分离行或分离列完成——但我们不需要都做并且可能只有足够的空间去做一个或其它的。

public static View create(Context context) {
    GridLayout p = new GridLayout(context);
    p.setUseDefaultMargins(true);
    p.setAlignmentMode(ALIGN_BOUNDS);
    Configuration configuration = context.getResources().getConfiguration();
    if ((configuration.orientation == Configuration.ORIENTATION_PORTRAIT)) {
        p.setColumnOrderPreserved(false);
    } else {
        p.setRowOrderPreserved(false);
    }

    Spec titleRow              = spec(0);
    Spec introRow              = spec(1);
    Spec emailRow              = spec(2, BASELINE);
    Spec passwordRow           = spec(3, BASELINE);
    Spec button1Row            = spec(5);
    Spec button2Row            = spec(6);

    Spec centerInAllColumns    = spec(0, 4, CENTER);
    Spec leftAlignInAllColumns = spec(0, 4, LEFT);
    Spec labelColumn           = spec(0, RIGHT);
    Spec fieldColumn           = spec(1, LEFT);
    Spec defineLastColumn      = spec(3);
    Spec fillLastColumn        = spec(3, FILL);

    {
        TextView c = new TextView(context);
        c.setTextSize(32);
        c.setText("Email setup");
        p.addView(c, new LayoutParams(titleRow, centerInAllColumns));
    }
    {
        TextView c = new TextView(context);
        c.setTextSize(16);
        c.setText("You can configure email in a few simple steps:");
        p.addView(c, new LayoutParams(introRow, leftAlignInAllColumns));
    }
    {
        TextView c = new TextView(context);
        c.setText("Email address:");
        p.addView(c, new LayoutParams(emailRow, labelColumn));
    }
    {
        EditText c = new EditText(context);
        c.setEms(10);
        c.setInputType(TYPE_CLASS_TEXT | TYPE_TEXT_VARIATION_EMAIL_ADDRESS);
        p.addView(c, new LayoutParams(emailRow, fieldColumn));
    }
    {
        TextView c = new TextView(context);
        c.setText("Password:");
        p.addView(c, new LayoutParams(passwordRow, labelColumn));
    }
    {
        EditText c = new EditText(context);
        c.setEms(8);
        c.setInputType(TYPE_CLASS_TEXT | TYPE_TEXT_VARIATION_PASSWORD);
        p.addView(c, new LayoutParams(passwordRow, fieldColumn));
    }
    {
        Button c = new Button(context);
        c.setText("Manual setup");
        p.addView(c, new LayoutParams(button1Row, defineLastColumn));
    }
    {
        Button c = new Button(context);
        c.setText("Next");
        p.addView(c, new LayoutParams(button2Row, fillLastColumn));
    }

    return p;
}

Palette

从设备MediaStore显示图片，在旁边生成android.support.v7.graphics.Palette的结果。
允许使用palette生成自定义颜色的数量，可以产生不同类型的图片。
最常用的六种颜色：

palette.getVibrantSwatch()
palette.getMutedSwatch()
palette.getLightVibrantSwatch()
palette.getLightMutedSwatch()
palette.getDarkVibrantSwatch()
palette.getDarkMutedSwatch()

AnimatedRecyclerView

演示了带有动画的RecyclerView的常见用法。

AsyncListUtil

一个说明了AsyncListUtil功能的例子。使用了RecyclerView来展示数据。

private static class TextViewHolder extends RecyclerView.ViewHolder {
    TextView textView;
    public TextViewHolder(Context context) {
        super(new TextView(context));
        textView = (TextView) itemView;
    }
}

private class AsyncAdapter extends RecyclerView.Adapter<TextViewHolder> {

    private AsyncListUtil<String> mAsyncListUtil;

    AsyncAdapter() {
        mAsyncListUtil = new AsyncStringListUtil();
    }

    @Override
    public TextViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        return new TextViewHolder(parent.getContext());
    }

    @Override
    public void onBindViewHolder(TextViewHolder holder, int position) {
        final String itemString = mAsyncListUtil.getItem(position);
        if (itemString == null) {
            holder.textView.setText("loading...");
        } else {
            holder.textView.setText(itemString);
        }
    }

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

private class AsyncStringListUtil extends AsyncListUtil<String> {

    private static final int TILE_SIZE = 5;

    private static final long DELAY_MS = 500;

    public AsyncStringListUtil() {
        super(String.class, TILE_SIZE,
                new AsyncListUtil.DataCallback<String>() {
                    @Override
                    public int refreshData() {
                        return Cheeses.sCheeseStrings.length;
                    }

                    @Override
                    public void fillData(String[] data, int startPosition, int itemCount) {
                        sleep();
                        for (int i = 0; i < itemCount; i++) {
                            data[i] = Cheeses.sCheeseStrings[startPosition + i];
                        }
                    }

                    private void sleep() {
                        try {
                            Thread.sleep(DELAY_MS);
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    }
                },
                new AsyncListUtil.ViewCallback() {
                    @Override
                    public void getItemRangeInto(int[] outRange) {
                        outRange[0] = mLinearLayoutManager.findFirstVisibleItemPosition();
                        outRange[1] = mLinearLayoutManager.findLastVisibleItemPosition();
                    }

                    @Override
                    public void onDataRefresh() {
                        mRecyclerView.getAdapter().notifyDataSetChanged();
                    }

                    @Override
                    public void onItemLoaded(int position) {
                        mRecyclerView.getAdapter().notifyItemChanged(position);
                    }
                });

        mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
            @Override
            public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
                onRangeChanged();
            }
        });
    }
}

Grid Layout Manager

一个说明了GridLayoutManager功能的例子。

Item TouchHelper —— Drag and Drop Activity

演示了ItemTouchHelper实现拖拽的例子。可以设置向上或向下拖拽，长按拖拽或指定控件拖拽。

Item TouchHelper —— Swipe To Dismiss

演示了ItemTouchHelper实现滑动消失的例子。可以设置左滑、右滑，指定控件滑动及自定义滑动效果。

Linear Layout Manager

使用LinearLayoutManager的例子。

RecyclerViewActivity

RecyclerView的创建：

final RecyclerView rv = new RecyclerView(this);
rv.setLayoutManager(new MyLayoutManager(this));
rv.setHasFixedSize(true);
rv.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
        ViewGroup.LayoutParams.MATCH_PARENT));
rv.setAdapter(new SimpleStringAdapter(this, Cheeses.sCheeseStrings) {
    @Override
    public SimpleStringAdapter.ViewHolder onCreateViewHolder(ViewGroup parent,
            int viewType) {
        final SimpleStringAdapter.ViewHolder vh = super
                .onCreateViewHolder(parent, viewType);
        vh.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                final int pos = vh.getAdapterPosition();
                if (pos == RecyclerView.NO_POSITION) {
                    return;
                }
                if (pos + 1 < getItemCount()) {
                    swap(pos, pos + 1);
                }
            }
        });
        return vh;
    }
});
rv.addItemDecoration(new DividerItemDecoration(this, DividerItemDecoration.VERTICAL_LIST));
setContentView(rv);

基本的ListView样式的布局管理器：

class MyLayoutManager extends RecyclerView.LayoutManager {

    private static final String TAG = "MyLayoutManager";

    private int mFirstPosition;

    private final int mScrollDistance;

    public MyLayoutManager(Context c) {
        final DisplayMetrics dm = c.getResources().getDisplayMetrics();
        mScrollDistance = (int) (SCROLL_DISTANCE * dm.density + 0.5f);
    }

    @Override
    public void onLayoutChildren(RecyclerView.Recycler recycler, RecyclerView.State state) {
        final int parentBottom = getHeight() - getPaddingBottom();
        final View oldTopView = getChildCount() > 0 ? getChildAt(0) : null;
        int oldTop = getPaddingTop();
        if (oldTopView != null) {
            oldTop = oldTopView.getTop();
        }

        detachAndScrapAttachedViews(recycler);

        int top = oldTop;
        int bottom;
        final int left = getPaddingLeft();
        final int right = getWidth() - getPaddingRight();

        final int count = state.getItemCount();
        for (int i = 0; mFirstPosition + i < count && top < parentBottom; i++, top = bottom) {
            View v = recycler.getViewForPosition(mFirstPosition + i);
            addView(v, i);
            measureChildWithMargins(v, 0, 0);
            bottom = top + getDecoratedMeasuredHeight(v);
            layoutDecorated(v, left, top, right, bottom);
        }
    }

    @Override
    public RecyclerView.LayoutParams generateDefaultLayoutParams() {
        return new RecyclerView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
                ViewGroup.LayoutParams.WRAP_CONTENT);
    }

    @Override
    public boolean canScrollVertically() {
        return true;
    }

    @Override
    public int scrollVerticallyBy(int dy, RecyclerView.Recycler recycler,
            RecyclerView.State state) {
        if (getChildCount() == 0) {
            return 0;
        }

        int scrolled = 0;
        final int left = getPaddingLeft();
        final int right = getWidth() - getPaddingRight();
        if (dy < 0) {
            while (scrolled > dy) {
                final View topView = getChildAt(0);
                final int hangingTop = Math.max(-getDecoratedTop(topView), 0);
                final int scrollBy = Math.min(scrolled - dy, hangingTop);
                scrolled -= scrollBy;
                offsetChildrenVertical(scrollBy);
                if (mFirstPosition > 0 && scrolled > dy) {
                    mFirstPosition--;
                    View v = recycler.getViewForPosition(mFirstPosition);
                    addView(v, 0);
                    measureChildWithMargins(v, 0, 0);
                    final int bottom = getDecoratedTop(topView);
                    final int top = bottom - getDecoratedMeasuredHeight(v);
                    layoutDecorated(v, left, top, right, bottom);
                } else {
                    break;
                }
            }
        } else if (dy > 0) {
            final int parentHeight = getHeight();
            while (scrolled < dy) {
                final View bottomView = getChildAt(getChildCount() - 1);
                final int hangingBottom =
                        Math.max(getDecoratedBottom(bottomView) - parentHeight, 0);
                final int scrollBy = -Math.min(dy - scrolled, hangingBottom);
                scrolled -= scrollBy;
                offsetChildrenVertical(scrollBy);
                if (scrolled < dy && state.getItemCount() > mFirstPosition + getChildCount()) {
                    View v = recycler.getViewForPosition(mFirstPosition + getChildCount());
                    final int top = getDecoratedBottom(getChildAt(getChildCount() - 1));
                    addView(v);
                    measureChildWithMargins(v, 0, 0);
                    final int bottom = top + getDecoratedMeasuredHeight(v);
                    layoutDecorated(v, left, top, right, bottom);
                } else {
                    break;
                }
            }
        }
        recycleViewsOutOfBounds(recycler);
        return scrolled;
    }

    @Override
    public View onFocusSearchFailed(View focused, int direction,
            RecyclerView.Recycler recycler, RecyclerView.State state) {
        final int oldCount = getChildCount();

        if (oldCount == 0) {
            return null;
        }

        final int left = getPaddingLeft();
        final int right = getWidth() - getPaddingRight();

        View toFocus = null;
        int newViewsHeight = 0;
        if (direction == View.FOCUS_UP || direction == View.FOCUS_BACKWARD) {
            while (mFirstPosition > 0 && newViewsHeight < mScrollDistance) {
                mFirstPosition--;
                View v = recycler.getViewForPosition(mFirstPosition);
                final int bottom = getDecoratedTop(getChildAt(0));
                addView(v, 0);
                measureChildWithMargins(v, 0, 0);
                final int top = bottom - getDecoratedMeasuredHeight(v);
                layoutDecorated(v, left, top, right, bottom);
                if (v.isFocusable()) {
                    toFocus = v;
                    break;
                }
            }
        }
        if (direction == View.FOCUS_DOWN || direction == View.FOCUS_FORWARD) {
            while (mFirstPosition + getChildCount() < state.getItemCount() &&
                    newViewsHeight < mScrollDistance) {
                View v = recycler.getViewForPosition(mFirstPosition + getChildCount());
                final int top = getDecoratedBottom(getChildAt(getChildCount() - 1));
                addView(v);
                measureChildWithMargins(v, 0, 0);
                final int bottom = top + getDecoratedMeasuredHeight(v);
                layoutDecorated(v, left, top, right, bottom);
                if (v.isFocusable()) {
                    toFocus = v;
                    break;
                }
            }
        }

        return toFocus;
    }

    public void recycleViewsOutOfBounds(RecyclerView.Recycler recycler) {
        final int childCount = getChildCount();
        final int parentWidth = getWidth();
        final int parentHeight = getHeight();
        boolean foundFirst = false;
        int first = 0;
        int last = 0;
        for (int i = 0; i < childCount; i++) {
            final View v = getChildAt(i);
            if (v.hasFocus() || (getDecoratedRight(v) >= 0 &&
                    getDecoratedLeft(v) <= parentWidth &&
                    getDecoratedBottom(v) >= 0 &&
                    getDecoratedTop(v) <= parentHeight)) {
                if (!foundFirst) {
                    first = i;
                    foundFirst = true;
                }
                last = i;
            }
        }
        for (int i = childCount - 1; i > last; i--) {
            removeAndRecycleViewAt(i, recycler);
        }
        for (int i = first - 1; i >= 0; i--) {
            removeAndRecycleViewAt(i, recycler);
        }
        if (getChildCount() == 0) {
            mFirstPosition = 0;
        } else {
            mFirstPosition += first;
        }
    }
}

Sorted List

演示了SortedList和RecyclerView结合使用。

private static class SortedListAdapter extends RecyclerView.Adapter<TodoViewHolder> {
    SortedList<Item> mData;
    final LayoutInflater mLayoutInflater;
    public SortedListAdapter(LayoutInflater layoutInflater, Item... items) {
        mLayoutInflater = layoutInflater;
        mData = new SortedList<Item>(Item.class, new SortedListAdapterCallback<Item>(this) {
            @Override
            public int compare(Item t0, Item t1) {
                if (t0.mIsDone != t1.mIsDone) {
                    return t0.mIsDone ? 1 : -1;
                }
                int txtComp = t0.mText.compareTo(t1.mText);
                if (txtComp != 0) {
                    return txtComp;
                }
                if (t0.id < t1.id) {
                    return -1;
                } else if (t0.id > t1.id) {
                    return 1;
                }
                return 0;
            }

            @Override
            public boolean areContentsTheSame(Item oldItem,
                    Item newItem) {
                return oldItem.mText.equals(newItem.mText);
            }

            @Override
            public boolean areItemsTheSame(Item item1, Item item2) {
                return item1.id == item2.id;
            }
        });
        for (Item item : items) {
            mData.add(item);
        }
    }

    public void addItem(Item item) {
        mData.add(item);
    }

    @Override
    public TodoViewHolder onCreateViewHolder(final ViewGroup parent, int viewType) {
        return new TodoViewHolder (
                mLayoutInflater.inflate(R.layout.sorted_list_item_view, parent, false)) {
            @Override
            void onDoneChanged(boolean isDone) {
                int adapterPosition = getAdapterPosition();
                if (adapterPosition == RecyclerView.NO_POSITION) {
                    return;
                }
                mBoundItem.mIsDone = isDone;
                mData.recalculatePositionOfItemAt(adapterPosition);
            }
        };
    }

    @Override
    public void onBindViewHolder(TodoViewHolder holder, int position) {
        holder.bindTo(mData.get(position));
    }

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

abstract private static class TodoViewHolder extends RecyclerView.ViewHolder {
    final CheckBox mCheckBox;
    Item mBoundItem;
    public TodoViewHolder(View itemView) {
        super(itemView);
        mCheckBox = (CheckBox) itemView;
        mCheckBox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                if (mBoundItem != null && isChecked != mBoundItem.mIsDone) {
                    onDoneChanged(isChecked);
                }
            }
        });
    }

    public void bindTo(Item item) {
        mBoundItem = item;
        mCheckBox.setText(item.mText);
        mCheckBox.setChecked(item.mIsDone);
    }

    abstract void onDoneChanged(boolean isChecked);
}

private static class Item {
    String mText;
    boolean mIsDone = false;
    final public int id;
    private static int idCounter = 0;

    public Item(String text) {
        id = idCounter ++;
        this.mText = text;
    }
}

Staggered Grid Layout Manager

从Android SDK目录可找到源码，或从这里下载