【Android】第5章（8）图片库（Galery）-php手册-php.cn

【Android】第5章（8）图片库（Galery）

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Release： 2016-07-06 13:30:52

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分类：C#、Android、VS2015；创建日期：2016-02-07 一、简介图库（也叫画廊）是一个布局小部件，用于在可水平滚动的列表中显示每一副图片，当前所选的图片将置于视图的中心。注意：Android已经弃用了这个小部件，弃用的原因是用Galery实现的效率比较低，

分类：C#、Android、VS2015；

创建日期：2016-02-07

一、简介

图库（也叫画廊）是一个布局小部件，用于在可水平滚动的列表中显示每一副图片，当前所选的图片将置于视图的中心。

注意：Android已经弃用了这个小部件，弃用的原因是用Galery实现的效率比较低，官方的建议是改为用HorizontalScrollView来替代这个小部件。但是，目前手机上的图片浏览功能很多都是用Galery来实现的，如果你仍然喜欢这个小部件，也可以在高版本的项目中继续使用它。

二、示例8--Demo08Gallery

1、运行截图

在模拟器中用鼠标左右拖放图片观察效果。

2、添加Demo08Gallery.axml文件

<span style="color: #0000ff;"></span><span style="color: #ff00ff;">xml version="1.0" encoding="utf-8"</span><span style="color: #0000ff;">?></span>
<span style="color: #0000ff;"><span style="color: #800000;">LinearLayout </span><span style="color: #ff0000;">xmlns:android</span><span style="color: #0000ff;">="http://schemas.android.com/apk/res/android"</span><span style="color: #ff0000;">
    android:orientation</span><span style="color: #0000ff;">="vertical"</span><span style="color: #ff0000;">
    android:layout_width</span><span style="color: #0000ff;">="fill_parent"</span><span style="color: #ff0000;">
    android:layout_height</span><span style="color: #0000ff;">="fill_parent"</span><span style="color: #ff0000;">
    android:gravity</span><span style="color: #0000ff;">="center_vertical"</span><span style="color: #0000ff;">></span>
    <span style="color: #0000ff;"><span style="color: #800000;">Gallery
        </span><span style="color: #ff0000;">android:id</span><span style="color: #0000ff;">="@+id/gallery"</span><span style="color: #ff0000;">
        android:layout_width</span><span style="color: #0000ff;">="fill_parent"</span><span style="color: #ff0000;">
        android:layout_height</span><span style="color: #0000ff;">="wrap_content"</span> <span style="color: #0000ff;">/></span>
<span style="color: #0000ff;"></span><span style="color: #800000;">LinearLayout</span><span style="color: #0000ff;">></span></span></span>

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保存文件，然后单击解决方案资源管理器上方的【刷新】按钮。

3、添加Demo08Gallery.cs文件

<span style="color: #0000ff;">using</span><span style="color: #000000;"> System;
</span><span style="color: #0000ff;">using</span><span style="color: #000000;"> Android.App;
</span><span style="color: #0000ff;">using</span><span style="color: #000000;"> Android.Content;
</span><span style="color: #0000ff;">using</span><span style="color: #000000;"> Android.OS;
</span><span style="color: #0000ff;">using</span><span style="color: #000000;"> Android.Views;
</span><span style="color: #0000ff;">using</span><span style="color: #000000;"> Android.Widget;
</span><span style="color: #0000ff;">using</span><span style="color: #000000;"> java.Lang;

</span><span style="color: #0000ff;">namespace</span><span style="color: #000000;"> ch05demos.SrcActivity
{
    [Activity(Label </span>= <span style="color: #800000;">"</span><span style="color: #800000;">Demo08Gallery</span><span style="color: #800000;">"</span><span style="color: #000000;">)]
    </span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">class</span><span style="color: #000000;"> Demo08Gallery : Activity
    {
        </span><span style="color: #0000ff;">PRotected</span> <span style="color: #0000ff;">override</span> <span style="color: #0000ff;">void</span><span style="color: #000000;"> OnCreate(Bundle savedInstanceState)
        {
            </span><span style="color: #0000ff;">base</span><span style="color: #000000;">.OnCreate(savedInstanceState);
            SetContentView(Resource.Layout.demo08_Gallery);
            </span><span style="color: #0000ff;">var</span> g = FindViewById<gallery><span style="color: #000000;">(Resource.Id.gallery);
            g.Adapter </span>= <span style="color: #0000ff;">new</span> ImageAdapter(<span style="color: #0000ff;">this</span><span style="color: #000000;">)
            {
                CurrentWidth </span>= <span style="color: #800080;">550</span><span style="color: #000000;">,
                CurrentHeight </span>= <span style="color: #800080;">550</span><span style="color: #000000;">
            };
            g.ItemClick </span>+=<span style="color: #000000;"> Gallery_ItemClick;
        }

        </span><span style="color: #0000ff;">private</span> <span style="color: #0000ff;">void</span> Gallery_ItemClick(<span style="color: #0000ff;">object</span><span style="color: #000000;"> sender, AdapterView.ItemClickEventArgs e)
        {
            Toast.MakeText(</span><span style="color: #0000ff;">this</span><span style="color: #000000;">, e.Position.ToString(), ToastLength.Short).Show();
        }
    }
    </span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">class</span><span style="color: #000000;"> ImageAdapter : BaseAdapter
    {
        </span><span style="color: #0000ff;">private</span><span style="color: #000000;"> Context context;
        </span><span style="color: #0000ff;">private</span> <span style="color: #0000ff;">int</span>[] thumbIds =<span style="color: #000000;"> {
            Resource.Drawable.sample_1,
            Resource.Drawable.sample_2,
            Resource.Drawable.sample_3,
            Resource.Drawable.sample_4,
            Resource.Drawable.sample_5,
            Resource.Drawable.sample_6,
            Resource.Drawable.sample_7
        };

        </span><span style="color: #008000;">//</span><span style="color: #008000;">默认值为500（这是C# 6.0新增的功能，仅VS2015可以这样用）</span>
         <span style="color: #0000ff;">public</span> <span style="color: #0000ff;">int</span> CurrentWidth { <span style="color: #0000ff;">get</span>; <span style="color: #0000ff;">set</span>; } = <span style="color: #800080;">500</span><span style="color: #000000;">;
        </span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">int</span> CurrentHeight { <span style="color: #0000ff;">get</span>; <span style="color: #0000ff;">set</span>; } = <span style="color: #800080;">500</span><span style="color: #000000;">;

        </span><span style="color: #0000ff;">public</span><span style="color: #000000;"> ImageAdapter(Context c)
        {
            context </span>=<span style="color: #000000;"> c;
        }

        </span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">override</span> <span style="color: #0000ff;">int</span><span style="color: #000000;"> Count
        {
            </span><span style="color: #0000ff;">get</span> { <span style="color: #0000ff;">return</span><span style="color: #000000;"> thumbIds.Length; }
        }

        </span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">override</span> View GetView(<span style="color: #0000ff;">int</span><span style="color: #000000;"> position, View convertView, ViewGroup parent)
        {
            ImageView i </span>= <span style="color: #0000ff;">new</span><span style="color: #000000;"> ImageView(context);
            i.SetImageResource(thumbIds[position]);
            i.LayoutParameters </span>= <span style="color: #0000ff;">new</span> Gallery.LayoutParams(<span style="color: #800080;">500</span>, <span style="color: #800080;">500</span><span style="color: #000000;">);
            i.SetScaleType(ImageView.ScaleType.FitXy);
            </span><span style="color: #0000ff;">return</span><span style="color: #000000;"> i;
        }

        </span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">override</span> <span style="color: #0000ff;">long</span> GetItemId(<span style="color: #0000ff;">int</span><span style="color: #000000;"> position)
        {
            </span><span style="color: #0000ff;">return</span> <span style="color: #800080;">0</span><span style="color: #000000;">;
        }

        </span><span style="color: #0000ff;">public</span> <span style="color: #0000ff;">override</span> Java.Lang.Object GetItem(<span style="color: #0000ff;">int</span><span style="color: #000000;"> position)
        {
            </span><span style="color: #0000ff;">return</span> <span style="color: #0000ff;">null</span><span style="color: #000000;">;
        }
    }
}</span></gallery>

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运行。