一.Gallery的简介
Gallery（画廊）是一个锁定中心条目并且拥有水平滚动列表的视图，一般用来浏览图片，并且可以响应事件显示信息。Gallery还可以和ImageSwitcher组件结合使用来实现一个通过缩略图来浏览图片的效果。
Gallery常用的XML属性
属性名称 描述 android:animationDuration 设置布局变化时动画的转换所需的时间（毫秒级）。仅在动画开始时计时。该值必须是整数，比如：100。 android:gravity 指定在对象的X和Y轴上如何放置内容。指定一下常量中的一个或多个（使用 “|”分割） Constant Value Description top 0x30 紧靠容器顶端，不改变其大小 bottom 0x50 紧靠容器底部，不改变其大小 left 0x03 紧靠容器左侧，不改变其大小 right 0x05 紧靠容器右侧，不改变其大小 center_vertical 0x10 垂直居中，不改变其大小 fill_vertical 0x70 垂直方向上拉伸至充满容器 center_horizontal 0x01 水平居中，不改变其大小 Fill_horizontal 0x07 水平方向上拉伸使其充满容器 center 0x11 居中对齐，不改变其大小 fill 0x77 在水平和垂直方向上拉伸，使其充满容器 clip_vertical 0x80 垂直剪切（当对象边缘超出容器的时候，将上下边缘超出的部分剪切掉） clip_horizontal 0x08 水平剪切（当对象边缘超出容器的时候，将左右边缘超出的部分剪切掉） android:spacing 图片之间的间距 android:unselectedAlpha 设置未选中的条目的透明度(Alpha)。该值必须是float类型，比如：“1.2”。
首先介绍Gallery单独使用的例子：
MainActivity.java
package com.android.gallerydemo; import android.app.Activity; import android.content.Context; import android.os.Bundle; import android.view.View; import android.view.ViewGroup; import android.widget.AdapterView; import android.widget.AdapterView.OnItemClickListener; import android.widget.BaseAdapter; import android.widget.Gallery; import android.widget.ImageView; import android.widget.Toast; public class MainActivity extends Activity { private Gallery gallery; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); gallery = (Gallery)findViewById(R.id.gallery); //设置图片适配器 gallery.setAdapter(new ImageAdapter(this)); //设置监听器 gallery.setOnItemClickListener(new OnItemClickListener() { @Override public void onItemClick(AdapterView<?>parent, View v, int position, long id) { Toast.makeText(MainActivity.this, "点击了第"+(position+1)+"张图片", Toast.LENGTH_LONG).show(); } }); } } class ImageAdapter extends BaseAdapter{ //声明Context private Context context; //图片源数组 private Integer[] imageInteger={ R.drawable.pic1, R.drawable.pic2, R.drawable.pic3, R.drawable.pic4, R.drawable.pic5, R.drawable.pic6, R.drawable.pic7 }; //声明 ImageAdapter public ImageAdapter(Context c){ context = c; } @Override //获取图片的个数 public int getCount() { return imageInteger.length; } @Override //获取图片在库中的位置 public Object getItem(int position) { return position; } @Override //获取图片在库中的位置 public long getItemId(int position) { // TODO Auto-generated method stub return position; } @Override public View getView(int position, View convertView, ViewGroup parent) { ImageView imageView = new ImageView(context); //给ImageView设置资源 imageView.setImageResource(imageInteger[position]); //设置比例类型 imageView.setScaleType(ImageView.ScaleType.FIT_XY); //设置布局 图片128x192显示 imageView.setLayoutParams(new Gallery.LayoutParams(128, 192)); return imageView; } }
main.xml
<?xml version="1.0" encoding="utf-8"?> <Gallery xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/gallery" android:layout_width="fill_parent" android:layout_height="wrap_content" android:gravity="center_vertical" android:background="?android:galleryItemBackground" />
效果图：
Gallery和ImageSwitcher组件结合使用的例子：
MainActivity.java
package com.android.gallerytest; import android.app.Activity; import android.content.Context; import android.os.Bundle; import android.view.View; import android.view.ViewGroup; import android.view.Window; import android.view.animation.AnimationUtils; import android.widget.AdapterView; import android.widget.BaseAdapter; import android.widget.Gallery; import android.widget.ImageSwitcher; import android.widget.ImageView; import android.widget.AdapterView.OnItemSelectedListener; import android.widget.Gallery.LayoutParams; import android.widget.ViewSwitcher.ViewFactory; public class MainActivity extends Activity implements OnItemSelectedListener, ViewFactory { private ImageSwitcher mSwitcher; //大图片对应的缩略图源数组 private Integer[] mThumbIds = { R.drawable.sample_thumb_0, R.drawable.sample_thumb_1, R.drawable.sample_thumb_2, R.drawable.sample_thumb_3, R.drawable.sample_thumb_4, R.drawable.sample_thumb_5, R.drawable.sample_thumb_6, R.drawable.sample_thumb_7 }; //大图片源数组 private Integer[] mImageIds = { R.drawable.sample_0, R.drawable.sample_1, R.drawable.sample_2, R.drawable.sample_3, R.drawable.sample_4, R.drawable.sample_5, R.drawable.sample_6, R.drawable.sample_7 }; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); //设置窗口无标题 requestWindowFeature(Window.FEATURE_NO_TITLE); setContentView(R.layout.main); mSwitcher = (ImageSwitcher) findViewById(R.id.switcher); //注意在使用一个ImageSwitcher之前， //一定要调用setFactory方法，要不setImageResource这个方法会报空指针异常。 mSwitcher.setFactory(this); //设置动画效果 mSwitcher.setInAnimation(AnimationUtils.loadAnimation(this, android.R.anim.fade_in)); mSwitcher.setOutAnimation(AnimationUtils.loadAnimation(this, android.R.anim.fade_out)); Gallery g = (Gallery) findViewById(R.id.gallery); //添加OnItemSelectedListener监听器 g.setAdapter(new ImageAdapter(this)); g.setOnItemSelectedListener(this); } //创建内部类ImageAdapter public class ImageAdapter extends BaseAdapter { public ImageAdapter(Context c) { mContext = c; } public int getCount() { return mThumbIds.length; } public Object getItem(int position) { return position; } public long getItemId(int position) { return position; } public View getView(int position, View convertView, ViewGroup parent) { ImageView i = new ImageView(mContext); i.setImageResource(mThumbIds[position]); //设置边界对齐 i.setAdjustViewBounds(true); //设置布局参数 i.setLayoutParams(new Gallery.LayoutParams( LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT)); //设置背景资源 i.setBackgroundResource(R.drawable.picture_frame); return i; } private Context mContext; } @Override //实现onItemSelected()方法，更换图片 public void onItemSelected(AdapterView<?> adapter, View v, int position, long id) { //设置图片资源 mSwitcher.setImageResource(mImageIds[position]); } @Override public void onNothingSelected(AdapterView<?> arg0) { } @Override //实现makeView()方法，为ImageView设置布局格式 public View makeView() { ImageView i = new ImageView(this); //设置背景颜色 i.setBackgroundColor(0xFF000000); //设置比例类型 i.setScaleType(ImageView.ScaleType.FIT_CENTER); //设置布局参数 i.setLayoutParams(new ImageSwitcher.LayoutParams( LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT)); return i; } }
main.xml
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" > <ImageSwitcher android:id="@+id/switcher" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_alignParentTop="true" android:layout_alignParentLeft="true" /> <Gallery android:id="@+id/gallery" android:background="#55000000" android:layout_width="fill_parent" android:layout_height="60dp" android:layout_alignParentBottom="true" android:layout_alignParentLeft="true" android:gravity="center_vertical" android:spacing="16dp" /> </RelativeLayout>
效果图:
二.GridView的简介
GridView(网格视图)是按照行列的方式来显示内容的，一般用于显示图片，图片等内容，比如实现九宫格图，用GridView是首选，也是最简单的。主要用于设置Adapter。
GridView常用的XML属性：
属性名称 描述 android:columnWidth 设置列的宽度。 android:gravity 设置此组件中的内容在组件中的位置。可选的值有：top、bottom、left、right、center_vertical、fill_vertical、center_horizontal、fill_horizontal、center、fill、clip_vertical 可以多选，用“|”分开。 android:horizontalSpacing 两列之间的间距。 android:numColumns 设置列数。 android:stretchMode 缩放模式。 android:verticalSpacing 两行之间的间距。
下面有三个例子，第一个是只显示图片的，第二个是显示图片文字的(这里的图片是Android系统自带的图片)，第三个是显示自定义的图片文字。前面两个例子的实现都不是很难，第三个例子的实现有些复杂，学习GridView的时候，就想着能不能自定义自己喜欢的图片加上文字，在网上找些资料，一般都是第二个例子的形式的，最后在视频学习上找到了能实现自定义自己的图片的例子。自己就照着例子去学习，修改成了第三个例子。
第一个例子：
MainActivity.java
package com.android.gridview.activity; import android.app.Activity; import android.content.Context; import android.os.Bundle; import android.view.View; import android.view.ViewGroup; import android.widget.AdapterView; import android.widget.AdapterView.OnItemClickListener; import android.widget.BaseAdapter; import android.widget.GridView; import android.widget.ImageView; import android.widget.Toast; public class MainActivity extends Activity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); GridView gv = (GridView)findViewById(R.id.GridView1); //为GridView设置适配器 gv.setAdapter(new MyAdapter(this)); //注册监听事件 gv.setOnItemClickListener(new OnItemClickListener() { public void onItemClick(AdapterView<?> parent, View v, int position, long id) { Toast.makeText(MainActivity.this, "pic" + position, Toast.LENGTH_SHORT).show(); } }); } } //自定义适配器 class MyAdapter extends BaseAdapter{ //上下文对象 private Context context; //图片数组 private Integer[] imgs = { R.drawable.pic0, R.drawable.pic1, R.drawable.pic2, R.drawable.pic3, R.drawable.pic4, R.drawable.pic5, R.drawable.pic6, R.drawable.pic7, R.drawable.pic8, R.drawable.pic0, R.drawable.pic1, R.drawable.pic2, R.drawable.pic3, R.drawable.pic4, R.drawable.pic5, R.drawable.pic6, R.drawable.pic7, R.drawable.pic8, }; MyAdapter(Context context){ this.context = context; } public int getCount() { return imgs.length; } public Object getItem(int item) { return item; } public long getItemId(int id) { return id; } //创建View方法 public View getView(int position, View convertView, ViewGroup parent) { ImageView imageView; if (convertView == null) { imageView = new ImageView(context); imageView.setLayoutParams(new GridView.LayoutParams(75, 75));//设置ImageView对象布局 imageView.setAdjustViewBounds(false);//设置边界对齐 imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);//设置刻度的类型 imageView.setPadding(8, 8, 8, 8);//设置间距 } else { imageView = (ImageView) convertView; } imageView.setImageResource(imgs[position]);//为ImageView设置图片资源 return imageView; } }
main.xml
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" > <GridView android:id="@+id/GridView1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:columnWidth="90dp" android:numColumns="3" android:verticalSpacing="10dp" android:horizontalSpacing="10dp" android:stretchMode="columnWidth" android:gravity="center" /> </LinearLayout>
效果图：
第二个例子：
MainActivity.java
package com.android.gridview2.activity; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import android.app.Activity; import android.os.Bundle; import android.widget.GridView; import android.widget.SimpleAdapter; public class MainActivity extends Activity { private GridView gv; @Override protected void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub super.onCreate(savedInstanceState); setContentView(R.layout.gridview); //准备要添加的数据条目 List<Map<String, Object>> items = new ArrayList<Map<String,Object>>(); for (int i = 0; i < 9; i++) { Map<String, Object> item = new HashMap<String, Object>(); item.put("imageItem", R.drawable.icon);//添加图像资源的ID item.put("textItem", "icon" + i);//按序号添加ItemText items.add(item); } //实例化一个适配器 SimpleAdapter adapter = new SimpleAdapter(this, items, R.layout.grid_item, new String[]{"imageItem", "textItem"}, new int[]{R.id.image_item, R.id.text_item}); //获得GridView实例 gv = (GridView)findViewById(R.id.mygridview); //为GridView设置适配器 gv.setAdapter(adapter); } }
gridview.xml
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="wrap_content" android:layout_height="wrap_content" > <GridView android:id="@+id/mygridview" android:numColumns="3" android:gravity="center_horizontal" android:layout_width="wrap_content" android:layout_height="wrap_content" android:stretchMode="columnWidth" /> </LinearLayout>
grid_item.xml
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/RelativeLayout1" android:layout_width="wrap_content" android:layout_height="fill_parent" android:paddingBottom="6dip" > <ImageView android:id="@+id/image_item" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerHorizontal="true" /> <TextView android:id="@+id/text_item" android:layout_below="@+id/image_item" android:layout_height="wrap_content" android:layout_width="wrap_content" android:layout_centerHorizontal="true" /> </RelativeLayout>
效果图：
第三个例子：
MainActivity.java
package com.android.gridview3; import java.util.ArrayList; import java.util.List; import android.app.Activity; import android.content.Context; import android.os.Bundle; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.AdapterView; import android.widget.BaseAdapter; import android.widget.GridView; import android.widget.ImageView; import android.widget.TextView; import android.widget.Toast; import android.widget.AdapterView.OnItemClickListener; public class MainActivity extends Activity { private GridView gridView; //图片的文字标题 private String[] titles = new String[] { "pic1", "pic2", "pic3", "pic4", "pic5", "pic6", "pic7", "pic8", "pic9"}; //图片ID数组 private int[] images = new int[]{ R.drawable.pic1, R.drawable.pic2, R.drawable.pic3, R.drawable.pic4, R.drawable.pic5, R.drawable.pic6, R.drawable.pic7, R.drawable.pic8,R.drawable.pic9 }; @Override public void onCreate(Bundle savedInstanceState){ super.onCreate(savedInstanceState); setContentView(R.layout.main); gridView = (GridView) findViewById(R.id.gridview); PictureAdapter adapter = new PictureAdapter(titles, images, this); gridView.setAdapter(adapter); gridView.setOnItemClickListener(new OnItemClickListener() { public void onItemClick(AdapterView<?> parent, View v, int position, long id) { Toast.makeText(MainActivity.this, "pic" + (position+1), Toast.LENGTH_SHORT).show(); } }); } } //自定义适配器 class PictureAdapter extends BaseAdapter{ private LayoutInflater inflater; private List<Picture> pictures; public PictureAdapter(String[] titles, int[] images, Context context) { super(); pictures = new ArrayList<Picture>(); inflater = LayoutInflater.from(context); for (int i = 0; i < images.length; i++) { Picture picture = new Picture(titles[i], images[i]); pictures.add(picture); } } @Override public int getCount() { if (null != pictures) { return pictures.size(); } else { return 0; } } @Override public Object getItem(int position) { return pictures.get(position); } @Override public long getItemId(int position) { return position; } @Override public View getView(int position, View convertView, ViewGroup parent) { ViewHolder viewHolder; if (convertView == null) { convertView = inflater.inflate(R.layout.picture_item, null); viewHolder = new ViewHolder(); viewHolder.title = (TextView) convertView.findViewById(R.id.title); viewHolder.image = (ImageView) convertView.findViewById(R.id.image); convertView.setTag(viewHolder); } else { viewHolder = (ViewHolder) convertView.getTag(); } viewHolder.title.setText(pictures.get(position).getTitle()); viewHolder.image.setImageResource(pictures.get(position).getImageId()); return convertView; } } class ViewHolder { public TextView title; public ImageView image; } class Picture { private String title; private int imageId; public Picture() { super(); } public Picture(String title, int imageId) { super(); this.title = title; this.imageId = imageId; } public String getTitle() { return title; } public void setTitle(String title) { this.title = title; } public int getImageId() { return imageId; } public void setImageId(int imageId) { this.imageId = imageId; } }
main.xml
<?xml version="1.0" encoding="utf-8"?> <GridView xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/gridview" android:layout_width="fill_parent" android:layout_height="fill_parent" android:columnWidth="90dp" android:numColumns="auto_fit" android:verticalSpacing="10dp" android:horizontalSpacing="10dp" android:stretchMode="columnWidth" android:gravity="center" />
picture_item.xml
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/root" android:orientation="vertical" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginTop="5dp" > <ImageView android:id="@+id/image" android:layout_width="100dp" android:layout_height="150dp" android:layout_gravity="center" android:scaleType="fitXY" android:padding="4dp" /> <TextView android:id="@+id/title" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center" android:gravity="center_horizontal" /> </LinearLayout>
效果图：
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