Android开发学习笔记：Gallery和GridView浅析.doc

Android开发学习笔记：Gallery和GridView浅析2011-08-23 22:15:00标签：GridView移动开发Android休闲浅析原创作品，允许转载，转载时请务必以超链接形式标明文章原始出处、作者信息和本声明。否则将追究法律责任。/3061169/647355一.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）ConstantValueDescriptiontop0x30紧靠容器顶端，不改变其大小bottom0x50紧靠容器底部，不改变其大小left0x03紧靠容器左侧，不改变其大小right0x05紧靠容器右侧，不改变其大小center_vertical0x10垂直居中，不改变其大小fill_vertical0x70垂直方向上拉伸至充满容器center_horizontal0x01水平居中，不改变其大小Fill_horizontal0x07水平方向上拉伸使其充满容器center0x11居中对齐，不改变其大小fill0x77在水平和垂直方向上拉伸，使其充满容器clip_vertical0x80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_horizontal0x08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.javapackagecom.android.gallerydemo; importandroid.app.Activity; importandroid.content.Context; importandroid.os.Bundle; importandroid.view.View; importandroid.view.ViewGroup; importandroid.widget.AdapterView; importandroid.widget.AdapterView.OnItemClickListener; importandroid.widget.BaseAdapter; importandroid.widget.Gallery; importandroid.widget.ImageView; importandroid.widget.Toast; publicclassMainActivityextendsActivity privateGallerygallery; OverridepublicvoidonCreate(BundlesavedInstanceState) super.onCreate(savedInstanceState); setContentView(R.layout.main); gallery=(Gallery)findViewById(R.id.gallery); /设置图片适配器 gallery.setAdapter(newImageAdapter(this); /设置监听器 gallery.setOnItemClickListener(newOnItemClickListener() OverridepublicvoidonItemClick(AdapterViewparent,Viewv,intposition,longid) Toast.makeText(MainActivity.this,点击了第+(position+1)+张图片,Toast.LENGTH_LONG).show(); ); classImageAdapterextendsBaseAdapter /声明Context privateContextcontext; /图片源数组 privateIntegerimageInteger= R.drawable.pic1, R.drawable.pic2, R.drawable.pic3, R.drawable.pic4, R.drawable.pic5, R.drawable.pic6, R.drawable.pic7 ; /声明ImageAdapter publicImageAdapter(Contextc) context=c; Override/获取图片的个数 publicintgetCount() returnimageInteger.length; Override/获取图片在库中的位置 publicObjectgetItem(intposition) returnposition; Override/获取图片在库中的位置 publiclonggetItemId(intposition) /TODOAuto-generatedmethodstub returnposition; OverridepublicViewgetView(intposition,ViewconvertView,ViewGroupparent) ImageViewimageView=newImageView(context); /给ImageView设置资源 imageView.setImageResource(imageIntegerposition); /设置比例类型 imageView.setScaleType(ImageView.ScaleType.FIT_XY); /设置布局图片128x192显示 imageView.setLayoutParams(newGallery.LayoutParams(128,192); returnimageView; main.xml效果图：Gallery和ImageSwitcher组件结合使用的例子：MainActivity.javapackagecom.android.gallerytest; importandroid.app.Activity; importandroid.content.Context; importandroid.os.Bundle; importandroid.view.View; importandroid.view.ViewGroup; importandroid.view.Window; importandroid.view.animation.AnimationUtils; importandroid.widget.AdapterView; importandroid.widget.BaseAdapter; importandroid.widget.Gallery; importandroid.widget.ImageSwitcher; importandroid.widget.ImageView; importandroid.widget.AdapterView.OnItemSelectedListener; importandroid.widget.Gallery.LayoutParams; importandroid.widget.ViewSwitcher.ViewFactory; publicclassMainActivityextendsActivityimplementsOnItemSelectedListener, ViewFactory privateImageSwitchermSwitcher; /大图片对应的缩略图源数组 privateIntegermThumbIds=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 privateIntegermImageIds=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; OverridepublicvoidonCreate(BundlesavedInstanceState) 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); Galleryg=(Gallery)findViewById(R.id.gallery); /添加OnItemSelectedListener监听器 g.setAdapter(newImageAdapter(this); g.setOnItemSelectedListener(this); /创建内部类ImageAdapter publicclassImageAdapterextendsBaseAdapter publicImageAdapter(Contextc) mContext=c; publicintgetCount() returnmThumbIds.length; publicObjectgetItem(intposition) returnposition; publiclonggetItemId(intposition) returnposition; publicViewgetView(intposition,ViewconvertView,ViewGroupparent) ImageViewi=newImageView(mContext); i.setImageResource(mThumbIdsposition); /设置边界对齐 i.setAdjustViewBounds(true); /设置布局参数 i.setLayoutParams(newGallery.LayoutParams( LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT); /设置背景资源 i.setBackgroundResource(R.drawable.picture_frame); returni; privateContextmContext; Override/实现onItemSelected()方法，更换图片 publicvoidonItemSelected(AdapterViewadapter,Viewv,intposition, longid) /设置图片资源 mSwitcher.setImageResource(mImageIdsposition); OverridepublicvoidonNothingSelected(AdapterViewarg0) Override/实现makeView()方法，为ImageView设置布局格式 publicViewmakeView() ImageViewi=newImageView(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(newImageSwitcher.LayoutParams( LayoutParams.FILL_PARENT,LayoutParams.FILL_PARENT); returni; main.xml 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.javapackage 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(imgsposition);/为ImageView设置图片资源 return imageView; main.xml 效果图：第二个例子：MainActivity.javapackage 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 ListMap items = new ArrayListMap(); for (int i = 0; i 9; i+) Map item = new HashMap(); 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 StringimageItem, textItem, new intR.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 grid_item.xml 效果图：第三个例子：MainActivity.javapackage 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