Android开发—Android_Gallery与衍生BaseAdapter讲解.doc

BaseAdapter新建项目定义layout 外部resource 的xml 文件，用来改变layout 的背景1234567 修改main.xml布局，添加一个Gallery和一个ImageView12345678910111213141516171819202122新建一个myImageAdapter类Gallery的适配器，它继承于BaseAdapter类.1234567891011121314151617181920212223242526package zyf.Ex_Ctrl_10ME;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;public class myImageAdapter extends BaseAdapter Overridepublic int getCount() / TODO Auto-generated method stubreturn 0;Overridepublic Object getItem(int position) / TODO Auto-generated method stubreturn null;Overridepublic long getItemId(int position) / TODO Auto-generated method stubreturn 0;Overridepublic View getView(int position, View convertView, ViewGroup parent) / TODO Auto-generated method stubreturn null;修改mainActivity.java，添加Gallery相关操作123456789101112131415161718192021222324252627282930313233343536373839404142package zyf.Ex_Ctrl_10ME; import android.app.Activity;import android.os.Bundle;import android.view.View;import android.widget.AdapterView;import android.widget.Gallery;import android.widget.ImageView;import android.widget.Toast; public class Ex_Ctrl_10ME extends Activity /* Called when the activity is first created. */*定义要使用的对象*/private Gallery gallery;private ImageView imageview;private myImageAdapter imageadapter; Override public void onCreate(Bundle savedInstanceState) super.onCreate(savedInstanceState); setContentView(R.layout.main); imageadapter=new myImageAdapter(this); /* 通过findViewById 取得 资源对象*/ gallery=(Gallery)findViewById(R.id.Gallery_preView); imageview=(ImageView)findViewById(R.id.ImageView_photo); /*给Gallery设置适配器 把Ex_Ctrl_10ME类传入参数*/ gallery.setAdapter(imageadapter); /*设置Gallery的点击事件监听器*/ gallery.setOnItemClickListener(new Gallery.OnItemClickListener()Overridepublic void onItemClick(AdapterView parent, View v, int position,long id) / TODO Auto-generated method stub/*显示该图片是几号*/Toast.makeText(Ex_Ctrl_10ME.this, 这是图片：+position+号, Toast.LENGTH_SHORT).show(); /*设置大图片*/imageview.setBackgroundResource(imageadapter.myImageIdsposition); ); 修改myImageAdapter.java文件，实现相簿浏览效果123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566package zyf.Ex_Ctrl_10ME; import android.content.Context;import android.content.res.TypedArray;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.Gallery;import android.widget.ImageView; public class myImageAdapter extends BaseAdapter/自定义的类变量/*变量声明*/int mGalleryItemBackground;private Context context;/上下文/* 构建一Integer array 并取得预加载Drawable 的图片id */public Integer myImageIds = R.drawable.photo1, R.drawable.photo2,R.drawable.photo3, R.drawable.photo4, R.drawable.photo5,R.drawable.photo6, ;/*自定义的构造方法*/public myImageAdapter(Context context) / TODO Auto-generated constructor stubthis.context=context;/* 使用在res/values/attrs.xml 中的定义 的Gallery 属性.*/TypedArray typed_array=context.obtainStyledAttributes(R.styleable.Gallery);/* 取得Gallery 属性的Index id */mGalleryItemBackground=typed_array.getResourceId(R.styleable.Gallery_android_galleryItemBackground, 0);/* 让对象的styleable 属性能够反复使用 */typed_array.recycle();/* 重写的方法getCount,返回图片数目 */Overridepublic int getCount() / TODO Auto-generated method stubreturn myImageIds.length;/* 重写的方法getItemId,返回图像的数组id */Overridepublic Object getItem(int position) / TODO Auto-generated method stubreturn position;Overridepublic long getItemId(int position) / TODO Auto-generated method stubreturn position;/* 重写的方法getView,返回一View 对象 */Overridepublic View getView(int position, View convertView, ViewGroup parent) / TODO Auto-generated method stub/* 产生ImageView 对象 */ImageView imageview = new ImageView(context);/* 设置图片给imageView 对象 */imageview.setImageResource(myImageIdsposition);/* 重新设置图片的宽高 */imageview.setScaleType(ImageView.ScaleType.FIT