Android(安卓)UI开发第七篇之Android(安卓)Gallery

新建项目

②　定义layout外部resource的xml文件，用来改变layout的背景

<?xml version="1.0" encoding="utf-8"?><resources><declare-styleable name="Gallery"><attr name="android:galleryItemBackground" /></declare-styleable><!-- 定义layout 外部resource 的xml 文件，用来改变layout 的背景图。 --></resources>

③　修改main.xml布局，添加一个Gallery和一个ImageView

<?xml version="1.0" encoding="utf-8"?><AbsoluteLayout    android:id="@+id/widget_absolutelayout"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    xmlns:android="http://schemas.android.com/apk/res/android"><Gallery    android:layout_width="fill_parent"    android:layout_height="143px"    android:layout_x="0px"    android:layout_y="51px"    android:id="@+id/Gallery_preView"></Gallery><ImageView    android:layout_width="239px"    android:layout_height="218px"    android:layout_x="38px"    android:layout_y="184px"    android:id="@+id/ImageView_photo"></ImageView></AbsoluteLayout>

④　新建一个myImageAdapter类--Gallery的适配器，它继承于BaseAdapter类.

package 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;}}

⑤　修改mainActivity.java，添加Gallery相关操作

package 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 {    /*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(newGallery.OnItemClickListener(){        @Override        public 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.myImageIds[position]);        }        });    }}

⑥　修改myImageAdapter.java文件，实现相簿浏览效果

package 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) {this.context=context;/* * 使用在res/values/attrs.xml 中的<declare-styleable>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() {return myImageIds.length;}/* 重写的方法getItemId,返回图像的数组id */@Overridepublic Object getItem(int position) {return position;}@Overridepublic long getItemId(int position) {return position;}/* 重写的方法getView,返回一View 对象 */@Overridepublic View getView(int position, View convertView, ViewGroup parent) {/* 产生ImageView 对象 */ImageView imageview = new ImageView(context);/* 设置图片给imageView 对象 */imageview.setImageResource(myImageIds[position]);/* 重新设置图片的宽高 */imageview.setScaleType(ImageView.ScaleType.FIT_XY);/* 重新设置Layout 的宽高 */imageview.setLayoutParams(new Gallery.LayoutParams(128, 128));/* 设置Gallery 背景图 */imageview.setBackgroundResource(mGalleryItemBackground);/* 返回imageView 对象 */return imageview;}}

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