Eg:Gallery与ImageSwitcher结合的图片浏览小程序

先来看一下程序运行截图：

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1.Gallery功能模块的实现：

    1.1.res/layout,相应的xml文件中添加<Gallery/>元素，注意布局文件是相对布局(RelativeLayout)

   

<Gallery
    android:id="@+id/gallery"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"/>

    1.2.activity中Gallery实例化

Gallery gallery = (Gallery) findViewById(R.id.gallery);

    1.3.为项目添加图片资源(sample_1~sample_7)

   

    1.4.为Gallery定制适配器(adapter)

//定制适配器
    public class ImageAdapter extends BaseAdapter {
        int mGalleryItemBackground;
        private Context mContext;

        private Integer[] mImageIds = {
                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
        };

        public ImageAdapter(Context c) {
            mContext = c;
            TypedArray attr = mContext.obtainStyledAttributes(R.styleable.HelloGallery);
            mGalleryItemBackground = attr.getResourceId(
                    R.styleable.HelloGallery_android_galleryItemBackground, 0);
            attr.recycle();
        }

        public int getCount() {
            return mImageIds.length;
        }

        public Object getItem(int position) {
            return null;
        }

        public long getItemId(int position) {
            return mImageIds[position];
        }

        public View getView(int position, View convertView, ViewGroup parent) {
            ImageView imageView = new ImageView(mContext);

            imageView.setImageResource(mImageIds[position]);
            imageView.setLayoutParams(new Gallery.LayoutParams(150, 100));
            imageView.setScaleType(ImageView.ScaleType.FIT_XY);
            imageView.setBackgroundResource(mGalleryItemBackground);

            return imageView;
        }
    }

    1.5.为Gallery实例设置适配器

final ImageAdapter myImageAdapter=new ImageAdapter(this);
gallery.setAdapter(myImageAdapter);

2.ImageSwitcher功能模块的实现：

    2.1.为activity添加(实现)ViewFactory接口

public class Ch04_GalleryWithImageSwitcherActivity extends Activity implements ViewFactory{...}

    2.2.实现该接口的函数(该函数用来创建View并返回给ImageSwitcher实例)

   /**   
     * override for ViewSwitcher.ViewFactory#makeView()
     */
	@Override
	public View makeView() {
		// TODO Auto-generated method stub
		ImageView tmp_imageView=new ImageView(this);
		tmp_imageView.setBackgroundColor(0xff0000);
		tmp_imageView.setScaleType(ImageView.ScaleType.FIT_XY);
		tmp_imageView.setLayoutParams(new ImageSwitcher.LayoutParams(LayoutParams.FILL_PARENT,LayoutParams.FILL_PARENT));
		return tmp_imageView;
	}

    2.3.res/layout，<Gallery/>标签所在的布局文件xml中添加<ImageSwitcher/>，注意<ImageSwitcher>标签一定要在<Gallery/>标签前面

<ImageSwitcher android:id="@+id/switcher"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true"
    />

    2.2.ImageSwitcher实例化，并进行动态设置

        //ImageSwitcher
        mSwitcher=(ImageSwitcher)findViewById(R.id.switcher);
        mSwitcher.setFactory(this);
        //设置动态效果
        mSwitcher.setInAnimation(AnimationUtils.loadAnimation(this,android.R.anim.slide_in_left));
        mSwitcher.setOutAnimation(AnimationUtils.loadAnimation(this,android.R.anim.slide_out_right));

3.将两者结合起来(通过给Gallery设置监听器，并在监听器中调用ImageSwitcher实例的setImageResource()函数)：

   

        mSwitcher.setImageResource((int) myImageAdapter.getItemId(0));  //为ImageSwitcher设置默认图片
        gallery.setOnItemClickListener(new OnItemClickListener() {
            public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
                Toast.makeText(Ch04_GalleryWithImageSwitcherActivity.this, "" + position, Toast.LENGTH_SHORT).show();
                mSwitcher.setImageResource((int) myImageAdapter.getItemId(position));
            }
        });

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   1.本文对应实例源代码