android gallery和Animation组合使用， 看美女美图

今天主要探究Gallery和Animation的使用。 制作一个美女图片集锦。


1. 首先需要做一个列表， 用来显示类别：

public class CategoryActivity extends Activity implements OnItemClickListener{
	private ListView mList;
	LayoutInflater mInflater;
	
	private Integer[] title = {
			R.string.jingxuan,
			R.string.mingxing,
			R.string.xinggan,
			R.string.cosplay,
			R.string.socks,
			R.string.more
	};
	@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.category_list);
        mList = (ListView) findViewById(R.id.category_list);
        long time = System.currentTimeMillis();
        if (time%3==0) {
        	mList.setBackgroundResource(R.drawable.longze2);
        } else if (time%3==1){
        	mList.setBackgroundResource(R.drawable.pic02);
        } else {
        	mList.setBackgroundResource(R.drawable.pic05);
        }
        mInflater = LayoutInflater.from(this);
        mList.setAdapter(new TitleAdapter(this));
        mList.setOnItemClickListener(this);
        
           }

...
需要自定义个一个TitleAdapter集成BaseAdapter,

private class TitleAdapter extends BaseAdapter {

    	private Context mContext;
    	
    	
    	public TitleAdapter(Context context) {
    		mContext = context;
    	}
		@Override
		public int getCount() {
			// TODO Auto-generated method stub
			return title.length;
		}

		@Override
		public Object getItem(int arg0) {
			// TODO Auto-generated method stub
			return title[arg0];
		}

		@Override
		public long getItemId(int position) {
			// TODO Auto-generated method stub
			return position;
		}

		@Override
		public View getView(int position, View convertView, ViewGroup parent) {
			ViewHolder vh = null;
			
			if (convertView == null) {
				convertView = mInflater.inflate(R.layout.category_item, null);
				
				vh = new ViewHolder();
				vh.titleView = (TextView) convertView.findViewById(R.id.cate_title);
				
				//hilight the last 'more' title
				if (position == title.length -1) {
					vh.titleView.setTextColor(CategoryActivity.this.getResources().getColor(R.color.red));
				}
				convertView.setTag(vh);
			} else {
				vh = (ViewHolder) convertView.getTag();
			}
			
			//set image resource
			vh.titleView.setText(title[position]);
			
			return convertView;
		}
		
		/**
		 * holder for caching UI component
		 * @author hp
		 *
		 */
		class ViewHolder {
			public TextView titleView;
		}
    	
    }

使用ViewHolder的好处就是对控件进行缓存， 以便下次取方便，提高访问效率。

2. 接下来就是对类别中的美女图片的显示了，
定义xml布局文件如下：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
<ImageView android:id="@+id/large_image"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    />

    <TextView android:id="@+id/tip"
        android:layout_width="fill_parent"
        android:layout_height="30dp"
        android:text="@string/slide_tip"
        android:gravity="center_vertical"
        android:textColor="#dd0000"
        android:layout_above="@+id/gallery"/>
   
    <Gallery
        android:id="@+id/gallery"
        android:layout_width="fill_parent"
        android:layout_height="60dp"
        android:gravity="center"
        android:padding="5dp"
        android:layout_alignParentBottom="true"
        android:paddingBottom="10dp"       />
<LinearLayout
            android:id="@+id/miniAdLinearLayout"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:gravity="center_horizontal"
            />
</RelativeLayout>

类代码如下：

public class ViewActivity extends Activity implements OnItemSelectedListener {
	private Gallery mGallery;
	private ImageAdapter mAdapter;
	LayoutInflater mInflater;
	
	private ImageView largeView;
	
	private Animation mAnimation;
	
	private int categoryId;
	
	private String imgDir = "";
	
	private Bitmap[] imageUri;
	
	private int showCount = 0;
	
	
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        this.setTitle(getIntent().getIntExtra(Constants.KEY_TITLE, R.string.app_name));
        mGallery = (Gallery) findViewById(R.id.gallery);
        mInflater = LayoutInflater.from(this);
        
        mAdapter = new ImageAdapter(this);
        
        largeView = (ImageView) findViewById(R.id.large_image);
        largeView.setScaleType(ImageView.ScaleType.FIT_XY);
        mAnimation = AnimationUtils.loadAnimation(this, R.anim.alpha_ani);
        largeView.startAnimation(mAnimation);
        
    }
    
    
    public void onResume() {
    	super.onResume();
    	showCount++;
    	
    	if (getIntent().getBooleanExtra(Constants.KEY_AD, false)) {
    		if (showCount == 1) {
    			AppConnect.getInstance(this).showOffers(this);
    		}
    	} else {
    		//build from asset
            initFromIntent();
            mGallery.setAdapter(mAdapter);
            mGallery.setOnItemSelectedListener(this);
    	}
    	}
    
    private void initFromIntent() {
    	//set title
    	Intent intent = getIntent();
    	
    	categoryId = getIntent().getIntExtra(Constants.KEY_CATEGORY, 0);
    	String basePath = "images/";
    	switch (categoryId) {
    	//suggest hot images
    	case 0:
    		imgDir = "jingxuantuijian";
    		break;
    		
    	//super starts	
    	case 1:
    		imgDir = "mingxing";
    		break;
    	
    	//sexy girls
    	case 2:
    		imgDir = "xinggan";
    		break;
    		
    	//cosplay 
    	case 3:
    		imgDir = "cosplay";
    		break;
    	case 4:
    		imgDir = "socks";
    		break;
    	default:
    		imgDir = "xinggan";
    		break;
    	}
    	
    	try {
    		basePath += imgDir;
    		AssetManager am = this.getAssets();
			String[] files = am.list(basePath);
			imageUri = new Bitmap[files.length];
			basePath += "/";
			for(int i = 0; i < files.length; i++) {
				imageUri[i] = BitmapFactory.decodeStream(am.open(basePath + files[i]));
			}
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
    }

    
    private class ImageAdapter extends BaseAdapter {

    	private Context mContext;
    	
    	
    	public ImageAdapter(Context context) {
    		mContext = context;
    	}
		@Override
		public int getCount() {
			// TODO Auto-generated method stub
			return imageUri.length;
		}

		@Override
		public Object getItem(int arg0) {
			// TODO Auto-generated method stub
			return imageUri[arg0];
		}

		@Override
		public long getItemId(int position) {
			// TODO Auto-generated method stub
			return position;
		}

		@Override
		public View getView(int position, View convertView, ViewGroup parent) {
			ViewHolder vh = null;
			
			if (convertView == null) {
				convertView = mInflater.inflate(R.layout.item, null);
				
				vh = new ViewHolder();
				vh.imgV = (ImageView) convertView.findViewById(R.id.imageV);
				vh.imgV.setScaleType(ImageView.ScaleType.FIT_XY);
				convertView.setTag(vh);
			} else {
				vh = (ViewHolder) convertView.getTag();
			}
			
			//set image resource
			vh.imgV.setImageBitmap(imageUri[position]);
			return convertView;
		}
		
		/**
		 * holder for caching UI component
		 * @author hp
		 *
		 */
		class ViewHolder {
			public ImageView imgV;
		}
    	
    }

	@Override
	public void onItemSelected(AdapterView<?> arg0, View arg1, int position,
			long arg3) {
		//recyle old bitmap
		BitmapDrawable drawable = (BitmapDrawable) largeView.getDrawable();
		if (drawable != null && !drawable.getBitmap().isRecycled()) {
			drawable.getBitmap().recycle();
		}
		largeView.setImageBitmap(imageUri[position]);
		largeView.startAnimation(mAnimation);
	}

	@Override
	public void onNothingSelected(AdapterView<?> arg0) {
		
		
	}
}

中间大图片的显示加上动画，
动画文件如下
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
  <alpha android:fromAlpha="0.1"
      android:toAlpha="1.0"
      android:duration="1500"/>
</set>
放在res/anim下。
实际效果请运行附件。
至此可完成。