assets文件下资源的访问

public class MainActivity extends Activity {

private Button btn_next;
private ImageView iv_picture;
private AssetManager assets=null;
private String[] image=null;
private int currentImageId=0;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
init();
}

private void init() {
iv_picture = (ImageView) findViewById(R.id.iv_picture);

try {
//获取assets下的所有文件
assets = getAssets();
image=assets.list("");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
btn_next = (Button) findViewById(R.id.btn_next);
btn_next.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
//处理越界问题
if(currentImageId>=image.length){
currentImageId=0;
}
//判断是否是图片文件
while(!image[currentImageId].endsWith(".png")
&&!image[currentImageId].endsWith(".jpg")
&&!image[currentImageId].endsWith(".gif")){
currentImageId++;
if(currentImageId>=image.length){
currentImageId=0;
}
}
//输入流
InputStream assetFile=null;

try {
assetFile=assets.open(image[currentImageId++]);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
//获取图片对象
BitmapDrawable bitmapDrawable=(BitmapDrawable) iv_picture.getDrawable();
//判断是否为空并且是否回收
if(bitmapDrawable!=null&&!bitmapDrawable.getBitmap().isRecycled()){
bitmapDrawable.getBitmap().recycle();
}
//设置下一张图片
iv_picture.setImageBitmap(BitmapFactory.decodeStream(assetFile));
}
});
}