最近要做一个带滑动和点击效果的一组图片，用了差不多俩周的时间我也没搞出来。蛋疼啊。。。
今天老板给了我一个Demo，说是公司技术顾问做的。。。一看效果，hoho，正是想要的效果，心里呐喊，大牛啊
Demo中用到了从SD卡中读取图片（包括图片的名称），然后将图片以8个一组的形式显示在屏幕上，左右滑动会更换图片（滑动效果）。点击图片可以得到图片的位置。
下面贴一些关键代码：
判断SD卡是否挂载：
private static boolean isMount() {
String SDState = Environment.getExternalStorageState();
if (Environment.MEDIA_MOUNTED.equals(SDState)) {
return true;
}
return false;
}
获取SD卡路径：
public static String getSDCartPath() {
String SDCardPath = null;
if (isMount()) {
SDCardPath = Environment.getExternalStorageDirectory().getAbsolutePath();
}
return SDCardPath;
}
获取目标目录下得文件信息，列表形式返回：
public static List<String> getFiles() {
List<String> apklist = new ArrayList<String>();
File[] files = new File(getSDCartPath()+PATH).listFiles();
for (int i = 0; i < files.length; i++) {
File f = files[i];
if (f.isFile()) {
apklist.add(f.getPath());
}
}
return apklist;
}
通过文件路径获取文件：
public static File findFileByName(String filePath) {
File file = null;
String SDCardPath = getSDCartPath();
if (SDCardPath != null) {
file = new File( filePath);
if (file.exists()) {
return file;
}
}
return file;
}
通过文件路径生成一个输入流：
public static InputStream findStreamByName(String filePath) {
InputStream inputStream = null;
File file = findFileByName(filePath);
try {
inputStream = new BufferedInputStream(new FileInputStream(file));
} catch (FileNotFoundException e) {
e.printStackTrace();
}
return inputStream;
}
将文件转换成字节存放到数组中：
public static byte[] findByteByName(String filePath) {
InputStream inputStream = null;
ByteArrayOutputStream byteStrem = new ByteArrayOutputStream();
try {
inputStream = findStreamByName(filePath);
copy(inputStream, byteStrem);
// byte[] data = new byte[inputStream.available()];
// inputStream.read(data);
byteStrem.flush();
return byteStrem.toByteArray();
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
if (inputStream != null) {
inputStream.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
return null;
}
public static int copy(InputStream in, OutputStream out) throws IOException {
byte[] buffer = new byte[1024 * 4];
int readSize = -1;
int result = 0;
while ((readSize = in.read(buffer)) >= 0) {
out.write(buffer, 0, readSize);
result = calcNewNrReadSize(readSize, result);
}
out.flush();
return result;
}
protected static int calcNewNrReadSize(int nrRead, int totalNrNread) {
if (totalNrNread < 0) {
return totalNrNread;
}
if (totalNrNread > (Integer.MAX_VALUE - nrRead)) {
return -1;
} else {
return (totalNrNread + nrRead);
}
}
以上方法是在工具类中的。。。
该包下得另外另个类的分别是图片的装载和View的控制，将图片加载进View中。
用图片装载类的方法获取图片：
public synchronized Bitmap loadImg(final String imageUrl) {
if (TextUtils.isEmpty(imageUrl)) {
return null;
}
return getBitmap(imageUrl);
}
private Bitmap getBitmap(final String imageUrl) {
try {
byte[] b = SDCardUtils.findByteByName(imageUrl);
if (b != null && b.length > 0) {
Bitmap bit = BitmapFactory.decodeByteArray(b, 0, b.length);
if (bit != null) {
return bit;
}
}
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
工具类：获取视图中的View、数据列表
public static LayoutInflater getInflater(Context context) {
if (null != context) {
return (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
return null;
}
public static View getView(Context context, int resId) {
LayoutInflater layoutInflater = getInflater(context);
if (layoutInflater != null) {
return layoutInflater.inflate(resId, null);
}
return null;
}
public static List<FoodstuffBean> getDatas() {
List<String> files = SDCardUtils.getFiles();
List<FoodstuffBean> list = new ArrayList<FoodstuffBean>();
for (String url : files) {
FoodstuffBean bean = new FoodstuffBean(url, getName(url), null, 0.00);
list.add(bean);
}
return list;
}
private static String getName(String url) {
return url.substring(url.lastIndexOf("/") + 1, url.length());
}
GridView适配器：
private List<FoodstuffBean> list = new ArrayList<FoodstuffBean>();
private Context context;
private SyncImageLoader loader;
public GridViewAdapter(Context context) {
this.context = context;
loader = new SyncImageLoader();
}
public void setList(List<FoodstuffBean> list) {
this.list = list;
}
@Override
public int getCount() {
return list.size();
}
@Override
public FoodstuffBean getItem(int position) {
return list.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewCache cache;
if (null == convertView) {
cache = new ViewCache();
convertView = ViewUtil.getView(context, R.layout.foodstuff_gridview_item_layout);
cache.imageView = (ImageView) convertView.findViewById(R.id.foodstuffICON_imageView_id);
cache.textView = (TextView) convertView.findViewById(R.id.foodstuffName_textView_id);
convertView.setTag(cache);
} else {
cache = (ViewCache) convertView.getTag();
}
BindData(cache, position);
return convertView;
}
private void BindData(ViewCache cache, int position) {
FoodstuffBean item = getItem(position);
cache.imageView.setImageBitmap(loader.loadImg(item.getImageURL()));
cache.textView.setText(item.getName());
// cache.textView.setText("54555");
}
class ViewCache {
ImageView imageView;
TextView textView;
}
ViewPager适配器：
private static final int DEFAULT_CONUT = 8;
private Context context;
private List<FoodstuffBean> mList;
private int surplus;
private int screenCount;
private boolean loop = true;
public SlideScreenAdapter(Context context, List<FoodstuffBean> mList) {
this.context = context;
this.mList = mList;
surplus = mList.size() % DEFAULT_CONUT;
screenCount = (mList.size() - 1) / DEFAULT_CONUT + 1;
}
private View tempView = null;
/*
* (销毁position位置的页面)
* @see android.support.v4.view.PagerAdapter#destroyItem(android.view.View, int, java.lang.Object)
*/
@Override
public void destroyItem(View collection, int position, Object view) {
tempView = (View) view;
((ViewPager) collection).removeView(tempView);
}
private GridViewAdapter adapter;
private class CacheView {
GridView gridview;
}
private List<FoodstuffBean> getGridViewDatas(int position) {
List<FoodstuffBean> subList;
int pos = position * DEFAULT_CONUT;
if (position + 1 < screenCount) {
subList = mList.subList(pos, pos + DEFAULT_CONUT);
} else {
if (surplus > 0) {
subList = mList.subList(pos, pos + surplus);
} else {
subList = mList.subList(pos, pos + DEFAULT_CONUT);
}
}
return subList;
}
/*
* (初始化position位置的页面)
* @see android.support.v4.view.PagerAdapter#instantiateItem(android.view.View, int)
*/
@Override
public Object instantiateItem(View collection, int position) {
View view = null;
CacheView cache = null;
Log.i("other", "position1=" + position);
if (loop && position + 1 > screenCount) {
if (position % screenCount == 0) {
position = 0;
Log.i("other", "position2=" + position);
} else {
position = position % screenCount;
Log.i("other", "position3=" + position);
}
}
List<FoodstuffBean> list = getGridViewDatas(position);
if (tempView != null) {
view = tempView;
cache = (CacheView) view.getTag();
adapter = (GridViewAdapter) cache.gridview.getAdapter();
adapter.setList(list);
tempView = null;
} else {
cache = new CacheView();
view = ViewUtil.getView(context, R.layout.foodstuff_screen_item_layout);
adapter = new GridViewAdapter(context);
adapter.setList(list);
cache.gridview = (GridView) view.findViewById(R.id.foodstuff_screen_item_gridview_id);
cache.gridview.setAdapter(adapter);
cache.gridview.setOnItemClickListener(new GridViewListener(context));
view.setTag(cache);
}
adapter.notifyDataSetChanged();
((ViewPager) collection).addView(view);// , 0
return view;
}
@Override
public void finishUpdate(View arg0) {
}
@Override
public void startUpdate(View arg0) {
}
@Override
public int getCount() {
if (loop) {
return Integer.MAX_VALUE;
} else {
return screenCount;
}
}
@Override
public boolean isViewFromObject(View arg0, Object arg1) {
return arg0 == arg1;
}
@Override
public void restoreState(Parcelable arg0, ClassLoader arg1) {
}
@Override
public Parcelable saveState() {
return null;
}
实体类：
private String imageURL;
private String name;
private String details;
private double price;
public FoodstuffBean() {
}
public FoodstuffBean(String imageURL, String name, String details, double price) {
this.imageURL = imageURL;
this.name = name;
this.details = details;
this.price = price;
}
public String getImageURL() {
return imageURL;
}
public void setImageURL(String imageURL) {
this.imageURL = imageURL;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getDetails() {
return details;
}
public void setDetails(String details) {
this.details = details;
}
public double getPrice() {
return price;
}
public void setPrice(double price) {
this.price = price;
}
设置GridView中的事件监听器：
private Context context;
public GridViewListener(Context context) {
this.context = context;
}
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Toast.makeText(context, "position= " + position, Toast.LENGTH_SHORT).show();
}
MainActivity：
slideScreen = (ViewPager) findViewById(R.id.foodstuff_slideScreen_id); adapter = new SlideScreenAdapter(getApplicationContext(), ViewUtil.getDatas()); slideScreen.setAdapter(adapter);