效果图：
图片存在bmob(http://www.bmob.com )后台，所以下载Demo运行的话要到官网申请 Application ID。
先点击上传图片，再点击缓存图片，不然没数据。
代码：
- paths=new String[5];
- for(int i=0;i<5;i++){
- //图片路径
- paths[i]=Environment.getExternalStorageDirectory()+"/"+i+".jpg";
- }
复制代码
上面的代码要改为自己的图片路径。
主要代码：
IndexActivity
public class IndexActivity extends Activity {
private String[] paths;
private int j;
private File cache;
private String appid=""; //你的Application ID
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Bmob.initialize(this, appid);
setContentView(R.layout.activity_index);
///创建缓存目录
cache=new File(Environment.getExternalStorageDirectory(),"cache");
if(!cache.exists()){
cache.mkdirs();
}
}
public void skip(View v){
Intent intent=new Intent(this,MainActivity.class);
startActivity(intent);
}
public void upload(View v){
paths=new String[5];
for(int i=0;i<5;i++){
//图片路径
paths[i]=Environment.getExternalStorageDirectory()+"/"+i+".jpg";
}
//批量上传图片
Bmob.uploadBatch(this, paths, new UploadBatchListener() {
@Override
public void onSuccess(List<BmobFile> arg0, List<String> arg1) {
// TODO Auto-generated method stub
String strurl="";
for(String url:arg1){
strurl=url;
}
Person p=new Person();
p.setIcPath(strurl);
p.setStr("s"+j);
p.save(IndexActivity.this);
j++;
toast("第"+j+"个上传成功！");
}
@Override
public void onProgress(int curIndex, int curPercent, int total, int totalPercent) {
// TODO Auto-generated method stub
//1、curIndex--表示当前第几个文件正在上传
//2、curPercent--表示当前上传文件的进度值（百分比）
//3、total--表示总的上传文件数
//4、totalPercent--表示总的上传进度（百分比）
MyUtil.logI(curIndex+" "+curPercent+" "+total+" "+totalPercent);
}
@Override
public void onError(int arg0, String arg1) {
// TODO Auto-generated method stub
toast("error "+arg1);
MyUtil.logI("errer "+arg1);
}
});
}
// 清理缓存
public void clear(View v){
if(cache.length()!=0){
File[] files=cache.listFiles();
for(File file:files){
file.delete();
}
cache.delete();
toast("缓存清理成功");
}else{
toast("暂无缓存");
}
}
public void toast(String msg){
Toast.makeText(this, msg, Toast.LENGTH_SHORT).show();
}
}
MainActivity
-
public class MainActivity extends Activity { private ListView lv; private MyAdapter adapter; private File cache; private List<Person> list; protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); initView(); } private void initView() { // TODO Auto-generated method stub lv=(ListView)findViewById(R.id.listView1); list=new ArrayList<Person>(); cache=new File(Environment.getExternalStorageDirectory(),"cache"); if(!cache.exists()){ cache.mkdirs(); } getData(); } private void getData() { // TODO Auto-generated method stub //查询数据 BmobQuery<Person> bq=new BmobQuery<Person>(); bq.setCachePolicy(CachePolicy.CACHE_ELSE_NETWORK); //缓存查询 bq.findObjects(this, new FindListener<Person>() { @Override public void onSuccess(List<Person> arg0) { // TODO Auto-generated method stub list=arg0; adapter=new MyAdapter(MainActivity.this, list, cache); lv.setAdapter(adapter); } @Override public void onError(int arg0, String arg1) { // TODO Auto-generated method stub MyUtil.logI("errer "+arg1); } }); }
MyAdapter
-
public class MyAdapter extends BaseAdapter { private Context context; private List<Person> list; private File cache; public MyAdapter(Context context, List<Person> list, File cache) { this.context = context; this.list = list; this.cache = cache; } @Override public int getCount() { // TODO Auto-generated method stub return list.size(); } @Override public Object getItem(int position) { // TODO Auto-generated method stub return list.get(position); } @Override public long getItemId(int position) { // TODO Auto-generated method stub return position; } @Override public View getView(int position, View convertView, ViewGroup parent) { // TODO Auto-generated method stub ViewHolder vh; if(convertView==null){ convertView=LayoutInflater.from(context).inflate(R.layout.item, null); vh=new ViewHolder(); vh.tv=(TextView)convertView.findViewById(R.id.tv); vh.iv=(ImageView)convertView.findViewById(R.id.iv); convertView.setTag(vh); }else{ vh=(ViewHolder)convertView.getTag(); } final Person p=list.get(position); vh.tv.setText(p.getStr()); // 异步的加载图片 MyUtil mu=new MyUtil(); AsyncImageTask as=new AsyncImageTask(mu,vh.iv,cache); if(p.getIcPath()!=null){ as.execute(p.getIcPath()); }else{ vh.iv.setImageResource(R.drawable.ic_launcher); } return convertView; } class ViewHolder{ TextView tv; ImageView iv; } }
MyUtil
-
public class MyUtil { /** * 从网络上获取图片，如果图片在本地存在的话就直接拿，如果不存在再去服务器上下载图片 * */ public Uri getImageURI(String path,File cache) throws Exception{ String name=MD5.getMD5(path)+path.substring(path.lastIndexOf(".")); logI("name"+name); File file=new File(cache, name); // 如果图片存在本地缓存目录，则不去服务器下载 if(file.exists()){ logI("cache"); return Uri.fromFile(file); }else{ URL url=new URL(path); HttpURLConnection conn=(HttpURLConnection)url.openConnection(); conn.setConnectTimeout(5000); conn.setRequestMethod("GET"); conn.setDoInput(true); if(conn.getResponseCode()==200){ InputStream is=conn.getInputStream(); FileOutputStream fos=new FileOutputStream(file); byte[] b=new byte[2*1024]; int len=0; while((len=is.read(b))!=-1){ fos.write(b,0,len); } is.close(); fos.close(); return Uri.fromFile(file); } } return null; } public static void logI(String msg){ Log.i("-------", msg); } }
AsyncImageTask
public class AsyncImageTask extends AsyncTask<String, Integer, Uri> {
private ImageView ivIcon;
private MyUtil mu;
private File cache;
public AsyncImageTask(MyUtil mu,ImageView ivIcon,File cache) {
this.mu=mu;
this.ivIcon = ivIcon;
this.cache=cache;
}
@Override
// TODO Auto-generated method stub
try {
return mu.getImageURI(arg0[0], cache);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(Uri result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
if(ivIcon!=null && result!=null){
ivIcon.setImageURI(result);
}
}
}
