在androi中，volley适合小文件的获取和大并发，如果支持大文件的下载可以用Android原生的DownloadManager。DownloadManager默认支持多线程下载、断点续传等。
基础代码如下：
public class MainActivity extends Activity {
private DownloadManager manager ;
private DownloadCompleteReceiver receiver;
private Button downBtn ;
private Context mContext;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mContext = this;
//获取下载服务
IntentFilter filter = new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE);
receiver = new DownloadCompleteReceiver();
registerReceiver(receiver, filter);
downBtn = (Button)findViewById(R.id.button1);
downBtn.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
//创建下载请求
DownloadManager.Request request = new DownloadManager.Request(
Uri.parse("http://www.bz55.com/uploads/allimg/110807/2019341501-0.jpg"));
request.setAllowedNetworkTypes(Request.NETWORK_WIFI);
//定义notification提示
request.setNotificationVisibility(Request.VISIBILITY_VISIBLE);
request.setTitle("下载");
request.setDescription("壁纸正在下载");
//在onclick中无法直接通过this取到Context上下文
request.setDestinationInExternalFilesDir(mContext, null, "test_download");
manager =(DownloadManager)getSystemService(DOWNLOAD_SERVICE);
manager.enqueue(request);
}
});
}
//接受下载完成后的intent
class DownloadCompleteReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
if(intent.getAction().equals(DownloadManager.ACTION_DOWNLOAD_COMPLETE)){
Toast.makeText(context, "download complete", Toast.LENGTH_SHORT).show();
}
}
}
@Override
protected void onDestroy() {
if(receiver != null){
unregisterReceiver(receiver);
}
super.onDestroy();
}
}