安装： 
String str = "/CanavaCancel.apk";
 String fileName = Environment.getExternalStorageDirectory() + str;
 Intent intent = new Intent(Intent.ACTION_VIEW);
 intent.setDataAndType(Uri.fromFile(new File(fileName)), "application/vnd.android.package-archive");
 startActivity(intent);
卸载：
Uri packageURI = Uri.parse("package:com.demo.CanavaCancel");   
Intent uninstallIntent = new Intent(Intent.ACTION_DELETE, packageURI);   
startActivity(uninstallIntent);