Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(Uri.fromFile(new File(Environment.getExternalStorageDirectory() + "/download/" + "app.apk")), "application/vnd.android.package-archive");
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
Intent intent = new Intent(Intent.ACTION_DELETE);
intent.setData(Uri.parse("package:com.example.mypackage"));
startActivity(intent);