String dirPath = "/data/data/" + getPackageName() + "/files/test.apk"; //文件需有可读权限
Intent intent = new Intent();
intent.setAction(android.content.Intent.ACTION_VIEW);
intent.setDataAndType(Uri.parse("file://" + filePath), "application/vnd.android.package-archive");
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);

private void startUninstall(final String pkg) {
  if (!InstallUtils.isApkInstalled(mContext, pkg)) {
   Toast.makeText(mContext, "程序未安装，无需卸载！", Toast.LENGTH_SHORT).show();
   return;
  } else {
   Uri packageURI = Uri.parse("package:" + pkg);
   Intent uninstallIntent = new Intent(Intent.ACTION_DELETE, packageURI);
   startActivity(uninstallIntent);
  }
 }

Intent to = new Intent();
  to.putExtra("TOP", "你好，来自上层信息");
  to.setClassName(pkgName, clsName);
  to.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
  startActivity(to);

InstallUtils.java　public static boolean isApkInstalled(Context context, final String pkgName) {
　try {
   context.getPackageManager().getPackageInfo(pkgName, 0);
   return true;
  } catch (NameNotFoundException e) {
   //e.printStackTrace();
  }
  return false;

<intent-filter >
       <action android:name="android.intent.action.VIEW" />
       <category android:name="android.intent.category.DEFAULT" />
</intent-filter>就不会在桌面出现该应用的启动图标了。

<intent-filter >
       <action android:name="android.intent.action.VIEW" />
       <category android:name="android.intent.category.DEFAULT" />
</intent-filter>