Android实现应用下载并自动安装apk包

安装：

1 String str = "/CanavaCancel.apk";
2 String fileName = Environment.getExternalStorageDirectory() + str;
3 Intent intent = new Intent(Intent.ACTION_VIEW);
4 intent.setDataAndType(Uri.fromFile(new File(fileName)),"application/vnd.android.package-archive");
5 startActivity(intent);

卸载：

1 Uri packageURI = Uri.parse("package:com.demo.CanavaCancel");
2 Intent uninstallIntent = new Intent(Intent.ACTION_DELETE, packageURI);
3 startActivity(uninstallIntent);

Environment拥有一些可以获取环境变量的方法 

package:com.demo.CanavaCancel 这个形式是 package:程序完整的路径 (包名+程序名).