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