android完全退出程序

 AlertDialog.Builder builder = new Builder(this);
	          builder.setMessage("确定要退出吗?");
	          builder.setTitle("提示");
	          builder.setPositiveButton("确认",new android.content.DialogInterface.OnClickListener() {
	             @Override
	                      public void onClick(DialogInterface dialog, int which) {
	                          dialog.dismiss();
	                          android.os.Process.killProcess(android.os.Process.myPid());
	                      }
	                  });
	          builder.setNegativeButton("取消", new android.content.DialogInterface.OnClickListener() {
	                      public void onClick(DialogInterface dialog, int which) {
	                          dialog.dismiss();
	                      }
	                  });
	          builder.create().show();