Android重写返回键处理事件

@Override
	public void onBackPressed() {
		Dialog dialog = new AlertDialog.Builder(this).setTitle("信息提示")
				.setMessage("确定要退出系统吗?")
				.setPositiveButton("确定", new DialogInterface.OnClickListener() {
					@Override
					public void onClick(DialogInterface dialog, int which) {
						finish();
					}
				})
				.setNeutralButton("取消", new DialogInterface.OnClickListener() {
					@Override
					public void onClick(DialogInterface dialog, int which) {
						return;
					}
				}).create();
		dialog.show();
	}