Android重写返回键处理事件
@Overridepublic 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();}