为dialog添加items，并且控制每个activity只能出现一个dialog，不会重复弹出

public static void showDialogex(final Context context)
{
final String items[]={"我要截屏反馈","禁用摇一摇反馈功能","没啥事"};
//dialog参数设置
AlertDialog.Builder builder=new AlertDialog.Builder(context);
builder.setTitle(FeedbackManager.DIALOG_TITLE);
//        builder.setMessage(FeedbackManager.DIALOG_PROMPT);
builder.setOnDismissListener(new DialogInterface.OnDismissListener() {
@Override
public void onDismiss(DialogInterface dialog) {
isShow=false;
FeedbackManager.isFirstTime=false;
}
});
builder.setItems(items, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
switch (which) {
case 0:
DoScreenShot.shoot((Activity) context);
Intent intent = new Intent(context,ScreenShotActivity.class);
context.startActivity(intent);
break;
case 1:
FeedbackManager.disableScreenShot();
break;
case 2:
break;
}
dialog.dismiss();
}
});
if((isShow==false)||(context!=exContext)){//摇一摇之后立即切换界面时也会出现dialog
builder.show();
isShow=true;
}
exContext=context;
}