死代码 android setMultiChoiceItems

发布于 2025-01-02 08:20:37 字数 670 浏览 4 评论 0原文

我使用 setMultiChoiceItems 作为对话框中的列表。当单击“确定”时，代码是

 .setPositiveButton(R.string.alert_remove, new DialogInterface.OnClickListener(){
public void onClick(DialogInterface dialog, int which){
String[] res = null;
for(int i=-1,l=usrCats.length; ++i<l;){
    if(selections[i])
       res[i] = usrCats[i].toString();
}
if(res != null && res.length>0)
   dbManager.removeUserShoppingCategories(res);
}       
})

我想检查是否使用 if(selections[i] 选择了某个项目，如果是，请将名称添加到 String

i 在 res[i] = usrCats[i].toString() 中具有空指针访问权限，并且在最后一个 if 语句中出现死代码警告。

我正在使用最后一个 if 来检查是否有任何选择以便调用我的方法。

我做错了什么？

原文

i use setMultiChoiceItems for a list in a dialog.
when click on ok the code is

 .setPositiveButton(R.string.alert_remove, new DialogInterface.OnClickListener(){
public void onClick(DialogInterface dialog, int which){
String[] res = null;
for(int i=-1,l=usrCats.length; ++i<l;){
    if(selections[i])
       res[i] = usrCats[i].toString();
}
if(res != null && res.length>0)
   dbManager.removeUserShoppingCategories(res);
}       
})

i want to check if an item is selected with if(selections[i] and if so, add the name in a
String

i am having a null pointer access in the res[i] = usrCats[i].toString() and a dead code warning in the last if statement.

i am using the last if, to check if there has been any selection so as to call my method.

what am i doing wrong?

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黯然#的苍凉 2025-01-09 08:20:37

        .setPositiveButton(R.string.alert_remove, new DialogInterface.OnClickListener(){
        public void onClick(DialogInterface dialog, int which){
        String[] res = null; // you initialised it with null
        for(int i=-1,l=usrCats.length; ++i<l;){ /*this line and the below line are condition 
    statemnts whose code may not run. so there are chances that your **res** will 
    remain initialised with null*/
            if(selections[i])
               res[i] = usrCats[i].toString();
        }
        if(res != null && res.length>0)// so here it shows a dead code warning.
           dbManager.removeUserShoppingCategories(res);
        }       
        })

        .setPositiveButton(R.string.alert_remove, new DialogInterface.OnClickListener(){
        public void onClick(DialogInterface dialog, int which){
        String[] res = null; // you initialised it with null
        for(int i=-1,l=usrCats.length; ++i<l;){ /*this line and the below line are condition 
    statemnts whose code may not run. so there are chances that your **res** will 
    remain initialised with null*/
            if(selections[i])
               res[i] = usrCats[i].toString();
        }
        if(res != null && res.length>0)// so here it shows a dead code warning.
           dbManager.removeUserShoppingCategories(res);
        }       
        })

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