如何在android中使用if-else
我正在尝试使用if-else方法初始化字符串数组。。但它不起作用。怎么做如何在android中使用if-else,android,string,if-statement,Android,String,If Statement,我正在尝试使用if-else方法初始化字符串数组。。但它不起作用。怎么做 if(itemno==2){ String[] values = new String[] { "Category31", "Category32", "Category33", "Category34", "Category35", "Cat
if(itemno==2){
String[] values = new String[] { "Category31",
"Category32",
"Category33",
"Category34",
"Category35",
"Category36",
"Category37",
"Android Example List View" ,
"daniel",
"dude",
"hello",
"super,","dukker"
};}
else if(itemno==3){
String[] values = new String[] { "Category31",
"Category32",
"Category33",
"Category34",
"Category35",
"Category36",
"Category37",
"Android Example List View" ,
"daniel",
"dude",
"hello",
"super,","dukker"
};}
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, android.R.id.text1, values);
l.setAdapter(adapter);
if(itemno==2){
字符串[]值=新字符串[]{“类别31”,
“类别32”,
“类别33”,
“类别34”,
“类别35”,
“类别36”,
“类别37”,
“Android示例列表视图”,
“丹尼尔”,
“伙计”,
“你好”,
“超级”,“杜克”
};}
否则如果(itemno==3){
字符串[]值=新字符串[]{“类别31”,
“类别32”,
“类别33”,
“类别34”,
“类别35”,
“类别36”,
“类别37”,
“Android示例列表视图”,
“丹尼尔”,
“伙计”,
“你好”,
“超级”,“杜克”
};}
ArrayAdapter=新的ArrayAdapter(此,
android.R.layout.simple_list_item_1,android.R.id.text1,值);
l、 设置适配器(适配器);
但在适配器中,显示变量不被接受的错误。。“帮助我”因为如果无法访问,则您的值变量位于括号内
外部请将其声明为类变量,然后在if块中初始化。您被声明为
local
。因此它只能访问本地,这意味着在If
块内。它不能在If
语句之外访问。所以请制作String[]值
在全局变量处关于if-else的语法是正确的。若要删除错误,请在if-else语句之外声明“String[]values;”。您在if
的块内声明值变量。在您的案例中,变量的范围是从if
的开始到结束
if(something)
{
//start of if scope
String[] values = {"one"};
//values available here with contents: {"one"}
//end of if scope
}
else
{
//start of else scope
String[] values;
//values available here - different from the values above. this variable value is null here
//end of else scope
}
//none of the values declared above are available here. From the compiler's PoW, no values variable has been declared here.
您试图实现的解决方案是将值
声明移到if
或else
范围之外:放置字符串[]值在if
之前进行编码,并删除if
和else
块中的String[]
声明。您需要在if-else块的范围之外声明String[]值。您应该查看“java scopes variable”并了解它