初学android的一个小问题,请各位朋友来帮忙

我修改了 main.xml  然后我在主函数中调用main里面的东西 
例如在main.xml加了一个id  我在主函数用 R.id老是调用不出来 
如何才能快速的准确的调用出 main.xml里面的东西呢?

答案：额，你在main.xml中加了一个id以后，要右键点save，才会将这个id加入到R中，否则是没有的。。。R里的东西是程序自动生成的～～～

其他：public final class R {
    public static final class attr {
    }
    public static final class drawable {
        public static final int back01=0x7f020000;
        public static final int back02=0x7f020001;
        public static final int black=0x7f020007;
        public static final int blue=0x7f020008;
        public static final int doc=0x7f020002;
        public static final int folder=0x7f020003;
        public static final int icon=0x7f020004;
        public static final int pdf=0x7f020005;
        public static final int violet=0x7f020009;
        public static final int white=0x7f020006;
    }
    public static final class id {
        public static final int btBrowse=0x7f050009;
        public static final int btExit=0x7f050006;
        public static final int btOK=0x7f050007;
        public static final int btShow=0x7f05000c;
        public static final int cbKeepCaches=0x7f05000b;
        public static final int cbUseFontSubstitution=0x7f05000a;
        public static final int etPassword=0x7f050005;
        public static final int filename=0x7f050008;
        public static final int icon=0x7f050003;
        public static final int mPath=0x7f050002;
        public static final int output=0x7f05000d;
        public static final int pagenum_edit=0x7f050001;
        public static final int text=0x7f050004;
        public static final int username_view=0x7f050000;
    }
    public static final class layout {
        public static final int dialog_pagenumber=0x7f030000;
        public static final int file_explorer=0x7f030001;
        public static final int file_row=0x7f030002;
        public static final int pdf_file_password=0x7f030003;
        public static final int pdf_file_select=0x7f030004;
        public static final int scroll_layout=0x7f030005;
    }
    public static final class string {
        public static final int app_name=0x7f040001;
        public static final int hello=0x7f040000;
    }
}

像上面的一样,在id里有的就能显示出来  调出来
还有就是  id的格式是
android:id="@+id/filename"
其中
android:id="@+id/XXX"
XXX是id的名字 注意书写方式
android:id="@+id/XXX"

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