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TA貢獻1842條經驗 獲得超22個贊
long lastClick放在 函數外, 是對象的成員變量, 默認初始化為0.
放在函數內, 稱為本地變量. JLS7, #16 里有寫:
"EACH local variable (§14.4) and every blank final field (§4.12.4,
§8.3.1.2) must have a definitely assigned value when any access of its
value occurs. An access to its value consists of the simple name of
the variable (or, for a field, the simple name of the field qualified
by this) occurring anywhere in an expression except as the left-hand
operand of the simple assignment operator = (§15.26.1). For every
access of a local variable or blank final field x, x must be
definitely assigned before the access, or a compile-time error occurs"
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