* @return the number of elements in this list */ public int size() { return size; } 有时我们需要保证ArrayList的capacity能满足一个最小值,比如ArrayList的当前capacity为10,且size也为10,这时需要插入一个成员,就要保证ArrayList的capacity至少为11。这时就需要ArrayList的扩容机制发挥作用。 ArrayList的扩容相...
1. ArrayList add() andaddAll()Methods TheArrayList.add()method inserts the specified element at the specified position in this list. Itshifts the element currently at that position (if any) and any subsequent elements to the right (will add one to their indices). Note that indices start fr...
源码中一目了然,在往list中插入数据之前会先对你插入的位置作检查,插入的位置只能是[0, list.size()], 另外要说明的是,这个size在ArrayList中的定义是: /** * The size of the ArrayList (the number of elements it contains). * @serial */ private int size; 即list实际包含元素的个数。目前为止我们...
* The array buffer into which the elements of the ArrayList are stored. * The capacity of the ArrayList is the length of this array buffer. Any * empty ArrayList with elementData == DEFAULTCAPACITY_EMPTY_ELEMENTDATA * will be expanded to DEFAULT_CAPACITY when the first element is added. */...
* Inserts the specified element at the specified position in this * list. Shifts the element currently at that position (if any) and * any subsequent elements to the right (adds one to their indices). * * @param index index at which the specified element is to be inserted ...
/*** The size of the ArrayList (the number of elements it contains).** @serial*/private int size; 那么,我们看到之前异常截图,显示Size为0,这是为啥来,我们好像已经初始化了大小。 看来,问题,在于初始化。我们就来看看,我们自定义集合时,到底干了点什么。
第一,ArrayList不是Array,容量自动增加,不需要初始化。好吧事实上,Array也不需要初始化,因为新生成的Array所有值都是null或者primitive type的默认值,除非你用initializer。 第二,add不是赋值,如果不确定,RTFM Inserts the specified element at the specified position in this list. Shifts the element currently at...
Console.WriteLine( "The ArrayList initially contains the following:" ); PrintValues( myAL, '\t' ); Console.WriteLine( "The Queue initially contains the following:" ); PrintValues( myQueue, '\t' ); // Copies the Queue elements to the end of the ArrayList. myAL.AddRange( myQueue );...
* Inserts the specified element at the specified position in this * list. Shifts the element currently at that position (if any) and * any subsequent elements to the right (adds one to their indices). * * @param index index at which the specified element is to be inserted ...
* The array buffer into which the elements of the ArrayList are stored. * The capacity of the ArrayList is the length of this array buffer. Any * empty ArrayList with elementData == DEFAULTCAPACITY_EMPTY_ELEMENTDATA * will be expanded to DEFAULT_CAPACITY when the first element is added. ...