java 在android中调整字节数组的大小
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/10595064/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
resize a byte array in android
提问by Riskhan
I am newbie in android. I want to resize a byte array in function. Is it possible or not. If any problem please suggest a solution to do it.
我是安卓新手。我想在函数中调整一个字节数组的大小。有没有可能。如果有任何问题，请提出解决方案。
public void myfunction(){
byte[] bytes = new byte[1024];
....................
.... do some operations........
................................
byte[] bytes = new byte[2024];
}
采纳答案by UVM
You can do it like this:
你可以这样做：
bytes = new byte[2024];
But your old content will be discarded.If you need the old data as well, then need to create a new byte array with a diff size and call System.arrayCopy()method to copy data from old to new.
但是你的旧内容会被丢弃。如果你还需要旧数据，那么需要创建一个具有差异大小的新字节数组，并调用System.arrayCopy()方法将数据从旧数据复制到新数据。
回答by Hartmut Pfitzinger
To achieve the effect of resizing a byte array without loosing the content, there are several solutions in Java already mentioned:
为了达到在不丢失内容的情况下调整字节数组大小的效果，Java中已经提到了几种解决方案：
1)ArrayList<Byte>(see the answers of a.ch. and kgiannakakis)
1）ArrayList<Byte>（见a.ch.和kgiannakakis的回答）
2)System.arraycopy()(see the answers of jimpic, kgiannakakis, and UVM)
2）System.arraycopy()（见jimpic、kgiannakakis、UVM的回答）
Something like:
就像是：
byte[] bytes = new byte[1024];
//
// Do some operations with array bytes
//
byte[] bytes2 = new byte[2024];
System.arraycopy(bytes,0,bytes2,0,bytes.length);
//
// Do some further operations with array bytes2 which contains
// the same first 1024 bytes as array bytes
3)I would like to add a third way which I think is most elegant: Arrays.copyOfRange()
3）我想添加第三种我认为最优雅的方式：Arrays.copyOfRange()
byte[] bytes = new byte[1024];
//
// Do some operations with array bytes
//
bytes = Arrays.copyOfRange(bytes,0,2024);
//
// Do some further operations with array bytes whose first 1024 bytes
// didn't change and whose remaining bytes are padded with 0
Of course there are further solutions (e.g. copying the bytes in a loop). Concerning efficiency, see this
当然还有进一步的解决方案（例如在循环中复制字节）。关于效率，看这个
回答by kgiannakakis
You can't resize an array in Java. You could use a Listto do what you want:
您不能在 Java 中调整数组的大小。你可以使用List来做你想做的事：
List<Byte> bytes = new ArrayList<Byte>();
Another way will be to use System.arraycopy. In that case you will create a second array and copy the content of the first array into it.
另一种方法是使用System.arraycopy。在这种情况下，您将创建第二个数组并将第一个数组的内容复制到其中。
回答by jimpic
You cannot do that. But you can create a new array and use System.arraycopy to copy the old contents to the new one.
你不能这样做。但是您可以创建一个新数组并使用 System.arraycopy 将旧内容复制到新内容。
回答by a.ch.
Use ArrayList<Byte>instead, Java arrays don't allow resizing, ArrayLists do, but make it a little bit different. You can't specify their size (actually you needn't - it is done automatically), you may specify initial capacity (which is good practice if you know how many elements will the ArrayListcontain):
使用ArrayList<Byte>代替，Java 数组不允许调整大小，ArrayLists 允许，但让它有点不同。您无法指定它们的大小（实际上您不需要 - 它会自动完成），您可以指定初始容量（如果您知道将ArrayList包含多少个元素，这是一种很好的做法）：
byte myByte = 0;
ArrayList<Byte> bytes = new ArrayList<Byte>(); //size is 0
ArrayList<Byte> bytes2 = new ArrayList<Byte>(1024); //initial capacity specified
bytes.add(myByte); //size is 1
...
I'd recommend you to look through this Java Collections tutorial.
我建议您阅读此Java 集合教程。
