java - android 异步任务

Question

在 Android 中定义 ASyncTask 及其关联方法时，会出现 3 个点，例如 protected Long doInBackground(URL... urls)

这些点是什么意思？

Answer 1

这并不完全相同。考虑以下示例

示例1:

public String concatenateStrings(String... strings){
  StringBuffer sb = new StringBuffer();
  for( int i = 0; i < strings.length; i++ )
    sb.append( strings[i] );

  return sb.toString();
}

示例2:

public String concatenateStrings2(String[] strings){
  StringBuffer sb = new StringBuffer();
  for( int i = 0; i < strings.length; i++ )
    sb.append( strings[i] );

  return sb.toString();
}

它们几乎完全相同，对吧？错了，叫他们区别就大了。第一个示例允许添加未定义数量的字符串。

示例1:

concantenateStrings("hello", "World", " I ", " can ", " add ", " so ", " many strings here" );

示例2:

Strings[] myStrings = new Strings[7];
myStrings[0] = "Hello";
myStrings[1] = "world";
myStrings[2] = " I ";
...
myStrings[6] = " many strings here";
concatenateStrings2( myStrings );