房产公司网站建设方案ppt,网站建设都有哪些方面,wordpress diy插件,贝壳找房房源以前用过android.text.TextWatcher来监听文本发生变化#xff0c;但没有仔细去想它#xff0c;今天兴致来了就发个疯来玩玩吧#xff01; 有点担心自己理解错#xff0c;所以还是先把英文API解释给大家看看 1、什么情况下使用了#xff1f; When an object of a type is a…以前用过android.text.TextWatcher来监听文本发生变化但没有仔细去想它今天兴致来了就发个疯来玩玩吧 有点担心自己理解错所以还是先把英文API解释给大家看看 1、什么情况下使用了 When an object of a type is attached to an Editable, its methods will be called when the text is changed. 2、下面是它的三个抽象方法 /**
*This method is called to notify you that, within s, the count characters beginning at start are about to be replaced by new text with length *after. It is an error to attempt to make changes to s from this callback.
*/
public void beforeTextChanged(CharSequence s, int start, int count, int after)/**
*This method is called to notify you that, within s, the count characters beginning at start have just replaced old text that had length *before. It is an error to attempt to make changes to s from this callback.
*/
public void onTextChanged(CharSequence s, int start, int before, int count)/**
*This method is called to notify you that, somewhere within s, the text has been changed. It is legitimate(合理) to make further changes to s *from this callback, but be careful not to get yourself into an infinite loop, because any changes you make will cause this method to be *called again recursively(递归). (You are not told where the change took place because other afterTextChanged() methods may already have made *other changes and invalidated the offsets. But if you need to know here, you can use Spannable.setSpan in onTextChanged to mark your place *and then look up from here where the span ended up.
*/
public void afterTextChanged(Editable s)3、英文看的不汪不楚的还是实际来进行调试看结果(注意我是按他们触发的顺序来进行排列的) 我输入结果a ab about abou
得到的结果
s:是改变前的结果start是改变前的位置count是减少时改变的个数after是增加时改变的个数
beforeTextChanged(CharSequence s, int start, int count,int after) //null 0 0 1//a 1 0 1//ab 2 0 3//about 4 1 0
s:是改变后的结果start是改变前的位置before是减少时改变的个数count是增加时改变的个数
onTextChanged(CharSequence s, int start, int before,int count)//a 0 0 1//ab 1 0 1//about 2 0 3//abou 4 1 0afterTextChanged(Editable s)//a//ab//about//abou 现在来看看怎么实现吧 首先是实现他的接口 implements TextWatcher 这是他的监听事件addTextChangedListener(this)转载于:https://www.cnblogs.com/xiaolonghome/p/6728612.html
