一、前言：
关于EditText的输入问题，网上也有很多，一般处理EditText的输入问题，通常有两种方式：
1、使用addTextChangedListener 方法
代码如下：
editText.addTextChangedListener(new TextWatcher() {
@Override
public void onTextChanged(CharSequence s,
int start, int before,
int count) {
}
@Override
public void beforeTextChanged(CharSequence s,
int start, int count,
int after) {
}
@Override
public void afterTextChanged(Editable s) {
}
});
不过，此种方法对于处理EditText的回显，会很麻烦，在输入完成的监听方法中afterTextChanged 处理输入内容，再设置到EditText中，会出现死循环的问题，虽然也有方法避免，但是工作量会增加不少。
2、使用EditText的输入过滤器InputFilter
使用方法如下：
editText.setFilters(new InputFilter[]{new EtInputFilter()});
其中的EtInputFilter 为集成InputFilter的自定义过滤器，而且InputFilter 也提供了两个已经处理好的过滤器：
AllCaps ：此过滤器将大写所有小写字母。
LengthFilter ：此过滤器将限制输入内容的长度在指定长度范围内。
本人总结了一些常用的过滤器，集成到了一起，使用很简单：
EtInputFilters filter = new EtInputFilters(EtInputFilters.TYPE_PHONENUMBER);
filter.setPhone();
editText.setFilters(new InputFilter[]{filter});
自定义过滤器如下：
/**
* Created by Administrator on 2017-11-20.
* EditText的过滤器
*/
public class EtInputFilters implements InputFilter {
/**
* 限制输入的最大值
*/
public static final int TYPE_MAXNUMBER = 1;
/**
* 限制输入最大长度
*/
public static final int TYPE_MAXLENGTH = 2;
/**
* 限制输入小数位数
*/
public static final int TYPE_DECIMAL = 3;
/**
* 限制输入最小整数
*/
public static final int TYPE_MINNUMBER = 4;
/**
* 限制输入手机号
*/
public static final int TYPE_PHONENUMBER = 5;
private Pattern mPattern;
private double mMaxNum; //最大数值
private int mMaxLength; //最大长度
private int mType = 0;
public EtInputFilters(int type) {
this.mType = type;
}
@Override
public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {
switch (mType) {
case TYPE_MAXNUMBER:
return filterMaxNum(source, start, end, dest, dstart, dend);
case TYPE_MAXLENGTH:
return filterMaxLength(source, start, end, dest, dstart, dend);
case TYPE_DECIMAL:
return filterDecimal(source, dest, dstart, dend);
case TYPE_MINNUMBER:
return filterMinnum(source, dest, dstart);
case TYPE_PHONENUMBER:
return filterPhoneNum(source, dest, dstart);
}
return source;
}
/**
* 最大值的限制
* @param min 允许的最小值
* @param maxNum 允许的最大值
* @param numOfDecimals 允许的小数位
*/
public EtInputFilters setMaxNum(int min, double maxNum, int numOfDecimals) {
this.mMaxNum = maxNum;
this.mPattern = Pattern.compile("^" + (min < 0 ? "-?" : "")
+ "[0-9]*\\.?[0-9]" + (numOfDecimals > 0 ? ("{0," + numOfDecimals + "}$") : "*"));
return this;
}
/**
* 过滤最大值
*/
private CharSequence filterMaxNum(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {
if (source.equals(".")) {
if (dstart == 0 || !(dest.charAt(dstart - 1) >= '0' && dest.charAt(dstart - 1) <= '9') || dest.charAt(0) == '0') {
return "";
}
}
if (source.equals("0") && (dest.toString()).contains(".") && dstart == 0) {
return "";
}
StringBuilder builder = new StringBuilder(dest);
builder.delete(dstart, dend);
builder.insert(dstart, source);
if (!mPattern.matcher(builder.toString()).matches()) {
return "";
}
if (!TextUtils.isEmpty(builder)) {
double num = Double.parseDouble(builder.toString());
if (num > mMaxNum) {
return "";
}
}
return source;
}
/**
* 设置最大长度
* @param maxLength 最大长度
*/
public EtInputFilters setMaxNum(int maxLength) {
this.mMaxLength = maxLength;
return this;
}
/**
* 过滤最大长度
*/
private CharSequence filterMaxLength(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {
int keep = mMaxLength - (dest.length() - (dend - dstart));
if (keep <= 0) {
return "";
} else if (keep >= end - start) {
return null; // keep original
} else {
keep += start;
if (Character.isHighSurrogate(source.charAt(keep - 1))) {
--keep;
if (keep == start) {
return "";
}
}
return source.subSequence(start, keep);
}
}
/**
* 设置可输入小数位数
* @param decimal 允许的小数位
*/
public EtInputFilters setDecimal(int decimal) {
this.mPattern = Pattern.compile("^[0-9]*\\.?[0-9]"
+ (decimal > 0 ? ("{0," + decimal + "}$") : "*"));
return this;
}
/**
* 过滤小数
*/
private CharSequence filterDecimal(CharSequence source, Spanned dest, int dstart, int dend) {
if (source.equals(".")) {
if (dstart == 0 || !(dest.charAt(dstart - 1) >= '0' && dest.charAt(dstart - 1) <= '9') || dest.charAt(0) == '0') {
return "";
}
}
if (source.equals("0") && (dest.toString()).contains(".") && dstart == 0) { //防止在369.369的最前面输入0变成0369.369这种不合法的形式
return "";
}
StringBuilder builder = new StringBuilder(dest);
builder.delete(dstart, dend);
builder.insert(dstart, source);
if (!mPattern.matcher(builder.toString()).matches()) {
return "";
}
return source;
}
/**
* 设置只能输入整数，限制最小整数
* @param minnum 最小整数
*/
public EtInputFilters setMinnumber(int minnum) {
this.mPattern = Pattern.compile("^" + (minnum < 0 ? "-?" : "") + "[0-9]*$");
return this;
}
/**
* 过滤整数
*/
private CharSequence filterMinnum(CharSequence source, Spanned dest, int dstart) {
StringBuilder builder = new StringBuilder(dest);
builder.insert(dstart, source);
if (!mPattern.matcher(builder.toString()).matches()) {
return "";
}
return source;
}
/**
* 设置只能输入手机号
* @return
*/
public EtInputFilters setPhone() {
this.mPattern = Pattern.compile("^((13[0-9])|(15[^4])|(18[0-9])|(17[0-8])|(1[57]))\\d{8}$");
return this;
}
/**
* 过滤手机号
*/
private CharSequence filterPhoneNum(CharSequence source, Spanned dest, int dstart) {
StringBuilder builder = new StringBuilder(dest);
builder.insert(dstart, source);
int length = builder.length();
if (length == 1) {
if (builder.charAt(0) == '1') {
return source;
} else {
return "";
}
}
if (length > 0 && length <= 11) {
if (mPattern.matcher(builder.toString()).matches()) {
return source;
} else {
return "";
}
}
return "";
}
}
