在开发中总会遇到输入框的输入规则限制
比如 电话输入框电话号码的校验，密码规则的校验等 ，我们通常做法是提交操作时对每个输入框的输入内容进行校验，很多的if else ，代码看起来很乱，其实我们可以用反射注解的方式去声明一些判断规则这样会更好，代码可读性更强。
java反射文章推荐：http://www.jianshu.com/p/5b3acad0f025
下面我们通过一个例子去讲解注解方式去实现表达式的校验
这个包下定义的是注解实体类，每一个类都是一个注解规则，如Index类代码：
这个包下都是一些javabean, 如AttrBean代码：
BaseBean基础类，每个bean是一个规则javabean类，
结果回调类
处理回调校验结果
上面主要是校验器和工具类：
public class ValidateUtil {
/**
* 设置校验view的信息
* @param view
* @param isEditText
* @param msg
* @param validateResult
*/
private static void setViewInfo(Object view, boolean isEditText, String msg, IValidateResult validateResult) {
if (isEditText) {
validateResult.onValidateError(msg, ((EditText) view));
} else {
validateResult.onValidateError(msg, null);
}
}
/**
* 不可为空
* @param view
* @param isEt
* @param msg
* @param validateResult
* @return
*/
public static boolean notNull(Object view, boolean isEt, String msg, IValidateResult validateResult) {
if (TextUtils.isEmpty(((TextView) view).getText().toString())) {
setViewInfo(view, isEt, msg, validateResult);
return true;
}
return false;
}
/**
* 判断是否为空
* @param view
* @return
*/
public static boolean isNull(Object view) {
if (view == null)
throw new NullPointerException("view can not be null");
if (TextUtils.isEmpty(((TextView) view).getText().toString())) {
return true;
}
return false;
}
/**
* 根据正则表达式校验
* @param view
* @param isEt
* @param bean
* @param validateResult
* @return
*/
public static boolean checkPattern(Object view, boolean isEt, PatternBean bean, IValidateResult validateResult) {
if (isNull(view)) return true;
Pattern r = Pattern.compile(bean.pattern);
Matcher m = r.matcher(((TextView) view).getText().toString());
if (!m.matches()) {
setViewInfo(view, isEt, bean.msg, validateResult);
return true;
}
return false;
}
/**
* 最大长度校验
* @param view
* @param isEt
* @param bean
* @param validateResult
* @return
*/
public static boolean maxLenght(Object view, boolean isEt, LengthBean bean, IValidateResult validateResult) {
if (isNull(view)) return true;
if (((TextView) view).getText().toString().length() > bean.length) {
setViewInfo(view, isEt, bean.msg, validateResult);
return true;
}
return false;
}
}
public class ValidateManager {
private static final String TAG = "ValidateManager";
/**
* 注册的页面
*/
private static Map> registList = new HashMap<>();
/**
* 类型
*/
private static final String TYPE_NOTNULL = "NotNull";
private static final String TYPE_PATTERN = "PATTERN";
private static final String TYPE_MAXLENGTH = "MAXLENGTH";
private static final String TYPE_MINLENGTH = "MINLENGTH";
private static final String TYPE_PASSWORDFIRST = "PASSWORD_FIRST";
private static final String TYPE_PASSWORDSECOND = "PASSWORD_SECOND";
private static final String TYPE_SKIP = "SKIP";
public static void check(Object activity, boolean isSkip, IValidateResult validateResult) {
if (activity == null || validateResult == null) return;
List list = registList.get(activity);
if (list == null) return;
for (AttrBean attrBean : list) {
if (attrBean.index == null) {
return;
}
}
Collections.sort(list, new Comparator() {
public int compare(AttrBean arg0, AttrBean arg1) {
return arg0.index.compareTo(arg1.index);
}
});
for (AttrBean attrBean : list) {
for (Basebean bean : attrBean.annos) {
if (isSkip) {
if (TYPE_SKIP.equals(attrBean.annos.getLast().type)) {
break;
}
}
if (TYPE_NOTNULL.equals(bean.type)) {
if (ValidateUtil.notNull(attrBean.view, attrBean.isEditText, bean.msg, validateResult)) {
return;
}
} else if (TYPE_PATTERN.equals(bean.type)) {
if (ValidateUtil.checkPattern(attrBean.view, attrBean.isEditText, (PatternBean) bean, validateResult)) {
return;
}
} else if (TYPE_MAXLENGTH.equals(bean.type)) {
if (ValidateUtil.maxLenght(attrBean.view, attrBean.isEditText, (LengthBean) bean, validateResult)) {
return;
}
} else if (TYPE_MINLENGTH.equals(bean.type)) {
if (ValidateUtil.minLenght(attrBean.view, attrBean.isEditText, (LengthBean) bean, validateResult)) {
return;
}
} else if (TYPE_PASSWORDFIRST.equals(bean.type)) {
if (ValidateUtil.isNull(attrBean.view)) {
return;
}
pwd1Attr = attrBean;
} else if (TYPE_PASSWORDSECOND.equals(bean.type)) {
if (ValidateUtil.password(attrBean, pwd1Attr, (PasswordBean) bean, validateResult)) {
return;
}
pwd1Attr = null;
}
}
}
validateResult.onValidateSuccess();
pwd1Attr = null;
}
private static AttrBean pwd1Attr = null;
private static class ValidateRegRunnable implements Runnable {
Object target;
public ValidateRegRunnable(Object target) {
this.target = target;
}
@Override
public void run() {
try {
Class clazz = target.getClass();
for (Field field : clazz.getDeclaredFields()) {
if (field.isAnnotationPresent(NotNull.class) ||
field.isAnnotationPresent(Pattern.class) ||
field.isAnnotationPresent(MaxLength.class) ||
field.isAnnotationPresent(MinLength.class) ||
field.isAnnotationPresent(Index.class) ||
field.isAnnotationPresent(PasswordFirst.class) ||
field.isAnnotationPresent(PasswordSecond.class)) {
if (field.getType() != EditText.class) {
throw new RuntimeException("annotation must be on the EditText");
}
field.setAccessible(true);
List editTextMap = registList.get(target);
if (editTextMap == null) {
editTextMap = new LinkedList<>();
registList.put(target, editTextMap);
}
AttrBean attr = new AttrBean();
attr.name = field.getName();
attr.view = field.get(target);
if (field.getType() == EditText.class) {
attr.isEditText = true;
} else if (field.getType() == TextView.class) {
attr.isEditText = false;
}
if (attr.annos == null) {
attr.annos = new LinkedList<>();
}
editTextMap.add(attr);
if (field.isAnnotationPresent(NotNull.class))
attr.annos.add(validateType(field, TYPE_NOTNULL));
if (field.isAnnotationPresent(Pattern.class))
attr.annos.add(validateType(field, TYPE_PATTERN));
if (field.isAnnotationPresent(MaxLength.class)) {
attr.annos.add(validateType(field, TYPE_MAXLENGTH));
if (attr.view != null && attr.isEditText) {
int length = field.getAnnotation(MaxLength.class).length();
((EditText) attr.view).setFilters(new InputFilter[]{new InputFilter.LengthFilter(length)});
}
}
if (field.isAnnotationPresent(MinLength.class))
attr.annos.add(validateType(field, TYPE_MINLENGTH));
if (field.isAnnotationPresent(PasswordFirst.class)) {
attr.annos.add(validateType(field, TYPE_PASSWORDFIRST));
if (attr.view != null && attr.isEditText) {
((EditText) attr.view).setTransformationMethod(PasswordTransformationMethod.getInstance());
}
}
if (field.isAnnotationPresent(PasswordSecond.class)) {
attr.annos.add(validateType(field, TYPE_PASSWORDSECOND));
if (attr.view != null && attr.isEditText) {
((EditText) attr.view).setTransformationMethod(PasswordTransformationMethod.getInstance());
}
}
if (field.isAnnotationPresent(Index.class))
attr.index = field.getAnnotation(Index.class).value();
if (field.isAnnotationPresent(Skip.class))
attr.annos.add(validateType(field, TYPE_SKIP));
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
/**
* 根据不同类型校验
* @param field
* @param type
* @return
* @throws IllegalAccessException
*/
private static Basebean validateType(Field field, String type) throws IllegalAccessException {
if (type.equals(TYPE_NOTNULL)) {
NotNull notnull = field.getAnnotation(NotNull.class);
NotNullBean bean = new NotNullBean();
bean.msg = notnull.msg();
bean.type = type;
return bean;
} else if (type.equals(TYPE_PATTERN)) {
Pattern re = field.getAnnotation(Pattern.class);
PatternBean reBean = new PatternBean();
reBean.msg = re.msg();
reBean.type = TYPE_PATTERN;
reBean.pattern = re.pattern();
return reBean;
} else if (type.equals(TYPE_MAXLENGTH)) {
MaxLength anno = field.getAnnotation(MaxLength.class);
LengthBean bean = new LengthBean();
bean.msg = anno.msg();
bean.type = TYPE_MAXLENGTH;
bean.length = anno.length();
return bean;
} else if (type.equals(TYPE_MINLENGTH)) {
MinLength anno = field.getAnnotation(MinLength.class);
LengthBean bean = new LengthBean();
bean.msg = anno.msg();
bean.type = TYPE_MINLENGTH;
bean.length = anno.length();
return bean;
} else if (type.equals(TYPE_PASSWORDFIRST)) {
PasswordBean bean = new PasswordBean();
bean.type = TYPE_PASSWORDFIRST;
return bean;
} else if (type.equals(TYPE_PASSWORDSECOND)) {
PasswordSecond anno = field.getAnnotation(PasswordSecond.class);
PasswordBean bean = new PasswordBean();
bean.msg = anno.msg();
bean.type = TYPE_PASSWORDSECOND;
return bean;
} else if (type.equals(TYPE_SKIP)) {
Basebean bean = new Basebean();
bean.type = TYPE_SKIP;
return bean;
}
return null;
}
/**
* 注册
* @param target
*/
public static void regist(final Object target) {
new Thread(new ValidateRegRunnable(target)).start();
}
/**
* 解注册
* @param target
*/
public static void unregist(Object target) {
registList.remove(target);
}
}
我只贴出了部分代码，可以根据项目实际需求去添加规则，再把相应的校验器代码扩展到这个类里。
我们在主页面使用 按照正常的注解方式去实现 如下：
index是校验的顺序，需要正则表达式校验的输入框我们通过pattern去通过正则表达式去实现，minLength和maxLength是最小最大长度校验
完成后调用ValidateManager.check(this , isSkip , this);实现校验功能，经过回调处理（isSkip是否可以忽略不校验此项）
可以对指定输入框的view进行错误提醒，比如上面 对输入框背景色设置红色等操作。需源码的留邮箱。