InputFilter主要是对输入的文本进行过滤的，里面只有一个filter方法
//InputFilter接口，需要重写filter方法
public interface InputFilter
{
/**
* @param source 输入的文字
* @param start 输入-0，删除-0
* @param end 输入-source文字的长度，删除-0
* @param dest 原先显示的内容
* @param dstart 输入-原光标位置，删除-光标删除结束位置
* @param dend 输入-原光标位置，删除-光标删除开始位置
* @return
*/
//主要重写这个方法
public CharSequence filter(CharSequence source, int start, int end,
Spanned dest, int dstart, int dend);
/**
* This filter will capitalize all the lower case letters that are added
* through edits.
*/
//接口内的静态内部类，，，输入小写转换成大写
public static class AllCaps implements InputFilter {
public CharSequence filter(CharSequence source, int start, int end,
Spanned dest, int dstart, int dend) {
for (int i = start; i < end; i++) {
if (Character.isLowerCase(source.charAt(i))) {
char[] v = new char[end - start];
TextUtils.getChars(source, start, end, v, 0);
String s = new String(v).toUpperCase();
if (source instanceof Spanned) {
SpannableString sp = new SpannableString(s);
TextUtils.copySpansFrom((Spanned) source,
start, end, null, sp, 0);
return sp;
} else {
return s;
}
}
}
return null; // keep original
}
}
/**
* This filter will constrain edits not to make the length of the text
* greater than the specified length.
*/
// 长度过滤器，限制输入的长度
public static class LengthFilter implements InputFilter {
private final int mMax;
public LengthFilter(int max) {
mMax = max;
}
public CharSequence filter(CharSequence source, int start, int end, Spanned dest,
int dstart, int dend) {
int keep = mMax - (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);
}
}
/**
* @return the maximum length enforced by this input filter
*/
public int getMax() {
return mMax;
}
}
}
使用：
editext.setText(string);
editext.setFilters(filter);
Editext的setText函数：
private void setText(CharSequence text, BufferType type,
boolean notifyBefore, int oldlen) {
......//其他代码
int n = mFilters.length;
//重点：设置文本需要提前经过设置的所有过滤器filter
for (int i = 0; i < n; i++) {
CharSequence out = mFilters[i].filter(text, 0, text.length(), EMPTY_SPANNED, 0, 0);
if (out != null) {
text = out;
}
}
if (notifyBefore) {
if (mText != null) {
oldlen = mText.length();
sendBeforeTextChanged(mText, 0, oldlen, text.length());
} else {
sendBeforeTextChanged("", 0, 0, text.length());
}
}
......//其他代码
//监听器TextWatcher的接口
sendOnTextChanged(text, 0, oldlen, textLength);
onTextChanged(text, 0, oldlen, textLength);
notifyViewAccessibilityStateChangedIfNeeded(AccessibilityEvent.CONTENT_CHANGE_TYPE_TEXT);
if (needEditableForNotification) {
sendAfterTextChanged((Editable) text);
} else {
// Always notify AutoFillManager - it will return right away if autofill is disabled.
notifyAutoFillManagerAfterTextChangedIfNeeded();
}
// SelectionModifierCursorController depends on textCanBeSelected, which depends on text
if (mEditor != null) mEditor.prepareCursorControllers();
}
1.不让输入框输入内容
private InputFilter[] filter = new InputFilter[] {
new InputFilter() {
// 不让输入框输入内容
@Override
public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {
return null;
}
},
/**这里限制输入的长度为5个字母*/
new InputFilter.LengthFilter(5),
/**输入小写转换成大写*/
new InputFilter.AllCaps();
};
2.只要你输入内容都会替换成“I LOVE YOU”，删除 - 正常删除
@Override
public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {
if (end > 0){
return "I LOVE YOU";
}else {
return null;
}
}
3. 控制不让输入空格，不让输入数字大于13位（解决手机号输入问题）
@Override
public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {
if(source.equals(" ") || source.toString().contentEquals("\n") || dstart == 13)return "";
else return null;
}
4.不让输入框接着输入内容（原来有内容，禁止输入）
@Override
public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {
return dest.subSequence(dstart,dend);
