原文网址:http://blog.csdn.net/fulinwsuafcie/article/details/7437768
方法一:
在 xml 文件中设置文本编辑框属性作字符数限制
如:android:maxLength="10" 即限制最大输入字符个数为10
方法二:
在代码中使用InputFilter 进行过滤
//editText.setFilters(new InputFilter[]{new InputFilter.LengthFilter(20)}); 即限定最大输入字符数为20
- public class TextEditActivity extends Activity {
- /** Called when the activity is first created. */
- @Override
- public void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.main);
- EditText editText = (EditText)findViewById(R.id.entry);
- editText.setFilters(new InputFilter[]{new InputFilter.LengthFilter(20)});
- }
- }
方法三:
利用 TextWatcher 进行监听
- package cie.textEdit;
- import android.text.Editable;
- import android.text.Selection;
- import android.text.TextWatcher;
- import android.widget.EditText;
- /*
- * 监听输入内容是否超出最大长度,并设置光标位置
- * */
- public class MaxLengthWatcher implements TextWatcher {
- private int maxLen = 0;
- private EditText editText = null;
- public MaxLengthWatcher(int maxLen, EditText editText) {
- this.maxLen = maxLen;
- this.editText = editText;
- }
- public void afterTextChanged(Editable arg0) {
- // TODO Auto-generated method stub
- }
- public void beforeTextChanged(CharSequence arg0, int arg1, int arg2,
- int arg3) {
- // TODO Auto-generated method stub
- }
- public void onTextChanged(CharSequence arg0, int arg1, int arg2, int arg3) {
- // TODO Auto-generated method stub
- Editable editable = editText.getText();
- int len = editable.length();
- if(len > maxLen)
- {
- int selEndIndex = Selection.getSelectionEnd(editable);
- String str = editable.toString();
- //截取新字符串
- String newStr = str.substring(0,maxLen);
- editText.setText(newStr);
- editable = editText.getText();
- //新字符串的长度
- int newLen = editable.length();
- //旧光标位置超过字符串长度
- if(selEndIndex > newLen)
- {
- selEndIndex = editable.length();
- }
- //设置新光标所在的位置
- Selection.setSelection(editable, selEndIndex);
- }
- }
- }
对应的 activity 部分的调用为:
- package cie.textEdit;
- import android.app.Activity;
- import android.os.Bundle;
- import android.text.InputFilter;
- import android.widget.EditText;
- public class TextEditActivity extends Activity {
- /** Called when the activity is first created. */
- @Override
- public void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.main);
- EditText editText = (EditText) findViewById(R.id.entry);
- editText.addTextChangedListener(new MaxLengthWatcher(10, editText));
- }
- }
限制输入字符数为10个
main.xml 文件
- <?xml version="1.0" encoding="utf-8"?>
- <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
- android:layout_width="fill_parent"
- android:layout_height="fill_parent">
- <TextView
- android:id="@+id/label"
- android:layout_width="fill_parent"
- android:layout_height="wrap_content"
- android:text="Type here:"/>
- <EditText
- android:id="@+id/entry"
- android:singleLine="true"
- android:layout_width="fill_parent"
- android:layout_height="wrap_content"
- android:background="@android:drawable/editbox_background"
- android:layout_below="@id/label"/>
- <Button
- android:id="@+id/ok"
- android:layout_width="wrap_content"
- android:layout_height="wrap_content"
- android:layout_below="@id/entry"
- android:layout_alignParentRight="true"
- android:layout_marginLeft="10dip"
- android:text="OK" />
- <Button
- android:layout_width="wrap_content"
- android:layout_height="wrap_content"
- android:layout_toLeftOf="@id/ok"
- android:layout_alignTop="@id/ok"
- android:text="Cancel" />
- </RelativeLayout>
效果为输入了10个字符后,光标停在末尾