android 中如何限制 EditText 最大输入字符数 |
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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 效果为输入了10个字符后,光标停在末尾
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