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
public class TextEditActivity extends Activity {
@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)});
}
}
editText.setFilters(new InputFilter[]{new
InputFilter.LengthFilter(20)}); 即限定最大输入字符数为20
方法三：
利用 TextWatcher 进行监听
自定义TextWatcher
/*
* 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);
}
}
}
调用自定义TextWatcher
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));
}
}