<?xml version="1.0" encoding="utf-8"?>　　<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 　　android:orientation="vertical" 　　android:layout_width="fill_parent" 　　android:layout_height="fill_parent"　　>　　<TextView android:id="@+id/tv" 　　android:layout_width="fill_parent" 　　android:layout_height="wrap_content" 　　android:textColor="@android:color/white" 　　android:ellipsize="marquee" 　　android:focusable="true" 　　android:marqueeRepeatLimit="marquee_forever" 　　android:focusableInTouchMode="true" 　　android:scrollHorizontally="true" 　　android:text="Please input the text:"　　/>　　<EditText android:id="@+id/ET" 　　android:layout_width="match_parent" 　　android:layout_height="wrap_content" 　　android:inputType="number"/>　　</LinearLayout>

package com.android.text; import android.app.Activity; import android.os.Bundle; import android.text.Editable; import android.text.TextWatcher; import android.util.Log; import android.widget.EditText; import android.widget.TextView; import android.widget.Toast; public class TextWatcherDemo extends Activity { private TextView mTextView; private EditText mEditText; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super .onCreate(savedInstanceState); setContentView(R.layout.main); mTextView = (TextView)findViewById(R.id.tv); mEditText = (EditText)findViewById(R.id.ET); mEditText.addTextChangedListener(mTextWatcher); } TextWatcher mTextWatcher = new TextWatcher() { private CharSequence temp; private int editStart ; private int editEnd ; @Override public void beforeTextChanged(CharSequence s, int arg1, int arg2, int arg3) { temp = s; } @Override public void onTextChanged(CharSequence s, int arg1, int arg2, int arg3) { mTextView.setText(s); } @Override public void afterTextChanged(Editable s) { editStart = mEditText.getSelectionStart(); editEnd = mEditText.getSelectionEnd(); if (temp.length() > 10 ) { Toast.makeText(TextWatcherDemo. this , "你输入的字数已经超过了限制！" , Toast.LENGTH_SHORT) .show(); s.delete(editStart-1 , editEnd); int tempSelection = editStart; mEditText.setText(s); mEditText.setSelection(tempSelection); } } };}