小程序 提示文本框还能输入多少个字符源码.rar

package com.wang; import android.app.Activity; import android.os.Bundle; import android.text.Editable; import android.text.TextWatcher; import android.view.KeyEvent; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.TextView; public class EditTextTest extends Activity { Button clearbtn; EditText et; TextView tv; final int MAX_LENGTH = 50; int Rest_Length = MAX_LENGTH; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); tv =(TextView)findViewById(R.id.tv); et = (EditText)findViewById(R.id.et); et.addTextChangedListener(new TextWatcher() { @Override public void onTextChanged(CharSequence s, int start, int before, int count) { if(Rest_Length>0){ Rest_Length = MAX_LENGTH - et.getText().length(); } } @Override public void beforeTextChanged(CharSequence s, int start, int count, int after) { tv.setText("还可以输入"+Rest_Length+"个字"); } @Override public void afterTextChanged(Editable s) { tv.setText("还可以输入"+Rest_Length+"个字"); } }); clearbtn = (Button)findViewById(R.id.btn); clearbtn.setOnClickListener(new Button.OnClickListener() { @Override public void onClick(View v) { et.setText(""); Rest_Length = MAX_LENGTH; } }); } }