监听EditText的变化

package com.lingdududu.watcher; import android.app.Activity; import android.app.AlertDialog; import android.content.DialogInterface; import android.os.Bundle; import android.text.Editable; import android.text.TextWatcher; import android.util.Log; import android.widget.EditText; public class MainActivity extends Activity { private EditText text; String str; &＃64;Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); text &＃61; (EditText)findViewById(R.id.text); text.addTextChangedListener(textWatcher); } private TextWatcher textWatcher &＃61; new TextWatcher() { &＃64;Override public void afterTextChanged(Editable s) { // TODO Auto-generated method stub Log.d("TAG","afterTextChanged--------------->"); } &＃64;Override public void beforeTextChanged(CharSequence s, int start, int count, int after) { // TODO Auto-generated method stub Log.d("TAG","beforeTextChanged--------------->"); } &＃64;Override public void onTextChanged(CharSequence s, int start, int before, int count) { Log.d("TAG","onTextChanged--------------->"); str &＃61; text.getText().toString(); try { //if ((heighText.getText().toString())!&＃61;null) Integer.parseInt(str); } catch (Exception e) { // TODO: handle exception showDialog(); } } }; private void showDialog(){ AlertDialog dialog; AlertDialog.Builder builder &＃61; new AlertDialog.Builder(MainActivity.this); builder.setTitle("消息").setIcon(android.R.drawable.stat_notify_error); builder.setMessage("你输出的整型数字有误&＃xff0c;请改正"); builder.setPositiveButton("确定", new DialogInterface.OnClickListener(){ &＃64;Override public void onClick(DialogInterface dialog, int which) { // TODO Auto-generated method stub } }); dialog &＃61; builder.create(); dialog.show(); } }


package com.lingdududu.test; import android.app.Activity; import android.os.Bundle; import android.text.Editable; import android.text.TextWatcher; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.TextView; public class MainActivity extends Activity { private Button clearBtn; private EditText et; private TextView tv; final int MAX_LENGTH &＃61; 20; int Rest_Length &＃61; MAX_LENGTH; &＃64;Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); tv &＃61;(TextView)findViewById(R.id.tv); et &＃61; (EditText)findViewById(R.id.et); clearBtn &＃61; (Button)findViewById(R.id.btn); et.addTextChangedListener(new TextWatcher() { &＃64;Override public void beforeTextChanged(CharSequence s, int start, int count, int after) { tv.setText("还能输入"&＃43;Rest_Length&＃43;"个字"); } &＃64;Override public void afterTextChanged(Editable s) { tv.setText("还能输入"&＃43;Rest_Length&＃43;"个字"); } &＃64;Override public void onTextChanged(CharSequence s, int start, int before, int count) { if(Rest_Length>0){ Rest_Length &＃61; MAX_LENGTH - et.getText().length(); } } }); clearBtn.setOnClickListener(new Button.OnClickListener() { &＃64;Override public void onClick(View v) { et.setText(""); Rest_Length &＃61; MAX_LENGTH; } }); } }