Android登录界面的实现代码分享

package com.example.logindemo; 
import android.support.v7.app.ActionBarActivity; 
import android.text.Editable; 
import android.text.TextWatcher; 
import android.text.method.HideReturnsTransformationMethod; 
import android.text.method.PasswordTransformationMethod; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.Button; 
import android.widget.EditText; 
import android.widget.Toast; 
import android.os.Bundle; 
/** 
* 登录界面Demo 
* 
* @author ZHY 
* 
*/ 
public class MainActivity extends ActionBarActivity implements OnClickListener { 
private EditText username, password; 
private Button bt_username_clear; 
private Button bt_pwd_clear; 
private Button forgive_pwd; 
private Button bt_pwd_eye; 
private Button login; 
private Button register; 
private boolean isOpen = false; 
@Override 
protected void onCreate(Bundle savedInstanceState) { 
super.onCreate(savedInstanceState); 
setContentView(R.layout.activity_main); 
initView(); 
} 
private void initView() { 
username = (EditText) findViewById(R.id.username); 
// 监听文本框内容变化 
username.addTextChangedListener(new TextWatcher() { 
@Override 
public void onTextChanged(CharSequence s, int start, int before, 
int count) { 
// 获得文本框中的用户 
String user = username.getText().toString().trim(); 
if ("".equals(user)) { 
// 用户名为空,设置按钮不可见 
bt_username_clear.setVisibility(View.INVISIBLE); 
} else { 
// 用户名不为空，设置按钮可见 
bt_username_clear.setVisibility(View.VISIBLE); 
} 
} 
@Override 
public void beforeTextChanged(CharSequence s, int start, int count, 
int after) { 
} 
@Override 
public void afterTextChanged(Editable s) { 
} 
}); 
password = (EditText) findViewById(R.id.password); 
// 监听文本框内容变化 
password.addTextChangedListener(new TextWatcher() { 
@Override 
public void onTextChanged(CharSequence s, int start, int before, 
int count) { 
// 获得文本框中的用户 
String pwd = password.getText().toString().trim(); 
if ("".equals(pwd)) { 
// 用户名为空,设置按钮不可见 
bt_pwd_clear.setVisibility(View.INVISIBLE); 
} else { 
// 用户名不为空，设置按钮可见 
bt_pwd_clear.setVisibility(View.VISIBLE); 
} 
} 
@Override 
public void beforeTextChanged(CharSequence s, int start, int count, 
int after) { 
} 
@Override 
public void afterTextChanged(Editable s) { 
} 
}); 
bt_username_clear = (Button) findViewById(R.id.bt_username_clear); 
bt_username_clear.setOnClickListener(this); 
bt_pwd_clear = (Button) findViewById(R.id.bt_pwd_clear); 
bt_pwd_clear.setOnClickListener(this); 

bt_pwd_eye = (Button) findViewById(R.id.bt_pwd_eye); 
bt_pwd_eye.setOnClickListener(this); 
login = (Button) findViewById(R.id.login); 
login.setOnClickListener(this); 
egister = (Button) findViewById(R.id.register); 
register.setOnClickListener(this); 
forgive_pwd = (Button) findViewById(R.id.forgive_pwd); 
forgive_pwd.setOnClickListener(this); 
} 
@Override 
public void onClick(View v) { 
switch (v.getId()) { 
case R.id.bt_username_clear: 
// 清除登录名 
username.setText(""); 
break; 
case R.id.bt_pwd_clear: 
// 清除密码 
password.setText(""); 
break; 
case R.id.bt_pwd_eye: 
// 密码可见与不可见的切换 
if (isOpen) { 
isOpen = false; 
} else { 
isOpen = true; 
} 
// 默认isOpen是false,密码不可见 
changePwdOpenOrClose(isOpen); 
break; 
case R.id.login: 
// TODO 登录按钮 
break; 
case R.id.register: 
// 注册按钮 
Toast.makeText(MainActivity.this, "注册", 0).show(); 
break; 
case R.id.forgive_pwd: 
// 忘记密码按钮 
Toast.makeText(MainActivity.this, "忘记密码", 0).show(); 
break; 
default: 
break; 
} 
} 
/** 
* 密码可见与不可见的切换 
* 
* @param flag 
*/ 
private void changePwdOpenOrClose(boolean flag) { 
// 第一次过来是false，密码不可见 
if (flag) { 
// 密码可见 
bt_pwd_eye.setBackgroundResource(R.drawable.password_open); 
// 设置EditText的密码可见 
password.setTransformationMethod(HideReturnsTransformationMethod 
.getInstance()); 
} else { 
// 密码不接见 
bt_pwd_eye.setBackgroundResource(R.drawable.password_close); 
// 设置EditText的密码隐藏 
password.setTransformationMethod(PasswordTransformationMethod 
.getInstance()); 
} 
} 
}