(一）
1.效果图：实现用户名为张三密码为123则登陆成功，其他则登陆失败，并且可以记住密码
2.activity_main.xml
1 <?xml version="1.0" encoding="utf-8"?> 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 3 xmlns:tools="http://schemas.android.com/tools" 4 android:layout_width="match_parent" 5 android:layout_height="match_parent" 6 android:orientation="vertical" 7 tools:context="com.example.administrator.hello11.MainActivity"> 8 9 10 11 <LinearLayout 12 android:orientation="horizontal" 13 android:layout_width="match_parent" 14 android:layout_height="wrap_content"> 15 <TextView 16 android:id="@+id/tv" 17 android:text="用户名:" 18 android:layout_width="wrap_content" 19 android:layout_height="wrap_content" /> 20 <EditText 21 android:id="@+id/name" 22 android:layout_width="match_parent" 23 android:layout_height="wrap_content" /> 24 </LinearLayout> 25 <LinearLayout 26 android:orientation="horizontal" 27 android:layout_width="match_parent" 28 android:layout_height="wrap_content"> 29 <TextView 30 android:id="@+id/tv2" 31 android:text="密 码:" 32 android:layout_width="wrap_content" 33 android:layout_height="wrap_content" /> 34 <EditText 35 android:id="@+id/pass" 36 android:layout_width="match_parent" 37 android:layout_height="wrap_content" /> 38 </LinearLayout> 39 <CheckBox 40 android:id="@+id/cb" 41 android:text="记住密码" 42 android:layout_width="wrap_content" 43 android:layout_height="wrap_content" /> 44 <LinearLayout 45 android:orientation="horizontal" 46 android:layout_width="wrap_content" 47 android:layout_height="wrap_content" 48 android:layout_gravity="center_horizontal"> 49 <Button 50 android:text="登陆" 51 android:onClick="doClick" 52 android:id="@+id/btn_login" 53 android:layout_width="wrap_content" 54 android:layout_height="wrap_content" /> 55 <Button 56 android:text="重置" 57 android:onClick="doClick" 58 android:id="@+id/btn_reset" 59 android:layout_width="wrap_content" 60 android:layout_height="wrap_content" /> 61 </LinearLayout> 62 63 </LinearLayout>
3.MainActivity.java
1 package com.example.administrator.hello11; 2 3 import android.content.SharedPreferences; 4 import android.support.v7.app.AppCompatActivity; 5 import android.os.Bundle; 6 import android.view.View; 7 import android.widget.Button; 8 import android.widget.CheckBox; 9 import android.widget.EditText; 10 import android.widget.Toast; 11 12 public class MainActivity extends AppCompatActivity { 13 private EditText name; 14 private EditText password; 15 private CheckBox checkBox; 16 private SharedPreferences.Editor editor; 17 18 19 20 @Override 21 protected void onCreate(Bundle savedInstanceState) { 22 super.onCreate(savedInstanceState); 23 setContentView(R.layout.activity_main); 24 25 name = (EditText)findViewById(R.id.name); 26 password =(EditText)findViewById(R.id.pass); 27 checkBox=(CheckBox)findViewById(R.id.cb); 28 29 //获取sp对象 30 SharedPreferences sp = getSharedPreferences("userInfo",MainActivity.MODE_PRIVATE); 31 // 获取editor 对象 32 editor = sp.edit(); 33 34 //二次登陆 35 String user_name=sp.getString("u_name",""); 36 String user_pass=sp.getString("u_pass",""); 37 name.setText(user_name); 38 if (user_name==null||user_pass.length()==0){ 39 checkBox.setChecked(false); 40 }else { 41 checkBox.setChecked(true); 42 password.setText(user_pass); 43 } 44 45 46 } 47 public void doClick(View v){ 48 switch (v.getId()){ 49 case R.id.btn_login: 50 String username = name.getText().toString(); 51 String userpass = password.getText().toString(); 52 editor.putString("u_name",username); 53 if("zhangsan".equals(username)&&"123".equals(userpass)){ 54 if(checkBox.isChecked()){ 55 editor.putString("u_pass",userpass); 56 editor.commit(); 57 }else { 58 editor.remove("u_pass"); 59 editor.commit(); 60 } 61 Toast.makeText(MainActivity.this, "登陆成功", Toast.LENGTH_SHORT).show(); 62 }else { 63 Toast.makeText(MainActivity.this, "登陆失败", Toast.LENGTH_SHORT).show(); 64 } 65 editor.commit(); 66 break; 67 case R.id.btn_reset: 68 name.setText(""); 69 password.setText(""); 70 checkBox.setChecked(false); 71 break; 72 73 } 74 } 75 }