案例------用户登录记住密码

1.任务要求运行效果图：



2.操作步骤及内容

首先使用Android Studio创建一个项目Case_Login, 使Activity name为LoginActivity,然后把所需的图片添加到drawable中，并在里面新建btn_select.xml,btn_shape.xml,btn_shape_after.xml,loginbg.xml和logintop_roundbg.xml,然后再新建一个login_top.xml,最后新建一个MainActivity及其对应的activity_main.xml

详细代码如下：

LoginActivity:

package cn.edu.bzu.case_login;

import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.Toast;

public class LoginActivity extends AppCompatActivity {
private EditText etName;
private EditText etPassword;
private CheckBox cbIsRememberPass;
private SharedPreferences sharedPreferences;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
initViews();
sharedPreferences=getSharedPreferences("rememberpassword", Context.MODE_PRIVATE);
boolean isRemember=sharedPreferences.getBoolean("rememberpassword",false);
if(isRemember) {
String name = sharedPreferences.getString("name", "");
String password = sharedPreferences.getString("password", "");
etName.setText(name);
etPassword.setText(password);
cbIsRememberPass.setChecked(true);
}
}
private void initViews(){
etName=(EditText)findViewById(R.id.etName);
etPassword=(EditText)findViewById(R.id.etPassword);
cbIsRememberPass=(CheckBox)findViewById(R.id.cbIsRememberPass);
}
public void login(View view){
String name=etName.getText().toString();
String password=etPassword.getText().toString();
if("admin".equals(name)&&"123456".equals(password)){
SharedPreferences.Editor editor=sharedPreferences.edit();
if(cbIsRememberPass.isChecked()){
editor.putBoolean("rememberpassword",true);
editor.putString("name",name);
editor.putString("password",password);
}else{
editor.clear();

}
editor.commit();
Intent intent=new Intent(this,MainActivity.class);
startActivity(intent);
finish();

}else {
Toast.makeText(this,"账号或密码有误",Toast.LENGTH_LONG).show();
}

}
}

MainActivity:

package cn.edu.bzu.case_login;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
}

activity_login.xml:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_login"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft=
4000
"@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:background="@drawable/loginbg"
tools:context="cn.edu.bzu.case_login.LoginActivity">

<include layout="@layout/login_top"></include>

<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:srcCompat="@drawable/deer"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"
android:layout_marginBottom="20dp"
android:id="@+id/imageView" />

</RelativeLayout>

activity_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="cn.edu.bzu.case_login.MainActivity">

<TextView
android:text="Welcome you"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:textSize="50sp"
android:layout_marginTop="260dp"
android:id="@+id/textView" />
</RelativeLayout>

login_top.xml:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="@dimen/activity_horizontal_margin"
android:background="@drawable/logintop_roundbg">

<EditText
android:id="@+id/etName"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@android:drawable/edit_text"
android:drawableLeft="@drawable/icon_user"
android:drawablePadding="10dp"
android:ems="10"
android:hint="@string/etName">

<requestFocus />
</EditText>

<EditText
android:id="@+id/etPassword"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@id/etName"
android:background="@android:drawable/edit_text"
android:drawableLeft="@drawable/icon_pass"
android:drawablePadding="10dp"
android:ems="10"
android:hint="@string/etPass"
android:inputType="textPassword">

<requestFocus />
</EditText>

<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@id/etPassword">

<CheckBox
android:text="记住密码"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:id="@+id/cbIsRememberPass"
android:textSize="20sp"
android:layout_weight="1" />

<Button
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:background="@drawable/btn_select"
android:onClick="login"
android:text="@string/btnLogin" />

</LinearLayout>
</RelativeLayout>

drawable中btn_select.xml:

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="@drawable/btn_shape" android:state_pressed="false"></item>
<item android:drawable="@drawable/btn_shape_after" android:state_pressed="true"></item>
</selector>

drawable中btn_shape.xml:

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
<solid android:color="#FF72CAE1"></solid>
<corners android:radius="10dp"></corners>
</shape>

drawable中btn_shape_after.xml:

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
<solid android:color="#87cefa"></solid>
<corners android:radius="10dp"></corners>
</shape>

drawable中loginbg.xml:

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" >
<gradient
android:startColor="#FFACDAE5"
android:endColor="#FF72CAE1"
android:angle="45"
/>
</shape>

drawable中logintop_roundbg.xml:

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle">
<corners android:radius="10dp"></corners>
<solid android:color="#55FFFFFF"></solid>
</shape>

3.最终运行结果图如下：



输入账号和密码并勾选记住密码选框



点击登录进入欢迎界面



退出再重新登录时会出现如下界面，记住了用户的登录密码