用户登录密码保存

首先我们做的案例是用户登录密码实现保存功能，效果界面如下：



首先进行页面设计，在activity_main.xml实现如下代码

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/activity_main"
android:background="@drawable/loginbg"
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="bzu.edu.cn.case_login.MainActivity">
<include layout="@layout/login_top">
</include>
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:srcCompat="@drawable/deer"
android:id="@+id/imageView"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true" />
</RelativeLayout>

然后我们新建一个login.xml,代码如下：

<?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="match_parent"
android:background="@drawable/logintop_groungdg"
android:padding="@dimen/activity_horizontal_margin">
<EditText
android:id="@+id/etName"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:ems="10"
android:background="@android:drawable/edit_text"
android:drawableLeft="@drawable/icon_user"
android:hint="@string/etName"
android:drawablePadding="10dp"
>
<requestFocus/>
</EditText>
<EditText
android:id="@+id/etPassword"
android:layout_below="@id/etName"
android:inputType="textPassword"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:ems="10"
android:background="@android:drawable/edit_text"
android:drawableLeft="@drawable/icon_pass"
android:hint="@string/etName"
android:drawablePadding="10dp">
<requestFocus/>
</EditText>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@+id/etPassword"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true">
<CheckBox
android:layout_width="0dp"
android:layout_height="48dp"
android:layout_weight="1"
android:id="@+id/cblsRemember"
android:textSize="20sp"
android:text="记住密码"/>
<Button
android:onClick="login"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:layout_marginLeft="10dp"
android:background="@drawable/btn_select"
android:text="@string/btnLogin"
android:textSize="20sp"/>
</LinearLayout>
</RelativeLayout>

所需样式依次建立如下：

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>

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>

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>

然后建立welcome.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_welcome"
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="bzu.edu.cn.case_login.WelcomeActivity">
<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="welcome you"
android:textSize="45sp"/>
</RelativeLayout>

完成界面设计后，我们实现功能代码，首先实现MainActivity：

package bzu.edu.cn.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 MainActivity extends AppCompatActivity {
private EditText etName;
private EditText etPassword;
private SharedPreferences sharedPreferences;
private CheckBox cblsRemember;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
sharedPreferences = getSharedPreferences("rememberpassword", Context.MODE_PRIVATE);
boolean isRemembered=sharedPreferences.getBoolean("rememberpassword",false);
if (isRemembered){
String name=sharedPreferences.getString("name","");
String password=sharedPreferences.getString("password","");
etName.setText(name);
etPassword.setText(password);
cblsRemember.setChecked(true);
}
}
private void initView() {
etName = (EditText) findViewById(R.id.etName);
etPassword = (EditText) findViewById(R.id.etPassword);
cblsRemember = (CheckBox) findViewById(R.id.cblsRemember);
}

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 (cblsRemember.isChecked()) {
editor.putBoolean("rememberpassword", true);
editor.putString("name", name);
editor.putString("password", password);
}else{
editor.clear();
}
editor.commit();
Intent intent=new Intent(this,WelcomeActivity.class);
startActivity(intent);
finish();
}else {
Toast.makeText(this,"账号或密码有误",Toast.LENGTH_LONG).show();
}
}
}

再次实现welcome.xml的实现：

package bzu.edu.cn.case_login;

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

public class WelcomeActivity extends AppCompatActivity {
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_welcome);
}
}

最后进行清单文件的配置：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="bzu.edu.cn.case_login">
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".WelcomeActivity"></activity>
</application>
</manifest>

这样我们简单的案例就完成了。