首页 > 资讯 > 移动开发 >安卓studio 个人课设项目：“这个app“——实现注册登录，显示用户信息功能，并跳转对应网页

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安卓studio 个人课设项目：“这个app“——实现注册登录，显示用户信息功能，并跳转对应网页

android java webview 2023-09-15 14:09:23 809人浏览独家记忆

摘要

目录目录功能说明登录页面注册页面登录后界面点击头像出现侧滑界面，并显示用户信息点击编辑按钮进入信息编辑页面保存后返回用户名已更改跳转网页相关代码布局登录界面注册界面信息显示界面主界面实现侧滑布局

功能说明

登录页面

注册页面

能够验证用户名是否已存在，并判断两次密码是否一致

登录后界面

点击头像出现侧滑界面，并显示用户信息

当前用户无信息

点击编辑按钮进入信息编辑页面

编辑信息

保存后返回

信息页面显示更改后的信息

用户名已更改

修改用户名后，下次登录需要填写更改后的用户名

跳转网页

点击按钮进入相应的网页，这里点击 “长知识”>>“菜鸟学编程”

相关代码

布局

登录界面

注册界面

信息显示界面

主界面

实现侧滑布局

信息编辑界面

网页显示界面

manifest

逻辑代码

LoginActivity

package com.example.myfirst;import Androidx.appcompat.app.AppCompatActivity;import android.content.Intent;import android.os.Bundle;import android.text.TextUtils;import android.view.View;import android.widget.Button;import android.widget.EditText;import com.example.myfirst.util.DBHelper;import com.example.myfirst.util.ToastUtil;import com.example.myfirst.util.User;import java.util.ArrayList;public class LoginActivity extends AppCompatActivity implements View.OnClickListener {     //当需要用到新的onClick()时，要 implements View.OnClickListener    private Button mBtLogin;            //声明变量    private EditText mEtUser;    private EditText mEtPassWord;    private Button mBtReGISter;    private DBHelper dbHelper;    public static int userId;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_login);        mBtLogin = findViewById(R.id.bt_login);        mEtPassword = findViewById(R.id.Ed_password);        mEtUser = findViewById(R.id.Ed_username);        mBtRegister = findViewById(R.id.bt_register);        dbHelper = new DBHelper(this);        mBtLogin.setOnClickListener(this);       //当需要用到新的onClick()时，就用this        mBtRegister.setOnClickListener(this);    }    public void onClick(View view){        switch (view.getId()){            case R.id.bt_login:                String username = mEtUser.getText().toString().trim();                String password = mEtPassword.getText().toString().trim();                if(!TextUtils.isEmpty(username) && !TextUtils.isEmpty(password)){                    ArrayList userData = dbHelper.getData();  //在User list创建一个实例userData                    boolean judge = false;                          //并让userData获取数据库里的数据                    for (int i = 0; i < userData.size(); i++){                        User user = userData.get(i);                        if (username.equals(user.getName()) && password.equals(user.getPassword())){judge = true;userId = i;break;                        }              //遍历user id，当输入的用户名和密码与数据库里的数据匹配则judge=true                        else {judge = false;                        }                    }                    if (judge){                        ToastUtil.showMsg(LoginActivity.this,"登陆成功!");                        Intent intent2 = new Intent(this,Slideactivity.class);                        startActivity(intent2);                        finish();                    }                    else {                        ToastUtil.showMsg(LoginActivity.this,"用户名错误或密码错误!");                    }                }                else {                    ToastUtil.showMsg(LoginActivity.this,"用户名或密码不能为空");                }                break;            case R.id.bt_register:                Intent intent1 = new Intent(LoginActivity.this,RegisterActivity.class);                startActivity(intent1);                break;        }    }    public  static int getUserId(){        return userId;    }}

RegisterActivity

package com.example.myfirst;import androidx.appcompat.app.AppCompatActivity;import android.content.Intent;import android.os.Bundle;import android.text.TextUtils;import android.view.View;import android.widget.Button;import android.widget.EditText;import com.example.myfirst.util.DBHelper;import com.example.myfirst.util.ToastUtil;public class RegisterActivity extends AppCompatActivity implements View.OnClickListener{    private Button mBtToRegister;    private DBHelper dbHelper;    private EditText mEtSetUsername;    private EditText mEtSetUserPassword1;    private EditText mEtSetUserPassword2;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_register);        mEtSetUsername = findViewById(R.id.set_username);        mEtSetUserPassword1 = findViewById(R.id.set_userPassword1);        mEtSetUserPassword2 = findViewById(R.id.set_userPassword2);        mBtToRegister = findViewById(R.id.bt_startRegister);        dbHelper = new DBHelper(this);        mBtToRegister.setOnClickListener(this);    }    public void onClick(View view){        String username = mEtSetUsername.getText().toString().trim();        String password1 = mEtSetUserPassword1.getText().toString().trim();        String password2 = mEtSetUserPassword2.getText().toString().trim();        if (!TextUtils.isEmpty(username) && !TextUtils.isEmpty(password1)&& !TextUtils.isEmpty(password2)  ) {                if ((password1.equals(password2))) {                    if (dbHelper.add(username, password2)){                        //将用户名和密码加入到数据库中                        Intent intent2 = new Intent(this, LoginActivity.class);                        startActivity(intent2);                        finish();                        ToastUtil.showMsg(RegisterActivity.this,"注册成功！");                    }                    else {                        ToastUtil.showMsg(RegisterActivity.this,"该用户名已存在！");                    }                }                else {                    ToastUtil.showMsg(RegisterActivity.this,"密码输入不一致");                }        }        else {            ToastUtil.showMsg(RegisterActivity.this,"用户名和密码不能为空！");        }    }}

EditInfORMationActivity

信息编辑activity

package com.example.myfirst;import androidx.appcompat.app.AppCompatActivity;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.view.View;import android.widget.Button;import android.widget.EditText;import android.widget.RadioButton;import android.widget.RadioGroup;import com.example.myfirst.util.DBHelper;import com.example.myfirst.util.ToastUtil;import com.example.myfirst.util.User;import java.util.ArrayList;public class EditInformationActivity extends AppCompatActivity implements View.OnClickListener{    private EditText mEtUsername,mEtAge,mEtFavorite,mEtSignature;    private Button mBtSaveInformation;    private DBHelper dbHelper;    private RadioButton mRbMale,mRbFemale;    private String sexString;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_edit_infor);        mEtUsername = findViewById(R.id.Et_EditUsername);        mEtAge = findViewById(R.id.Et_editAge);        mRbMale = findViewById(R.id.rdB_male);        mRbFemale = findViewById(R.id.rdB_female);        mEtFavorite = findViewById(R.id.Et_editFavorite);        mEtSignature = findViewById(R.id.Et_editSignature);        mBtSaveInformation = findViewById(R.id.bt_saveInformation);        dbHelper = new DBHelper(this);        showRadioButtonIsCheck();        mBtSaveInformation.setOnClickListener(this);    }    private void showRadioButtonIsCheck(){            //定义一个根据用户性别显示 哪个radiobutton被选中的方法        ArrayList userData = dbHelper.getData();        User user = userData.get(LoginActivity.getUserId());        if (!(user.getSex() == null)){            if (user.getSex().equals("男")){                mRbMale.setChecked(true);            }else if (user.getSex().equals("女")){                mRbFemale.setChecked(true);            }        }    }    @Override    public void onClick(View view) {        String username = mEtUsername.getText().toString().trim();        String age = mEtAge.getText().toString();        String favorite = mEtFavorite.getText().toString();        String signature = mEtSignature.getText().toString();         //分别获取输入的用户信息        if (!username.isEmpty()){            dbHelper.updateUsername(username);        }        if (!age.isEmpty()){            dbHelper.updateAge(age);        }        if (mRbMale.isChecked()){            sexString = "男";        }else if (mRbFemale.isChecked()){            sexString = "女";        }        dbHelper.updateSex(sexString);        if (!favorite.isEmpty()){            dbHelper.updateFavorite(favorite);        }        if (!signature.isEmpty()){            dbHelper.updateSignature(signature);        //分别保存到数据库中的User表，必须做一个是否为空的检查        }                   //否则表中数据可能会被覆盖        SlideActivity.slideActivity.finish();              //更改后销毁原来的信息显示页面        ToastUtil.showMsg(this,"更改成功");        Intent intent = new Intent(EditInformationActivity.this,SlideActivity.class);        startActivity(intent);        finish();    }}

RelaxActivity

娱乐

package com.example.myfirst;import androidx.appcompat.app.AppCompatActivity;import android.content.Intent;import android.os.Bundle;import android.view.View;import android.widget.Button;public class RelaxActivity extends AppCompatActivity {    private Button btnGame1,btnGame2,btnGame3,btnGame4,btnGame5,btnGame6,btnGame7,btnGame8,btnGame9;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_relax);        btnGame1 = findViewById(R.id.bt_game1);        btnGame2 = findViewById(R.id.bt_game2);        btnGame3 = findViewById(R.id.bt_game3);        btnGame4 = findViewById(R.id.bt_game4);        btnGame5 = findViewById(R.id.bt_game5);        btnGame6 = findViewById(R.id.bt_game6);        btnGame7 = findViewById(R.id.bt_game7);        btnGame8 = findViewById(R.id.bt_game8);        btnGame9 = findViewById(R.id.bt_game9);        setClickListener();    }    private class OnClick implements View.OnClickListener{      //新建私有类OnClick，实现View.OnClickListener        @Override                   //重写onClick方法        public void onClick(View view) {            Intent intent = null;            switch (view.getId()){                case R.id.bt_game1:                    intent = new Intent(RelaxActivity.this,WEBZTypeActivity.class);                    break;                case R.id.bt_game2:                    intent = new Intent(RelaxActivity.this,EatwhatActivity.class);                    break;                case R.id.bt_game3:                    intent = new Intent(RelaxActivity.this, SummondraGonActivity.class);                    break;                case R.id.bt_game4:                    intent = new Intent(RelaxActivity.this,WhichoneActivity.class);                    break;                case R.id.bt_game5:                    intent = new Intent(RelaxActivity.this,MikutapActivity.class);                    break;                case R.id.bt_game6:                    intent = new Intent(RelaxActivity.this,HenxiangsiActivity.class);                    break;                case R.id.bt_game7:                    intent = new Intent(RelaxActivity.this, LoopTapActivity.class);                    break;                case R.id.bt_game8:                    intent = new Intent(RelaxActivity.this, FlowerActivity.class);                    break;                case R.id.bt_game9:                    intent = new Intent(RelaxActivity.this, EndlessLakeActivity.class);                    break;            }            startActivity(intent);        }    }    //设计方法    private void setClickListener(){        OnClick onClick = new OnClick();       //在OnClick新建onClick实体，否则36行OnClick是灰色的，也就是没被调用        btnGame1.setOnClickListener(onClick); //每个button都调用监听，并用上面的方法        btnGame2.setOnClickListener(onClick);        btnGame3.setOnClickListener(onClick);        btnGame4.setOnClickListener(onClick);        btnGame5.setOnClickListener(onClick);        btnGame6.setOnClickListener(onClick);        btnGame7.setOnClickListener(onClick);        btnGame8.setOnClickListener(onClick);        btnGame9.setOnClickListener(onClick);    }}

StudyActivity

学习

package com.example.myfirst;import androidx.appcompat.app.AppCompatActivity;import android.content.Intent;import android.os.Bundle;import android.view.SearchEvent;import android.view.View;import android.widget.Button;public class StudyActivity extends AppCompatActivity {    private Button btnStudy1,btnStudy2,btnStudy3,btnStudy4,btnStudy5,btnStudy6;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_study);        btnStudy1 = findViewById(R.id.btn_study1);        btnStudy2 = findViewById(R.id.btn_study2);        btnStudy3 = findViewById(R.id.btn_study3);        btnStudy4 = findViewById(R.id.btn_study4);        btnStudy5 = findViewById(R.id.btn_study5);        btnStudy6 = findViewById(R.id.btn_study6);        setClickListener();    }    private class OnClick implements View.OnClickListener{     //新建私有类OnClick，与 View.OnClickListener接口对接        @Override        public void onClick(View view) {            Intent intent = null;            switch (view.getId()){                case R.id.btn_study1:                    intent = new Intent(StudyActivity.this,RunoobActivity.class);                    break;                case R.id.btn_study2:                    intent = new Intent(StudyActivity.this,TechnologyMuseuMactivity.class);                    break;                case R.id.btn_study3:                    intent = new Intent(StudyActivity.this,MedicineActivity.class);                    break;                case R.id.btn_study4:                    intent = new Intent(StudyActivity.this,AnswerActivity.class);                    break;                case R.id.btn_study5:                    intent = new Intent(StudyActivity.this,SpaceActivity.class);                    break;                case R.id.btn_study6:                    intent = new Intent(StudyActivity.this, DeepSeaActivity.class);                    break;            }            startActivity(intent);        }    }    private void setClickListener(){        OnClick onClick = new OnClick();        btnStudy1.setOnClickListener(onClick);        btnStudy2.setOnClickListener(onClick);        btnStudy3.setOnClickListener(onClick);        btnStudy4.setOnClickListener(onClick);        btnStudy5.setOnClickListener(onClick);        btnStudy6.setOnClickListener(onClick);          //每个button都调用监听，并用上面的方法    }}

SlideActivity

侧滑

package com.example.myfirst;import androidx.appcompat.app.AppCompatActivity;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.view.View;import android.widget.Button;import android.widget.ImageView;import android.widget.TextView;import com.example.myfirst.util.DBHelper;import com.example.myfirst.util.SlideMenu;import com.example.myfirst.util.User;import java.util.ArrayList;public class SlideActivity extends AppCompatActivity {    private ImageView mIvHead;    private SlideMenu slideMenu;    private Button buttonStudy;    private Button buttonRelax;    private Button buttonToEdit;    private TextView mTvUsername,mTvSex,mTvAge,mTvFavorite,mTvSignature;    private DBHelper dbHelper;    public static SlideActivity slideActivity;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_slide);        slideActivity = this;        mIvHead = findViewById(R.id.iv_head);        slideMenu = findViewById(R.id.slideMenu);        buttonStudy = findViewById(R.id.btn_study);        buttonRelax = findViewById(R.id.btn_relax);        buttonToEdit = findViewById(R.id.bt_toEdit);        mTvUsername = findViewById(R.id.tv_username);               //用户信息显示控件        mTvSex = findViewById(R.id.tv_userSex);        mTvAge = findViewById(R.id.tv_userAge);        mTvFavorite = findViewById(R.id.tv_userFavorite);        mTvSignature = findViewById(R.id.tv_userSignature);        mIvHead.setOnClickListener(v -> slideMenu.switchMenu());        setClickListener();        dbHelper = new DBHelper(this);        showUserInformation();    }//由于button太多，设计一个方法，设计方法之前写好要调用的类    private class OnClick implements View.OnClickListener{      //新建私有类OnClick，实现View.OnClickListener        @Override                   //重写onClick方法        public void onClick(View view) {            Intent intent = null;            switch (view.getId()){                case R.id.btn_study:                    intent = new Intent(SlideActivity.this,StudyActivity.class);                    break;                case R.id.btn_relax:                    intent = new Intent(SlideActivity.this,RelaxActivity.class);                    break;                case R.id.bt_toEdit:                    intent = new Intent(SlideActivity.this,EditInformationActivity.class);            }            startActivity(intent);        }    }//设计方法    private void setClickListener(){        OnClick onClick = new OnClick();         //在OnClick新建onClick实体，否则36行OnClick是灰色的，也就是没被调用        buttonStudy.setOnClickListener(onClick); //每个button都调用监听，并用上面的方法        buttonRelax.setOnClickListener(onClick);        buttonToEdit.setOnClickListener(onClick);    }    private void showUserInformation() {                          //建立获取用户信息的方法        ArrayList userData2 = dbHelper.getData();           //创建User队列 userData2        User user = userData2.get(LoginActivity.getUserId());      //创建一个实体user，并获取当前用户id的数据        mTvUsername.setText(user.getName());        mTvAge.setText(user.getAge());        mTvSex.setText(user.getSex());        mTvFavorite.setText(user.getFavorite());                  //分别获取用户信息到TV控件        mTvSignature.setText(user.getSignature());    }}

实现侧滑功能

这里是使用了别人封装好的类，👇（顺带一提，小姐姐在b站的教学视频很好） b站材料1-代码之侧滑界面的java文件_小小小白冷的博客-CSDN博客

package com.example.myfirst.util;import android.content.Context;import android.util.AttributeSet;import android.view.MotionEvent;import android.view.View;import android.widget.FrameLayout;import android.widget.Scroller;public class SlideMenu extends FrameLayout {    private View menuView,mainView;    private int menuWidth;    private Scroller scroller;    public SlideMenu(Context context) {        super(context);        init();    }    public SlideMenu(Context context, AttributeSet attrs) {        super(context, attrs);        init();    }    private void init(){        scroller = new Scroller(getContext());    }        @Override    protected void onFinishInflate() {        super.onFinishInflate();        menuView = getChildAt(0);        mainView = getChildAt(1);        menuWidth = menuView.getLayoutParams().width;    }    //使Menu也具有滑动功能    public boolean onInterceptTouchEvent(MotionEvent ev){        switch (ev.getAction()) {            case MotionEvent.ACTION_DOWN:                downX = (int) ev.getX();                break;            case MotionEvent.ACTION_MOVE:                int deltaX = (int) (ev.getX() - downX);                if (Math.abs(deltaX) > 8){                    return true;                }                break;        }        return super.onInterceptTouchEvent(ev);    }        @Override    protected void onLayout(boolean changed, int l, int t, int r, int b) {        menuView.layout(-menuWidth, 0, 0, b);        mainView.layout(0, 0, r, b);    }        private int downX;    public boolean onTouchEvent(MotionEvent event) {        switch (event.getAction()) {            case MotionEvent.ACTION_DOWN:                downX = (int) event.getX();                break;            case MotionEvent.ACTION_MOVE:                int moveX = (int) event.getX();                int deltaX = moveX - downX;                int newScrollX = getScrollX() - deltaX;                if (newScrollX < -menuWidth) newScrollX = -menuWidth;                if (newScrollX > 0) newScrollX = 0;                scrollTo(newScrollX, 0);                downX = moveX;                break;            case MotionEvent.ACTION_UP:                //当滑动距离小于Menu宽度的一半时，平滑滑动到主页面                if(getScrollX()>-menuWidth/2){                    closeMenu();                }else {                    //当滑动距离大于Menu宽度的一半时，平滑滑动到Menu页面                    openMenu();                }                break;        }        return true;    }    //关闭menu    private void closeMenu(){        scroller.startScroll(getScrollX(),0,0-getScrollX(),0,400);        invalidate();    }    //打开menu    private void openMenu(){        scroller.startScroll(getScrollX(),0,-menuWidth-getScrollX(),0,400);        invalidate();    }        public void computeScroll(){        super.computeScroll();        if(scroller.computeScrollOffset()){            //返回true,表示动画没结束            scrollTo(scroller.getCurrX(),0);            invalidate();        }    }        public void switchMenu(){        if(getScrollX()==0){            openMenu();        }else {            closeMenu();        }    }}

网页activity

每个网页activity的内容步骤都一样，这里以菜鸟编程为例

package com.example.myfirst;import androidx.appcompat.app.AppCompatActivity;import android.os.Bundle;import android.webkit.WebSettings;import android.webkit.WebView;import android.webkit.WebViewClient;import android.widget.ProgressBar;import com.example.myfirst.util.SetProgressBar;import com.example.myfirst.util.SetWebView;public class RunoobActivity extends AppCompatActivity {    private WebView webView;    private String url = "https://www.runoob.com/";    private ProgressBar progressBar;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_runoob);        webView = findViewById(R.id.wv_runOob);        progressBar = findViewById(R.id.pb_run_oob);        SetProgressBar.setProgressBar(webView,progressBar);        SetWebView.setWebView(webView,url);    }}

网页配置——SetWebView.class

package com.example.myfirst.util;import android.webkit.WebSettings;import android.webkit.WebView;import android.webkit.WebViewClient;public class SetWebView {    public static void setWebView(WebView webView,String url){        webView.getSettings().setSupportZoom(true);                        //设置可以支持缩放        webView.getSettings().setBuiltInZoomControls(true);                //设置出现缩放工具        webView.getSettings().setUseWideViewPort(true);                    //扩大比例的缩放        webView.getSettings().setLayoutAlgorithm(WebSettings.LayoutAlgorithm.SINGLE_COLUMN);                    //自适应屏幕,也就是不能左右滑动        webView.getSettings().setLoadWithOverviewMode(true);                //加载完全缩小的WebView        webView.getSettings().setjavascriptEnabled(true);                  //支持JavaScript        webView.getSettings().setAppCacheEnabled(true);                    //开启应用缓存        webView.getSettings().setCacheMode(WebSettings.LOAD_DEFAULT);      //设置缓存模式        webView.getSettings().setDomStorageEnabled(true);                  //开启 DOM storage api 功能        webView.setWebViewClient(new WebViewClient(){       //防止访问网页时跳转到外部页面            @Override            public boolean shouldOverrideUrlLoading(WebView view, String url) {   //防止跳转到外部浏览器                return false;            }        });        webView.loadUrl(url);    }}

进度条加载——SetProgressBar.class

package com.example.myfirst.util;import android.view.View;import android.webkit.WebChromeClient;import android.webkit.WebView;import android.widget.ProgressBar;public class SetProgressBar {                    //单独建立一个加载进度条的类和方法    public static void setProgressBar(WebView webView,ProgressBar progressBar){        webView.setWebChromeClient(new WebChromeClient(){            @Override            public void onProgressChanged(WebView view, int newProgress) {                super.onProgressChanged(view, newProgress);                if (newProgress == 100){                    progressBar.setVisibility(View.GONE);           //加载完成后消失                }else {                    progressBar.setVisibility(View.VISIBLE);        //未加载完成则可见                    progressBar.setProgress(newProgress);           //让控件获取当前加载进度                }            }        });    }}

数据库helper

package com.example.myfirst.util;import android.annotation.SuppressLint;import android.content.Context;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteOpenHelper;import java.util.ArrayList;public class DBHelper extends SQLiteOpenHelper {    private SQLiteDatabase db;    public DBHelper(Context context){                  //构造函数        super(context,"db_thisApp",null,1);        db = getReadableDatabase();    }    @Override    public void onCreate(SQLiteDatabase db) {        db.execSQL("create table if not exists user(" +                "_id integer primary key autoincrement,"+                "name text,"+                "password text," +                "sex text," +                "age text," +                "favorite text," +                "signature text" +                ")");    }    @Override    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {        db.execSQL("drop table if exists user");        onCreate(db);    }    public boolean add(String name, String password){           //验证用户名是否已存在并注册        boolean judge2 = true;        ArrayList userData = this.getData(); //在User list创建一个实例userData,并让userData获取数据库里的数据        for (int i = 0; i < userData.size(); i++){            User user = userData.get(i);            if (name.equals(user.getName())){                judge2 = false;                break;            }              //遍历user id，当输入的用户名已存在则false        }        if (judge2){            db.execSQL("insert into user(name,password) values(?,?)", new Object[]{name,password});        }        return judge2;    }                         // 需要用Object[]把值传进 ？中    public void delete(String name,String password){        db.execSQL("delete from user where name = and password =" + name + password);    }    public void update(String name,String password){        db.execSQL("update user set password = ?",new Object[]{password});    }    public void updateUsername(String name){        db.execSQL("update user set name = ?", new Object[]{name});       //创建一个更新用户信息的DB方法    }    public void updateSex(String sex){        db.execSQL("update user set sex = ?", new Object[]{sex});    }    public void updateAge(String age){        db.execSQL("update user set age = ?", new Object[]{age});    }    public void updateFavorite(String favorite){        db.execSQL("update user set favorite = ?", new Object[]{favorite});    }    public void updateSignature(String signature){        db.execSQL("update user set signature = ?", new Object[]{signature});    }    public ArrayList getData(){        //从数据库获取数据到list中        ArrayList userList = new ArrayList();             //队列，以User结构建立队列，也就是建立User队列        Cursor cursor = db.query("user",null,null,    null,    null,    null,    "name desc");        while (cursor.moveToNext()){                     //因为value must be>0，所以不能使用moveToFirst，否则程序会崩溃：            @SuppressLint("Range") String name = cursor.getString(cursor.getColumnIndex("name"));            @SuppressLint("Range") String password = cursor.getString(cursor.getColumnIndex("password"));            @SuppressLint("Range") String sex = cursor.getString(cursor.getColumnIndex("sex"));            @SuppressLint("Range") String age = cursor.getString(cursor.getColumnIndex("age"));            @SuppressLint("Range") String favorite = cursor.getString(cursor.getColumnIndex("favorite"));            @SuppressLint("Range") String signature = cursor.getString(cursor.getColumnIndex("signature"));            userList.add(new User(name,password,sex,age,favorite,signature));        }        cursor.close();                      //游标一定要关掉！！！不然遍历过后会停留在最后一个位置，语句的位置也很讲究        return userList;                        //从表中遍历的值依次存入list中    }}

这里考虑到真实情况下，用户进去可能只更新一种属性，所以把用户的每种属性实现了单独更新

user类

package com.example.myfirst.util;public class User {                          //构造User结构    private String name;    private String password;    private String sex,age,favorite,signature;    public User(String name,String password,String sex,String age,String favorite,String signature){        this.name = name;        this.password = password;        this.sex = sex;        this.age = age;        this.favorite = favorite;        this.signature = signature;    }    public String getName() {        return name;    }    public String getPassword() {        return password;    }    public String getSex(){        return sex;    }    public String getAge(){        return age;    }    public String getFavorite(){        return favorite;    }    public String getSignature(){        return signature;    }}

ToastUtil

这个是用来学习而创建的，上面的一些activity都用到了这里面的方法，无关紧要，可以直接Toast.makeText()

package com.example.myfirst.util;import android.content.Context;import android.widget.Toast;public class ToastUtil {    public static Toast mToast;    public static void showMsg(Context context,String msg){      if(mToast == null){          mToast = Toast.makeText(context,msg,Toast.LENGTH_SHORT);       }       else{          mToast.setText(msg);       }       mToast.show();    }             }