Android Studio实现简单的通讯录

网上找的一个单页面通讯录，修改之后将添加联系人和修改/删除联系人分为两个独立页面

mainactivity

package com.example.test;
 
import androidx.appcompat.app.appcompatactivity;
import android.content.context;
import android.content.intent;
import android.os.bundle;
import android.database.cursor;
import android.database.sqlite.sqlitedatabase;
import android.text.method.scrollingmovementmethod;
import android.view.view;
import android.view.inputmethod.inputmethodmanager;
import android.widget.button;
import android.widget.edittext;
import android.widget.textview;
import android.widget.toast;
 
public class mainactivity extends appcompatactivity implements view.onclicklistener{
    myhelper myhelper;
    private textview tvshow;
    private button btnadd;
    private button btnquery;
    private button btnupdate;
 
 
    @override
    protected void oncreate(bundle savedinstancestate) {
        super.oncreate(savedinstancestate);
        setcontentview(r.layout.activity_main);
        myhelper = new myhelper(this);
        init();
    }
    private void init(){
        tvshow = (textview)findviewbyid(r.id.tv_show);
        btnadd = (button)findviewbyid(r.id.btn_add);
        btnquery = (button)findviewbyid(r.id.btn_query);
        btnupdate = (button)findviewbyid(r.id.btn_update);
        btnadd.setonclicklistener(this);   //button控件设置监听
        btnquery.setonclicklistener(this);
        btnupdate.setonclicklistener(this);
        findviewbyid(r.id.traceroute_rootview).setonclicklistener(this);
        tvshow.setmovementmethod(scrollingmovementmethod.getinstance()); //设置文本滚动
    }
    public void onclick(view v){
        sqlitedatabase db;
        switch (v.getid()){
            case r.id.traceroute_rootview:
                inputmethodmanager imm=(inputmethodmanager)
                        getsystemservice(context.input_method_service);
                imm.hidesoftinputfromwindow(v.getwindowtoken(),0);
                break;
            case r.id.btn_add:  //添加联系人
                intent intent=new intent(mainactivity.this,nextactivity.class);
                startactivity(intent);
                break;
            case r.id.btn_query: //查询联系人
                db = myhelper.getreadabledatabase();
                cursor cursor = db.rawquery("select name,phone from person",null);
                if (cursor.getcount() == 0){
                    tvshow.settext("");
                    toast.maketext(this,"当前无联系人",toast.length_short).show();
                }else {
                    cursor.movetofirst();
                    tvshow.settext("name：" + cursor.getstring(0) + " ; tel：" + cursor.getstring(1));
                    while (cursor.movetonext()){
                        tvshow.append("\n" + "name：" + cursor.getstring(0) + " ; tel：" + cursor.getstring(1));
                    }
                }
                cursor.close();
                db.close();
                break;
            case r.id.btn_update: //修改联系人
                intent intent1=new intent(mainactivity.this,xiugaiactivity.class);
                startactivity(intent1);
                break;
        }
    }
}

nextactivity

package com.example.test;
 
import androidx.appcompat.app.appcompatactivity;
import android.content.context;
import android.content.intent;
import android.os.bundle;
import android.database.sqlite.sqlitedatabase;
import android.view.view;
import android.view.inputmethod.inputmethodmanager;
import android.widget.button;
import android.widget.edittext;
import android.widget.toast;
 
public class nextactivity extends appcompatactivity implements view.onclicklistener {
    myhelper myhelper;
    private edittext etname;
    private edittext etphone;
    private button btnadd;
    @override
    protected void oncreate(bundle savedinstancestate) {
        super.oncreate(savedinstancestate);
        setcontentview(r.layout.next);
        myhelper = new myhelper(this);
        init();
    }
    private void init(){
        etname = (edittext)findviewbyid(r.id.et_name);
        etphone = (edittext)findviewbyid(r.id.et_phone);
        btnadd = (button)findviewbyid(r.id.btn_add);
        btnadd.setonclicklistener(this);   //button控件设置监听
        findviewbyid(r.id.traceroute_rootview).setonclicklistener(this);
    }
    public void onclick(view v){
        string name;
        string phone;
        sqlitedatabase db;
        switch (v.getid()) {
            case r.id.traceroute_rootview:
                inputmethodmanager imm = (inputmethodmanager)
                        getsystemservice(context.input_method_service);
                imm.hidesoftinputfromwindow(v.getwindowtoken(), 0);
                break;
            case r.id.btn_add:  //添加联系人
                name = etname.gettext().tostring().trim();
                phone = etphone.gettext().tostring().trim();
                db = myhelper.getwritabledatabase();
                if (name.equals("") || phone.equals("")) { //联系人信息不能为空
                    toast.maketext(this, "联系人信息添加失败", toast.length_short).show();
                } else {
                    db.execsql("insert into person (name,phone) values(?,?)", new object[]{name, phone});
                    toast.maketext(this, "联系人信息添加成功", toast.length_short).show();
                }
                db.close();
                intent intent=new intent(nextactivity.this,mainactivity.class);
                startactivity(intent);
                break;
        }
    }
}

xiugaiactivity

package com.example.test;
 
import androidx.appcompat.app.appcompatactivity;
import android.content.context;
import android.os.bundle;
import android.database.cursor;
import android.database.sqlite.sqlitedatabase;
import android.text.method.scrollingmovementmethod;
import android.view.view;
import android.view.inputmethod.inputmethodmanager;
import android.widget.button;
import android.widget.edittext;
import android.widget.textview;
import android.widget.toast;
public class xiugaiactivity extends appcompatactivity implements view.onclicklistener{
    myhelper myhelper;
    private edittext etname;
    private edittext etphone;
    private textview tvshow;
    private button btnquery;
    private button btnupdate;
    private button btndelete;
 
    @override
    protected void oncreate(bundle savedinstancestate) {
        super.oncreate(savedinstancestate);
        setcontentview(r.layout.xiugai);
        myhelper = new myhelper(this);
        init();
    }
    private void init(){
        etname = (edittext)findviewbyid(r.id.et_name);
        etphone = (edittext)findviewbyid(r.id.et_phone);
        tvshow = (textview)findviewbyid(r.id.tv_show);
        btnquery = (button)findviewbyid(r.id.btn_query);
        btnupdate = (button)findviewbyid(r.id.btn_update);
        btndelete = (button)findviewbyid(r.id.btn_delete);
        btnquery.setonclicklistener(this);
        btnupdate.setonclicklistener(this);
        btndelete.setonclicklistener(this);
        findviewbyid(r.id.traceroute_rootview).setonclicklistener(this);
        tvshow.setmovementmethod(scrollingmovementmethod.getinstance()); //设置文本滚动
    }
    public void onclick(view v){
        string name;
        string phone;
        sqlitedatabase db;
        switch (v.getid()){
            case r.id.traceroute_rootview:
                inputmethodmanager imm=(inputmethodmanager)
                        getsystemservice(context.input_method_service);
                imm.hidesoftinputfromwindow(v.getwindowtoken(),0);
                break;
            case r.id.btn_query: //查询联系人
                db = myhelper.getreadabledatabase();
                cursor cursor = db.rawquery("select name,phone from person",null);
                if (cursor.getcount() == 0){
                    tvshow.settext("");
                    toast.maketext(this,"当前无联系人",toast.length_short).show();
                }else {
                    cursor.movetofirst();
                    tvshow.settext("name：" + cursor.getstring(0) + " ; tel：" + cursor.getstring(1));
                    while (cursor.movetonext()){
                        tvshow.append("\n" + "name：" + cursor.getstring(0) + " ; tel：" + cursor.getstring(1));
                    }
                }
                cursor.close();
                db.close();
                break;
            case r.id.btn_update: //修改联系人
                db = myhelper.getwritabledatabase();
                name = etname.gettext().tostring().trim();
                phone = etphone.gettext().tostring().trim();
                if (name.equals("") || phone.equals("")){ //联系人信息不能为空
                    toast.maketext(this,"不存在该联系人",toast.length_short).show();
                }
                else {
                    db.execsql("update person set name=?,phone=? where name=?", new object[]{name, phone, name});
                    toast.maketext(this,"联系人信息修改成功",toast.length_short).show();
                }
                db.close();
                break;
            case r.id.btn_delete: //删除联系人
                db = myhelper.getwritabledatabase();
                name = etname.gettext().tostring().trim();
                phone = etphone.gettext().tostring().trim();
                if (name.equals("") || phone.equals("")){ //联系人信息不能为空
                    toast.maketext(this,"不存在该联系人",toast.length_short).show();
                }
                else {
                    db.execsql("delete from person where name=? and phone=?", new object[]{name, phone});
                    toast.maketext(this,"联系人信息删除成功",toast.length_short).show();
                }
                db.close();
                break;
        }
    }
}

myhelper

package com.example.test;
import android.content.context;
import android.database.sqlite.sqlitedatabase;
import android.database.sqlite.sqliteopenhelper;
public class myhelper extends sqliteopenhelper{
    public myhelper(context context){
        super(context, "alan.db", null ,2);
    }
    @override
 
    public void oncreate(sqlitedatabase db){
        db.execsql("create table person(id integer primary key autoincrement,name varchar(20),phone varchar(20) unique)");
    }
    public void onupgrade(sqlitedatabase db, int oldversion, int newversion){
 
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<linearlayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/traceroute_rootview"
    android:background="@color/white"
    android:clickable="true"
    android:gravity="center_horizontal"
    tools:context=".mainactivity">
        <textview
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="通 讯 录"
            android:textsize="30dp"
            android:textstyle="italic"
            android:gravity="center"
            android:textcolor="@color/black">
        </textview>
        <button
            android:id="@+id/btn_add"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="@drawable/shape"
            android:text=" 添加联系人"
            android:textsize="16dp"
            android:textcolor="#c2c8ec"
            android:textstyle="bold"/>
        <button
            android:id="@+id/btn_query"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="@drawable/shape"
            android:text="查看联系人"
            android:textsize="16dp"
            android:textcolor="#c2c8ec"
            android:textstyle="bold"/>
        <button
            android:id="@+id/btn_update"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="@drawable/shape"
            android:text=" 修改联系人"
            android:textsize="16dp"
            android:textcolor="#c2c8ec"
            android:textstyle="bold"/>
    <textview
        android:id="@+id/tv_show"
        android:layout_width="match_parent"
        android:layout_height="180dp"
        android:scrollbars="vertical"
        android:layout_below="@+id/linefour"
        android:layout_margintop="20dp"
        android:layout_marginleft="20dp"
        android:layout_marginright="18dp"
        android:textcolor="#c2c8ec"
        android:textsize="24dp"/>
</linearlayout>

next.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:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/traceroute_rootview"
    android:background="@color/white"
    android:clickable="true"
    android:orientation="vertical"
    android:gravity="center_horizontal"
    tools:context=".nextactivity">
    <linearlayout
        android:id="@+id/linetwo"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/lineone"
        android:layout_margintop="20dp"
        android:layout_marginleft="18dp"
        android:layout_marginright="18dp">
        <textview
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="姓 名 : "
            android:textsize="18dp"
            android:textstyle="bold"/>
        <edittext
            android:id="@+id/et_name"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="请输入姓名"
            android:textsize="16dp"
            android:maxlines="1"
            android:singleline="true"
            android:maxlength="14"/>
    </linearlayout>
    <linearlayout
        android:id="@+id/linetree"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/linetwo"
        android:layout_margintop="10dp"
        android:layout_marginleft="18dp"
        android:layout_marginright="18dp">
    <textview
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="电 话 : "
        android:textsize="18dp"
        android:textstyle="bold"/>
    <edittext
        android:id="@+id/et_phone"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="请输入手机号码"
        android:textsize="16dp"
        android:maxlines="1"
        android:singleline="true"
        android:maxlength="11"/>
    </linearlayout>
    <linearlayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/linefour"
        android:layout_below="@+id/linetree"
        android:layout_margintop="30dp"
        android:layout_marginleft="18dp"
        android:layout_marginright="18dp"
        android:orientation="horizontal">
    <button
        android:id="@+id/btn_add"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="@drawable/shape"
        android:layout_weight="1"
        android:text=" 确 定 "
        android:textsize="16dp"
        android:textcolor="#c2c8ec"
        android:textstyle="bold"/>
    </linearlayout>
</relativelayout>
xiugai.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:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/traceroute_rootview"
    android:background="@color/white"
    android:clickable="true"
    android:orientation="vertical"
    android:gravity="center_horizontal"
    tools:context=".xiugaiactivity">
    <linearlayout
        android:id="@+id/linetwo"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/lineone"
        android:layout_margintop="20dp"
        android:layout_marginleft="18dp"
        android:layout_marginright="18dp">
        <textview
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="姓 名 : "
            android:textsize="18dp"
            android:textstyle="bold"/>
        <edittext
            android:id="@+id/et_name"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="  请输入姓名"
            android:textsize="16dp"
            android:maxlines="1"
            android:singleline="true"
            android:maxlength="14"/>
    </linearlayout>
    <linearlayout
        android:id="@+id/linetree"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/linetwo"
        android:layout_margintop="10dp"
        android:layout_marginleft="18dp"
        android:layout_marginright="18dp">
        <textview
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="电 话 : "
            android:textsize="18dp"
            android:textstyle="bold"/>
        <edittext
            android:id="@+id/et_phone"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="  请输入手机号码"
            android:textsize="16dp"
            android:maxlines="1"
            android:singleline="true"
            android:maxlength="11"/>
    </linearlayout>
    <linearlayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/linefour"
        android:layout_below="@+id/linetree"
        android:layout_margintop="30dp"
        android:layout_marginleft="18dp"
        android:layout_marginright="18dp"
        android:orientation="horizontal">
        <button
            android:id="@+id/btn_query"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="@drawable/shape"
            android:layout_weight="1"
            android:layout_marginleft="4dp"
            android:text="查看联系人"
            android:textsize="16dp"
            android:textcolor="#c2c8ec"
            android:textstyle="bold"/>
        <button
            android:id="@+id/btn_update"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="@drawable/shape"
            android:layout_weight="1"
            android:layout_marginleft="4dp"
            android:text=" 修 改 "
            android:textsize="16dp"
            android:textcolor="#c2c8ec"
            android:textstyle="bold"/>
        <button
            android:id="@+id/btn_delete"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="@drawable/shape"
            android:layout_weight="1"
            android:layout_marginleft="4dp"
            android:text=" 删 除 "
            android:textsize="16dp"
            android:textcolor="#c2c8ec"
            android:textstyle="bold"/>
    </linearlayout>
    <textview
        android:id="@+id/tv_show"
        android:layout_width="match_parent"
        android:layout_height="180dp"
        android:scrollbars="vertical"
        android:layout_below="@+id/linefour"
        android:layout_margintop="20dp"
        android:layout_marginleft="20dp"
        android:layout_marginright="18dp"
        android:textcolor="#c2c8ec"
        android:textsize="24dp"/>
</relativelayout>

mainfest

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.test">
 
    <application
        android:allowbackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundicon="@mipmap/ic_launcher_round"
        android:supportsrtl="true"
        android:theme="@style/theme.test">
        <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=".nextactivity"></activity>
        <activity android:name=".xiugaiactivity"></activity>
    </application>
 
</manifest>

初学android,程序还存在许多bug，大家多提修改建议。

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。