简单ListView实例
数据库读取数据存入ListView
一、具体思路
1、创建Listview控件
2、创建子布局
创建数据库
主方法调用数据库继承类且初始化数据库，写入数据
MyDatabaseHelper databaseHelper = new MyDatabaseHelper(this,"Co.db",null,1);
SQLiteDatabase db = databaseHelper.getWritableDatabase();
SQLiteDatabase db2 = databaseHelper.getReadableDatabase();
3、写入
ContentValues values = new ContentValues();
values.put("Code","1");
values.put("Name","Admin");
values.put("Post","32");
values.put("Tel","123456789");
db.insert("employee",null,values);
values.clear();
values.put("Code","2");
values.put("Name","Admin1");
values.put("Post","22");
values.put("Tel","23342e");
db.insert("employee",null,values);
4、读取
Cursor cursor = db2.query("Employee",null,null,null,null,null,null);
arrayList = new ArrayList<>();
if (cursor.moveToFirst()) {
do {
name = cursor.getString(cursor.getColumnIndex("Name"));
code = cursor.getString(cursor.getColumnIndex("Code"));
post = cursor.getString(cursor.getColumnIndex("Post"));
tel = cursor.getString(cursor.getColumnIndex("Tel"));
System.out.println("查找到的值:" name "---" code "---" post "---" tel);
Employee employee=new Employee(name, tel, post, code);
arrayList.add(employee);
}while (cursor.moveToNext());
}
5、创建对象，构造器，GETSET方法
6、创建Adapter
二、具体实施
1、适配器
lv.setAdapter(new BaseAdapter() {
@Override
public int getCount() {
return arrayList.size();
}
@Override
public Object getItem(int position) {
return null;
}
@Override
public long getItemId(int position) {
return 0;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View view;
if (convertView==null){
view=View.inflate(getBaseContext(),R.layout.listitem,null);
}else{
view=convertView;
}
Employee ee=(Employee) arrayList.get(position);
TextView eename=view.findViewById(R.id.name);
TextView eedianhua=view.findViewById(R.id.dianhua);
TextView eezhiwei=view.findViewById(R.id.zhiwei);
TextView eekahao=view.findViewById(R.id.kahao);
eename.setText(ee.getName());
eedianhua.setText(ee.getTel());
eezhiwei.setText(ee.getPost());
eekahao.setText(ee.getCode());
return view;
}
});
2、数据库
public class MyDatabaseHelper extends SQLiteOpenHelper {
public static final String CREATE_Employees = "create table employee ("
"Code text, "
"Name text unique, "
"Post text, "
"Tel text)";
private Context mContext;
public MyDatabaseHelper(Context context, String name, SQLiteDatabase.CursorFactory
factory, int version) {
super(context, name, factory, version);
mContext = context;
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(CREATE_Employees);
Toast.makeText(mContext, "Create succeeded", Toast.LENGTH_SHORT).show();
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}
3、对象
package com.example.a4_7_1_lv;
public class Employee {
private String name;
private String tel;
private String post;
private String code;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getTel() {
return tel;
}
public void setTel(String tel) {
this.tel = tel;
}
public String getPost() {
return post;
}
public void setPost(String post) {
this.post = post;
}
public String getCode() {
return code;
}
public void setCode(String code) {
this.code = code;
}
public Employee(String name, String tel, String post, String code) {
this.name = name;
this.tel = tel;
this.post = post;
this.code = code;
}
public Employee() {
}
}
4、等等等等
三、案例分享
activity_main.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:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<ListView
android:id="@ id/list"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</RelativeLayout>
listitem.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="姓名"
android:textSize="30dp"/>
<TextView
android:layout_marginLeft="30dp"
android:id="@ id/name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text=""
android:textSize="30dp"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="电话"
android:layout_marginLeft="100dp"
android:textSize="30dp"/>
<TextView
android:layout_marginLeft="30dp"
android:id="@ id/dianhua"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text=""
android:textSize="30dp"/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="职位"
android:textSize="30dp"/>
<TextView
android:layout_marginLeft="30dp"
android:id="@ id/zhiwei"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text=""
android:textSize="30dp"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="卡号"
android:layout_marginLeft="100dp"
android:textSize="30dp"/>
<TextView
android:layout_marginLeft="30dp"
android:id="@ id/kahao"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text=""
android:textSize="30dp"/>
</LinearLayout>
</LinearLayout>
MyDatabaseHelper.java
package com.example.a4_7_1_lv;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.widget.Toast;
public class MyDatabaseHelper extends SQLiteOpenHelper {
public static final String CREATE_Employees = "create table employee ("
"Code text, "
"Name text unique, "
"Post text, "
"Tel text)";
private Context mContext;
public MyDatabaseHelper(Context context, String name, SQLiteDatabase.CursorFactory
factory, int version) {
super(context, name, factory, version);
mContext = context;
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(CREATE_Employees);
Toast.makeText(mContext, "Create succeeded", Toast.LENGTH_SHORT).show();
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}
MainActivity.java
package com.example.a4_7_1_lv;
import androidx.appcompat.app.AppCompatActivity;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.TextView;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
private ListView lv;
private MyDatabaseHelper databaseHelper;
private SQLiteDatabase db;
private SQLiteDatabase db2;
private ArrayList arrayList;
private String name;
private String code;
private String post;
private String tel;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
lv = findViewById(R.id.list);
}
@Override
protected void onStart() {
super.onStart();
MyDatabaseHelper databaseHelper = new MyDatabaseHelper(this,"Co.db",null,1);
db = databaseHelper.getWritableDatabase();
db2 = databaseHelper.getReadableDatabase();
DBInsert();
Cursor cursor = db2.query("Employee",null,null,null,null,null,null);
arrayList = new ArrayList<>();
if (cursor.moveToFirst()) {
do {
name = cursor.getString(cursor.getColumnIndex("Name"));
code = cursor.getString(cursor.getColumnIndex("Code"));
post = cursor.getString(cursor.getColumnIndex("Post"));
tel = cursor.getString(cursor.getColumnIndex("Tel"));
System.out.println("查找到的值:" name "---" code "---" post "---" tel);
Employee employee=new Employee(name, tel, post, code);
arrayList.add(employee);
}while (cursor.moveToNext());
}
lv.setAdapter(new BaseAdapter() {
@Override
public int getCount() {
return arrayList.size();
}
@Override
public Object getItem(int position) {
return null;
}
@Override
public long getItemId(int position) {
return 0;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View view;
if (convertView==null){
view=View.inflate(getBaseContext(),R.layout.listitem,null);
}else{
view=convertView;
}
Employee ee=(Employee) arrayList.get(position);
TextView eename=view.findViewById(R.id.name);
TextView eedianhua=view.findViewById(R.id.dianhua);
TextView eezhiwei=view.findViewById(R.id.zhiwei);
TextView eekahao=view.findViewById(R.id.kahao);
eename.setText(ee.getName());
eedianhua.setText(ee.getTel());
eezhiwei.setText(ee.getPost());
eekahao.setText(ee.getCode());
return view;
}
});
}
private void DBInsert() {
ContentValues values = new ContentValues();
values.put("Code","1");
values.put("Name","Admin");
values.put("Post","32");
values.put("Tel","123456789");
db.insert("employee",null,values);
values.clear();
values.put("Code","2");
values.put("Name","Admin1");
values.put("Post","22");
values.put("Tel","23342e");
db.insert("employee",null,values);
values.clear();
values.put("Code","4");
values.put("Name","Admin13");
values.put("Post","2sda2");
values.put("Tel","233asd42e");
db.insert("employee",null,values);
values.clear();
values.put("Code","Code");
values.put("Name","Name");
values.put("Post","Post");
values.put("Tel","Tel");
db.insert("employee",null,values);
}
}
Employee.java
package com.example.a4_7_1_lv;
import androidx.appcompat.app.AppCompatActivity;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.TextView;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
private ListView lv;
private MyDatabaseHelper databaseHelper;
private SQLiteDatabase db;
private SQLiteDatabase db2;
private ArrayList arrayList;
private String name;
private String code;
private String post;
private String tel;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
lv = findViewById(R.id.list);
}
@Override
protected void onStart() {
super.onStart();
MyDatabaseHelper databaseHelper = new MyDatabaseHelper(this,"Co.db",null,1);
db = databaseHelper.getWritableDatabase();
db2 = databaseHelper.getReadableDatabase();
DBInsert();
Cursor cursor = db2.query("Employee",null,null,null,null,null,null);
arrayList = new ArrayList<>();
if (cursor.moveToFirst()) {
do {
name = cursor.getString(cursor.getColumnIndex("Name"));
code = cursor.getString(cursor.getColumnIndex("Code"));
post = cursor.getString(cursor.getColumnIndex("Post"));
tel = cursor.getString(cursor.getColumnIndex("Tel"));
System.out.println("查找到的值:" name "---" code "---" post "---" tel);
Employee employee=new Employee(name, tel, post, code);
arrayList.add(employee);
}while (cursor.moveToNext());
}
lv.setAdapter(new BaseAdapter() {
@Override
public int getCount() {
return arrayList.size();
}
@Override
public Object getItem(int position) {
return null;
}
@Override
public long getItemId(int position) {
return 0;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View view;
if (convertView==null){
view=View.inflate(getBaseContext(),R.layout.listitem,null);
}else{
view=convertView;
}
Employee ee=(Employee) arrayList.get(position);
TextView eename=view.findViewById(R.id.name);
TextView eedianhua=view.findViewById(R.id.dianhua);
TextView eezhiwei=view.findViewById(R.id.zhiwei);
TextView eekahao=view.findViewById(R.id.kahao);
eename.setText(ee.getName());
eedianhua.setText(ee.getTel());
eezhiwei.setText(ee.getPost());
eekahao.setText(ee.getCode());
return view;
}
});
}
private void DBInsert() {
ContentValues values = new ContentValues();
values.put("Code","1");
values.put("Name","Admin");
values.put("Post","32");
values.put("Tel","123456789");
db.insert("employee",null,values);
values.clear();
values.put("Code","2");
values.put("Name","Admin1");
values.put("Post","22");
values.put("Tel","23342e");
db.insert("employee",null,values);
values.clear();
values.put("Code","4");
values.put("Name","Admin13");
values.put("Post","2sda2");
values.put("Tel","233asd42e");
db.insert("employee",null,values);
values.clear();
values.put("Code","Code");
values.put("Name","Name");
values.put("Post","Post");
values.put("Tel","Tel");
db.insert("employee",null,values);
}
}
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