【黑马Android】(04)数据库的创建和sql语句增删改查/LinearLayout展示列表数据/ListView的使用和BaseAdater/内容提供者创建
2023-09-14 08:57:16 时间
数据库的创建和sql语句增删改查
Android零基础入门第25节：最简单最常用的LinearLayout线性布局 原文:Android零基础入门第25节：最简单最常用的LinearLayout线性布局 良好的布局设计对于UI界面至关重要，在前面也简单介绍过，目前Android中的布局主要有6种，创建的布局文件默认为RelativeLayout相对布局，而在前面的示例学习中，我们只是简单利用了一下LinearLayout线性布局，那么接下来分别对其进行详细学习。
1. 加载驱动.
2. 连接数据库.
3. 操作数据库.
创建表:
create table person(
_id integer primary key,
name varchar(20),
age integer
);
添加: insert into person(name, age) values(lisi, 19);
删除: delete from person where _id = 1;
修改: update person set name = 李四 where name = 王五;
查询所有: select * from person;
查询单条: select * from person where name = zhangsan;
SQLiteExpert3, pc上的工具软件。
package com.itheima28.sqlitedemo.dao;
import java.util.ArrayList;
import java.util.List;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import com.itheima28.sqlitedemo.db.PersonSQLiteOpenHelper;
import com.itheima28.sqlitedemo.entities.Person;
public class PersonDao {
private PersonSQLiteOpenHelper mOpenHelper; // 数据库的帮助类对象
public PersonDao(Context context) {
mOpenHelper = new PersonSQLiteOpenHelper(context);
* 添加到person表一条数据
* @param person
public void insert(Person person) {
SQLiteDatabase db = mOpenHelper.getWritableDatabase();
if(db.isOpen()) { // 如果数据库打开, 执行添加的操作
// 执行添加到数据库的操作
db.execSQL("insert into person(name, age) values(?, ?);", new Object[]{person.getName(), person.getAge()});
db.close(); // 数据库关闭
* 更据id删除记录
* @param id
public void delete(int id) {
SQLiteDatabase db = mOpenHelper.getWritableDatabase(); // 获得可写的数据库对象
if(db.isOpen()) { // 如果数据库打开, 执行添加的操作
db.execSQL("delete from person where _id = ?;", new Integer[]{id});
db.close(); // 数据库关闭
public void update(int id, String name) {
SQLiteDatabase db = mOpenHelper.getWritableDatabase();
if(db.isOpen()) { // 如果数据库打开, 执行添加的操作
db.execSQL("update person set name = ? where _id = ?;", new Object[]{name, id});
db.close(); // 数据库关闭
public List Person queryAll() {
SQLiteDatabase db = mOpenHelper.getReadableDatabase(); // 获得一个只读的数据库对象
if(db.isOpen()) {
Cursor cursor = db.rawQuery("select _id, name, age from person;", null);
if(cursor != null cursor.getCount() 0) {
List Person personList = new ArrayList Person
int id;
String name;
int age;
while(cursor.moveToNext()) {
id = cursor.getInt(0); // 取第0列的数据 id
name = cursor.getString(1); // 取姓名
age = cursor.getInt(2); // 取年龄
personList.add(new Person(id, name, age));
db.close();
return personList;
db.close();
return null;
* 根据id查询人
* @param id
* @return
public Person queryItem(int id) {
SQLiteDatabase db = mOpenHelper.getReadableDatabase(); // 获得一个只读的数据库对象
if(db.isOpen()) {
Cursor cursor = db.rawQuery("select _id, name, age from person where _id = ?;", new String[]{id + ""});
if(cursor != null cursor.moveToFirst()) {
int _id = cursor.getInt(0);
String name = cursor.getString(1);
int age = cursor.getInt(2);
db.close();
return new Person(_id, name, age);
db.close();
return null;
}
package com.itheima28.sqlitedemo.db;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
* @author andong
* 数据库帮助类, 用于创建和管理数据库的.
public class PersonSQLiteOpenHelper extends SQLiteOpenHelper {
private static final String TAG = "PersonSQLiteOpenHelper";
* 数据库的构造函数
* @param context
* name 数据库名称
* factory 游标工程
* version 数据库的版本号 不可以小于1
public PersonSQLiteOpenHelper(Context context) {
super(context, "itheima28.db", null, 2);
* 数据库第一次创建时回调此方法.
* 初始化一些表
@Override
public void onCreate(SQLiteDatabase db) {
// 操作数据库
String sql = "create table person(_id integer primary key, name varchar(20), age integer);";
db.execSQL(sql); // 创建person表
* 数据库的版本号更新时回调此方法,
* 更新数据库的内容(删除表, 添加表, 修改表)
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
if(oldVersion == 1 newVersion == 2) {
Log.i(TAG, "数据库更新啦");
// 在person表中添加一个余额列balance
db.execSQL("alter table person add balance integer;");
}
package com.itheima28.sqlitedemo.entities;
public class Person {
private int id;
private String name;
private int age;
public int getId() {
return id;
public void setId(int id) {
this.id = id;
public String getName() {
return name;
public void setName(String name) {
this.name = name;
public int getAge() {
return age;
public void setAge(int age) {
this.age = age;
public Person() {
super();
// TODO Auto-generated constructor stub
public Person(int id, String name, int age) {
super();
this.id = id;
this.name = name;
this.age = age;
@Override
public String toString() {
return "Person [id=" + id + ", name=" + name + ", age=" + age + "]";
}
package com.itheima28.sqlitedemo.test;
import java.util.List;
import com.itheima28.sqlitedemo.dao.PersonDao;
import com.itheima28.sqlitedemo.db.PersonSQLiteOpenHelper;
import com.itheima28.sqlitedemo.entities.Person;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.test.AndroidTestCase;
import android.util.Log;
public class TestCase extends AndroidTestCase {
private static final String TAG = "TestCase";
public void test() {
// 数据库什么时候创建
PersonSQLiteOpenHelper openHelper = new PersonSQLiteOpenHelper(getContext());
// 第一次连接数据库时创建数据库文件. onCreate会被调用
openHelper.getReadableDatabase();
public void testInsert() {
PersonDao dao = new PersonDao(getContext());
dao.insert(new Person(0, "冠希", 28));
public void testDelete() {
PersonDao dao = new PersonDao(getContext());
dao.delete(1);
public void testUpdate() {
PersonDao dao = new PersonDao(getContext());
dao.update(3, "凤姐");
public void testQueryAll() {
PersonDao dao = new PersonDao(getContext());
List Person personList = dao.queryAll();
for (Person person : personList) {
Log.i(TAG, person.toString());
public void testQueryItem() {
PersonDao dao = new PersonDao(getContext());
Person person = dao.queryItem(4);
Log.i(TAG, person.toString());
public void testTransaction() {
PersonSQLiteOpenHelper openHelper = new PersonSQLiteOpenHelper(getContext());
SQLiteDatabase db = openHelper.getWritableDatabase();
if(db.isOpen()) {
try {
// 开启事务
db.beginTransaction();
// 1. 从张三账户中扣1000块钱
db.execSQL("update person set balance = balance - 1000 where name = zhangsan;");
// ATM机, 挂掉了.
// int result = 10 / 0;
// 2. 向李四账户中加1000块钱
db.execSQL("update person set balance = balance + 1000 where name = lisi;");
// 标记事务成功
db.setTransactionSuccessful();
} finally {
// 停止事务
db.endTransaction();
db.close();
public void testTransactionInsert() {
PersonSQLiteOpenHelper openHelper = new PersonSQLiteOpenHelper(getContext());
SQLiteDatabase db = openHelper.getWritableDatabase();
if(db.isOpen()) {
// 1. 记住当前的时间
long start = System.currentTimeMillis();
// 2. 开始添加数据
try {
db.beginTransaction();
for (int i = 0; i 10000; i++) {
db.execSQL("insert into person(name, age, balance) values(wang" + i + ", " + (10 + i) + ", " + (10000 + i) + ")");
db.setTransactionSuccessful();
} finally {
db.endTransaction();
// 3. 记住结束时间, 计算耗时时间
long end = System.currentTimeMillis();
long diff = end - start;
Log.i(TAG, "耗时: " + diff + "毫秒");
db.close();
}
?xml version="1.0" encoding="utf-8"? manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.itheima28.sqlitedemo" android:versionCode="1" android:versionName="1.0" instrumentation android:name="android.test.InstrumentationTestRunner" android:targetPackage="com.itheima28.sqlitedemo" /instrumentation uses-sdk android:minSdkVersion="8" android:targetSdkVersion="17" / application android:allowBackup="true" android:icon="@drawable/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme" uses-library android:name="android.test.runner" / activity android:name="com.itheima28.sqlitedemo.MainActivity" android:label="@string/app_name" intent-filter action android:name="android.intent.action.MAIN" / category android:name="android.intent.category.LAUNCHER" / /intent-filter /activity /application /manifest使用api方式查询数据库和sqlite3工具
adb shell
package com.itheima28.sqlitedemo.dao;
import java.util.ArrayList;
import java.util.List;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.util.Log;
import com.itheima28.sqlitedemo.db.PersonSQLiteOpenHelper;
import com.itheima28.sqlitedemo.entities.Person;
public class PersonDao2 {
private static final String TAG = "PersonDao2";
private PersonSQLiteOpenHelper mOpenHelper; // 数据库的帮助类对象
public PersonDao2(Context context) {
mOpenHelper = new PersonSQLiteOpenHelper(context);
* 添加到person表一条数据
* @param person
public void insert(Person person) {
SQLiteDatabase db = mOpenHelper.getWritableDatabase();
if(db.isOpen()) { // 如果数据库打开, 执行添加的操作
ContentValues values = new ContentValues();
values.put("name", person.getName()); // key作为要存储的列名, value对象列的值
values.put("age", person.getAge());
long id = db.insert("person", "name", values);
Log.i(TAG, "id: " + id);
db.close(); // 数据库关闭
* 更据id删除记录
* @param id
public void delete(int id) {
SQLiteDatabase db = mOpenHelper.getWritableDatabase(); // 获得可写的数据库对象
if(db.isOpen()) { // 如果数据库打开, 执行添加的操作
String whereClause = "_id = ?";
String[] whereArgs = {id + ""};
int count = db.delete("person", whereClause, whereArgs);
Log.i(TAG, "删除了: " + count + "行");
db.close(); // 数据库关闭
public void update(int id, String name) {
SQLiteDatabase db = mOpenHelper.getWritableDatabase();
if(db.isOpen()) { // 如果数据库打开, 执行添加的操作
ContentValues values = new ContentValues();
values.put("name", name);
int count = db.update("person", values, "_id = ?", new String[]{id + ""});
Log.i(TAG, "修改了: " + count + "行");
db.close(); // 数据库关闭
public List Person queryAll() {
SQLiteDatabase db = mOpenHelper.getReadableDatabase(); // 获得一个只读的数据库对象
if(db.isOpen()) {
String[] columns = {"_id", "name", "age"}; // 需要的列
String selection = null; // 选择条件, 给null查询所有
String[] selectionArgs = null; // 选择条件的参数, 会把选择条件中的? 替换成数据中的值
String groupBy = null; // 分组语句 group by name
String having = null; // 过滤语句
String orderBy = null; // 排序
Cursor cursor = db.query("person", columns, selection, selectionArgs, groupBy, having, orderBy);
int id;
String name;
int age;
if(cursor != null cursor.getCount() 0) {
List Person personList = new ArrayList Person
while(cursor.moveToNext()) { // 向下移一位, 知道最后一位, 不可以往下移动了, 停止.
id = cursor.getInt(0);
name = cursor.getString(1);
age = cursor.getInt(2);
personList.add(new Person(id, name, age));
db.close();
return personList;
db.close();
return null;
* 根据id查询人
* @param id
* @return
public Person queryItem(int id) {
SQLiteDatabase db = mOpenHelper.getReadableDatabase(); // 获得一个只读的数据库对象
if(db.isOpen()) {
String[] columns = {"_id", "name", "age"}; // 需要的列
String selection = "_id = ?"; // 选择条件, 给null查询所有
String[] selectionArgs = {id + ""}; // 选择条件的参数, 会把选择条件中的? 替换成数据中的值
String groupBy = null; // 分组语句 group by name
String having = null; // 过滤语句
String orderBy = null; // 排序
Cursor cursor = db.query("person", columns, selection, selectionArgs, groupBy, having, orderBy);
if(cursor != null cursor.moveToFirst()) { // cursor对象不为null, 并且可以移动到第一行
int _id = cursor.getInt(0);
String name = cursor.getString(1);
int age = cursor.getInt(2);
db.close();
return new Person(_id, name, age);
db.close();
return null;
package com.itheima28.sqlitedemo.test;
import java.util.List;
import android.test.AndroidTestCase;
import android.util.Log;
import com.itheima28.sqlitedemo.dao.PersonDao2;
import com.itheima28.sqlitedemo.db.PersonSQLiteOpenHelper;
import com.itheima28.sqlitedemo.entities.Person;
public class TestCase2 extends AndroidTestCase {
private static final String TAG = "TestCase";
public void test() {
// 数据库什么时候创建
PersonSQLiteOpenHelper openHelper = new PersonSQLiteOpenHelper(getContext());
// 第一次连接数据库时创建数据库文件. onCreate会被调用
openHelper.getReadableDatabase();
public void testInsert() {
PersonDao2 dao = new PersonDao2(getContext());
dao.insert(new Person(0, "zhouqi", 88));
public void testDelete() {
PersonDao2 dao = new PersonDao2(getContext());
dao.delete(8);
public void testUpdate() {
PersonDao2 dao = new PersonDao2(getContext());
dao.update(3, "fengjie");
public void testQueryAll() {
PersonDao2 dao = new PersonDao2(getContext());
List Person personList = dao.queryAll();
for (Person person : personList) {
Log.i(TAG, person.toString());
public void testQueryItem() {
PersonDao2 dao = new PersonDao2(getContext());
Person person = dao.queryItem(4);
Log.i(TAG, person.toString());
}
事务的操作
事务:
update person set balance = balance - 100 where name = lisi;
update person set balance = balance + 100 where name = zhangsan;
// 开启事务
db.beginTransaction();
// 标记事务成功
db.setTransactionSuccessful();
// 停止事务
db.endTransaction();
public void testTransaction() {
PersonSQLiteOpenHelper openHelper = new PersonSQLiteOpenHelper(getContext());
SQLiteDatabase db = openHelper.getWritableDatabase();
if(db.isOpen()) {
try {
// 开启事务
db.beginTransaction();
// 1. 从张三账户中扣1000块钱
db.execSQL("update person set balance = balance - 1000 where name = zhangsan;");
// ATM机, 挂掉了.
// int result = 10 / 0;
// 2. 向李四账户中加1000块钱
db.execSQL("update person set balance = balance + 1000 where name = lisi;");
// 标记事务成功
db.setTransactionSuccessful();
} finally {
// 停止事务
db.endTransaction();
db.close();
public void testTransactionInsert() {
PersonSQLiteOpenHelper openHelper = new PersonSQLiteOpenHelper(getContext());
SQLiteDatabase db = openHelper.getWritableDatabase();
if(db.isOpen()) {
// 1. 记住当前的时间
long start = System.currentTimeMillis();
// 2. 开始添加数据
try {
db.beginTransaction();
for (int i = 0; i 10000; i++) {
db.execSQL("insert into person(name, age, balance) values(wang" + i + ", " + (10 + i) + ", " + (10000 + i) + ")");
db.setTransactionSuccessful();
} finally {
db.endTransaction();
// 3. 记住结束时间, 计算耗时时间
long end = System.currentTimeMillis();
long diff = end - start;
Log.i(TAG, "耗时: " + diff + "毫秒");
db.close();
}
LinearLayout展示列表数据
ScrollView xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" LinearLayout android:id="@+id/ll_list" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" /LinearLayout /ScrollView
package com.itheima28.sqlitedemo;
import java.util.List;
import com.itheima28.sqlitedemo.dao.PersonDao;
import com.itheima28.sqlitedemo.entities.Person;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.TextView;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
LinearLayout llList = (LinearLayout) findViewById(R.id.ll_list);
PersonDao dao = new PersonDao(this);
List Person personList = dao.queryAll();
if(personList != null) {
TextView tv;
for (Person person : personList) {
// 向线性布局中添加一个textview
tv = new TextView(this);
tv.setText(person.toString());
tv.setTextSize(18);
llList.addView(tv);
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
ListView的使用和BaseAdater
LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" ListView android:id="@+id/listview" android:layout_width="match_parent" android:layout_height="match_parent" /ListView /LinearLayout
package com.itheima28.sqlitedemo;
import java.util.List;
import com.itheima28.sqlitedemo.dao.PersonDao;
import com.itheima28.sqlitedemo.entities.Person;
import android.os.Bundle;
import android.app.Activity;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.TextView;
public class MainActivity extends Activity {
private List Person personList;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ListView mListView = (ListView) findViewById(R.id.listview);
PersonDao dao = new PersonDao(this);
personList = dao.queryAll();
// 把view层对象ListView和控制器BaseAdapter关联起来
mListView.setAdapter(new MyAdapter());
* @author andong
* 数据适配器
class MyAdapter extends BaseAdapter {
private static final String TAG = "MyAdapter";
* 定义ListView的数据的长度
@Override
public int getCount() {
return personList.size();
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return null;
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return 0;
* 此方法返回的是ListView的列表中某一行的View对象
* position 当前返回的view的索引位置
* convertView 缓存对象
* parent 就是ListView对象
@Override
public View getView(int position, View convertView, ViewGroup parent) {
TextView tv = null;
if(convertView != null) { // 判断缓存对象是否为null, 不为null时已经缓存了对象
Log.i(TAG, "getView: 复用缓存" + position);
tv = (TextView) convertView;
} else { // 等于null, 说明第一次显示, 新创建
Log.i(TAG, "getView: 新建" + position);
tv = new TextView(MainActivity.this);
tv.setTextSize(25);
Person person = personList.get(position); // 获得指定位置的数据, 进行对TextView的绑定
tv.setText(person.toString());
return tv;
package com.itheima28.sqlitedemo;
import java.util.List;
import com.itheima28.sqlitedemo.dao.PersonDao;
import com.itheima28.sqlitedemo.entities.Person;
import android.os.Bundle;
import android.app.Activity;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.TextView;
public class MainActivity2 extends Activity {
private List Person personList;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ListView mListView = (ListView) findViewById(R.id.listview);
PersonDao dao = new PersonDao(this);
personList = dao.queryAll();
// 把view层对象ListView和控制器BaseAdapter关联起来
mListView.setAdapter(new MyAdapter());
* @author andong
* 数据适配器
class MyAdapter extends BaseAdapter {
private static final String TAG = "MyAdapter";
* 定义ListView的数据的长度
@Override
public int getCount() {
return personList.size();
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return null;
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return 0;
* 此方法返回的是ListView的列表中某一行的View对象
* position 当前返回的view的索引位置
* convertView 缓存对象
* parent 就是ListView对象
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View view = null;
if(convertView == null) {
// 布局填充器对象, 用于把xml布局转换成view对象
LayoutInflater inflater = MainActivity2.this.getLayoutInflater();
view = inflater.inflate(R.layout.listview_item, null);
} else {
view = convertView;
// 给view中的姓名和年龄赋值
TextView tvName = (TextView) view.findViewById(R.id.tv_listview_item_name);
TextView tvAge = (TextView) view.findViewById(R.id.tv_listview_item_age);
Person person = personList.get(position);
tvName.setText("姓名: " + person.getName());
tvAge.setText("年龄: " + person.getAge());
return view;
}
listview_item.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="wrap_content" android:orientation="horizontal" android:padding="10dip" ImageView android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@drawable/f078" / LinearLayout android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_marginLeft="10dip" android:orientation="vertical" TextView android:id="@+id/tv_listview_item_name" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="张三" / TextView android:id="@+id/tv_listview_item_age" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginTop="5dip" android:textColor="#FF0000" android:text="35" / /LinearLayout /LinearLayout其他两种绑定ListView数据的方式
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" tools:context=".MainActivity" ListView android:id="@+id/listview" android:layout_width="match_parent" android:layout_height="match_parent" / /RelativeLayout
listview_item.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="wrap_content" android:gravity="center_vertical" android:orientation="horizontal" android:padding="10dip" ImageView android:id="@+id/iv_icon" android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@drawable/f007" / TextView android:id="@+id/tv_name" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginLeft="10dip" android:text="张三" android:textColor="#FF0000" android:textSize="23sp" / /LinearLayout
package com.itheima28.simpleadapterdemo;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ListView mListView = (ListView) findViewById(R.id.listview);
List Map String, Object data = new ArrayList Map String,Object ();
Map String, Object map = new HashMap String, Object
map.put("name", "张三1");
map.put("icon", R.drawable.f007);
data.add(map);
map = new HashMap String, Object
map.put("name", "张三2");
map.put("icon", R.drawable.f007);
data.add(map);
map = new HashMap String, Object
map.put("name", "张三3");
map.put("icon", R.drawable.f007);
data.add(map);
map = new HashMap String, Object
map.put("name", "张三4");
map.put("icon", R.drawable.f007);
data.add(map);
map = new HashMap String, Object
map.put("name", "张三5");
map.put("icon", R.drawable.f007);
data.add(map);
SimpleAdapter adapter = new SimpleAdapter(
this, // 上下文
data, // listView绑定的数据
R.layout.listview_item, // listview的子条目的布局的id
new String[]{"name", "icon"}, // data数据中的map集合里的key
new int[]{R.id.tv_name, R.id.iv_icon}); // resource 中的id
mListView.setAdapter(adapter);
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
内容提供者创建
?xml version="1.0" encoding="utf-8"? manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.itheima28.sqlitedemo" android:versionCode="1" android:versionName="1.0" instrumentation android:name="android.test.InstrumentationTestRunner" android:targetPackage="com.itheima28.sqlitedemo" /instrumentation permission android:name="aa.bb.cc.read" /permission permission android:name="aa.bb.cc.write" /permission uses-sdk android:minSdkVersion="8" android:targetSdkVersion="17" / application android:allowBackup="true" android:icon="@drawable/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme" uses-library android:name="android.test.runner" / activity android:name="com.itheima28.sqlitedemo.MainActivity" android:label="@string/app_name" intent-filter action android:name="android.intent.action.MAIN" / category android:name="android.intent.category.LAUNCHER" / /intent-filter /activity provider android:name=".providers.PersonContentProvider" android:authorities="com.itheima28.sqlitedemo.providers.PersonContentProvider" android:readPermission="aa.bb.cc.read" android:writePermission="aa.bb.cc.write" /provider /application /manifest
package com.itheima28.sqlitedemo.providers;
import com.itheima28.sqlitedemo.db.PersonSQLiteOpenHelper;
import android.content.ContentProvider;
import android.content.ContentUris;
import android.content.ContentValues;
import android.content.UriMatcher;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.net.Uri;
public class PersonContentProvider extends ContentProvider {
private static final String AUTHORITY = "com.itheima28.sqlitedemo.providers.PersonContentProvider";
private static final int PRESON_INSERT_CODE = 0; // 操作person表添加的操作的uri匹配码
private static final int PERSON_DELETE_CODE = 1;
private static final int PERSON_UPDATE_CODE = 2;
private static final int PERSON_QUERY_ALL_CODE = 3;
private static final int PERSON_QUERY_ITEM_CODE = 4;
private static UriMatcher uriMatcher;
private PersonSQLiteOpenHelper mOpenHelper; // person表的数据库帮助对象
static {
uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
// 添加一些uri(分机号)
// content://com.itheima28.sqlitedemo.providers.PersonContentProvider/person/insert
uriMatcher.addURI(AUTHORITY, "person/insert", PRESON_INSERT_CODE);
// content://com.itheima28.sqlitedemo.providers.PersonContentProvider/person/delete
uriMatcher.addURI(AUTHORITY, "person/delete", PERSON_DELETE_CODE);
// content://com.itheima28.sqlitedemo.providers.PersonContentProvider/person/update
uriMatcher.addURI(AUTHORITY, "person/update", PERSON_UPDATE_CODE);
// content://com.itheima28.sqlitedemo.providers.PersonContentProvider/person/queryAll
uriMatcher.addURI(AUTHORITY, "person/queryAll", PERSON_QUERY_ALL_CODE);
// content://com.itheima28.sqlitedemo.providers.PersonContentProvider/person/query/#
uriMatcher.addURI(AUTHORITY, "person/query/#", PERSON_QUERY_ITEM_CODE);
@Override
public boolean onCreate() {
mOpenHelper = new PersonSQLiteOpenHelper(getContext());
return true;
@Override
public Cursor query(Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder) {
SQLiteDatabase db = mOpenHelper.getReadableDatabase();
switch (uriMatcher.match(uri)) {
case PERSON_QUERY_ALL_CODE: // 查询所有人的uri
if(db.isOpen()) {
Cursor cursor = db.query("person", projection, selection, selectionArgs, null, null, sortOrder);
return cursor;
// db.close(); 返回cursor结果集时, 不可以关闭数据库
break;
case PERSON_QUERY_ITEM_CODE: // 查询的是单条数据, uri末尾出有一个id
if(db.isOpen()) {
long id = ContentUris.parseId(uri);
Cursor cursor = db.query("person", projection, "_id = ?", new String[]{id + ""}, null, null, sortOrder);
return cursor;
break;
default:
throw new IllegalArgumentException("uri不匹配: " + uri);
return null;
@Override
public String getType(Uri uri) {
switch (uriMatcher.match(uri)) {
case PERSON_QUERY_ALL_CODE: // 返回多条的MIME-type
return "vnd.android.cursor.dir/person";
case PERSON_QUERY_ITEM_CODE: // 返回单条的MIME-TYPE
return "vnd.android.cursor.item/person";
default:
break;
return null;
@Override
public Uri insert(Uri uri, ContentValues values) {
switch (uriMatcher.match(uri)) {
case PRESON_INSERT_CODE: // 添加人到person表中
SQLiteDatabase db = mOpenHelper.getWritableDatabase();
if(db.isOpen()) {
long id = db.insert("person", null, values);
db.close();
return ContentUris.withAppendedId(uri, id);
break;
default:
throw new IllegalArgumentException("uri不匹配: " + uri);
return null;
@Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
switch (uriMatcher.match(uri)) {
case PERSON_DELETE_CODE: // 在person表中删除数据的操作
SQLiteDatabase db = mOpenHelper.getWritableDatabase();
if(db.isOpen()) {
int count = db.delete("person", selection, selectionArgs);
db.close();
return count;
break;
default:
throw new IllegalArgumentException("uri不匹配: " + uri);
return 0;
@Override
public int update(Uri uri, ContentValues values, String selection,
String[] selectionArgs) {
switch (uriMatcher.match(uri)) {
case PERSON_UPDATE_CODE: // 更新person表的操作
SQLiteDatabase db = mOpenHelper.getWritableDatabase();
if(db.isOpen()) {
int count = db.update("person", values, selection, selectionArgs);
db.close();
return count;
break;
default:
throw new IllegalArgumentException("uri不匹配: " + uri);
return 0;
内容提供者访问和权限
?xml version="1.0" encoding="utf-8"? manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.itheima28.othercontentprovider" android:versionCode="1" android:versionName="1.0" uses-sdk android:minSdkVersion="8" android:targetSdkVersion="17" / instrumentation android:name="android.test.InstrumentationTestRunner" android:targetPackage="com.itheima28.othercontentprovider" /instrumentation uses-permission android:name="aa.bb.cc.read"/ uses-permission android:name="aa.bb.cc.write"/ application android:allowBackup="true" android:icon="@drawable/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme" uses-library android:name="android.test.runner" / activity android:name="com.itheima28.othercontentprovider.MainActivity" android:label="@string/app_name" intent-filter action android:name="android.intent.action.MAIN" / category android:name="android.intent.category.LAUNCHER" / /intent-filter /activity /application /manifest
package com.itheima28.othercontentprovider;
import android.content.ContentResolver;
import android.content.ContentUris;
import android.content.ContentValues;
import android.database.Cursor;
import android.net.Uri;
import android.test.AndroidTestCase;
import android.util.Log;
public class TextCase extends AndroidTestCase {
private static final String TAG = "TextCase";
public void testInsert() {
Uri uri = Uri.parse("content://com.itheima28.sqlitedemo.providers.PersonContentProvider/person/insert");
// 内容提供者访问对象
ContentResolver resolver = getContext().getContentResolver();
ContentValues values = new ContentValues();
values.put("name", "fengjie");
values.put("age", 90);
uri = resolver.insert(uri, values);
Log.i(TAG, "uri: " + uri);
long id = ContentUris.parseId(uri);
Log.i(TAG, "添加到: " + id);
public void testDelete() {
Uri uri = Uri.parse("content://com.itheima28.sqlitedemo.providers.PersonContentProvider/person/delete");
// 内容提供者访问对象
ContentResolver resolver = getContext().getContentResolver();
String where = "_id = ?";
String[] selectionArgs = {"21"};
int count = resolver.delete(uri, where, selectionArgs);
Log.i(TAG, "删除行: " + count);
public void testUpdate() {
Uri uri = Uri.parse("content://com.itheima28.sqlitedemo.providers.PersonContentProvider/person/update");
// 内容提供者访问对象
ContentResolver resolver = getContext().getContentResolver();
ContentValues values = new ContentValues();
values.put("name", "lisi");
int count = resolver.update(uri, values, "_id = ?", new String[]{"20"});
Log.i(TAG, "更新行: " + count);
public void testQueryAll() {
Uri uri = Uri.parse("content://com.itheima28.sqlitedemo.providers.PersonContentProvider/person/queryAll");
// 内容提供者访问对象
ContentResolver resolver = getContext().getContentResolver();
Cursor cursor = resolver.query(uri, new String[]{"_id", "name", "age"}, null, null, "_id desc");
if(cursor != null cursor.getCount() 0) {
int id;
String name;
int age;
while(cursor.moveToNext()) {
id = cursor.getInt(0);
name = cursor.getString(1);
age = cursor.getInt(2);
Log.i(TAG, "id: " + id + ", name: " + name + ", age: " + age);
cursor.close();
public void testQuerySingleItem() {
Uri uri = Uri.parse("content://com.itheima28.sqlitedemo.providers.PersonContentProvider/person/query/#");
// 在uri的末尾添加一个id content://com.itheima28.sqlitedemo.providers.PersonContentProvider/person/query/20
uri = ContentUris.withAppendedId(uri, 20);
// 内容提供者访问对象
ContentResolver resolver = getContext().getContentResolver();
Cursor cursor = resolver.query(uri, new String[]{"_id", "name", "age"}, null, null, null);
if(cursor != null cursor.moveToFirst()) {
int id = cursor.getInt(0);
String name = cursor.getString(1);
int age = cursor.getInt(2);
cursor.close();
Log.i(TAG, "id: " + id + ", name: " + name + ", age: " + age);
Android零基础入门第25节：最简单最常用的LinearLayout线性布局 原文:Android零基础入门第25节：最简单最常用的LinearLayout线性布局 良好的布局设计对于UI界面至关重要，在前面也简单介绍过，目前Android中的布局主要有6种，创建的布局文件默认为RelativeLayout相对布局，而在前面的示例学习中，我们只是简单利用了一下LinearLayout线性布局，那么接下来分别对其进行详细学习。
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