这篇文章主要介绍了Android内容提供者ContentProvider用法,结合实例形式较为详细的分析了内容提供者ContentProvider获取及解析数据的相关技巧,需要的朋友可以参考下
正文
Android内容提供者ContentProvider用法实例分析
本文实例讲述了android内容提供者contentprovider用法。分享给大家供大家参考，具体如下：
personcontentprovider内容提供者类
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package com.ljq.db;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;import android.text.textutils;/** * 内容提供者 * * 作用：统一数据访问方式，方便外部调用 * * @author jiqinlin * */public class personcontentprovider extends contentprovider { // 数据集的mime类型字符串则应该以vnd.android.cursor.dir/开头 public static final string persons_type = "vnd.android.cursor.dir/person"; // 单一数据的mime类型字符串应该以vnd.android.cursor.item/开头 public static final string persons_item_type = "vnd.android.cursor.item/person"; public static final string authority = "com.ljq.provider.personprovider";// 主机名 /* 自定义匹配码 */ public static final int persons = 1; /* 自定义匹配码 */ public static final int person = 2; public static final uri persons_uri = uri.parse("content://" + authority + "/person"); private dbopenhelper dbopenhelper = null; // urimatcher类用来匹配uri，使用match()方法匹配路径时返回匹配码 private static final urimatcher urimatcher; static { // 常量urimatcher.no_match表示不匹配任何路径的返回码 urimatcher = new urimatcher(urimatcher.no_match); // 如果match()方法匹配content://com.ljq.provider.personprovider/person路径，返回匹配码为persons urimatcher.adduri(authority, "person", persons); // 如果match()方法匹配content://com.ljq.provider.personprovider/person/230路径，返回匹配码为person urimatcher.adduri(authority, "person/#", person); } @override public boolean oncreate() { dbopenhelper = new dbopenhelper(this.getcontext()); return true; } @override public uri insert(uri uri, contentvalues values){ sqlitedatabase db = dbopenhelper.getwritabledatabase(); long id = 0; switch (urimatcher.match(uri)) { case persons: id = db.insert("person", "name", values);// 返回的是记录的行号，主键为int，实际上就是主键值 return contenturis.withappendedid(uri, id); case person: id = db.insert("person", "name", values); string path = uri.tostring(); return uri.parse(path.substring(0, path.lastindexof("/"))+id); // 替换掉id default: throw new illegalargumentexception("unknown uri " + uri); } } @override public int delete(uri uri, string selection, string[] selectionargs) { sqlitedatabase db = dbopenhelper.getwritabledatabase(); int count = 0; switch (urimatcher.match(uri)) { case persons: count = db.delete("person", selection, selectionargs); break; case person: // 下面的方法用于从uri中解析出id，对这样的路径content://com.ljq.provider.personprovider/person/10 // 进行解析，返回值为10 long personid = contenturis.parseid(uri); string where = "id=" + personid;// 删除指定id的记录 where += !textutils.isempty(selection) ? " and (" + selection + ")" : "";// 把其它条件附加上 count = db.delete("person", where, selectionargs); break; default: throw new illegalargumentexception("unknown uri " + uri); } db.close(); return count; } @override public int update(uri uri, contentvalues values, string selection, string[] selectionargs) { sqlitedatabase db = dbopenhelper.getwritabledatabase(); int count = 0; switch (urimatcher.match(uri)) { case persons: count = db.update("person", values, selection, selectionargs); break; case person: // 下面的方法用于从uri中解析出id，对这样的路径content://com.ljq.provider.personprovider/person/10 // 进行解析，返回值为10 long personid = contenturis.parseid(uri); string where = "id=" + personid;// 获取指定id的记录 where += !textutils.isempty(selection) ? " and (" + selection + ")" : "";// 把其它条件附加上 count = db.update("person", values, where, selectionargs); break; default: throw new illegalargumentexception("unknown uri " + uri); } db.close(); return count; } @override public string gettype(uri uri) { switch (urimatcher.match(uri)) { case persons: return persons_type; case person: return persons_item_type; default: throw new illegalargumentexception("unknown uri " + uri); } } @override public cursor query(uri uri, string[] projection, string selection, string[] selectionargs, string sortorder) { sqlitedatabase db = dbopenhelper.getreadabledatabase(); switch (urimatcher.match(uri)) { case persons: return db.query("person", projection, selection, selectionargs, null, null, sortorder); case person: // 下面的方法用于从uri中解析出id，对这样的路径content://com.ljq.provider.personprovider/person/10 // 进行解析，返回值为10 long personid = contenturis.parseid(uri); string where = "id=" + personid;// 获取指定id的记录 where += !textutils.isempty(selection) ? " and (" + selection + ")" : "";// 把其它条件附加上 return db.query("person", projection, where, selectionargs, null, null, sortorder); default: throw new illegalargumentexception("unknown uri " + uri); } }} |
文件清单
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<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.ljq.sql" android:versioncode="1" android:versionname="1.0"> <application android:icon="@drawable/icon" android:label="@string/app_name"> <uses-library android:name="android.test.runner" /> <activity android:name=".sqlactivity" 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="com.ljq.db.personcontentprovider" android:authorities="com.ljq.provider.personprovider" /> </application> <uses-sdk android:minsdkversion="7" /> <instrumentation android:name="android.test.instrumentationtestrunner" android:targetpackage="com.ljq.sql" android:label="tests for my app" /></manifest> |
personcontentprovidertest内容提供者测试类
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package com.ljq.test;import android.content.contentresolver;import android.content.contentvalues;import android.database.cursor;import android.net.uri;import android.test.androidtestcase;import android.util.log;/** * 外部访问内容提供者 * * @author jiqinlin * */public class personcontentprovidertest extends androidtestcase{ private static final string tag = "personcontentprovidertest"; public void testsave() throws throwable{ contentresolver contentresolver = this.getcontext().getcontentresolver(); uri inserturi = uri.parse("content://com.ljq.provider.personprovider/person"); contentvalues values = new contentvalues(); values.put("name", "ljq"); values.put("phone", "1350000009"); uri uri = contentresolver.insert(inserturi, values); log.i(tag, uri.tostring()); } public void testupdate() throws throwable{ contentresolver contentresolver = this.getcontext().getcontentresolver(); uri updateuri = uri.parse("content://com.ljq.provider.personprovider/person/1"); contentvalues values = new contentvalues(); values.put("name", "linjiqin"); contentresolver.update(updateuri, values, null, null); } public void testfind() throws throwable{ contentresolver contentresolver = this.getcontext().getcontentresolver(); //uri uri = uri.parse("content://com.ljq.provider.personprovider/person"); uri uri = uri.parse("content://com.ljq.provider.personprovider/person"); cursor cursor = contentresolver.query(uri, null, null, null, "id asc"); while(cursor.movetonext()){ int personid = cursor.getint(cursor.getcolumnindex("id")); string name = cursor.getstring(cursor.getcolumnindex("name")); string phone = cursor.getstring(cursor.getcolumnindex("phone")); log.i(tag, "personid="+ personid + ",name="+ name+ ",phone="+ phone); } cursor.close(); } public void testdelete() throws throwable{ contentresolver contentresolver = this.getcontext().getcontentresolver(); uri uri = uri.parse("content://com.ljq.provider.personprovider/person/1"); contentresolver.delete(uri, null, null); }} |
希望本文所述对大家android程序设计有所帮助。
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