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Android内容提供者ContentProvider用法实例分析

︶ㄣ米米素材网 メ
米米素材网V管理员 / 阅读
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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

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。