自定义ContentProvider(内容提供者)简单使用例子
功能：跨app访问本app数据库一些基本操作
1、在配置清单里配置权限和自定义ContentProvider对外暴露给其他应用访问的路径
代码
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.contentprovider_custom"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="21" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".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>
<!-- 自定义ContentProvider name :包名.类名 -->
<!-- 自定义ContentProvider authirities :最好 是包名.类名 也可以是任意 -->
<!-- 自定义ContentProvider exported ：是否允许别的app访问 -->
<provider
android:name="com.example.contentprovider_custom.Custom"
android:authorities="com.example.contentprovider_custom.custom"
android:exported="true" >
</provider>
</application>
=======================
2、其他app操作本app数据库基本操作的主要代码
//自定义ContentProvider 要继承ContentProvider类
public class Custom extends ContentProvider {
//在功能清单配置的 -- URI 的autauthorities部分
private static String autauthorities = "com.example.contentprovider_custom.custom";
//在声明一个工具类对象
private static UriMatcher uriMatcher;//匹配URI的匹配器
static{//静态代码块
uriMatcher = new UriMatcher(-1);//如果uri匹配不上 返回-1
//第一个参数 -- uri部分
//第二份参数 -- path -- 最好填数据库表名
//第三个参数 -- 如果uri匹配 就返回 匹配成功码 code
uriMatcher.addURI(autauthorities, "student", 100);//code随便定义
uriMatcher.addURI(autauthorities, "student/*", 101);//斜杠后面跟着*代表文本标志
uriMatcher.addURI(autauthorities, "stu/#", 102);//斜杠后面跟着#号代表数字
}
private Sqlite_table sqlite_table ;
@Override
public boolean onCreate() {
sqlite_table = new Sqlite_table(getContext());
return false;
}
@Override
public Cursor query(Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder) {
Cursor cursor = null;
SQLiteDatabase db = sqlite_table.getReadableDatabase();
switch(uriMatcher.match(uri)){
case 100://uri匹配成功
cursor = db.query("student", projection, selection, selectionArgs, null, null,sortOrder);
break;
case 101:
String keyword = uri.getLastPathSegment();//用getLastPathSegment方法 获得文本标志
//模糊查询 名字第一个是 ...
cursor = db.query("student", projection, "s_name like ?", new String[]{keyword + "%"}, null,null,null);
break;
case 102:
long score = ContentUris.parseId(uri);//获取uri后面的数字
cursor = db.query("student", projection, "score = ?", new String[]{score + ""}, null, null, null);
break;
}
return cursor;
}
@Override
public String getType(Uri uri) {
return null;
}
@Override
public Uri insert(Uri uri, ContentValues values) {
SQLiteDatabase db = sqlite_table.getReadableDatabase();
Uri insert_uri = null;
switch(uriMatcher.match(uri)){
case 100:
long rowid = db.insert("student", null, values);//返回插入的行
insert_uri = ContentUris.withAppendedId(uri,rowid);//用工具类ContentUris拼接返回来的行号 变成插入新数据的uri
break;
}
return insert_uri;
}
@Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
SQLiteDatabase db = sqlite_table.getReadableDatabase();
int rownum = 0;
switch(uriMatcher.match(uri)){
case 100:
rownum = db.delete("student", selection, selectionArgs);
break;
}
return rownum;
}
@Override
public int update(Uri uri, ContentValues values, String selection,
String[] selectionArgs) {
SQLiteDatabase db = sqlite_table.getReadableDatabase();
int rows = 0;
switch(uriMatcher.match(uri)){
case 100:
rows = db.update("student", values, selection, selectionArgs);
break;
}
return rows;
}
}