一直想總結(jié)一下關(guān)于iOS的離線數(shù)據(jù)緩存的方面的問(wèn)題,然后最近也簡(jiǎn)單的對(duì)AFN進(jìn)行了再次封裝哈肖,所有想把這兩個(gè)結(jié)合起來(lái)寫一下受啥。數(shù)據(jù)展示型的頁(yè)面做離線緩存可以有更好的用戶體驗(yàn),用戶在離線環(huán)境下仍然可以獲取一些數(shù)據(jù)炼幔,這里的數(shù)據(jù)緩存首選肯定是SQLite秋茫,輕量級(jí),對(duì)數(shù)據(jù)的存儲(chǔ)讀取相對(duì)于其他幾種方式有優(yōu)勢(shì)乃秀,這里對(duì)AFN的封裝沒(méi)有涉及太多業(yè)務(wù)邏輯層面的需求肛著,主要還是對(duì)一些方法再次封裝方便使用,解除項(xiàng)目對(duì)第三方的耦合性跺讯,能夠簡(jiǎn)單的快速的更換底層使用的網(wǎng)絡(luò)請(qǐng)求代碼枢贿。這篇主要寫離線緩存思路,對(duì)AFN的封裝只做簡(jiǎn)單的介紹抬吟。
關(guān)于XLNetworkApi
XLNetworkApi的一些功能和說(shuō)明:
使用XLNetworkRequest做一些GET萨咕、POST、PUT火本、DELETE請(qǐng)求危队,與業(yè)務(wù)邏輯對(duì)接部分直接以數(shù)組或者字典的形式返回。
以及網(wǎng)絡(luò)下載钙畔、上傳文件茫陆,以block的形式返回實(shí)時(shí)的下載、上傳進(jìn)度擎析,上傳文件參數(shù)通過(guò)模型XLFileConfig去存取簿盅。
通過(guò)繼承于XLDataService來(lái)將一些數(shù)據(jù)處理挥下,模型轉(zhuǎn)化封裝起來(lái),于業(yè)務(wù)邏輯對(duì)接返回的是對(duì)應(yīng)的模型桨醋,減少Controllor處理數(shù)據(jù)處理邏輯的壓力棚瘟。
自定義一些回調(diào)的block
/**
請(qǐng)求成功block
*/
typedef void (^requestSuccessBlock)(id responseObj);
/**
請(qǐng)求失敗block
*/
typedef void (^requestFailureBlock) (NSError *error);
/**
請(qǐng)求響應(yīng)block
*/
typedef void (^responseBlock)(id dataObj, NSError *error);
/**
監(jiān)聽進(jìn)度響應(yīng)block
*/
typedef void (^progressBlock)(int64_t bytesWritten, int64_t totalBytesWritten, int64_t totalBytesExpectedToWrite);
- XLNetworkRequest.m部分實(shí)現(xiàn)
#import "XLNetworkRequest.h"
#import "AFNetworking.h"
@implementation XLNetworkRequest
+ (void)getRequest:(NSString *)url params:(NSDictionary *)params success:(requestSuccessBlock)successHandler failure:(requestFailureBlock)failureHandler {
AFHTTPRequestOperationManager *manager = [self getRequstManager];
[manager GET:url parameters:params success:^(AFHTTPRequestOperation * _Nonnull operation, id _Nonnull responseObject) {
successHandler(responseObject);
} failure:^(AFHTTPRequestOperation * _Nullable operation, NSError * _Nonnull error) {
XLLog(@"------請(qǐng)求失敗-------%@",error);
failureHandler(error);
}];
}
- 下載部分代碼
//下載文件,監(jiān)聽下載進(jìn)度
+ (void)downloadRequest:(NSString *)url successAndProgress:(progressBlock)progressHandler complete:(responseBlock)completionHandler {
NSURLSessionConfiguration *sessionConfiguration = [NSURLSessionConfiguration defaultSessionConfiguration];
AFURLSessionManager *manager = [[AFURLSessionManager alloc] initWithSessionConfiguration:sessionConfiguration];
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:url]];
NSProgress *kProgress = nil;
NSURLSessionDownloadTask *downloadTask = [manager downloadTaskWithRequest:request progress:&kProgress destination:^NSURL * _Nonnull(NSURL * _Nonnull targetPath, NSURLResponse * _Nonnull response) {
NSURL *documentUrl = [[NSFileManager defaultManager] URLForDirectory :NSDocumentDirectory inDomain:NSUserDomainMask appropriateForURL:nil create:NO error:nil];
return [documentUrl URLByAppendingPathComponent:[response suggestedFilename]];
} completionHandler:^(NSURLResponse * _Nonnull response, NSURL * _Nonnull filePath, NSError * _Nonnull error){
if (error) {
XLLog(@"------下載失敗-------%@",error);
}
completionHandler(response, error);
}];
[manager setDownloadTaskDidWriteDataBlock:^(NSURLSession * _Nonnull session, NSURLSessionDownloadTask * _Nonnull downloadTask, int64_t bytesWritten, int64_t totalBytesWritten, int64_t totalBytesExpectedToWrite) {
progressHandler(bytesWritten, totalBytesWritten, totalBytesExpectedToWrite);
}];
[downloadTask resume];
}
- 上傳部分代碼
//上傳文件喜最,監(jiān)聽上傳進(jìn)度
+ (void)updateRequest:(NSString *)url params:(NSDictionary *)params fileConfig:(XLFileConfig *)fileConfig successAndProgress:(progressBlock)progressHandler complete:(responseBlock)completionHandler {
NSMutableURLRequest *request = [[AFHTTPRequestSerializer serializer] multipartFormRequestWithMethod:@"POST" URLString:url parameters:params constructingBodyWithBlock:^(id<AFMultipartFormData> _Nonnull formData) {
[formData appendPartWithFileData:fileConfig.fileData name:fileConfig.name fileName:fileConfig.fileName mimeType:fileConfig.mimeType];
} error:nil];
//獲取上傳進(jìn)度
AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];
[operation setUploadProgressBlock:^(NSUInteger bytesWritten, long long totalBytesWritten, long long totalBytesExpectedToWrite) {
progressHandler(bytesWritten, totalBytesWritten, totalBytesExpectedToWrite);
}];
[operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation * _Nonnull operation, id _Nonnull responseObject) {
completionHandler(responseObject, nil);
} failure:^(AFHTTPRequestOperation * _Nonnull operation, NSError * _Nonnull error) {
completionHandler(nil, error);
if (error) {
XLLog(@"------上傳失敗-------%@",error);
}
}];
[operation start];
}
- XLDataService.m部分實(shí)現(xiàn)
+ (void)getWithUrl:(NSString *)url param:(id)param modelClass:(Class)modelClass responseBlock:(responseBlock)responseDataBlock {
[XLNetworkRequest getRequest:url params:param success:^(id responseObj) {
//數(shù)組偎蘸、字典轉(zhuǎn)化為模型數(shù)組
dataObj = [self modelTransformationWithResponseObj:responseObj modelClass:modelClass];
responseDataBlock(dataObj, nil);
} failure:^(NSError *error) {
responseDataBlock(nil, error);
}];
}
- (關(guān)鍵)下面這個(gè)方法提供給繼承XLDataService的子類重寫,將轉(zhuǎn)化為模型的代碼寫在這里瞬内,相似業(yè)務(wù)的網(wǎng)絡(luò)數(shù)據(jù)請(qǐng)求都可以用這個(gè)子類去請(qǐng)求數(shù)據(jù)迷雪,直接返回對(duì)應(yīng)的模型數(shù)組。
/**
數(shù)組虫蝶、字典轉(zhuǎn)化為模型
*/
+ (id)modelTransformationWithResponseObj:(id)responseObj modelClass:(Class)modelClass {
return nil;
}
關(guān)于離線數(shù)據(jù)緩存
當(dāng)用戶進(jìn)入程序的展示頁(yè)面章咧,有三個(gè)情況下可能涉及到數(shù)據(jù)庫(kù)存取操作,簡(jiǎn)單畫了個(gè)圖來(lái)理解能真,思路比較簡(jiǎn)單赁严,主要是一些存取的細(xì)節(jié)處理。
-
進(jìn)入展示頁(yè)面
進(jìn)入頁(yè)面.png -
下拉刷新最新數(shù)據(jù)
下拉刷新.png -
上拉加載更多數(shù)據(jù)
上拉加載更多.png 需要注意的是舟陆,上拉加載更多的時(shí)候误澳,每次從數(shù)據(jù)庫(kù)返回一定數(shù)量的數(shù)據(jù),而不是一次性將數(shù)據(jù)全部加載秦躯,否則會(huì)有內(nèi)存問(wèn)題,直到數(shù)據(jù)庫(kù)中沒(méi)有更多數(shù)據(jù)時(shí)再發(fā)生網(wǎng)絡(luò)請(qǐng)求裆装,再次將新數(shù)據(jù)存入數(shù)據(jù)庫(kù)踱承。這里存儲(chǔ)數(shù)據(jù)的方式是將服務(wù)器返回每組數(shù)據(jù)的字典歸檔成二進(jìn)制作為數(shù)據(jù)庫(kù)字段直接存儲(chǔ),這樣存儲(chǔ)在模型屬性比較多的情況下更有優(yōu)勢(shì)哨免,避免每一個(gè)屬性作為一個(gè)字段茎活,另外增加了一個(gè)idStr字段用來(lái)判斷數(shù)據(jù)的唯一性,避免重復(fù)存儲(chǔ)琢唾。
首先定義一個(gè)工具類XLDataBase來(lái)做數(shù)據(jù)庫(kù)相關(guān)的操作载荔,這里用的是第三方的FMDB。
#import "XLDataBase.h"
#import "FMDatabase.h"
#import "Item.h"
#import "MJExtension.h"
@implementation XLDataBase
static FMDatabase *_db;
+ (void)initialize {
NSString *path = [NSString stringWithFormat:@"%@/Library/Caches/Data.db",NSHomeDirectory()];
_db = [FMDatabase databaseWithPath:path];
[_db open];
[_db executeUpdate:@"CREATE TABLE IF NOT EXISTS t_item (id integer PRIMARY KEY, itemDict blob NOT NULL, idStr text NOT NULL)"];
}
//存入數(shù)據(jù)庫(kù)
+ (void)saveItemDict:(NSDictionary *)itemDict {
//此處把字典歸檔成二進(jìn)制數(shù)據(jù)直接存入數(shù)據(jù)庫(kù)采桃,避免添加過(guò)多的數(shù)據(jù)庫(kù)字段
NSData *dictData = [NSKeyedArchiver archivedDataWithRootObject:itemDict];
[_db executeUpdateWithFormat:@"INSERT INTO t_item (itemDict, idStr) VALUES (%@, %@)",dictData, itemDict[@"id"]];
}
//返回全部數(shù)據(jù)
+ (NSArray *)list {
FMResultSet *set = [_db executeQuery:@"SELECT * FROM t_item"];
NSMutableArray *list = [NSMutableArray array];
while (set.next) {
// 獲得當(dāng)前所指向的數(shù)據(jù)
NSData *dictData = [set objectForColumnName:@"itemDict"];
NSDictionary *dict = [NSKeyedUnarchiver unarchiveObjectWithData:dictData];
[list addObject:[Item mj_objectWithKeyValues:dict]];
}
return list;
}
//取出某個(gè)范圍內(nèi)的數(shù)據(jù)
+ (NSArray *)listWithRange:(NSRange)range {
NSString *SQL = [NSString stringWithFormat:@"SELECT * FROM t_item LIMIT %lu, %lu",range.location, range.length];
FMResultSet *set = [_db executeQuery:SQL];
NSMutableArray *list = [NSMutableArray array];
while (set.next) {
NSData *dictData = [set objectForColumnName:@"itemDict"];
NSDictionary *dict = [NSKeyedUnarchiver unarchiveObjectWithData:dictData];
[list addObject:[Item mj_objectWithKeyValues:dict]];
}
return list;
}
//通過(guò)一組數(shù)據(jù)的唯一標(biāo)識(shí)判斷數(shù)據(jù)是否存在
+ (BOOL)isExistWithId:(NSString *)idStr
{
BOOL isExist = NO;
FMResultSet *resultSet= [_db executeQuery:@"SELECT * FROM t_item where idStr = ?",idStr];
while ([resultSet next]) {
if([resultSet stringForColumn:@"idStr"]) {
isExist = YES;
}else{
isExist = NO;
}
}
return isExist;
}
@end
- 一些繼承于XLDataService的子類的數(shù)據(jù)庫(kù)存儲(chǔ)和模型轉(zhuǎn)換的邏輯代碼
#import "GetTableViewData.h"
#import "XLDataBase.h"
@implementation GetTableViewData
//重寫父類方法
+ (id)modelTransformationWithResponseObj:(id)responseObj modelClass:(Class)modelClass {
NSArray *lists = responseObj[@"data"][@"list"];
NSMutableArray *array = [NSMutableArray array];
for (NSDictionary *dict in lists) {
[modelClass mj_setupReplacedKeyFromPropertyName:^NSDictionary *{
return @{ @"ID" : @"id" };
}];
[array addObject:[modelClass mj_objectWithKeyValues:dict]];
//通過(guò)idStr先判斷數(shù)據(jù)是否存儲(chǔ)過(guò)懒熙,如果沒(méi)有,網(wǎng)絡(luò)請(qǐng)求新數(shù)據(jù)存入數(shù)據(jù)庫(kù)
if (![XLDataBase isExistWithId:dict[@"id"]]) {
//存數(shù)據(jù)庫(kù)
NSLog(@"存入數(shù)據(jù)庫(kù)");
[XLDataBase saveItemDict:dict];
}
}
return array;
}
- 下面是一些控制器的代碼實(shí)現(xiàn):
#import "ViewController.h"
#import "GetTableViewData.h"
#import "Item.h"
#import "XLDataBase.h"
#import "ItemCell.h"
#import "MJRefresh.h"
#define URL_TABLEVIEW @"https://api.108tian.com/mobile/v3/EventList?cityId=1&step=10&theme=0&page=%lu"
@interface ViewController () <UITableViewDataSource, UITableViewDelegate>
{
NSMutableArray *_dataArray;
UITableView *_tableView;
NSInteger _currentPage;//當(dāng)前數(shù)據(jù)對(duì)應(yīng)的page
}
@end
@implementation ViewController
#pragma mark Life cycle
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
[self createTableView];
_dataArray = [NSMutableArray array];
}
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
NSRange range = NSMakeRange(0, 10);
//如果數(shù)據(jù)庫(kù)有數(shù)據(jù)則讀取普办,不發(fā)送網(wǎng)絡(luò)請(qǐng)求
if ([[XLDataBase listWithRange:range] count]) {
[_dataArray addObjectsFromArray:[XLDataBase listWithRange:range]];
NSLog(@"從數(shù)據(jù)庫(kù)加載");
}else{
[self getTableViewDataWithPage:0];
}
}
#pragma mark UI
- (void)createTableView {
_tableView = [[UITableView alloc] initWithFrame:self.view.bounds];
_tableView.delegate = self;
_tableView.dataSource = self;
_tableView.rowHeight = 100.0;
[self.view addSubview:_tableView];
_tableView.mj_header = [MJRefreshNormalHeader headerWithRefreshingBlock:^{
[self loadNewData];
}];
_tableView.mj_footer = [MJRefreshAutoNormalFooter footerWithRefreshingBlock:^{
[self loadMoreData];
}];
}
#pragma mark GetDataSoure
- (void)getTableViewDataWithPage:(NSInteger)page {
NSLog(@"發(fā)送網(wǎng)絡(luò)請(qǐng)求工扎!");
NSString *url = [NSString stringWithFormat:URL_TABLEVIEW, page];
[GetTableViewData getWithUrl:url param:nil modelClass:[Item class] responseBlock:^(id dataObj, NSError *error) {
[_dataArray addObjectsFromArray:dataObj];
[_tableView reloadData];
[_tableView.mj_header endRefreshing];
[_tableView.mj_footer endRefreshing];
}];
}
- (void)loadNewData {
NSLog(@"下拉刷新");
_currentPage = 0;
[_dataArray removeAllObjects];
[self getTableViewDataWithPage:_currentPage];
}
- (void)loadMoreData {
NSLog(@"上拉加載");
_currentPage ++;
NSRange range = NSMakeRange(_currentPage * 10, 10);
if ([[XLDataBase listWithRange:range] count]) {
[_dataArray addObjectsFromArray:[XLDataBase listWithRange:range]];
[_tableView reloadData];
[_tableView.mj_footer endRefreshing];
NSLog(@"數(shù)據(jù)庫(kù)加載%lu條更多數(shù)據(jù)",[[XLDataBase listWithRange:range] count]);
}else{
//數(shù)據(jù)庫(kù)沒(méi)更多數(shù)據(jù)時(shí)再網(wǎng)絡(luò)請(qǐng)求
[self getTableViewDataWithPage:_currentPage];
}
}
#pragma mark UITableViewDataSource
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return _dataArray.count;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
ItemCell *cell = [ItemCell itemCellWithTableView:tableView];
cell.item = _dataArray[indexPath.row];
return cell;
}
@end
最后附上代碼的下載地址,重要的部分代碼中都有相應(yīng)的注釋和文字打印衔蹲,運(yùn)行程序可以很直觀的表現(xiàn)肢娘。
https://github.com/ShelinShelin/OffLineCache.git
有考慮不周的地方,希望大家能提出一些意見,很樂(lè)意與大家互相交流橱健。