使用场景:
当从服务器请求的数据比较庞大时，这个时候，需要对数据进行分批处理，然后以当前的数据刷新界面
效果图:
image
原理分析图:
image
完整代码如下:
mDataInfo = new DataInfo();
List objects = new ArrayList<>();
for (int i = 0; i < 4000; i++) {
objects.add(i);
}
mDataInfo.l1 = objects;
objects = new ArrayList<>();
for (int i = 0; i < 8000; i++) {
objects.add(i);
}
mDataInfo.l2 = objects;
objects = new ArrayList<>();
for (int i = 0; i < 12000; i++) {
objects.add(i);
}
Observable.concat(Observable.just(mDataInfo.l1), Observable.just(mDataInfo.l2), Observable
.just(mDataInfo.l3)).subscribeOn(Schedulers.io()).
concatMap(new Function, Observable>() {
@Override
public Observable apply(List list1) throws Exception {
LoggerUtils.loge("concatMap list1.size = " + list1.size());
List list = new ArrayList<>();
int pageSize = list1.size() / 1000;
int start = -1, end = 0;
List tmp = new ArrayList<>(list1);
NewPageInfo newPageInfo = null;
String tagStr = "";
if (list1.size() == mDataInfo.l1.size()) {
tagStr = "l1";
} else if (list1.size() == mDataInfo.l2.size()) {
tagStr = "l2";
} else if (list1.size() == mDataInfo.l3.size()) {
tagStr = "l3";
}
for (int i = 0; i < pageSize; i++) {
// 0 : 0
// 1 1000
start = i * 1000;
end = (i + 1) * 1000 - 1;
LoggerUtils.loge("s : " + start + " , e : " + end);
List subList = tmp.subList(start, end);
newPageInfo = new NewPageInfo();
newPageInfo.tag = tagStr;
newPageInfo.datas = subList;
newPageInfo.page = i + "";
list.add(newPageInfo);
}
ThreadUtils.doSleep(1500);
return Observable.fromIterable(list);
}
})
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Consumer() {
@Override
public void accept(NewPageInfo newPageInfo) throws Exception {
List datas = newPageInfo.datas;
int size = datas.size();
String msg = "count : " + newPageInfo.page + " , dataSize : " + size + " " +
", " + "scope : start : " + datas.get(0) + " , end : " + datas
.get(size
- 1);
LoggerUtils.loge(msg);
UiUtils.postDelayed(new Runnable() {
@Override
public void run() {
if ("l1".equalsIgnoreCase(newPageInfo.tag)) {
line1.append(msg + "\r\n");
} else if ("l2".equalsIgnoreCase(newPageInfo.tag)) {
line2.append(msg + "\r\n");
} else if ("l3".equalsIgnoreCase(newPageInfo.tag)) {
line3.append(msg + "\r\n");
}
}
}, 800);
}
});
场景二
以上的操作，对象为空了，直接就会抛出空指针的异常，流程没办法往下走了。
改进后的操作如下
image
示例代码
private void initData() {
MPChartInfo mpChartInfo = new MPChartInfo();
mDataInfo = new DataInfo();
List objects = new ArrayList<>();
for (int i = 0; i < 1000; i++) {
objects.add(i);
}
mDataInfo.name = "l1";
mDataInfo.l1 = objects;
mpChartInfo.V52 = mDataInfo;
mDataInfo = new DataInfo();
objects = new ArrayList<>();
for (int i = 0; i < 2000; i++) {
objects.add(i);
}
mDataInfo.l1 = objects;
objects = new ArrayList<>();
for (int i = 0; i < 3000; i++) {
objects.add(i);
}
mDataInfo.l2 = objects;
mDataInfo.name = "l2";
mpChartInfo.V54 = mDataInfo;
mDataInfo = new DataInfo();
objects = new ArrayList<>();
for (int i = 0; i < 3000; i++) {
objects.add(i);
}
mDataInfo.l1 = objects;
objects = new ArrayList<>();
for (int i = 0; i < 4000; i++) {
objects.add(i);
}
mDataInfo.l2 = objects;
objects = new ArrayList<>();
for (int i = 0; i < 5000; i++) {
objects.add(i);
}
mDataInfo.name = "l3";
mDataInfo.l3 = objects;
mpChartInfo.V58 = mDataInfo;
showUI(mpChartInfo);
}
/**
* 标识传递,空数据的处理
*/
private void ll_02_03(MPChartInfo mpChartInfo) {
mV52 = mpChartInfo.getV52();
mV54 = mpChartInfo.getV54();
mV54 = null;
// 对象为空时就使用空的Observable
Observable empty = Observable.empty();
mV58 = mpChartInfo.getV58();
mV58 = null;
Observable.concat(mV52 != null ? Observable.just(mV52) : empty, mV54 != null ? Observable
.just(mV54) : empty, mV58 != null ? Observable
.just(mV58) : empty)
.subscribeOn(Schedulers.io()).
concatMap(new Function>>>() {
@Override
public Observable>> apply(DataInfo dataInfo) throws
Exception {
LoggerUtils.loge("concatMap apply = " + dataInfo.name);
ThreadUtils.doSleep(300);
List l1 = dataInfo.l1;
List l2 = dataInfo.l2;
List l3 = dataInfo.l3;
// 定义标识，标识一定要往下传递，要区分是刷新哪个控件使用
Map> map = new LinkedHashMap<>();
map.put(dataInfo.name, l1);
// 对象为空或集合为空时，使用空的Observable
Observable>> source1 = l1 != null && l1.size()
> 0 ?
Observable.just(map) : empty;
map = new LinkedHashMap<>();
map.put(dataInfo.name, l2);
Observable>> source2 = l2 != null && l2.size()
> 0 ? Observable
.just(map) : empty;
map = new LinkedHashMap<>();
map.put(dataInfo.name, l3);
Observable>> source3 = l3 != null && l3.size()
> 0 ?
Observable.just(map) :
empty;
Observable>> concat = Observable.concat
(source1, source2,
source3);
return concat;
}
})
.subscribeOn(Schedulers.io())
.concatMap(new Function>, Observable>() {
@Override
public Observable apply(Map> list1) throws
Exception {
Iterator>> iterator = list1.entrySet()
.iterator();
Map.Entry> entry = iterator.next();
List entryValue = entry.getValue();
String key = entry.getKey();
LoggerUtils.loge("concatMap apply tag = " + key + " , list1.size " +
"= " + entryValue.size());
List list = new ArrayList<>();
int pageSize = entryValue.size() / 1000;
int start = -1, end = 0;
List tmp = new ArrayList<>(entryValue);
NewPageInfo newPageInfo = null;
String tagStr = key;
for (int i = 0; i < pageSize; i++) {
// 0 : 0
// 1 1000
start = i * 1000;
end = (i + 1) * 1000 - 1;
// LoggerUtils.loge("s : " + start + " , e : " + end);
List subList = tmp.subList(start, end);
newPageInfo = new NewPageInfo();
newPageInfo.tag = tagStr;
newPageInfo.datas = subList;
newPageInfo.page = i + "";
list.add(newPageInfo);
}
ThreadUtils.doSleep(500);
return Observable.fromIterable(list);
}
}).observeOn(AndroidSchedulers.mainThread())
.subscribe(new Consumer() {
@Override
public void accept(NewPageInfo newPageInfo) throws Exception {
List datas = newPageInfo.datas;
int size = datas.size();
String msg = "count : " + newPageInfo.page + " , dataSize : " + size + " " +
", " + "scope : start : " + datas.get(0) + " , end : " + datas
.get(size
- 1);
LoggerUtils.loge("consumer name = " + newPageInfo.tag + " , dataSize : "
+ size);
UiUtils.postDelayed(new Runnable() {
@Override
public void run() {
// 根据标签刷新控件
if ("l1".equalsIgnoreCase(newPageInfo.tag)) {
line1.append(msg + "\r\n");
} else if ("l2".equalsIgnoreCase(newPageInfo.tag)) {
line2.append(msg + "\r\n");
} else if ("l3".equalsIgnoreCase(newPageInfo.tag)) {
line3.append(msg + "\r\n");
}
}
}, 400);
}
});
}