Java 如何为此代码设置异步任务?
我的listblogs=parseJSONResponse(result)有问题,结果带红色下划线,如果我将鼠标悬停在上面,它会显示,我无法将parseJSONResponse JSONARRAY应用于JSONARRAY[]。有人知道这是为什么吗?这和params有关吗Java 如何为此代码设置异步任务?,java,android,arrays,android-asynctask,Java,Android,Arrays,Android Asynctask,我的listblogs=parseJSONResponse(result)有问题,结果带红色下划线,如果我将鼠标悬停在上面,它会显示,我无法将parseJSONResponse JSONARRAY应用于JSONARRAY[]。有人知道这是为什么吗?这和params有关吗 class YourTask extends AsyncTask<JSONArray, String, ArrayList<Blogs> > { @Override protected
class YourTask extends AsyncTask<JSONArray, String, ArrayList<Blogs> > {
@Override
protected ArrayList<Blogs> doInBackground(JSONArray... result) {
listblogs.clear(); // here you clear the old data
listblogs=parseJSONResponse(result);
return listblogs;
}
@Override
protected void onPostExecute(ArrayList<Blogs> blogs) {
mAdapterDashBoard.setBloglist(listblogs);
}
}
private void JsonRequestMethod() {
final long start = SystemClock.elapsedRealtime();
mVolleySingleton = VolleySingleton.getInstance();
//intitalize Volley Singleton request key
mRequestQueue = mVolleySingleton.getRequestQueue();
//2 types of requests an Array request and an Object Request
JsonArrayRequest request = new JsonArrayRequest(Request.Method.GET, URL_API, (String) null, new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
System.out.print(response);
listblogs = new YourTask().doInBackground();
listblogs.clear();
listblogs=parseJSONResponse(response);
try {
listblogs = new YourTask().execute().get();
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
}
System.out.println(response);
Log.d("Testing", "Time elapsed: " + (SystemClock.elapsedRealtime() - start));
System.out.println("it worked!!!");
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
});
mRequestQueue.add(request);
}
private ArrayList<Blogs> parseJSONResponse(JSONArray response) {
if (!response.equals("")) {
try {
StringBuilder data = new StringBuilder();
for (int i = 0; i < response.length(); i++) {
JSONObject currentQuestions = response.getJSONObject(i);
String text = currentQuestions.getString("text");
String points = currentQuestions.getString("points");
String ID=currentQuestions.getString("id");
String studentId = currentQuestions.getString("studentId");
String DateCreated=currentQuestions.getString("created");
long time=Long.parseLong(DateCreated.trim());
data.append(text + "\n" + points + "\n");
System.out.println(data);
Blogs blogs = new Blogs();
blogs.setId(ID);
blogs.setMstudentId(studentId);
blogs.setMtext(text);
blogs.setPoints(points);
//The dateCreated was off by 1 hour so 3600000 ms where added=1hour, (UPDATE)
blogs.setDateCreated(getTimeAgo(time));
System.out.println(time + "time");
listblogs.add(blogs);
}
} catch (JSONException e) {
e.printStackTrace();
}
}
return listblogs;
}
class YourTask扩展了AsyncTask{
@凌驾
受保护的ArrayList doInBackground(JSONArray…结果){
listblogs.clear();//在这里可以清除旧数据
listblogs=parseJSONResponse(结果);
返回listblogs;
}
@凌驾
受保护的void onPostExecute(ArrayList博客){
mAdapterDashBoard.setBloglist(listblogs);
}
}
私有void JsonRequestMethod(){
最终长启动=SystemClock.elapsedRealtime();
mVolleySingleton=VolleySingleton.getInstance();
//初始化截击单例请求键
mRequestQueue=mVolleySingleton.getRequestQueue();
//两种类型的请求—数组请求和对象请求
JsonArrayRequest=newJSONArrayRequest(request.Method.GET,URL_API,(String)null,new Response.Listener(){
@凌驾
公共void onResponse(JSONArray响应){
系统输出打印(响应);
listblogs=newyourtask().doInBackground();
listblogs.clear();
listblogs=parseJSONResponse(response);
试一试{
listblogs=newyourtask().execute().get();
}捕捉(中断异常e){
e、 printStackTrace();
}捕获(执行例外){
e、 printStackTrace();
}
System.out.println(响应);
Log.d(“测试”,“经过的时间:”+(SystemClock.elapsedRealtime()-start));
System.out.println(“成功了!!!”;
}
},new Response.ErrorListener(){
@凌驾
公共无效onErrorResponse(截击错误){
}
});
mRequestQueue.add(请求);
}
专用ArrayList parseJSONResponse(JSONArray响应){
如果(!response.equals(“”){
试一试{
StringBuilder数据=新的StringBuilder();
对于(int i=0;i
您可以在异步任务中运行以下任何代码:
public class YourTask extends AsyncTask<String, Void, ArrayList<Blogs> > {
private static final String TAG = YourTask.class.getSimpleName();
private JSONArray mResponse;
private Activity mActivity;
public YourTask(final Activity activity, final JSONArray response) {
super();
this.mActivity = activity;
this.mResponse = response;
}
@Override
protected ArrayList<Blogs> doInBackground(String... params) {
if (!mResponse.equals("")) {
// Your Code
}
return listblogs;
}
@Override
protected void onPostExecute(final ArrayList<Blogs> blogs) {
if (mActivity instanceOf YourActivity) {
((YourActivity) activity).finishTask(blogs);
}
}
@Override
protected void onCancelled() {}
}
public类YourTask扩展了AsyncTask{
private static final String TAG=YourTask.class.getSimpleName();
私人JSONArray mResponse;
私人活动能力;
公共任务(最终活动、最终JSONArray响应){
超级();
这个。活动=活动;
this.mResponse=响应;
}
@凌驾
受保护的ArrayList doInBackground(字符串…参数){
如果(!mResponse.equals(“”){
//你的代码
}
返回listblogs;
}
@凌驾
受保护的void onPostExecute(最终ArrayList日志){
if(活动的MacActivity实例){
((YourActivity)活动)完成任务(blogs);
}
}
@凌驾
受保护的void onCancelled(){}
}
从活动中调用此任务,如:
AsyncTask<String, Void, JSONArray> task = new YourTask(this, response);
task.executeContent();
AsyncTask task=newyourtask(这个,响应);
task.executeContent();
基本上,只需将要解析的JSONArray发送到异步任务,并处理活动中den
finishTask
方法中的所有UI。这样做的好处是,您可以将任务提取到一个额外的文件中,而将活动留给您来处理控制视图的任务。AsyncTask
public class MyAsyncTask extends AsyncTask<Void, Void, ArrayList> {
JsonArray myJsonArray;
@Override
protected void onPreExecute() {
super.onPreExecute();
mVolleySingleton = VolleySingleton.getInstance();
mRequestQueue = mVolleySingleton.getRequestQueue();
listblogs.clear();
}
@Override
protected ArrayList doInBackground(Void... params) {
JsonArrayRequest request = new JsonArrayRequest(Request.Method.GET, URL_API, (String) null, new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
myJsonArray = response;
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
});
mRequestQueue.add(request);
return null;
}
@Override
protected void onPostExecute(ArrayList arrayList) {
super.onPostExecute(arrayList);
ArrayList<Blogs> blogsArrayList = new ArrayList<>();
try {
StringBuilder data = new StringBuilder();
for (int i = 0; i < myJsonArray.length(); i++) {
JSONObject currentQuestions = myJsonArray.getJSONObject(i);
String text = currentQuestions.getString("text");
String points = currentQuestions.getString("points");
String ID=currentQuestions.getString("id");
String studentId = currentQuestions.getString("studentId");
String DateCreated=currentQuestions.getString("created");
long time=Long.parseLong(DateCreated.trim());
data.append(text + "\n" + points + "\n");
System.out.println(data);
Blogs blogs = new Blogs();
blogs.setId(ID);
blogs.setMstudentId(studentId);
blogs.setMtext(text);
blogs.setPoints(points);
//The dateCreated was off by 1 hour so 3600000 ms where added=1hour, (UPDATE)
blogs.setDateCreated(getTimeAgo(time));
System.out.println(time+"time");
blogsArrayList.add(blogs);
}
} catch (JSONException e) {
e.printStackTrace();
}
return blogsArrayList;
}
异步:
listblogs = new MyAsyncTask().execute().get();
....
} catch (JSONException e) {
e.printStackTrace();
}
listblogs = blogsArrayList;
return blogsArrayList;
}
new MyAsyncTask().execute();
您好,您到底遇到了什么问题?您尝试了什么?为什么要在后台线程上解析它。是否真的有很多json,或者你只是简单地读到它应该在后台完成?换言之,这似乎是一个过早优化的案例。当我在SlidingTableOut中切换SlidingTab时,我经历了滞后,我查看了它并进行了堆转储,发现字符串占据了我heap的很大一部分,我也不断得到这些,我相信这是我在堆中的分配02-01 03:22:49.007 22066-22066/com.athena.athena D/dalvikvm:GC_FOR_ALLOC freed 189K,17%free 40212K/48140K,暂停18ms,总计18ms你的活动不应该使用弱引用吗?(
WeakReference
)