android - 关于如何为网络请求做队列系统的建议（连接不良时）
问题描述
我一直在构建一个网络请求队列类，以应对网络连接可能暂时无法在以后恢复联机的情况。最终目标是每次网络连接失败时，请求都会排队，直到网络再次可用。
这是到目前为止发送数据的代码：
import android.app.Activity;
import android.content.Context;
import android.os.AsyncTask;
import android.os.CountDownTimer;
import android.widget.Toast;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentActivity;
import androidx.fragment.app.FragmentTransaction;
import org.json.JSONObject;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.List;
import java.util.Observable;
import construction.site.logistics.foreman.Encryption.Encryption;
import construction.site.logistics.foreman.Fragments.FragmentJournal;
import construction.site.logistics.foreman.MainActivity;
import construction.site.logistics.foreman.R;
import construction.site.logistics.foreman.abstraction.Functions;
import construction.site.logistics.foreman.data.database.EntityFields;
import construction.site.logistics.foreman.data.database.EntityFiles;
import construction.site.logistics.foreman.data.database.EntityQueue;
import construction.site.logistics.foreman.data.database.LocalDatabaseOperations;
import construction.site.logistics.foreman.data.state;
public class SendData {
private Activity activity=null;
private FragmentActivity fragmentActivity=null;
private EntityQueue queue=null;
private List<EntityFields> fieldsInList=null;
private List<EntityFiles> filesInList=null;
private Boolean encrypt;
private String encryptionType="";
private Boolean waitForCode=false;
private Boolean loadMainPage=false;
private Boolean enableQueue=true;
private Integer retryCount;
private String title;
private static Boolean error;
private String responseMsg;
public ObservableValue DelayedResult;
public SendData (Activity _activity, FragmentActivity _fragmentActivity){
this.activity=_activity;
this.fragmentActivity=_fragmentActivity;
this.DelayedResult = new ObservableValue(getResponse());
this.retryCount=0;
}
public void setWaitForCode(Boolean _wait){ waitForCode=_wait;}
public void setloadMainPage(Boolean _load){ loadMainPage=_load;}
public String getResponse(){ return responseMsg; }
public Boolean getError(){ return error; }
public void addQueue(EntityQueue _queue){ queue=_queue;}
public void addFields(List<EntityFields> _fields){ fieldsInList=_fields;}
public void addfFiles(List<EntityFiles> _files){ filesInList=_files;}
public void setEnableQueue(Boolean _queue){ enableQueue=_queue; }
public void setEncryption(Boolean _encrypt, String _type){
encryptionType= _type;
encrypt=_encrypt;
}
public class ObservableValue extends Observable
{
private String responseMsg = "";
public ObservableValue(String _responseMsg)
{
this.responseMsg = _responseMsg;
}
public void setValue(String _responseMsg)
{
this.responseMsg = _responseMsg;
setChanged();
notifyObservers();
}
public String getValue()
{
return responseMsg;
}
}
public boolean send(){
error=false;
if (waitForCode) {
try{
SendDataAsync sendDataAsync =new SendDataAsync();
sendDataAsync.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR).get();
error=false;
return true;
}catch(Exception e){
Functions.SaveCrash(e, activity);
error=true;
return false;
}
}else{
SendDataAsync sendDataAsync =new SendDataAsync();
sendDataAsync.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
error=false;
return true;
}
}
private class SendDataAsync extends AsyncTask<Void, Void, String> {
@Override
protected String doInBackground(Void... params) {
error=true;
if (queue == null) {
responseMsg = "{'error':true,'message':'" + activity.getResources().getString(R.string.sendData_missing_queue) + "'}";
} else if (fieldsInList == null) {
responseMsg = "{'error':true,'message':'" + activity.getResources().getString(R.string.sendData_missing_fields) + "'}";
} else if (state.getNetworkStatus()) { // send immediately
//Json format var="{'error':true,'message':'some message'}";
String Data2Send = "{";
String temp = "";
JSONObject jObjectData = new JSONObject();
List<String> FileNamesList= new ArrayList<>();
FileNamesList.clear();
Data2Send = "";
EntityFields field = new EntityFields();
field.setRequestVar("tid");
field.setValue(state.serial);
fieldsInList.add(field);
try {
for (int i = 0; i < fieldsInList.size(); i++) {
jObjectData.put(fieldsInList.get(i).getRequestVar(), fieldsInList.get(i).getValue().replace("'", "\'").replace('"', '\"'));
}
if (filesInList != null) {
temp = "";
String temp2 = "";
for (int i = 0; i < filesInList.size(); i++) {
FileNamesList.add(filesInList.get(i).getFilename());
temp2 += filesInList.get(i).getAppendCode() ? "1" : "0";
temp += i == 0 ? temp2 : "," + temp2;
}
jObjectData.put("filecode", temp);
}
} catch (Exception e) {
Functions.SaveCrash(e, activity);
}
Data2Send = jObjectData.toString();
Encryption encryption = new Encryption(activity);
encryption.setSecretKey(state.encryptionKey);
if (encryption.encryptString(Data2Send)) {
HttpComm request = new HttpComm(activity);
request.setType("post");
request.setCharSet("UTF-8");
activity.runOnUiThread(new Runnable() {
public void run() {
Functions.showSimpleProgressDialog(activity, activity.getResources().getString(R.string.commServer_connect_title_msg), activity.getResources().getString(R.string.commServer_connect_msg),false);
}
});
String urlEncoded="";
try{
urlEncoded=URLEncoder.encode(encryption.getEncryptedString(), "UTF-8");
}catch (Exception e){
urlEncoded=encryption.getEncryptedString();
}
error = !request.send(queue.getUrl(), urlEncoded, FileNamesList);
activity.runOnUiThread(new Runnable() {
public void run() {
Functions.removeSimpleProgressDialog();
}
});
if(queue.getMsgError().equals("debug")) {
encryption.decryptString(request.getResponse());
responseMsg = "{'error':true,'message':'DEBUG: " + encryption.getDecryptedString() + "'}";
}else if(error && retryCount< 6){
activity.runOnUiThread(new Runnable() {
public void run() {
new CountDownTimer(20000, 1000) {
public void onTick(long millisUntilFinished) {
activity.setTitle(R.string.commServer_retry+" "+millisUntilFinished / 1000);
}
public void onFinish() {
activity.setTitle(title);
retryCount++;
send();
}
}.start();
}
});
return "retrying";
}else if (error && enableQueue) {
LocalDatabaseOperations localDatabaseOperations = new LocalDatabaseOperations(activity);
error = LocalDatabaseOperations.addQueue(queue, fieldsInList, filesInList);
if (error) {
responseMsg = "{'error':true,'message':'" + request.getMessage() + System.getProperty("line.separator") + localDatabaseOperations.getErrMessage() + "'}";
} else {
responseMsg = "{'error':false,'message':'" + activity.getResources().getString(R.string.sendData_added_queue) + "'}";
}
} else if (error && !enableQueue) {
responseMsg = "{'error':true,'message':'" + request.getMessage() + "'}";
} else { // success sending request
if (encryption.decryptString(request.getResponse())) {
if (encryption.getEncryptedVector().equals(encryption.getDecryptedVector())) {
responseMsg = encryption.getDecryptedString(); // success on retrieving data from server
} else {
String ss=encryption.getEncryptedVector();
String sss=encryption.getDecryptedVector();
String s=encryption.getDecryptedString();
responseMsg = "{'error':true,'message':'" + activity.getResources().getString(R.string.sendData_error_ivector) + "'}";
}
} else { // error decrypting string
responseMsg = "{'error':true,'message':'" + activity.getResources().getString(R.string.sendData_error_decrypt_data) + "'}";
String response= request.getResponse();
String str= "Message:"+encryption.getErrMessage()+" >>>>Encrypt:"+ encryption.getEncryptedVector()+" >>>>Dencrypt:"+ encryption.getDecryptedVector();
Exception e= new Exception(str);
Functions.SaveCrash(e, activity);
}
}
} else { // error encrypting string
responseMsg = "{'error':true,'message':'" + activity.getResources().getString(R.string.sendData_error_encrypt_data) + "'}";
}
}else if(!enableQueue){
responseMsg = "{'error':true,'message':'" + activity.getResources().getString(R.string.error_no_network) + "'}";
} else { // send to queue
LocalDatabaseOperations localDatabaseOperations = new LocalDatabaseOperations(activity);
error = LocalDatabaseOperations.addQueue(queue, fieldsInList, filesInList);
if (error) {
responseMsg = "{'error':true,'message':'" + localDatabaseOperations.getErrMessage() + "'}";
} else {
responseMsg = "{'error':false,'message':'" + activity.getResources().getString(R.string.sendData_added_queue) + "'}";
}
}
return responseMsg;
}
@Override
protected void onPostExecute(String response) {
if(response.equals("retrying")){
return;
}
DelayedResult.setValue(response);
if (queue.getMsgType().equals("toast")) {
if (Functions.isSuccess(response)) {
if (queue.getMsgSuccess().equals("") || queue.getMsgSuccess().equals("response")) {
activity.runOnUiThread(new Runnable() {
public void run() {
Toast.makeText(activity, Functions.getErrorCode(activity, response), Toast.LENGTH_SHORT).show();
}
});
} else {
activity.runOnUiThread(new Runnable() {
public void run() {
Toast.makeText(activity, queue.getMsgSuccess(), Toast.LENGTH_SHORT).show();
}
});
}
} else {
if (queue.getMsgError().equals("") || queue.getMsgError().equals("response")) {
activity.runOnUiThread(new Runnable() {
public void run() {
Toast.makeText(activity, Functions.getErrorCode(activity, response), Toast.LENGTH_SHORT).show();
}
});
} else {
activity.runOnUiThread(new Runnable() {
public void run() {
Toast.makeText(activity, queue.getMsgError(), Toast.LENGTH_SHORT).show();
}
});
}
}
} else if (queue.getMsgType().equals("alertbox")) { // alertbox
if (Functions.isSuccess(response)) {
if (queue.getMsgSuccess().equals("") || queue.getMsgSuccess().equals("response")) {activity.runOnUiThread(new Runnable() {
public void run() {
Functions.alertbox(activity.getResources().getString(R.string.commServer_submit_ok), Functions.getErrorCode(activity, response), activity);
}
});
} else {
activity.runOnUiThread(new Runnable() {
public void run() {
Functions.alertbox(activity.getResources().getString(R.string.commServer_submit_ok), queue.getMsgSuccess(), activity);
}
});
}
} else {
if (queue.getMsgError().equals("") || queue.getMsgError().equals("response") || queue.getMsgError().equals("debug")) {
activity.runOnUiThread(new Runnable() {
public void run() {
Functions.alertbox(activity.getResources().getString(R.string.commServer_submit_error), Functions.getErrorCode(activity, response), activity);
}
});
} else {
activity.runOnUiThread(new Runnable() {
public void run() {
Functions.alertbox(activity.getResources().getString(R.string.commServer_submit_error), queue.getMsgError(), activity);
}
});
}
}
}
// Show messageBox messages
if (Functions.hasMessageBox(response)) {
Functions.getMessageBox(response);
}
if (loadMainPage && !error) {
FragmentTransaction fragmentTransaction = fragmentActivity.getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.content_frame, new FragmentJournal());
fragmentTransaction.commit();
}
}
}
}
以下代码在哪里
LocalDatabaseOperations localDatabaseOperations = new LocalDatabaseOperations(activity);
error = LocalDatabaseOperations.addQueue(queue, fieldsInList, filesInList);
用于使用 Room 数据库将本地设备 SQL 服务器中的数据存储在普通 SQL 表中。接下来，我有一个侦听器侦听网络更改，这些更改在成功的网络连接上触发，再次发送数据请求。
解决方案
推荐阅读
- scala - Spark Df 检查基于上一列的列值
- python-3.x - 如何定义一个函数包含另一个函数？
- sql-server - 如何在 SQL Server 中生成使用其前任值计算的列
- javascript - 如何生成一个可以被另一个随机生成的数字整除的随机数
- php - Symfony 4如何上传有关oneToMany的多个图像？
- android - XAML 图像源在跨平台（Android 模拟器）中不起作用
- node.js - 如何导出具有多个静态方法的类
- python - 如何通过 selenium 从一个目录中抓取信息
- javascript - 将数据传递给从 javascript 到 yii2 href 的路由
- python - 解析命名空间 XML 的问题。显示为空。在 Python 中