我想从本地服务器获取工厂数据,而不知道工厂的确切数量。以下是一些代码:
public class StartActivity extends AppCompatActivity implements View.OnClickListener{
boolean isSuccess = false;
RequestQueue queue =NoHttp.newRequestQueue();
ArrayList<String> fac_name = new ArrayList<>();
ArrayList<String> lat = new ArrayList<>();
ArrayList<String> lng = new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//...
NoHttp.initialize(this);
//...
do {
int id = 1;
getFactories(id);
id++;
Log.d("wellS", String.valueOf(isSuccess));
}while(isSuccess);
}
public void getFactories(final int id){
isSuccess = false;
String url ="http://192.168.0.108:5000/factories/"+id;
Request<JSONObject> request = NoHttp.createJsonObjectRequest(url);
queue.add(0, request, new OnResponseListener<JSONObject>() {
@Override
public void onStart(int what) {
Log.d("wellS", "Started to get data from server");
}
@Override
public void onSucceed(int what, Response<JSONObject> response) {
if(response.responseCode() == 200){
Log.d("wellS", "Successfully connected to server");
JSONObject j1 = response.get();
Iterator<String> it = j1.keys();
String key = it.next();
String value = null;
try {
value = j1.getString(key);
JSONObject j2 = new JSONObject(value);
Iterator<String> it2 = j2.keys();
int count = 1;
while(it2.hasNext()) {
String key2 = it2.next();
String value2 = j2.getString(key2);
switch (count) {
case 1:
fac_name.add(value2);
break;
case 3:
lat.add(value2);
break;
case 4:
lng.add(value2);
break;
default:
break;
}
count++;
}
Log.d("wellS", "工厂名称:" + fac_name.get(id-1)+" 纬度:"+lat.get(id-1)+" 经度:"+lng.get(id-1));
isSuccess = true;
Log.d("wellS", String.valueOf(isSuccess)+ " ABC");
} catch (JSONException e) {
e.printStackTrace();
}
}
}
@Override
public void onFailed(int what, Response<JSONObject> response) {
Exception exception = response.getException();
if(exception instanceof NetworkError) {
Log.d("wellS", "Error");
}
}
@Override
public void onFinish(int what) {
Log.d("wellS", "Connection finished");
}
});
}
在
onSucceed
方法的getFactories
中,有一行Log.d("wellS", String.valueOf(isSuccess)+ " ABC");
,在do-while
中执行此方法后,有Log.d("wellS", String.valueOf(isSuccess))
。但Logcat显示:2019-05-12 19:42:17.597 18535-18535/?D/井:假
2019-05-12 19:42:17.646 18535-18535/?D/Wells:开始从服务器获取数据
2019-05-12 19:42:17.845 18535-18535/?D/Wells:已成功连接到服务器
2019-05-12 19:42:17.846 18535-18535/?D/井:施工
2019-05-12 19:42:17.846 18535-18535/?钻井:真ABC
2019-05-12 19:42:17.846 18535-18535/?D/井:连接完成
第二行似乎是在第一行之前执行的,而
do-while
只执行了一次。为什么? 最佳答案
因为队列将在一个新的made线程中异步处理请求。这意味着它没有阻塞主线程的运行(包含2019-05-12 19:42:17.597 18535-18535/? D/wellS: false
)。
服务器请求正在阻塞操作,事实上,它会阻塞正在运行的线程,直到收到响应。在分离线程中执行该操作有助于不阻塞父线程。