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我正在尝试创建一个使用 api 和 JSONObject 从网络提取信息的应用程序。我了解到我需要使用 asyncTask 来完成此操作,因此我创建了一个扩展 asyncTask 的类。但应用程序不断崩溃。
我的asynTask:
public class MyDownloadTask extends AsyncTask<String, String, String> {
SecondActivity secondActivity;
Context context;
boolean tof;
@Override
protected String doInBackground(String... urls) {
MyBoiler myData = null;
try {
myData = new MyBoiler("0e3a4cef498bc2ad18a97e1817c79e87", "50.4019514,30.6727719", "Ramat-Gan");
tof = myData.openBoiler(30, 20);
} catch (IOException e) {
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
}
return tof ? "true" : "false";
}
@Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
printToTV(tof, secondActivity);
}
public void printToTV(boolean turnOnOrNot, Context context){
int cloud = 0;
int temp = 0;
LinearLayout linearLayout = (LinearLayout)secondActivity.findViewById(R.id.secActLayout);
TextView tvToF = new TextView(context);
TextView tvCloud = new TextView(context);
TextView tvTemp = new TextView(context);
tvToF.setText(turnOnOrNot ? "Turn On" : "Dont Turn On");
String cloudString = String.valueOf(cloud);
tvCloud.setText(cloud + "% cloud coverage");
String tempString = String.valueOf(temp);
tvTemp.setText(temp + " Celsius Degrees");
linearLayout.addView(tvToF);
linearLayout.addView(tvCloud);
linearLayout.addView(tvTemp);
}
}
我尝试使用它的 Activity
public class SecondActivity extends AppCompatActivity {
Button boilerBtn;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_second);
boilerBtn = findViewById(R.id.openBoilerBtn);
boilerBtn.setOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View view) {
new MyDownloadTask().execute(MyBoiler.fullURL);
}
});
}
myBoiler 类:
public class MyBoiler {
public final String API_URL = "https://api.darksky.net/forecast/"; // url of the site
private String apiKey; // api key from the site
private String GPSlocation; // gps location -_-
private String rawData; // the raw data
protected static String fullURL; // the full url location
private String cityName; // name of the city
JSONObject jsonObject;
public MyBoiler(String apiKey, String GPSlocation, String cityName) throws IOException, JSONException {
this.apiKey = apiKey;
this.GPSlocation = GPSlocation;
this.cityName = cityName;
// create the full url
fullURL = API_URL + this.apiKey + "/" + this.GPSlocation;
}
private JSONObject readJsonFromUrl()throws IOException, JSONException{
//open a connection to the internet
InputStream is = new URL(this.fullURL).openStream();
// create a buffer for collection of all data
BufferedReader buf = new BufferedReader(new InputStreamReader(is, Charset.forName("UTF-8")));
// read all data and append it to one happy string
String jsonText = readAll(buf);
//convert to json object so we can use the json power
jsonObject = new JSONObject(jsonText);
// returns the json object
return jsonObject;
}
private String readAll(BufferedReader rd) throws IOException {
// create a string builder
StringBuilder sb = new StringBuilder();
// create a char point
int cp;
while((cp = rd.read()) != -1){
sb.append(cp);
}
// sets the rawData value to the string
rawData = sb.toString();
// return the result
return sb.toString();
}
public String getRaw(){
return rawData;
}
public int getCloud(JSONObject cur) throws IOException, JSONException{
int cloud = (int)(cur.getDouble("cloudCover")*100);
return cloud;
}
public int getTemp(JSONObject cur) throws IOException, JSONException{
int temp = (int)(cur.getDouble("temperature"));
return (int)((temp-32)/1.8);
}
public boolean openBoiler(int tolerance, int minTemp)throws IOException, JSONException{
JSONObject myData = readJsonFromUrl();
JSONObject currently = myData.getJSONObject("currently");
return getCloud(currently) > tolerance && getTemp(currently) < minTemp;
}
}
日志猫:
E/AndroidRuntime: FATAL EXCEPTION: AsyncTask #1
Process: com.example.myturnonboilerapp, PID: 24762
java.lang.RuntimeException: An error occurred while executing doInBackground()
at android.os.AsyncTask$3.done(AsyncTask.java:354)
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:383)
at java.util.concurrent.FutureTask.setException(FutureTask.java:252)
at java.util.concurrent.FutureTask.run(FutureTask.java:271)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:245)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
at java.lang.Thread.run(Thread.java:764)
Caused by: java.lang.SecurityException: Permission denied (missing INTERNET permission?)
at java.net.Inet6AddressImpl.lookupHostByName(Inet6AddressImpl.java:151)
at java.net.Inet6AddressImpl.lookupAllHostAddr(Inet6AddressImpl.java:105)
at java.net.InetAddress.getAllByName(InetAddress.java:1154)
at com.android.okhttp.Dns$1.lookup(Dns.java:39)
at com.android.okhttp.internal.http.RouteSelector.resetNextInetSocketAddress(RouteSelector.java:175)
at com.android.okhttp.internal.http.RouteSelector.nextProxy(RouteSelector.java:141)
at com.android.okhttp.internal.http.RouteSelector.next(RouteSelector.java:83)
at com.android.okhttp.internal.http.StreamAllocation.findConnection(StreamAllocation.java:174)
at com.android.okhttp.internal.http.StreamAllocation.findHealthyConnection(StreamAllocation.java:126)
at com.android.okhttp.internal.http.StreamAllocation.newStream(StreamAllocation.java:95)
at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:281)
at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:224)
at com.android.okhttp.internal.huc.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:461)
at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:407)
at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:244)
at com.android.okhttp.internal.huc.DelegatingHttpsURLConnection.getInputStream(DelegatingHttpsURLConnection.java:210)
at com.android.okhttp.internal.huc.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:26)
at java.net.URL.openStream(URL.java:1072)
at com.example.myturnonboilerapp.MyBoiler.readJsonFromUrl(MyBoiler.java:32)
at com.example.myturnonboilerapp.MyBoiler.openBoiler(MyBoiler.java:72)
at com.example.myturnonboilerapp.MyDownloadTask.doInBackground(MyDownloadTask.java:26)
at com.example.myturnonboilerapp.MyDownloadTask.doInBackground(MyDownloadTask.java:14)
at android.os.AsyncTask$2.call(AsyncTask.java:333)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:245)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
at java.lang.Thread.run(Thread.java:764)
Caused by: android.system.GaiException: android_getaddrinfo failed: EAI_NODATA (No address associated with hostname)
at libcore.io.Linux.android_getaddrinfo(Native Method)
at libcore.io.BlockGuardOs.android_getaddrinfo(BlockGuardOs.java:172)
at java.net.Inet6AddressImpl.lookupHostByName(Inet6AddressImpl.java:137)
at java.net.Inet6AddressImpl.lookupAllHostAddr(Inet6AddressImpl.java:105)
at java.net.InetAddress.getAllByName(InetAddress.java:1154)
at com.android.okhttp.Dns$1.lookup(Dns.java:39)
at com.android.okhttp.internal.http.RouteSelector.resetNextInetSocketAddress(RouteSelector.java:175)
at com.android.okhttp.internal.http.RouteSelector.nextProxy(RouteSelector.java:141)
at com.android.okhttp.internal.http.RouteSelector.next(RouteSelector.java:83)
at com.android.okhttp.internal.http.StreamAllocation.findConnection(StreamAllocation.java:174)
at com.android.okhttp.internal.http.StreamAllocation.findHealthyConnection(StreamAllocation.java:126)
at com.android.okhttp.internal.http.StreamAllocation.newStream(StreamAllocation.java:95)
at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:281)
at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:224)
at com.android.okhttp.internal.huc.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:461)
at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:407)
at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:244)
at com.android.okhttp.internal.huc.DelegatingHttpsURLConnection.getInputStream(DelegatingHttpsURLConnection.java:210)
at com.android.okhttp.internal.huc.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:26)
at java.net.URL.openStream(URL.java:1072)
at com.example.myturnonboilerapp.MyBoiler.readJsonFromUrl(MyBoiler.java:32)
at com.example.myturnonboilerapp.MyBoiler.openBoiler(MyBoiler.java:72)
at com.example.myturnonboilerapp.MyDownloadTask.doInBackground(MyDownloadTask.java:26)
at com.example.myturnonboilerapp.MyDownloadTask.doInBackground(MyDownloadTask.java:14)
at android.os.AsyncTask$2.call(AsyncTask.java:333)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:245)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
at java.lang.Thread.run(Thread.java:764)
Caused by: android.system.ErrnoException: android_getaddrinfo failed: EACCES (Permission denied)
at libcore.io.Linux.android_getaddrinfo(Native Method)
at libcore.io.BlockGuardOs.android_getaddrinfo(BlockGuardOs.java:172)
at java.net.Inet6AddressImpl.lookupHostByName(Inet6AddressImpl.java:137)
at java.net.Inet6AddressImpl.lookupAllHostAddr(Inet6AddressImpl.java:105)
at java.net.InetAddress.getAllByName(InetAddress.java:1154)
at com.android.okhttp.Dns$1.lookup(Dns.java:39)
at com.android.okhttp.internal.http.RouteSelector.resetNextInetSocketAddress(RouteSelector.java:175)
at com.android.okhttp.internal.http.RouteSelector.nextProxy(RouteSelector.java:141)
at com.android.okhttp.internal.http.RouteSelector.next(RouteSelector.java:83)
at com.android.okhttp.internal.http.StreamAllocation.findConnection(StreamAllocation.java:174)
at com.android.okhttp.internal.http.StreamAllocation.findHealthyConnection(StreamAllocation.java:126)
at com.android.okhttp.internal.http.StreamAllocation.newStream(StreamAllocation.java:95)
at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:281)
at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:224)
at com.android.okhttp.internal.huc.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:461)
at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:407)
at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:244)
at com.android.okhttp.internal.huc.DelegatingHttpsURLConnection.getInputStream(DelegatingHttpsURLConnection.java:210)
at com.android.okhttp.internal.huc.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:26)
at java.net.URL.openStream(URL.java:1072)
at com.example.myturnonboilerapp.MyBoiler.readJsonFromUrl(MyBoiler.java:32)
at com.example.myturnonboilerapp.MyBoiler.openBoiler(MyBoiler.java:72)
at com.example.myturnonboilerapp.MyDownloadTask.doInBackground(MyDownloadTask.java:26)
at com.example.myturnonboilerapp.MyDownloadTask.doInBackground(MyDownloadTask.java:14)
at android.os.AsyncTask$2.call(AsyncTask.java:333)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:245)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
at java.lang.Thread.run(Thread.java:764)
I/Process:发送信号。 PID:24762 SIG:9进程 24762 终止。
我的第二个 Activity xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".SecondActivity"
android:id="@+id/secActLayout">
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/openBoilerBtn"
android:text="Turn On"
android:textAllCaps="false"/>
</LinearLayout>
最佳答案
缺少 Internet 权限,请将以下代码添加到您的 AndroidManifest.xml
<uses-permission android:name="android.permission.INTERNET" />
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