我刚刚通过udacity阳光应用程序,我无法解决这个问题,即添加openweather api应用程序无法正常工作它只显示“不幸的阳光应用程序无法正常工作”
MainActivity.java文件如下:
package com.example.android.sunshine.app;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
public class MainActivity extends AppCompatActivity
{
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu)
{
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item)
{
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
MainActivityFragment.java文件如下:
package com.example.android.sunshine.app;
import android.support.v4.app.Fragment;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
/**
* A placeholder fragment containing a simple view.
*/
public class MainActivityFragment extends Fragment {
public MainActivityFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView=inflater.inflate(R.layout.fragment_main, container, false);
String[] forecastArray={
"Today-Sunny-88/63",
"Tomorrow-Foggy-70/40",
"Weds-Cloudy-72/63",
"Thurs-Asteroids-75/65",
"Fri-Heavy Rain-65/56",
"Sat-HELP-60/51",
"Sun-Sunny-80/68"
};
List<String> weekForecast=new ArrayList<String>(Arrays.asList(forecastArray));
ArrayAdapter<String> mForecastAdapter = new ArrayAdapter<String>(getActivity(),R.layout.list_item_forecast,R.id.list_item_forecast_textview,weekForecast);
ListView lv=(ListView) rootView.findViewById(R.id.list_view_forecast);
lv.setAdapter(mForecastAdapter);
// These two need to be declared outside the try/catch
// so that they can be closed in the finally block.
HttpURLConnection urlConnection = null;
BufferedReader reader = null;
// Will contain the raw JSON response as a string.
String forecastJsonStr = null;
try {
// Construct the URL for the OpenWeatherMap query
// Possible parameters are avaiable at OWM's forecast API page, at
// http://openweathermap.org/API#forecast
URL url = new URL("http://api.openweathermap.org/data/2.5/forecast/daily?q=London&mode=json&units=metric&cnt=7&appid=d0657975451a7efca018097b88c4d975");
// Create the request to OpenWeatherMap, and open the connection
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setRequestMethod("GET");
urlConnection.connect();
// Read the input stream into a String
InputStream inputStream = urlConnection.getInputStream();
StringBuffer buffer = new StringBuffer();
if (inputStream == null) {
// Nothing to do.
return null;
}
reader = new BufferedReader(new InputStreamReader(inputStream));
String line;
while ((line = reader.readLine()) != null) {
// Since it's JSON, adding a newline isn't necessary (it won't affect parsing)
// But it does make debugging a *lot* easier if you print out the completed
// buffer for debugging.
buffer.append(line + "\n");
}
if (buffer.length() == 0) {
// Stream was empty. No point in parsing.
return null;
}
forecastJsonStr = buffer.toString();
} catch (IOException e) {
Log.e("PlaceholderFragment", "Error ", e);
// If the code didn't successfully get the weather data, there's no point in attemping
// to parse it.
return null;
} finally{
if (urlConnection != null) {
urlConnection.disconnect();
}
if (reader != null) {
try {
reader.close();
} catch (final IOException e) {
Log.e("PlaceholderFragment", "Error closing stream", e);
}
}
}
return rootView;
}
}
答案 0 :(得分:3)
在android中你不能在UI线程上进行网络调用。
URL url = new URL("http://api.openweathermap.org/data/2.5/forecast/daily?q=London&mode=json&units=metric&cnt=7&appid=d0657975451a7efca018097b88c4d975");
urlConnection = (HttpURLConnection) url.openConnection(); //This causes an exception
您必须使用AsyncTask
或Runnable
传递给Thread
或Executor
,在后台线程中运行这些和任何网络操作代码。
答案 1 :(得分:1)
使用runOnUiThread
甚至AsyncTask
:
runOnUiThread(new Runnable() {
@Override
public void run() {
// your codes
}
});