我正在使用天气地下api构建天气应用程序。我有listView预测10天，我想创建详细活动，以便按下每个列表项后每天更详细的预测。而且我不知道如何将数据传递给详细活动。我使用listView与适配器，我有列表上的图像网址与maxtemp和最小临时和详细活动我希望相同的图像网址更详细我同样的ID为两个图像视图（详细和列表视图）但它只工作正常在列表上。我是否只在详细活动中实例化我的视图并使用id将其附加到适配器？我尝试了一些额外的意图，但它不适用于数据 来自web api。
我确实喜欢你说但是在我的适配器中我只夸大了列表项目视图，当我尝试启动应用程序时我得到这样的错误：
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
我的适配器类看起来像这样：
public class WeatherAdapter extends ArrayAdapter<Weather> {
public WeatherAdapter(Context context, ArrayList<Weather> weather) {
super(context, 0, weather);
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View listItemView = convertView;
if (listItemView == null) {
listItemView = LayoutInflater.from(getContext()).inflate(
R.layout.list_item, parent, false);
}
Weather currentWeather = getItem(position);
TextView date = (TextView) listItemView.findViewById(R.id.month);
date.setText(currentWeather.getDate());
TextView minTemp = (TextView) listItemView.findViewById(R.id.low_temperature);
minTemp.setText(String.valueOf(currentWeather.getMinTemp()) + " \u2103");
TextView maxTemp = (TextView) listItemView.findViewById(R.id.high_temperature);
maxTemp.setText(String.valueOf(currentWeather.getMaxTemp()) + " \u2103");
ImageView image = (ImageView) listItemView.findViewById(R.id.weather_icon);
Picasso.with(getContext()).load(currentWeather.getUrl()).into(image);
TextView day = (TextView) listItemView.findViewById(R.id.day);
day.setText(String.valueOf(currentWeather.getDay()));
TextView weekday = (TextView) listItemView.findViewById(R.id.weekday);
weekday.setText(String.valueOf(currentWeather.getWeekday()));
TextView conditions = (TextView) listItemView.findViewById(R.id.conditions);
conditions.setText(currentWeather.getConditions());
TextView humidity = (TextView) listItemView.findViewById(R.id.humidity);
humidity.setText(String.valueOf(currentWeather.getHumidity()));
return listItemView;
}
}
并且我的适配器无法识别activity_detail.xml，其中放置了我的湿度textView，并且我不知道如何在我的适配器中对此布局进行充气
这是我的工具类
public class WeatherUtils {
private static final String LOG_TAG = WeatherUtils.class.getSimpleName();
public WeatherUtils() {
}
public static List<Weather> fetchNewsData(String requestUrl) throws JSONException {
URL url = createUrl(requestUrl);
String jsonResponse = null;
try {
jsonResponse = makeHttpsRequest(url);
} catch (IOException e) {
Log.e(LOG_TAG, "Problem making the HTTP request.", e);
}
List<Weather> weather = extractFromJSONResponse(jsonResponse);
return weather;
}
private static URL createUrl(String stringUrl) {
URL url = null;
try {
url = new URL(stringUrl);
} catch (MalformedURLException e) {
Log.e(LOG_TAG, "Error with creating URL", e);
}
return url;
}
private static String makeHttpsRequest(URL url) throws IOException {
String jsonResponse = "";
if (url == null) {
return jsonResponse;
}
HttpURLConnection urlConnection = null;
InputStream inputStream = null;
try {
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setReadTimeout(10000 /*milliseconds*/);
urlConnection.setConnectTimeout(15000 /*milliseconds*/);
urlConnection.setRequestMethod("GET");
urlConnection.connect();
if (urlConnection.getResponseCode() == 200) {
inputStream = urlConnection.getInputStream();
jsonResponse = readFromStream(inputStream);
} else {
Log.e(LOG_TAG, "Error response code: " + urlConnection.getResponseCode());
}
} catch (IOException e) {
Log.e(LOG_TAG, "Problem retrieving Book JSON results.", e);
} finally {
if (urlConnection != null) {
urlConnection.disconnect();
}
if (inputStream != null) {
inputStream.close();
}
}
return jsonResponse;
}
private static String readFromStream(InputStream inputStream) throws IOException {
StringBuilder output = new StringBuilder();
if (inputStream != null) {
InputStreamReader inputStreamReader;
inputStreamReader = new InputStreamReader(inputStream, Charset.forName("UTF-8"));
BufferedReader reader = new BufferedReader(inputStreamReader);
String line = reader.readLine();
while (line != null) {
output.append(line);
line = reader.readLine();
}
}
return output.toString();
}
private static List<Weather> extractFromJSONResponse(String JSONResponse) throws JSONException {
if (TextUtils.isEmpty(JSONResponse)) {
return null;
}
List<Weather> weather = new ArrayList<>();
try {
JSONObject jsonResponse = new JSONObject(JSONResponse);
JSONObject forecast = jsonResponse.getJSONObject("forecast");
JSONObject simpleForecast = forecast.getJSONObject("simpleforecast");
JSONArray listArray = simpleForecast.getJSONArray("forecastday");
for (int i = 0; i < listArray.length(); i++) {
JSONObject currentWeather = listArray.getJSONObject(i);
String iconUrl = currentWeather.getString("icon_url");
double humidity = currentWeather.getDouble("avehumidity");
JSONObject highTempObject = currentWeather.getJSONObject("high");
String maxTemp = highTempObject.getString("celsius");
JSONObject lowTempObject = currentWeather.getJSONObject("low");
String minTemp = lowTempObject.getString("celsius");
JSONObject dateObject = currentWeather.getJSONObject("date");
String date = dateObject.getString("monthname");
String weekday = dateObject.getString("weekday");
int day = dateObject.getInt("day");
int year = dateObject.getInt("year");
Weather data = new Weather(maxTemp, minTemp, humidity, date, iconUrl, year, day, weekday);
weather.add(data);
}
} catch(JSONException e){
Log.e("QueryUtils", "Problem parsing the earthquake JSON results", e);
}
return weather;
}
}
这是我的天气课程
public class Weather {
private String maxTemp;
private String minTemp;
private double humidity;
private String date;
private int year;
private int day;
private String weekday;
private String url;
public Weather(String maxTemp, String minTemp, double humidity, String date, String url, int year, int day, String weekday) {
this.maxTemp = maxTemp;
this.minTemp = minTemp;
this.humidity = humidity;
this.date = date;
this.day = day;
this.year = year;
this.weekday = weekday;
this.url = url;
}
public String getMaxTemp() {
return maxTemp;
}
public String getMinTemp() {
return minTemp;
}
public double getHumidity() {
return humidity;
}
public int getYear() {
return year;
}
public int getDay() {
return day;
}
public String getDate() {
return date;
}
public String getUrl() {
return url;
}
public String getWeekday() {
return weekday;
}
}
答案 0 :(得分：0)
您可以通过意图传递详细信息数据。但是你需要使Weather实现Serializable或实现Parcelable。简单的方法是将天气序列化为：
public class Weather implements Serializable {
...
}
然后你可以像往常一样传递对象：
Intent intent = new Intent(ActivityCaller.this, DetailActivity.class);
intent.putExtra("weatherkey", weather);
startActivity(intent);
了解详情，请阅读Start Another Activity
要使用以下自定义适配器处理项目：
public class WeathersAdapter extends ArrayAdapter<Weather> {
private static class ViewHolder {
TextView tvMaxTemp;
TextView tvMinTemp;
// ...
}
public Weathers(Context context, ArrayList<Weather> weathers) {
super(context, R.layout.item_weather, weathers);
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
Weather weather = getItem(position);
ViewHolder viewHolder;
if (convertView == null) {
viewHolder = new ViewHolder();
LayoutInflater inflater = LayoutInflater.from(getContext());
convertView = inflater.inflate(R.layout.item_weather, parent, false);
viewHolder.name = (TextView) convertView.findViewById(R.id.tvMaxTemp);
viewHolder.home = (TextView) convertView.findViewById(R.id.tvMinTemp);
convertView.setTag(viewHolder);
} else {
viewHolder = (ViewHolder) convertView.getTag();
}
viewHolder.tvMaxTemp.setText(weather.getMaxTemp());
viewHolder.tvMinTemp.setText(user.getMinTemp());
// ...
return convertView;
}
}
您可以使用：
// assume that your Weather is inside a list
List<Weather> weathers = getWeathers();
listView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
// ActivityCaller is the activity where your ListView reside.
Intent intent = new Intent(ActivityCaller.this, DetailActivity.class);
intent.putExtra("weatherkey", weathers.get(position));
startActivity(intent);
}
});