Question

我在尝试将Parcelable传递给Intent时收到此错误。基本上，我已将我的课程实现为Parcelable，但我无法将该对象传递给另一个活动，因为它在阅读时会崩溃。我为这个问题尝试了几个答案，但没有人帮我解决这个问题。

到目前为止，这是我WeatherData.java的代码（抱歉，这个类有点大）：

public class WeatherData implements Parcelable {

private final static String ICON_ADDR = "http://openweathermap.org/img/w/";

static class City implements Parcelable {
    String name;

    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        Bundle bundle = new Bundle();
        bundle.putString("cityName", name);
        dest.writeBundle(bundle);
    }

    public static final Parcelable.Creator<City> CREATOR = new Creator<City>() {

        @Override
        public City createFromParcel(Parcel source) {
            // read the bundle containing key value pairs from the parcel
            Bundle bundle = source.readBundle();

            // instantiate the forecast info using values from the bundle
            return new City(bundle.getString("cityName"));
        }

        @Override
        public City[] newArray(int size) {
            return new City[size];
        }

    };

    private City (String cityName) {
        name = cityName;
    }
}

static class Weather implements Parcelable {
    String description;
    String icon;

    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        Bundle bundle = new Bundle();
        bundle.putString("description", description);
        bundle.putString("icon", icon);
        dest.writeBundle(bundle);
    }

    public static final Parcelable.Creator<Weather> CREATOR = new Creator<Weather>() {

        @Override
        public Weather createFromParcel(Parcel source) {
            // read the bundle containing key value pairs from the parcel
            Bundle bundle = source.readBundle();

            // instantiate the forecast info using values from the bundle
            return new Weather(bundle.getString("description"),
                    bundle.getString("icon"));
        }

        @Override
        public Weather[] newArray(int size) {
            return new Weather[size];
        }

    };

    private Weather (String description, String icon) {
        icon = icon;
        description = description;
    }

}

static class Temp implements Parcelable {
    float day;
    float min;
    float max;

    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        Bundle bundle = new Bundle();

        bundle.putFloat("day", day);
        bundle.putFloat("min", min);
        bundle.putFloat("max", max);

        dest.writeBundle(bundle);
    }

    public static final Parcelable.Creator<Temp> CREATOR = new Creator<Temp>() {

        @Override
        public Temp createFromParcel(Parcel source) {
            // read the bundle containing key value pairs from the parcel
            Bundle bundle = source.readBundle();

            // instantiate the forecast info using values from the bundle
            return new Temp(bundle.getFloat("day"),
                    bundle.getFloat("min"), bundle.getFloat("max"));
        }

        @Override
        public Temp[] newArray(int size) {
            return new Temp[size];
        }

    };

    private Temp (float tDay, float tMin, float tMax) {
        day = tDay;
        min = tMin;
        max = tMax;
    }
}

static class ForecastInfo implements Parcelable {
    Temp temp;
    ArrayList<Weather> weather;

    String getTemperatureInCelsius() {
        float t = temp.day - 273.15f;
        return String.format("%.0f" + (char) 0x00B0, t);
    };

    public String getIconAddress() {
        return ICON_ADDR + weather.get(0).icon + ".png";
    };

    public String getDescription() {
        if (weather != null && weather.size() > 0)
            return weather.get(0).description;
        return null;
    };

    @Override
    public int describeContents() {
        return 0;
    };

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        Bundle bundle = new Bundle();

        bundle.putParcelable("temp", this.temp);
        bundle.putParcelableArrayList("weatherList", this.weather);

        dest.writeBundle(bundle);
    };

    public static final Parcelable.Creator<ForecastInfo> CREATOR = new Creator<ForecastInfo>() {

        @Override
        public ForecastInfo createFromParcel(Parcel source) {
            // read the bundle containing key value pairs from the parcel
            Bundle bundle = source.readBundle();

            // instantiate the forecast info using values from the bundle
            return new ForecastInfo((Temp) bundle.get("temp"),
                    (ArrayList<Weather>) bundle.get("weatherList"));
        }

        @Override
        public ForecastInfo[] newArray(int size) {
            return new ForecastInfo[size];
        }

    };

    private ForecastInfo (Temp temp, ArrayList<Weather> weatherList) {
        this.temp = temp;
        this.weather = weatherList;
    };
}

// Relevant data for WeatherData
// The city (which only has a name in it)
City city;
// The array of forecast info extracted from the JSON
ArrayList<ForecastInfo> list;

private WeatherData (City city, ArrayList<ForecastInfo> forecastList) {
    city = city;
    list = forecastList;
}

// A method that converts temperature from Kelvin degrees to Celsius
String getTemperatureInCelsius(int day) {
    return list.get(day).getTemperatureInCelsius();
}

// getIconAddress concatenates the base address and the specific code for
// the icon
public String getIconAddress(int day) {
    return list.get(day).getIconAddress();
}

public String getName() {
    return city.name;
}

public String getDescription(int day) {
    return list.get(day).getDescription();
}

@Override
public int describeContents() {
    return 0;
}

@Override
public void writeToParcel(Parcel dest, int flags) {
    // create a bundle for the key value pairs
    Bundle bundle = new Bundle();

    // insert the key value pairs to the bundle
    bundle.putString("cityName", this.getName());
    bundle.putParcelableArrayList("forecastList", this.list);

    // write the key value pairs to the parcel
    dest.writeBundle(bundle);
}

public static final Parcelable.Creator<WeatherData> CREATOR = new Creator<WeatherData>() {

    @Override
    public WeatherData createFromParcel(Parcel source) {
        // read the bundle containing key value pairs from the parcel
        Bundle bundle = source.readBundle();
        return new WeatherData(bundle.getString("cityName"),
                new ArrayList<ForecastInfo>());

    }

    @Override
    public WeatherData[] newArray(int size) {
        return new WeatherData[size];
    }

};

private WeatherData (String name, ArrayList<ForecastInfo> forecastInfos) {
    City cityNew = new City(name);
    city = cityNew;
    forecastInfos.add(new ForecastInfo(
            new Temp(1.0f, 1.0f, 1.0f),
            new ArrayList<Weather>()));
    list = forecastInfos;
}

private WeatherData (String name) {
    City cityNew = new City(name);
    city = cityNew;
}  
}

然后，在我的MainActivity中，我调用了以下函数（对setExtrasClassLoader的多次调用感到抱歉）：

public void showDetails(View view) {
    Intent intent = new Intent(getApplicationContext(), ShowDetailsActivity.class);
    intent.setExtrasClassLoader(WeatherData.class.getClassLoader());
    intent.setExtrasClassLoader(WeatherData.ForecastInfo.class.getClassLoader());
    intent.setExtrasClassLoader(WeatherData.City.class.getClassLoader());
    intent.setExtrasClassLoader(WeatherData.Weather.class.getClassLoader());
    intent.setExtrasClassLoader(WeatherData.Temp.class.getClassLoader());
    intent.putExtra("bundleObject", weatherData.list);
    startActivity(intent);
}

之后，我试图通过以下方式获取onCreate方法中新活动的意图内容：

    Intent intent = getIntent();
    intent.setExtrasClassLoader(WeatherData.class.getClassLoader());
    intent.setExtrasClassLoader(WeatherData.ForecastInfo.class.getClassLoader());
    ArrayList<WeatherData.ForecastInfo> list = intent.getParcelableArrayListExtra("bundleObject");

如果我在weatherData.getName()中传递了weatherData.list而不是showDetails，那么它只适用于城市的字符串名称。当我尝试放置ArrayList<ForecastInfo>时，它会中断并引发此错误：

引起：android.os.BadParcelableException：解组时ClassNotFoundException： com.example.android.climapp.WeatherData $温度在android.os.Parcel.readParcelableCreator（Parcel.java:2411）在android.os.Parcel.readParcelable（Parcel.java:2337）......

Answer 1

解决！

对于正在努力解决此问题的任何人，因为Bundle方法中的新createFromParcel无法了解ForecastInfo类。因此，可以解决这个问题，告诉bundle通过setClassLoader加载缺失类的数据，如下所示：

       @Override
            public WeatherData createFromParcel(Parcel source) {
                // read the bundle containing key value pairs from the parcel
                Bundle bundle = source.readBundle();
                bundle.setClassLoader(ForecastInfo.class.getClassLoader());
                // instantiate the weather using values from the bundle
bundle.getParcelable("forecastList"));
                return new WeatherData(bundle.getString("cityName"),
                        new ArrayList<ForecastInfo>());

            }

BadParcelableException：ClassNotFoundException

1 个答案: