尝试显示我的应用程序的天气图标时遇到问题

Question

这个问题最初是在大约 20 天前被问到的，我试图根据其城市的响应（来自可绘制文件夹）\n来自天气官方 API 文档中列出的天气状况数量，在我的应用程序上显示天气图标https://openweathermap.org/weather-conditions（您可以随时通过查看编辑历史记录来查看）。\nAPI 提供了 9 种主要天气状况。

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这仍然是我的目标：

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• 首次打开应用程序时，不显示任何图标。

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• 如果用户搜索城市并且得到的响应是晴空，则显示晴空图标；

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• 否则，如果响应是该城市的少云，则显示少云图标

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• 否则，如果响应是该城市的散云，则显示散云图标

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• 否则，如果响应是该城市的破碎云，则显示破碎云图标

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• 否则，如果响应为该城市的阵雨，则显示阵雨图标

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• 否则，如果该城市的响应为 Rain，则显示 Rain 图标

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• 否则，如果该城市的响应为雷暴，则显示雷暴图标

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• 否则，如果响应为该城市下雪，则显示下雪图标

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• 否则，如果响应是该城市的“薄雾”，则显示“薄雾”图标。

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在 Magdalena Rowicka 的帮助下，我已经能够实现一些目标，但即使在尝试自己修复之后，问题仍然没有完全解决，这就是我重新奖励该帖子的原因。

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我做的第一件事是使用以下数据集创建一个单独的枚举类：

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public enum WeatherIcon {\n    Sun, Cloud1, Cloud2, Cloud3, Rain1, Rain2, Thunder, Snow, Mist\n}\n

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然后我添加了这段代码final ImageView imageofWeather = rootView.findViewById(R.id.imageView2);在片段上声明文本视图的地方添加了这段代码。

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然后我在int drawableResource;// 这里定义默认图标，例如\nR.drawable.default_weather_icon 之后添加viewModel.getWeatherDataLiveData().observe(getViewLifecycleOwner(), data -> {。

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然后我终于添加了这段代码：

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switch (data.getWeather().get(0).getIcon()) { \n                    case WeatherIcon.Sun:\n                        drawableResource = R.drawable.sun; //reference to drawable id\n                        break;\n                    case WeatherIcon.Cloud1:\n                        drawableResource = R.drawable.broken_clouds; //reference to drawable id\n                        break;\n                    case WeatherIcon.Cloud2:\n                        drawableResource = R.drawable.few_clouds; //reference to drawable id\n                        break;\n                    case WeatherIcon.Cloud3:\n                        drawableResource = R.drawable.scattered_clouds; //reference to drawable id\n                        break;\n                    case WeatherIcon.Rain1:\n                        drawableResource = R.drawable.small_rain; //reference to drawable id\n                        break;\n                    case WeatherIcon.Rain2:\n                        drawableResource = R.drawable.shower_rain; //reference to drawable id\n                        break;\n                    case WeatherIcon.Thunder:\n                        drawableResource = R.drawable.thunderstorm; //reference to drawable id\n                        break;\n                    case WeatherIcon.Snow:\n                        drawableResource = R.drawable.snow; //reference to drawable id\n                        break;\n                    case WeatherIcon.Mist:\n                        drawableResource = R.drawable.mist; //reference to drawable id\n                        break;\n\n\n\n        imageofWeather.setImageDrawable(drawableResource);\n            }\n

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在fragment中的if语句下直接访问API并显示天气图标。（相应的 9 个图标当前在第一个片段类的编号线上可见）。

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当前设置的问题是：

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• 对于每个 case 语句，我收到以下错误：
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分配给“drawableResource”的值 R.drawable.sun（和其余部分）从未使用过。

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和

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• 行 imageofWeather.setImageDrawable(drawableResource); 显示此错误：
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所需类型：Drawable，提供：int

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如果有人可以提供帮助，我一定会很感激。

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这是我的片段代码：

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public class FirstFragment extends Fragment {\n\n    private WeatherDataViewModel viewModel;\n\n    public FirstFragment() {\n        // Required empty public constructor\n    }\n\n    @Override\n    public View onCreateView(LayoutInflater inflater, ViewGroup container,\n                             Bundle savedInstanceState) {\n        // Inflate the layout for this fragment\n        View rootView = inflater.inflate(R.layout.fragment_first, container, false);\n        // For displaying weather data\n        // all field in Java should be type in camelCase, so not current_temp but currentTemp, not Cloud_out but cloudOut\n        // Capitalize name is for class not field\n        final TextView current_temp = rootView.findViewById(R.id.textView10);\n        final TextView current_output = rootView.findViewById(R.id.textView11);\n        final TextView rise_time = rootView.findViewById(R.id.textView25);\n        final TextView set_time = rootView.findViewById(R.id.textView26);\n        final TextView temp_out = rootView.findViewById(R.id.textView28);\n        final TextView Press_out = rootView.findViewById(R.id.textView29);\n        final TextView Humid_out = rootView.findViewById(R.id.textView30);\n        final TextView Ws_out = rootView.findViewById(R.id.textView33);\n        final TextView Visi_out = rootView.findViewById(R.id.textView34);\n        final TextView Cloud_out = rootView.findViewById(R.id.textView35);\n        final ImageView imageofWeather = rootView.findViewById(R.id.imageView2);\n\n\n        // Get our ViewModel instance\n        viewModel = new ViewModelProvider(this).get(WeatherDataViewModel.class);\n\n        // And whenever the data changes, refresh the UI\n        viewModel.getWeatherDataLiveData().observe(getViewLifecycleOwner(), data -> {\n\n            int drawableResource; // here define default icon for example R.drawable.default_weather_icon\n\n            if (data != null) {\n                current_temp.setVisibility(View.VISIBLE);\n                current_temp.setText(data.getMain().getTemp() + " \xe2\x84\x83"); // for that you can use strings resource and templates more in https://developer.android.com/guide/topics/resources/string-resource.html#formatting-strings\n                current_output.setVisibility(View.VISIBLE);\n                current_output.setText(data.getWeather().get(0).getDescription());\n                rise_time.setVisibility(View.VISIBLE);\n                rise_time.setText(data.getSys().getSunrise() + " ");\n                set_time.setVisibility(View.VISIBLE);\n                set_time.setText(data.getSys().getSunset() + " ");\n                temp_out.setVisibility(View.VISIBLE);\n                temp_out.setText(data.getMain().getTemp() + " \xe2\x84\x83");\n                Press_out.setVisibility(View.VISIBLE);\n                Press_out.setText(data.getMain().getPressure() + " hpa");\n                Humid_out.setVisibility(View.VISIBLE);\n                Humid_out.setText(data.getMain().getHumidity() + " %");\n                Ws_out.setVisibility(View.VISIBLE);\n                Ws_out.setText(data.getWind().getSpeed() + " Km/h");\n                Visi_out.setVisibility(View.VISIBLE);\n                Visi_out.setText(data.getVisibility() + " m");\n                Cloud_out.setVisibility(View.VISIBLE);\n                Cloud_out.setText(data.getClouds().getAll() + " %");\n\n                // get actual weather.\n                switch (data.getWeather().get(0).getIcon()) { //or data.getWeather()[0].getIcon() i don\'t remember how it work in Java\n                    case WeatherIcon.Sun:\n                        drawableResource = R.drawable.sun; //reference to drawable id\n                        break;\n                    case WeatherIcon.Cloud1:\n                        drawableResource = R.drawable.broken_clouds; //reference to drawable id\n                        break;\n                    case WeatherIcon.Cloud2:\n                        drawableResource = R.drawable.few_clouds; //reference to drawable id\n                        break;\n                    case WeatherIcon.Cloud3:\n                        drawableResource = R.drawable.scattered_clouds; //reference to drawable id\n                        break;\n                    case WeatherIcon.Rain1:\n                        drawableResource = R.drawable.small_rain; //reference to drawable id\n                        break;\n                    case WeatherIcon.Rain2:\n                        drawableResource = R.drawable.shower_rain; //reference to drawable id\n                        break;\n                    case WeatherIcon.Thunder:\n                        drawableResource = R.drawable.thunderstorm; //reference to drawable id\n                        break;\n                    case WeatherIcon.Snow:\n                        drawableResource = R.drawable.snow; //reference to drawable id\n                        break;\n                    case WeatherIcon.Mist:\n                        drawableResource = R.drawable.mist; //reference to drawable id\n                        break;\n\n\n\n                    imageofWeather.setImageDrawable(drawableResource);\n                }\n\n            } else {\n                Log.e("TAG", "No City found");\n                current_temp.setVisibility(View.GONE);\n                current_output.setVisibility(View.GONE);\n                rise_time.setVisibility(View.GONE);\n                set_time.setVisibility(View.GONE);\n                temp_out.setVisibility(View.GONE);\n                Press_out.setVisibility(View.GONE);\n                Humid_out.setVisibility(View.GONE);\n                Ws_out.setVisibility(View.GONE);\n                Visi_out.setVisibility(View.GONE);\n                Cloud_out.setVisibility(View.GONE);\n                Toast.makeText(requireActivity(), "No City found", Toast.LENGTH_SHORT).show();\n            }\n        });\n\n        return rootView;\n    }\n\n    public void getWeatherData(String name) {\n        // The ViewModel controls loading the data, so we just\n        // tell it what the new name is - this kicks off loading\n        // the data, which will automatically call through to\n        // our observe() call when the data load completes\n        viewModel.setCityName(name);\n    }\n}\n

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Answer 1

行 imageofWeather.setImageDrawable(drawableResource); 显示此错误：

Required type: Drawable, Provided: int

这意味着setImageDrawable()需要（期望）一个 Drawable 参数，但提供的（找到）参数是一个int.

要解决此问题，请使用setImageResource()可绘制int资源而不是Drawable

对于每个 case 语句，我收到以下错误：

The value R.drawable.sun(and the rest) assigned to 'drawableResource' is never used.

引发此错误的原因是之前的错误，它认为 的行drawableResource未使用setImageDrawable()，因此它警告您您为其分配了一个值但从未使用过它。

应通过修复第一个警告来修复此警告；尽管如此，我建议enum使用一个接受可绘制资源值的私有构造函数来重写int，它将处理 switch 语句，而不是让片段执行此操作。

新的枚举：

public enum WeatherIcon {

    Sun(R.drawable.sun),
    Cloud1(R.drawable.broken_clouds),
    Cloud2(R.drawable.few_clouds),
    Cloud3(R.drawable.scattered_clouds),
    Rain1(R.drawable.small_rain),
    Rain2(R.drawable.shower_rain),
    Thunder(R.drawable.thunderstorm),
    Snow(R.drawable.snow),
    Mist(R.drawable.mist);

    private int drawable;

    WeatherIcon(int drawable) {
        this.drawable = drawable;
    }

    public int getDrawable() {
        return drawable;
    }

}

然后，switch您可以删除它并通过使用枚举getDrawable()方法获取可绘制对象来简化它，而不是片段中的语句，如下所示：

WeatherIcon icon = data.getWeather().get(0).getIcon();
int drawableResource = icon.getDrawable();
imageofWeather.setImageResource(drawableResource);