用Android Studio做一个天气预报app详细代码

这是一个简单的天气预报app的示例代码，使用了OpenWeatherMap的API获取天气数据。你需要先注册OpenWeatherMap账号获取API Key。

1. 布局文件

在`res/layout`目录下创建一个名为`activity_main.xml`的布局文件，添加以下代码：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <TextView
        android:id="@+id/city_name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="30sp"
        android:text="Loading..." />

    <TextView
        android:id="@+id/temp"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="20sp"
        android:text="Loading..." />

    <TextView
        android:id="@+id/weather_desc"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="20sp"
        android:text="Loading..." />

</LinearLayout>

2. Java代码

在`app/src/main/java`目录下创建一个名为`MainActivity.java`的Java类，添加以下代码：

public class MainActivity extends AppCompatActivity {

    private static final String API_KEY = "YOUR_API_KEY"; // 替换成你的API Key
    private static final String API_URL = "https://api.openweathermap.org/data/2.5/weather?q=%s&appid=%s&units=metric";

    private TextView cityNameTextView;
    private TextView tempTextView;
    private TextView weatherDescTextView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        cityNameTextView = findViewById(R.id.city_name);
        tempTextView = findViewById(R.id.temp);
        weatherDescTextView = findViewById(R.id.weather_desc);

        String city = "beijing"; // 替换成你要查询的城市
        String apiUrl = String.format(API_URL, city, API_KEY);

        JsonObjectRequest request = new JsonObjectRequest(Request.Method.GET, apiUrl, null,
                response -> {
                    try {
                        JSONObject main = response.getJSONObject("main");
                        JSONArray weatherArray = response.getJSONArray("weather");
                        JSONObject weather = weatherArray.getJSONObject(0);

                        String cityName = response.getString("name");
                        String temp = main.getString("temp") + " °C";
                        String weatherDesc = weather.getString("description");

                        cityNameTextView.setText(cityName);
                        tempTextView.setText(temp);
                        weatherDescTextView.setText(weatherDesc);
                    } catch (JSONException e) {
                        e.printStackTrace();
                    }
                }, error -> {
                    Toast.makeText(this, "Failed to fetch weather data", Toast.LENGTH_SHORT).show();
                    Log.e("MainActivity", "Failed to fetch weather data", error);
                });

        RequestQueue queue = Volley.newRequestQueue(this);
        queue.add(request);
    }
}

注意替换代码中的`YOUR_API_KEY`和`city`变量。

3. 运行app

运行app并输入查询的城市名称，即可获取天气数据。