Android 入门

1distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip

1distributionUrl=https\://mirrors.cloud.tencent.com/gradle/gradle-8.9-all.zip

 1pluginManagement {
 2    repositories {
 3        google {
 4            content {
 5                includeGroupByRegex("com\\.android.*")
 6                includeGroupByRegex("com\\.google.*")
 7                includeGroupByRegex("androidx.*")
 8            }
 9        }
10        mavenCentral()
11        gradlePluginPortal()
12    }
13}
14dependencyResolutionManagement {
15    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
16    repositories {
17        google()
18        mavenCentral()
19    }
20}

 1pluginManagement {
 2    repositories {
 3        google {
 4            content {
 5                includeGroupByRegex("com\\.android.*")
 6                includeGroupByRegex("com\\.google.*")
 7                includeGroupByRegex("androidx.*")
 8            }
 9        }
10
11        maven { url = uri("https://maven.aliyun.com/repository/gradle-plugin") }
12        maven { url = uri("https://maven.aliyun.com/repository/google") }
13        maven { url = uri("https://maven.aliyun.com/repository/jcenter") }
14        maven { url = uri("https://maven.aliyun.com/repository/public") }
15        mavenLocal()
16        mavenCentral()
17        gradlePluginPortal()
18    }
19}
20dependencyResolutionManagement {
21    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
22    repositories {
23        google()
24        maven { url = uri("https://maven.aliyun.com/repository/gradle-plugin") }
25        maven { url = uri("https://maven.aliyun.com/repository/google") }
26        maven { url = uri("https://maven.aliyun.com/repository/jcenter") }
27        maven { url = uri("https://maven.aliyun.com/repository/public") }
28        mavenLocal()
29        mavenCentral()
30    }
31}

 1<?xml version="1.0" encoding="utf-8"?>
 2<manifest xmlns:android="http://schemas.android.com/apk/res/android"
 3    xmlns:tools="http://schemas.android.com/tools">
 4
 5    <application
 6        android:allowBackup="true"
 7        android:dataExtractionRules="@xml/data_extraction_rules"
 8        android:fullBackupContent="@xml/backup_rules"
 9        android:icon="@mipmap/ic_launcher"
10        android:label="@string/app_name"
11        android:roundIcon="@mipmap/ic_launcher_round"
12        android:supportsRtl="true"
13        android:theme="@style/Theme.Wordle"
14        tools:targetApi="31">
15        <activity
16            android:name=".MainActivity"
17            android:exported="true">
18            <intent-filter>
19                <action android:name="android.intent.action.MAIN" />
20
21                <category android:name="android.intent.category.LAUNCHER" />
22            </intent-filter>
23        </activity>
24    </application>
25
26</manifest>

 1public class MusicPlayerService extends Service {
 2
 3    private MediaPlayer mediaPlayer;
 4
 5    @Override
 6    public void onCreate() {
 7        super.onCreate();
 8        mediaPlayer = new MediaPlayer();
 9    }
10
11    @Override
12    public int onStartCommand(Intent intent, int flags, int startId) {
13        String musicUrl = intent.getStringExtra("music_url");
14        try {
15            mediaPlayer.setDataSource(musicUrl);
16            mediaPlayer.prepare();
17            mediaPlayer.start();
18        } catch (IOException e) {
19            e.printStackTrace();
20        }
21        return START_NOT_STICKY; // don't restart when killed by system
22    }
23
24    @Override
25    public void onDestroy() {
26        super.onDestroy();
27        if (mediaPlayer != null) {
28            mediaPlayer.release();
29            mediaPlayer = null;
30        }
31    }
32
33    @Nullable
34    @Override
35    public IBinder onBind(Intent intent) {
36        return null;
37    }
38}

 1Intent intent = new Intent(CurrentActivity.this, TargetActivity.class);
 2/* optional:
 3    Bundle bundle = new Bundle();
 4    bundle.putString("string1", "YOUR_STRING");
 5    intent.putExtras(bundle);
 6*/
 7startActivity(intent);
 8
 9/*  Get your bundle in the target activity:
10    Bundle bundle = this.getIntent().getExtras();
11    String str1 = bundle.getString("string1");
12*/

 1<TableLayout
 2    android:id="@+id/KeyboardLayout"
 3    android:layout_width="0dp"
 4    android:layout_height="wrap_content"
 5    app:layout_constraintTop_toBottomOf="@id/InputLayout"
 6    app:layout_constraintStart_toStartOf="parent"
 7    app:layout_constraintEnd_toEndOf="parent" >
 8
 9    <LinearLayout
10        android:layout_width="match_parent"
11        android:layout_height="match_parent"
12        android:orientation="horizontal">
13
14        <Button
15            android:id="@+id/button_Q"
16            android:layout_width="wrap_content"
17            android:layout_height="wrap_content"
18            android:layout_weight="1"
19            android:padding="0dp"
20            android:layout_marginEnd="1dp"
21            android:text="Q" />
22
23        <Button
24            android:id="@+id/button_W"
25            android:layout_width="wrap_content"
26            android:layout_height="wrap_content"
27            android:layout_weight="1"
28            android:padding="0dp"
29            android:layout_marginEnd="1dp"
30            android:text="W" />
31        <!-- Other buttons... -->
32
33    </LinearLayout>
34    
35    <LinearLayout> <!-- Other lines... --> </LinearLayout>
36    <LinearLayout> <!-- Other lines... --> </LinearLayout>
37</TableLayout>

1<GridLayout
2    android:id="@+id/InputLayout"
3    android:layout_width="match_parent"
4    android:layout_height="wrap_content"
5    app:layout_constraintTop_toTopOf="parent"
6    app:layout_constraintStart_toStartOf="parent"
7    app:layout_constraintEnd_toEndOf="parent">
8</GridLayout>

 1GridLayout inputLayout = binding.InputLayout;
 2
 3// 设置行数和列数
 4inputLayout.setRowCount(TOTAL_CHANCES);
 5inputLayout.setColumnCount(WORD_LENGTH);
 6// 设置元素居中方式
 7inputLayout.setForegroundGravity(Gravity.CENTER);
 8
 9for (int row = 0; row < inputLayout.getRowCount(); row++) {
10    for (int col = 0; col < inputLayout.getColumnCount(); col++) {
11        
12        // 每个 Grid 里准备放一个 TextView
13        TextView textView = new TextView(getContext());
14        textView.setText(" ");
15        textView.setGravity(Gravity.CENTER);
16        textView.setTextSize(50); // 设置文本大小
17        textView.setTextColor(Color.WHITE.getRgbCode());
18        textView.setBackgroundResource(R.drawable.gray_border); // 设置背景，默认为灰色
19        // 设置参数
20        GridLayout.LayoutParams params = new GridLayout.LayoutParams();
21        params.columnSpec = GridLayout.spec(col, 1); // 设置 TextView 占据一个整列
22        params.rowSpec = GridLayout.spec(row, 1); // 设置 TextView 占据一个整行
23
24        int screenWidth = getResources().getDisplayMetrics().widthPixels;
25        params.width = screenWidth / inputLayout.getColumnCount();
26        params.height = WRAP_CONTENT;
27
28        // 将 TextView 添加到 GridLayout
29        inputLayout.addView(textView, params);
30    }
31}

1// 每个 Grid 里准备放一个 TextView
2TextView textView = new TextView(getContext());
3textView.setText(" "); // 设置文本内容
4textView.setGravity(Gravity.CENTER); // 设置文本居中
5textView.setTextSize(50); // 设置文本大小
6textView.setTextColor(Color.WHITE.getRgbCode());
7textView.setBackgroundResource(R.drawable.gray_border); // 设置背景，默认为灰色

 1<Button
 2    android:id="@+id/myButton"
 3    android:layout_width="wrap_content"
 4    android:layout_height="wrap_content"
 5    android:text="Click Me"
 6    android:textSize="18sp"
 7    android:textColor="#FFFFFF"
 8    android:background="@drawable/button_background"
 9    android:padding="16dp"
10    android:layout_margin="8dp"
11    android:onClick="onButtonClick" />

1Button button = findViewById(R.id.myButton);
2button.setOnClickListener(new View.OnClickListener() {
3    @Override
4    public void onClick(View v) {
5        // 在这里处理点击事件
6        Toast.makeText(this, "Button Clicked!", Toast.LENGTH_SHORT).show();
7    }
8});

 1void processNewGame() {
 2    AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(getContext());
 3    dialogBuilder.setTitle("新的游戏")
 4        .setMessage("你确定要放弃此轮游戏吗？")
 5        .setPositiveButton("是，并查看答案", (dialogInterface, i) -> {
 6            Toast.makeText(getContext(), "答案为 " + state.answer.toLowerCase() + "。", Toast.LENGTH_SHORT).show();
 7            User user = ((MainActivity) getActivity()).loadUser();
 8            user.totalRounds += 1;
 9            ((MainActivity) getActivity()).saveUser(user);
10            // 重新开始游戏
11            startNewGame();
12        })
13        .setNegativeButton("否", (dialog, which) -> Log.i("DialogBuilder","点击了否"))
14        .create().show();
15}

 1public User loadUser() {
 2    Log.d("preferenceTest", "read");
 3    SharedPreferences preferences_winRounds =
 4            getSharedPreferences("winRounds", MODE_PRIVATE);
 5    SharedPreferences preferences_totalRounds =
 6            getSharedPreferences("totalRounds", MODE_PRIVATE);
 7    SharedPreferences preferences_guesses =
 8            getSharedPreferences("guesses", MODE_PRIVATE);
 9
10    int winRounds = preferences_winRounds.getInt("winRounds", 0);
11    int totalRounds = preferences_totalRounds.getInt("totalRounds", 0);
12    int[] guesses = new int[6];
13    for (int i = 0; i < TOTAL_CHANCES; i++)
14        guesses[i] = preferences_guesses.getInt("guesses[" + i + "]", 0);
15
16    Log.d("preferenceTest", "Read [winRounds = " + winRounds +
17            ", totalRounds = " + totalRounds +
18            ", guesses = " + Arrays.toString(guesses) + "]");
19    return new User(winRounds, totalRounds, guesses);
20}

 1import org.json.JSONArray;
 2import org.json.JSONObject;
 3
 4public class JsonExample {
 5    public static void main(String[] args) {
 6        // 创建 JSONObject
 7        JSONObject jsonObject = new JSONObject();
 8        jsonObject.put("name", "John Doe");
 9        jsonObject.put("age", 30);
10        
11        // 创建 JSONArray
12        JSONArray jsonArray = new JSONArray();
13        jsonArray.put("Apple");
14        jsonArray.put("Banana");
15        jsonArray.put("Cherry");
16        
17        // 将 JSONArray 添加到 JSONObject
18        jsonObject.put("fruits", jsonArray);
19        
20        // 输出整个 JSON 对象
21        System.out.println(jsonObject.toString());
22        
23        // 获取并输出 name
24        System.out.println(jsonObject.getString("name"));
25        
26        // 获取并遍历 fruits
27        JSONArray fruits = jsonObject.getJSONArray("fruits");
28        for (int i = 0; i < fruits.length(); i++) {
29            System.out.println(fruits.get(i));
30        }
31    }
32}

1Log.d("preferenceTest", "This is a debug message.");