是上面的脚本写成Android12的

Android 12 也可以使用类似的脚本来切换前台应用。以下是一个示例脚本：

import java.io.IOException;

public class Main {

    public static void main(String[] args) {
        // 获取当前前台应用的包名和 Activity 名称
        String[] currentFocus = getFocusedApp();
        String packageName = currentFocus[0];
        String activityName = currentFocus[1];
        System.out.println("当前前台应用的包名：" + packageName);
        System.out.println("当前前台应用的 Activity 名称：" + activityName);

        // 启动目标应用并将其切换到前台
        String targetPackageName = "<target_package_name>";
        String targetActivityName = "<target_activity_name>";
        startApp(targetPackageName, targetActivityName);
        System.out.println("已切换到目标应用：" + targetPackageName + "/" + targetActivityName);
    }

    /**
     * 获取当前前台应用的包名和 Activity 名称
     */
    private static String[] getFocusedApp() {
        String[] result = new String[2];
        try {
            Process process = Runtime.getRuntime().exec("dumpsys window windows | grep -E 'mCurrentFocus|mFocusedApp'");
            String output = readProcessOutput(process);
            String[] lines = output.split("\n");
            String currentFocusLine = lines[0];
            String focusedAppLine = lines[1];
            String[] currentFocus = currentFocusLine.split(" ");
            String[] focusedApp = focusedAppLine.split(" ");
            String packageName = currentFocus[4].split("/")[0];
            String activityName = currentFocus[4].split("/")[1];
            result[0] = packageName;
            result[1] = activityName;
        } catch (IOException e) {
            e.printStackTrace();
        }
        return result;
    }

    /**
     * 启动应用并将其切换到前台
     */
    private static void startApp(String packageName, String activityName) {
        try {
            Process process = Runtime.getRuntime().exec("adb shell am start -n " + packageName + "/" + activityName);
            readProcessOutput(process);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 读取进程的输出结果
     */
    private static String readProcessOutput(Process process) {
        StringBuilder output = new StringBuilder();
        try {
            process.waitFor();
            java.io.InputStream inputStream = process.getInputStream();
            java.util.Scanner scanner = new java.util.Scanner(inputStream).useDelimiter("\\A");
            if (scanner.hasNext()) {
                String out = scanner.next();
                output.append(out);
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return output.toString();
    }
}

这个 Java 代码可以通过 Android Studio 或其他 Java IDE 编译并运行，也可以通过命令行工具 javac 和 java 进行编译和运行。这个代码会先获取当前前台应用的包名和 Activity 名称，并输出到终端。然后，它会启动目标应用并将其切换到前台，并输出切换结果到终端。