如何在Android应用内编译.cpp文件并在TextView输出？求非在线API方案

Hey there! Let's break down your two questions step by step—since I know tracking down this kind of Android-specific C++ workflow can be tricky.

First off, Android doesn’t come with a built-in C++ compiler out of the box, so you’ll need to embed a lightweight compiler that runs on mobile architectures (arm64, armeabi-v7a, etc.). Here’s a practical approach using a port of TCC (Tiny C Compiler)—it’s small, fast, and supports running compiled code directly:

• Step 1: Package the Compiler
  Grab a precompiled TCC binary for Android (you can build it yourself using the NDK if you want full control) and drop it into your app's assets folder. On first launch, copy it to your app's private files directory (via getFilesDir()) and set executable permissions with chmod 755.

• Step 2: Prepare Your C++ Code
  Either let users input code via an EditText, or load a .cpp file from storage. Save the code to a temporary file in your app's private directory to avoid permission issues.

• Step 3: Run the Compiler and Capture Output
  Use ProcessBuilder to execute the compiler command, then read the standard output/error. Make sure to do this off the main thread (use Kotlin Coroutines, AsyncTask, or a Thread) to avoid ANRs.

  Here’s a quick Java snippet to illustrate:

  // Assume tccPath points to the copied compiler binary
  String cppSource = "#include <iostream>\nint main() { std::cout << \"Hello from mobile C++!\"; return 0; }";
  File tempCppFile = new File(getFilesDir(), "temp.cpp");
  
  // Write source code to temp file
  try (FileWriter writer = new FileWriter(tempCppFile)) {
      writer.write(cppSource);
  } catch (IOException e) {
      e.printStackTrace();
  }
  
  // Execute TCC to run the code
  ProcessBuilder pb = new ProcessBuilder(tccPath, "-run", tempCppFile.getAbsolutePath());
  pb.redirectErrorStream(true); // Merge error output with standard output
  Process process = pb.start();
  
  // Read output
  StringBuilder result = new StringBuilder();
  try (BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()))) {
      String line;
      while ((line = reader.readLine()) != null) {
          result.append(line).append("\n");
      }
      int exitCode = process.waitFor();
      result.append("\nExit Code: ").append(exitCode);
  } catch (IOException | InterruptedException e) {
      result.append("Error during compilation: ").append(e.getMessage());
  }
  
  // Update TextView on main thread
  runOnUiThread(() -> yourTextView.setText(result.toString()));
  

Absolutely—you’ve got two main categories to choose from: offline (local) compilers and alternative online APIs.

Offline (Local) Compilation Options #

These let you compile code without an internet connection:

• TCC (as above): Tiny footprint, great for simple C++ programs.
• Clang/LLVM for Android: More feature-complete, supports full C++ standards. You’ll need to package Clang binaries and supporting libraries with your app (it’s bigger than TCC, but worth it for complex code).
• GCC Port for Android: A viable option, though Clang is more actively maintained for mobile these days.

Online API Alternatives #

If you’d prefer to offload compilation to a server:

• Judge0: A robust, open-source API that supports C++ (and dozens of other languages). Send a POST request with your code, and get back JSON containing output, errors, and exit codes.
• JDoodle API: User-friendly, with free tiers for limited requests. Easy to integrate with Android using Retrofit or OkHttp.
• CompileX: Focused on code compilation, with simple endpoints for submitting C++ code and retrieving results.

A quick heads-up: Local compilation will increase your app's size (since you're bundling a compiler), so you might want to split APKs by architecture. For online APIs, remember to handle network errors and check free-tier rate limits.

内容的提问来源于stack exchange，提问作者user6731698