如何实现两个App间通信：替代邮件由App A向App B传输并展示数据

Alright, let's tackle this problem head-on. You've got App A that currently sends user input via email to teachers, and you want to cut out the email middleman by sending that data directly to App B for display. Here's how to pull this off across the main mobile platforms, with practical code examples:

iOS offers a few reliable ways to get data from App A to App B:

1. URL Scheme (Quick & Simple) #

This is the most straightforward method for basic data transfer:

• Set up App B to accept the scheme: Add this to your Info.plist (either via source code or Xcode's Info tab):

  <key>CFBundleURLTypes</key>
  <array>
      <dict>
          <key>CFBundleURLSchemes</key>
          <array>
              <string>appb-teacher-data</string> <!-- Pick a unique, descriptive scheme -->
          </array>
      </dict>
  </array>
  

• Handle incoming data in App B: In your SceneDelegate (iOS 13+):

  func scene(_ scene: UIScene, openURLContexts URLContexts: Set<UIOpenURLContext>) {
      guard let url = URLContexts.first?.url, url.scheme == "appb-teacher-data" else { return }
      
      // Extract and parse the data (we'll use JSON for structured input)
      if let encodedData = url.queryItems?.first(where: { $0.name == "input_data" })?.value,
         let data = encodedData.removingPercentEncoding?.data(using: .utf8),
         let userInput = try? JSONDecoder().decode(TeacherInput.self, from: data) {
          // Update App B's UI with userInput (e.g., populate a detail view)
          navigateToDisplayView(with: userInput)
      }
  }
  

• Send data from App A:

  func sendToAppB(input: TeacherInput) {
      guard let encodedData = try? JSONEncoder().encode(input),
            let dataString = String(data: encodedData, encoding: .utf8)?.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed),
            let appBUrl = URL(string: "appb-teacher-data://receive?input_data=\(dataString)") else {
          // Handle encoding failure
          return
      }
      
      if UIApplication.shared.canOpenURL(appBUrl) {
          UIApplication.shared.open(appBUrl)
      } else {
          // Prompt user to install App B (or fall back to email as a backup)
          showInstallPrompt()
      }
  }
  

2. App Groups (For Same Developer Account) #

If both apps are under your developer account, use App Groups to share a file container:

• Enable App Groups for both apps in Xcode's Signing & Capabilities tab.
• App A writes the input data to a shared file:

  let sharedContainer = FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: "group.com.yourcompany.teacherapps")!
  let dataFileUrl = sharedContainer.appendingPathComponent("teacher_input.json")
  try? JSONEncoder().encode(input).write(to: dataFileUrl)
  

• App B listens for changes to this file (using NSFilePresenter or periodic checks) and loads the data for display.

Android has robust intent-based communication that's perfect for this use case:

1. Implicit Intent (Direct Targeted Transfer) #

• Configure App B to receive data: Add an intent filter to your target Activity in AndroidManifest.xml:

  <activity android:name=".TeacherInputDisplayActivity">
      <intent-filter>
          <action android:name="com.yourcompany.action.RECEIVE_TEACHER_INPUT" />
          <category android:name="android.intent.category.DEFAULT" />
      </intent-filter>
  </activity>
  

• Receive data in App B:

  class TeacherInputDisplayActivity : AppCompatActivity() {
      override fun onCreate(savedInstanceState: Bundle?) {
          super.onCreate(savedInstanceState)
          setContentView(R.layout.activity_input_display)
          
          intent?.let { receivedIntent ->
              if (receivedIntent.action == "com.yourcompany.action.RECEIVE_TEACHER_INPUT") {
                  val inputJson = receivedIntent.getStringExtra("input_data")
                  inputJson?.let {
                      val userInput = Gson().fromJson(it, TeacherInput::class.java)
                      // Update UI with userInput
                      populateInputView(userInput)
                  }
              }
          }
      }
  }
  

• Send data from App A:

  fun sendToAppB(input: TeacherInput) {
      val inputJson = Gson().toJson(input)
      val sendIntent = Intent("com.yourcompany.action.RECEIVE_TEACHER_INPUT").apply {
          putExtra("input_data", inputJson)
          // Lock this to App B specifically to avoid interception
          setPackage("com.yourcompany.appb")
      }
      
      if (packageManager.resolveActivity(sendIntent, 0) != null) {
          startActivity(sendIntent)
      } else {
          // Show message to install App B
          Toast.makeText(this, "Please install App B to view this input", Toast.LENGTH_LONG).show()
      }
  }
  

• Data Serialization: Always use JSON (or a similar structured format) to package user input—this avoids messy string parsing and makes it easy to handle complex data (like multiple input fields).
• Fallback Plan: Add a backup option (like reverting to email) in case App B isn't installed on the user's device.
• Security: For sensitive data, encrypt the payload before sending. On iOS, use Universal Links instead of plain URL schemes for better security; on Android, specifying the app package ensures only App B receives the data.

内容的提问来源于stack exchange，提问作者ButterBoy42