Hey there, let's break down your problem into two parts: those compilation warnings and the "App not installed" error you're hitting on devices.

先说说那些编译警告 #

The notes you're seeing are coming from outdated versions of third-party packages (android_intent-0.3.7+3 and url_launcher-5.4.5) stored in your Flutter pub cache. These warnings point to:

• Unchecked/unsafe operations in the package code
• Deprecated Android APIs being used by the packages

These warnings usually don't cause installation failures, but they're worth fixing for better code health. To eliminate them:

• Open your pubspec.yaml file
• Update android_intent and url_launcher to their latest stable versions
• Run flutter pub upgrade to pull the updated packages
• Re-run your build command: flutter clean && flutter build apk --release

重点解决「应用未安装」问题 #

This is the critical issue, and there are several common fixes to try across different Android devices:

1. 确保Release APK已正确签名 #

Flutter requires signed APKs for release distribution. If you didn't configure signing, the generated release APK might not be installable on real devices. Here's how to set it up:

• Generate a signing key using keytool (replace paths and passwords with your own):

  keytool -genkey -v -keystore C:\Users\YourUsername\key.jks -keyalg RSA -keysize 2048 -validity 10000 -alias key
  

• Add the signing configuration to android/app/build.gradle:

  android {
      ...
      signingConfigs {
          release {
              keyAlias 'key'
              keyPassword 'your_key_password'
              storeFile file('C:/Users/YourUsername/key.jks')
              storePassword 'your_store_password'
          }
      }
      buildTypes {
          release {
              ...
              signingConfig signingConfigs.release
          }
      }
  }
  

• Re-run flutter clean && flutter build apk --release to generate a properly signed APK.

2. 检查设备的安装权限 #

• For Android 8.0 and above: Enable Unknown Sources in your device's settings (usually under Security > Install Unknown Apps). For Android 11+, grant specific permission to the app you're using to install the APK (e.g., your file manager or browser).

3. 卸载设备上的旧版本应用 #

If you previously installed a debug version of your app (or any version with a different signature), it will conflict with the release APK. Uninstall the old app completely before trying to install the release version.

4. 重新构建一个干净的APK #

Sometimes cache corruption can lead to broken APKs. Try these steps:

• Delete the build folder in your project's root directory
• Delete the android/build folder as well
• Run flutter clean
• Re-build with flutter build apk --release

5. 尝试构建架构拆分的APK #

If your device has a specific CPU architecture (e.g., arm64-v8a, x86), building a split APK for that architecture might resolve compatibility issues:

flutter build apk --release --split-per-abi

This will generate separate APKs for each architecture; install the one that matches your device's CPU type.

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