Android API 21/22下定位无返回问题求助（非过时方案）

问题核心原因 #

1. 权限逻辑缺失：API 21/22无需运行时权限，但必须在Manifest中声明定位权限且用户安装时授权，你的代码仅处理了API≥23的权限校验，低版本未做权限检查。
2. LocationRequest兼容性问题：LocationRequest.Builder是Google Play Services Location 18.0.0新增API，API21/22设备的Play Services版本可能低于该版本，导致无法正常创建请求。
3. 回调线程未指定：requestLocationUpdates最后一个参数传null，低版本系统中可能导致回调无法触发，需指定主线程Looper。

完整修正实现 #

1. 配置Manifest权限 #

确保AndroidManifest.xml中添加定位权限：

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />

2. 全版本权限校验逻辑 #

覆盖API21/22及更高版本的权限检查：

private boolean hasLocationPermission() {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
        return ActivityCompat.checkSelfPermission(requireActivity(), Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED
                || ActivityCompat.checkSelfPermission(requireActivity(), Manifest.permission.ACCESS_COARSE_LOCATION) == PackageManager.PERMISSION_GRANTED;
    } else {
        // API21/22 权限在安装时授予，直接检查应用是否已获得权限
        PackageManager pm = requireActivity().getPackageManager();
        return pm.checkPermission(Manifest.permission.ACCESS_FINE_LOCATION, requireActivity().getPackageName()) == PackageManager.PERMISSION_GRANTED
                || pm.checkPermission(Manifest.permission.ACCESS_COARSE_LOCATION, requireActivity().getPackageName()) == PackageManager.PERMISSION_GRANTED;
    }
}

3. 兼容的LocationRequest创建方式 #

改用LocationRequest.create()替代LocationRequest.Builder，同时适配低版本不支持的API：

private static LocationRequest createLocationRequest() {
    LocationRequest locationRequest = LocationRequest.create();
    locationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
    locationRequest.setInterval(5000);
    locationRequest.setFastestInterval(2000);
    locationRequest.setMaxWaitTime(100);
    locationRequest.setNumUpdates(1);
    
    // setWaitForAccurateLocation是API26+新增，API21/22不支持
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        locationRequest.setWaitForAccurateLocation(true);
    }
    return locationRequest;
}

4. 修正后的定位请求代码 #

添加权限校验，指定主线程Looper确保回调触发：

if (!hasLocationPermission()) {
    Log.d("Location", "无法获取用户位置：权限未授权");
    return;
}

Log.d("Location", "正在请求用户位置...");
FusedLocationProviderClient client = LocationServices.getFusedLocationProviderClient(requireActivity());
// 保存callback引用用于后续注销
LocationCallback locationCallback = new LocationCallback() {
    @Override
    public void onLocationResult(@NonNull LocationResult locationResult) {
        super.onLocationResult(locationResult);
        Location location = locationResult.getLastLocation();
        if (location != null) {
            Log.d("User location", location.toString());
            // 处理获取到的位置数据
        } else {
            Log.d("User location", "获取到的位置为空");
        }
    }

    @Override
    public void onLocationAvailability(@NonNull LocationAvailability locationAvailability) {
        super.onLocationAvailability(locationAvailability);
        if (!locationAvailability.isLocationAvailable()) {
            Log.d("Location", "当前位置不可用");
        }
    }
};

client.requestLocationUpdates(createLocationRequest(), locationCallback, Looper.getMainLooper());

5. 额外注意事项 #

• Play Services依赖版本：使用兼容API21/22的版本，推荐添加：

  implementation 'com.google.android.gms:play-services-location:21.0.1'
  

• 模拟器测试：API21/22模拟器需开启GPS功能，手动设置位置后可尝试重启定位服务；
• 回调注销：在Fragment生命周期中及时注销请求，避免内存泄漏：

  @Override
  public void onStop() {
      super.onStop();
      if (locationCallback != null) {
          LocationServices.getFusedLocationProviderClient(requireActivity())
                  .removeLocationUpdates(locationCallback);
      }
  }
  

内容的提问来源于stack exchange，提问作者user21193451