使用RequestMultiplePermissions合同的ActivityResultLauncher在启动时不显示权限UI

Question

我正在尝试使用ActivityResultLauncher和ActivityResultsContract.RequestMultiplePermissions来请求权限。

import android.content.pm.PackageManager;
import android.os.Bundle;
import android.util.Log;
import android.Manifest;

import androidx.activity.result.ActivityResultLauncher;
import.androidx.activity.result.contract.ActivityResultContracts;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;

public class MainActivity extends AppCompatActivity {

    final String[] PERMISSIONS = {
            Manifest.permission.FOREGROUND_SERVICE,
            Manifest.permission.ACCESS_FINE_LOCATION,
            Manifest.permission.ACCESS_BACKGROUND_LOCATION,
            Manifest.permission.REQUEST_IGNORE_BATTERY_OPTIMIZATIONS
    };

    private ActivityResultContracts.RequestMultiplePermissions multiplePermissionsContract;
    private ActivityResultLauncher<String[]> multiplePermissionLauncher;    

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        multiplePermissionsContract = new ActivityResultContracts.RequestMultiplePermissions();
        multiplePermissionLauncher = registerForActivityResult(multiplePermissionsContract, isGranted -> {
            Log.d("PERMISSIONS", "Launcher result: " + isGranted.toString());
            if (isGranted.containsValue(false)) {
                Log.d("PERMISSIONS", "At least one of the permissions was not granted, launching again...");
                multiplePermissionLauncher.launch(PERMISSIONS);
            }
        });

        askPermissions(multiplePermissionLauncher);
    }

    private void askPermissions(ActivityResultLauncher<String[]> multiplePermissionLauncher) {
        if (!hasPermissions(PERMISSIONS)) {
            Log.d("PERMISSIONS", "Launching multiple contract permission launcher for ALL required permissions");
            multiplePermissionLauncher.launch(PERMISSIONS);
        } else {
            Log.d("PERMISSIONS", "All permissions are already granted");
        }
    }

    private boolean hasPermissions(String[] permissions) {
        if (permissions != null) {
            for (String permission : permissions) {
                if (ActivityCompat.checkSelfPermission(this, permission) != PackageManager.PERMISSION_GRANTED) {
                    Log.d("PERMISSIONS", "Permission is not granted: " + permission);
                    return false;
                }
                Log.d("PERMISSIONS", "Permission already granted: " + permission);
            }
            return true;
        }
        return false;
    }
}

我还在 build.gradle 中包含了必要的依赖项：

implementation 'androidx.appcompat:appcompat:1.2.0'
implementation 'androidx.activity:activity:1.2.0'
implementation 'androidx.fragment:fragment:1.3.0'

当我在设备上启动应用程序时，没有显示允许权限的用户界面。在启动之前，我清除了缓存并从设备中删除了该应用程序。 日志：

15:02:43.584 D/PERMISSIONS: Permission already granted: android.permission.FOREGROUND_SERVICE
15:02:43.586 D/PERMISSIONS: Permission is not granted: android.permission.ACCESS_FINE_LOCATION
15:02:43.586 D/PERMISSIONS: Launching multiple contract permission launcher for ALL required permissions
15:02:43.753 D/PERMISSIONS: Launcher result: {android.permission.ACCESS_FINE_LOCATION=false, android.permission.ACCESS_BACKGROUND_LOCATION=false}
15:02:43.753 D/PERMISSIONS: At least one of the permissions was not granted, launching again...
15:02:43.857 D/PERMISSIONS: Launcher result: {android.permission.ACCESS_FINE_LOCATION=false, android.permission.ACCESS_BACKGROUND_LOCATION=false}
15:02:43.857 D/PERMISSIONS: At least one of the permissions was not granted, launching again...
15:02:43.939 D/PERMISSIONS: Launcher result: {android.permission.ACCESS_FINE_LOCATION=false, android.permission.ACCESS_BACKGROUND_LOCATION=false}

最后两行会一直重复，直到我关闭应用程序。 然而，当我使用ActivityResultContracts.RequestPermission并分别请求每个权限时，它按预期工作，显示所有必要的用户界面。

为什么在这种情况下ActivityResultsContract.RequestMultiplePermissions不起作用？

- Vladimir Kattsyn

Answer 1

我找到了关于我的问题的答案。原来自 Android 11 开始，ACCESS_BACKGROUND_LOCATION 权限不能与其他权限一起请求，否则系统将会忽略该请求。这个权限应该单独请求。

此外，如果用户在第一次请求时决定不授予该权限，则所有后续请求该权限的操作都会被忽略，因此该权限的设置页面也不会显示（在这种情况下，您可能需要提示用户手动允许该权限）。

- Vladimir Kattsyn

---

更确切地说，只有在您请求了一般位置权限之后才能请求它。 - user924

Answer 2

你需要在Java文件中添加一个库"import android.Manifest;"。

import android.Manifest;

当在代码中写一个单词Manifest时，

你会看到两个选项：

1. 项目的Manifest 2. 包含在库android.Manifest中的Manifest

选择第二个。

- احمد توفيق هاشل

---

使用android.Manifest对代码进行运行是很重要的，但它并不能解决问题。不管怎样，还是谢谢你，我已经在相关的代码中添加了导入语句。 - Vladimir Kattsyn