具有 RequestMultiplePermissions 合约的 ActivityResultLauncher 在启动时不显示权限 UI

Question

我正在尝试使用ActivityResultLauncherwith请求权限ActivityResultsContract.RequestMultiplePermissions。

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;
    }
}

我还将必要的依赖项包含在build.gradle：

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，不显示允许权限的 UI。我在启动之前清除了缓存并从设备中删除了该应用程序。日志：

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;
    }
}

最后两行重复，直到我关闭应用程序。但是，当我ActivityResultContracts.RequestPermission单独使用和请求每个权限时，它会按预期工作，显示所有必要的 UI。

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

Answer 1

我找到了我的问题的答案。事实证明，自 Android 11 起，ACCESS_BACKGROUND_LOCATION在授予一般位置权限之前不应请求权限（ACCESS_FINE_LOCATION或ACCESS_COARSE_LOCATION）。否则，系统将忽略该请求。因此，正确的方法是请求一般位置权限（ACCESS_FINE_LOCATION在我的例子中），然后，如果被授予，则请求ACCESS_BACKGROUND_LOCATION权限。

另外，如果第一次请求用户决定不授予此权限，则所有后续对此权限的请求都将被忽略，因此不会显示它的设置页面（在这种情况下，您可能应该提示用户手动允许该权限） ）。