java - 防止 Android One 设备中的屏幕捕获

Question

我想防止在安卓手机中截屏。我添加了行requireActivity().window.setFlags(WindowManager.LayoutParams.FLAG_SECURE, WindowManager.LayoutParams.FLAG_SECURE)这在普通设备中运行良好。但是当我在 android one 设备上尝试时，( https://www.android.com/intl/en_in/one/ )，它仍在捕获屏幕截图。
我在 android one 设备上尝试了其他应用程序，如 AmazonPrime、Hotstar 和 GooglePay……虽然它们正在捕获屏幕截图，但内容完全是黑色的。如何在 android one 设备中实现或防止屏幕截图。

Answer 1

我们可以收听FileObserver检测何时捕获屏幕截图。然后从存储中删除捕获的屏幕截图文件。
这是 MediaListenerService 的示例代码

import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.net.Uri;
import android.os.Environment;
import android.os.FileObserver;
import android.os.Handler;
import android.os.IBinder;
import android.os.Looper;
import android.util.Log;
import android.widget.Toast;

import androidx.documentfile.provider.DocumentFile;

import java.io.File;

public class MediaListenerService extends Service {

    public static FileObserver observer;
    private Context context;

    public MediaListenerService() {
    }

    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public void onCreate() {
        super.onCreate();
        context = this;
        startWatching();
    }

    private void startWatching() {
        //The desired path to watch or monitor
        String pathToWatch = Environment.getExternalStorageDirectory()
                + File.separator + Environment.DIRECTORY_PICTURES
                + File.separator + "Screenshots" + File.separator;
        Toast.makeText(this, "Service is Started and trying to watch " + pathToWatch, Toast.LENGTH_LONG).show();

        observer = new FileObserver(pathToWatch, FileObserver.ALL_EVENTS) { // set up a file observer to watch this directory
            @Override
            public void onEvent(int event, final String file) {
                if (event == FileObserver.CREATE || event == FileObserver.CLOSE_WRITE || event == FileObserver.MODIFY || event == FileObserver.MOVED_TO && !file.equals(".probe")) { // check that it's not equal to .probe because thats created every time camera is launched
                    String filePath = pathToWatch + file;
                    Log.d("MediaListenerService", "File created [" + filePath + "]");
                    new Handler(Looper.getMainLooper()).postDelayed(() -> {
//                        Toast.makeText(getBaseContext(), file + " was saved!", Toast.LENGTH_LONG).show();
                        File screenShotFile = new File(pathToWatch, file);
                        if (screenShotFile.exists()) {
                            try {
                                boolean isDeleted = screenShotFile.delete();
                                if (isDeleted) {
                                    Toast.makeText(getBaseContext(), file + " was deleted!", Toast.LENGTH_LONG).show();
                                    Log.d("MediaListenerService", "File deleted [" + filePath + "]");
                                }
                            } catch (Exception e) {
                                e.printStackTrace();
                            }
                        }
                    }, 200L);
                }
            }
        };
        observer.startWatching();
    }
}

在 Manifest 中添加文件权限

<uses-permission
        android:name="android.permission.WRITE_EXTERNAL_STORAGE"
        tools:ignore="ScopedStorage" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:requestLegacyExternalStorage="true"

在 Manifest 注册您的服务在应用程序标签下:

<service
  android:name=".MediaListenerService"
  android:enabled="true"
  android:exported="false" />

并在onCreate下的MainActivity中检查文件存储权限并启动服务

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        if (checkSelfPermission(Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {
            startService(Intent(baseContext, MediaListenerService::class.java))
        } else {
            ActivityCompat.requestPermissions(
                this,
                arrayOf(Manifest.permission.WRITE_EXTERNAL_STORAGE),
                123
            )
        }
    }
}