Android中的sharedUserId是什么，如何使用

xml
    ...
    android:sharedUserId="com.example.shareduid"
    android:sharedUserLabel="@string/shared_user_label">
    ...

java
public class MainActivity extends AppCompatActivity {
    ...
    
    private void shareData() {
        String data = "Hello from App 1!";
        
        // 获取应用2的包名
        String packageName = "com.example.shareduidapp2";
        
        // 创建一个Intent
        Intent intent = new Intent();
        intent.setPackage(packageName);
        
        // 设置Action和数据
        intent.setAction("com.example.shareduidapp2.ACTION_SHARE_DATA");
        intent.putExtra("data", data);
        
        // 发送广播
        sendBroadcast(intent);
    }
}

java
public class MyBroadcastReceiver extends BroadcastReceiver {
    ...
    
    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        
        if ("com.example.shareduidapp2.ACTION_SHARE_DATA".equals(action)) {
            String data = intent.getStringExtra("data");
            
            // 处理共享的数据
            Toast.makeText(context, "Received data: " + data, Toast.LENGTH_SHORT).show();
        }
    }
}