当我在android java中单击按钮时，当mainactivity在top view activity中不活动时，剪贴板数据返回null
我读过关于android10和更高版本的限制，但我的活动不是后台服务。我需要得到剪贴板数据时，我点击按钮位于顶部视图的活动，如谷歌翻译应用程序。在我的例子中，当mainactivity处于非活动状态时，剪贴板返回null。

https://developer.android.com/about/versions/10/privacy/changes#clipboard-数据

public class MainActivity extends BridgeActivity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // Initializes the Bridge
        this.init(savedInstanceState, new ArrayList<Class<? extends Plugin>>() {{
          // Additional plugins you've installed go here
          // Ex: add(TotallyAwesomePlugin.class);
        }});

        startActivity(new Intent(MainActivity.this, FloatingWindow.class));
    }
}

public class FloatingWindow extends Activity {
// ... additional code ....
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        floatingButtonDefinedInClass.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                try {
                    self.getClipboardText(); 
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        });
    }

    public void getClipboardText() throws IOException {
        try {
            ClipboardManager myClipboard = (ClipboardManager)getSystemService(CLIPBOARD_SERVICE);
            ClipData clipData = myClipboard.getPrimaryClip();
            if(clipData != null) {
                text = (String) clipData.getItemAt(0).getText();
                System.out.println(text); // returns null when mainactivity is not active 
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }    
// ... additional code ....
}