Question

我尝试了一个代码来检测手机上任何地方的长按。这是怎么回事：

WindowManager wm;
View myview;
LayoutInflater li;

@Override
public IBinder onBind(Intent intent) {
    // TODO Auto-generated method stub
    return null;
}

@Override
public void onCreate() {
    // TODO Auto-generated method stub
    super.onCreate();
    System.out.println("\n=\n=\n=\n" + "oncreate service" + "\n=\n=\n=\n");

    li = (LayoutInflater) getSystemService(LAYOUT_INFLATER_SERVICE);
    wm = (WindowManager) getSystemService(WINDOW_SERVICE);

    WindowManager.LayoutParams params = new WindowManager.LayoutParams(
            //WindowManager.LayoutParams.TYPE_INPUT_METHOD |
            WindowManager.LayoutParams.TYPE_SYSTEM_OVERLAY,// | WindowManager.LayoutParams.TYPE_SYSTEM_ALERT,
            WindowManager.LayoutParams.FLAG_WATCH_OUTSIDE_TOUCH | WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL,
            PixelFormat.TRANSLUCENT);
    System.out.println("\n=\n=\n=\n" + "lp " + params + "\n=\n=\n=\n");

    params.gravity = Gravity.RIGHT | Gravity.TOP;
    myview = li.inflate(R.layout.traslucent, null);
    System.out.println("\n=\n=\n=\n" + "View inflated" + "\n=\n=\n=\n");

    System.out.println("\n=\n=\n=\n" + "Layout inflator = " + li + "\nWindow manager = " + wm + "\nparams = " + params + "\nView = " + myview + "\n=\n=\n=\n");


    myview.setOnLongClickListener(this);
    System.out.println("\n=\n=\n=\n" + "On touch listener" + "\n=\n=\n=\n");

    wm.addView(myview, params);
    System.out.println("\n=\n=\n=\n" + "add view" + "\n=\n=\n=\n");


}


@Override
public void onDestroy() {
    // TODO Auto-generated method stub
    super.onDestroy();
    wm.removeView(myview);
    myview=null;
}


@Override
public boolean onLongClick(View arg0) {
    // TODO Auto-generated method stub
    Toast.makeText(getApplicationContext(), "LongPress", Toast.LENGTH_SHORT).show();
    return false;
}

它没有检测到longpress但是我尝试了一个类似的活动代码，它运行得很好。这是代码：

public class testlongpress extends Activity实现OnLongClickListener，OnClickListener {

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    LayoutInflater li = (LayoutInflater) getApplicationContext().getSystemService(LAYOUT_INFLATER_SERVICE);
    View v = li.inflate(R.layout.test_layout, null);
    v.setOnLongClickListener(this);
    setContentView(v);
}

@Override
public boolean onLongClick(View arg0) {
    // TODO Auto-generated method stub
    Toast.makeText(getApplicationContext(), "LongPress", Toast.LENGTH_SHORT).show();
    return true;
    }
}

我的问题是为什么它不是在开展活动而不是服务？

Answer 1

根据Android Docs

服务是一种应用程序组件，可以在后台执行长时间运行的操作，但不提供用户界面。另一个应用程序组件可以启动服务，即使用户切换到另一个应用程序，它也将继续在后台运行。

您无法在服务上进行UI操作，屏幕上显示的视图由Activity的UI而非服务组成。

有关详细信息，请查看服务上的official documentation。

长按功能不适用于服务？

1 个答案: