java - 将具有 Runnable 的处理程序升级为 lambda 表达式

Question

我想升级此代码以使用 lambda 表达式:

Handler handler = new Handler(Looper.getMainLooper());
handler.postDelayed(new Runnable() {
    @Override
    public void run() {
        missileX = ufoX;
        resetRecent();
        waitForUfoTimer = false;
    }
}, randomize(20000, 18000));

我用这种方式试过，但它没有编译:

Handler handler2 = new Handler(Looper.getMainLooper());
handler2.postDelayed(Runnable task = () -> {  
    missileX = ufoX;
    resetRecent();
    waitForUfoTimer = false; 
  }
}, randomize(20000, 18000));

哪里有一些说明可以让我学习如何操作？我必须猜测语法是荒谬的。

Answer 1

您不必声明要分配给 lambda 的变量。这足够了:

Handler handler2 = new Handler(Looper.getMainLooper());
handler2.postDelayed(() -> {  
    missileX = ufoX;
    resetRecent();
    waitForUfoTimer = false; 
  }
, randomize(20000, 18000));