Handler 的 postDelayed 回调：检查 FragmentActivity 是否不为 null 且未被销毁？

Question

我写了这个class:

public class SplashScreen extends AppCompatActivity {

    private Handler the_transition_handler;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.splash_screen);
    }

    @Override
    protected void onStart() {
        super.onStart();
        startTheTransitionAfterTheSplashScreen();
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        the_transition_handler.removeCallbacksAndMessages(null);
    }

    private void startTheTransitionAfterTheSplashScreen() {
        the_transition_handler = new Handler();
        the_transition_handler.postDelayed(new Runnable() {
            @Override
            public void run() {
                final Intent intentSplashScreenToActivityJustAfterSplashScreen = new Intent(SplashScreen.this, ActivityJustAfterSplashScreen.class);
                startActivity(intentSplashScreenToActivityJustAfterSplashScreen);
                overridePendingTransition(R.anim.animation_enter_activity, R.anim.animation_leave_activity);
                finish();
            }
        }, 1000);
    }
}

我的问题是：由于 run 回调是在我指定的时间之后执行的（根据此文档：https://developer.android.com/reference/android/os/Handler），我是否应该将其内容替换为以下代码（假设that 是 AppCompatActivity)?

@Override
public void run() {

    if(that == null || that.isDestroyed()) {
        return;
    }

    final Intent intentSplashScreenToActivityJustAfterSplashScreen = new Intent(SplashScreen.this, ActivityJustAfterSplashScreen.class);
    startActivity(intentSplashScreenToActivityJustAfterSplashScreen);
    overridePendingTransition(R.anim.animation_enter_activity, R.anim.animation_leave_activity);
    finish();
}

请注意，Android Studio 表示 that == null 始终为错误，应将其删除。

Answer 1

使用 isDestroyed() || isFinishing() 或仅调用 removeCallbacksAndMessages 删除任何待处理的回调帖子：

@Override
    protected void onDestroy() {
        if (the_transition_handler != null) {
            the_transition_handler.removeCallbacksAndMessages(null);
        }
        super.onDestroy();
    }

Handler 的 postDelayed 回调：检查 FragmentActivity 是否不为 null 且未被销毁？

Handler's postDelayed's callback: Checking if the FragmentActivity is not null and not destroyed?

android

android-activity

android-handler