【Android】在Activity中使用LifecycleScope替代GlobalScope

绝地灬酷狼 2022-12-11 13:43 240阅读 0赞

# GlobalScope的问题 #

我们在Activity或Fragment中使用协程时，要尽量避免使用`GlobalScope`。

class MainActivity : AppCompatActivity() { 
        override fun onCreate(savedInstanceState: Bundle?) { 
            super.onCreate(savedInstanceState)
            setContentView(R.layout.activity_main)
            setSupportActionBar(toolbar)
    
            GlobalScope.launch {  
                val data = withContext(Dispatchers.IO) { 
                    loadData()
                }
                initUi(data)
            }
        }
        ...
    }

`GlobalScope`是生命周期是process级别的，所以上面的例子中，即使Activity或Fragment已经被销毁，协程仍然在执行。

# 解决方法 #

使用`androidx.lifecycle:lifecycle-runtime-ktx:2.2.0-alpha01`或更高版本，会用`LifecycleScope`代替`GlobalScope`

class MainActivity : AppCompatActivity() { 
        override fun onCreate(savedInstanceState: Bundle?) { 
            super.onCreate(savedInstanceState)
            setContentView(R.layout.activity_main)
            setSupportActionBar(toolbar)
    
            lifecycleScope.launch {  
                val data = withContext(Dispatchers.IO) { 
                    loadData()
                }
                initUi(data)
            }
        }
        ...
    }

class MyFragment: Fragment() { 
        override fun onViewCreated(view: View, savedInstanceState: Bundle?) { 
            super.onViewCreated(view, savedInstanceState)
            viewLifecycleOwner.lifecycleScope.launch {  
                val data = withContext(Dispatchers.IO) { 
                    loadData()
                }
                initUi(data)
            }
        }
        ...
    }

参考 [https://developer.android.com/topic/libraries/architecture/coroutines][https_developer.android.com_topic_libraries_architecture_coroutines]

[https_developer.android.com_topic_libraries_architecture_coroutines]: https://developer.android.com/topic/libraries/architecture/coroutines