java - 执行savedInstanceState.containsKey()时崩溃

Question

使用此代码时出现崩溃:

if (!savedInstanceState.containsKey("mybool")) {
    //  my code
}

我的onCreate():

@Override
protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);}

我的代码中的其他地方:

savedInstanceState.putBoolean("mybool", true);  

Answer 1

savedInstanceState 首次启动 Activity 时将为 null。

重新创建 Activity 后，

savedInstanceState 将不会为 null(例如，由于配置更改，系统会终止应用程序的进程) .

@Override
protected void onCreate(Bundle savedInstanceState) {
    if (null == savedInstanceState) {
        // activity is being launched first time
    } else {
        // is called after configuration change or framework restore your app
    }
}