java - 在Android上单击手机硬件后退按钮时从未调用过onResume？

Question

我面临这个问题，我有MainActivity和SettingsPreference，所以当我从设置返回到MainActivity时，我想在MainActivity上重新加载适配器，我使用onResume()，当我单击ActionBar后退按钮时，它工作得很好，但是当我尝试时它位于硬件后退按钮上，它从未被调用，我发现系统调用 onPostResume() 而不是 onResume()，因此尝试使用它，但更改从未被应用

this is the SettingsActivity i'm using

当按下 ActionBar 后退按钮时，此代码起作用

      @Override
          protected void onResume() {
              super.onResume();
              dataFromSharedPrefrence = getSettingsSharedPreferences();
              adapterExample.notifyDataSetChanged();

          }

按下硬件后退按钮时系统会调用 onPostResume()，但更改从未应用

@Override
        protected void onPostResume() {
              super.onPostResume();
              dataFromSharedPrefrence = getSettingsSharedPreferences();
              adapterExample.notifyDataSetChanged();
}

这是设置 Activity

public class SettingsActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.settings_activity);
        getSupportFragmentManager()
                .beginTransaction()
                .replace(R.id.settings, new SettingsFragment())
                .commit();
        ActionBar actionBar = getSupportActionBar();
        if (actionBar != null) {
            actionBar.setDisplayHomeAsUpEnabled(true);
        }
    }


    public static class SettingsFragment extends PreferenceFragmentCompat {
        @Override
        public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
            setPreferencesFromResource(R.xml.root_preferences, rootKey);
        }
    }

当我重写生命周期方法时，我发现了这种差异

1. 按下 ActionBar 按钮时，这是输出

2020-05-05 06:00:44.899 23467-23467/com.example.test E/MainActivity: onDestroy
2020-05-05 06:00:44.907 23467-23467/com.example.test E/MainActivity: onDetachedFromWindow
2020-05-05 06:00:44.964 23467-23467/com.example.test E/MainActivity: onCreateView
2020-05-05 06:00:44.990 23467-23467/com.example.test E/MainActivity: onCreateView
2020-05-05 06:00:45.009 23467-23467/com.example.test E/MainActivity: onCreateView
2020-05-05 06:00:45.015 23467-23467/com.example.test E/MainActivity: onCreateView
2020-05-05 06:00:45.037 23467-23467/com.example.test E/MainActivity: onContentChanged
2020-05-05 06:00:45.048 23467-23467/com.example.test E/MainActivity: onStart
2020-05-05 06:00:45.051 23467-23467/com.example.test E/MainActivity: onPostCreate
2020-05-05 06:00:45.053 23467-23467/com.example.test E/MainActivity: onResume
2020-05-05 06:00:45.056 23467-23467/com.example.test E/MainActivity: onPostResume
2020-05-05 06:00:45.078 23467-23467/com.example.test E/MainActivity: onAttachedToWindow
2020-05-05 06:00:45.141 23467-23467/com.example.test E/MainActivity: onCreateView
2020-05-05 06:00:45.188 23467-23467/com.example.test E/MainActivity: onCreateView
2020-05-05 06:00:45.223 23467-23467/com.example.test E/MainActivity: onCreateView

当按下硬件后退按钮时，这是输出

2020-05-05 06:01:21.732 23467-23467/com.example.test E/MainActivity: onRestart
2020-05-05 06:01:21.734 23467-23467/com.example.test E/MainActivity: onStart
2020-05-05 06:01:21.738 23467-23467/com.example.test E/MainActivity: onResume
2020-05-05 06:01:21.739 23467-23467/com.example.test E/MainActivity: onPostResume

Answer 1

试试这个:

不要使用onResume()，而是尝试onStart():

  @Override
      protected void onStart() {
          super.onStart();
          dataFromSharedPrefrence = getSettingsSharedPreferences();
          adapterExample.notifyDataSetChanged();

      }