Question

我在调试涉及方向更改和一些空返回的情况时遇到困难。

我的问题分为：

1）当方向改变时，会执行Activity的生命周期回调。

2）当方向改变时，会执行Fragment生命周期的哪些回调。

3）如果我们合并第2点和第3点（通常是覆盖Activity的片段的情况），对于具有片段的Activity（执行流程？），回调执行流程是什么。

修改

如果在android清单文件中没有定义configChanges，那么就可以解决这个问题：

如果发生任何未选择由该属性报告的配置更改，则系统将停止并重新启动活动（而不是使用新配置启动），而不是报告它。

活动和片段的生命周期回调将被执行？

Answer 1

首先，在 AndroidManifest 中将其添加到您的活动中：android:configChanges="orientation"

1）。 onConfigurationChanged
2）。没什么，但你可以实施你的方法并通过onConfigurationChanged的活动来调用它 3）。流程为Activity.onConfigurationChanged -> Fragment.yourMethod

希望这有帮助。

<强>已更新

以下是您第一次开始活动时的流程：

Activity.onCreate
Activity.onStart
Fragment.onAttach
  Fragment.onCreate
Fragment.onCreateView
  Fragment.onViewStateRestored
Fragment.onStart
  Activity.onResume
Fragment.onResume

以下是改变方向后的流程：

Activity.onPause
Fragment.onPause
  Activity.onSaveInstanceState
Fragment.onSaveInstanceState
  Activity.onStop
Fragment.onStop
Activity.onDestroy
  Fragment.onDestroy
Fragment.onDetach
Fragment.onAttach
  Fragment.onCreate
Activity.onCreate
Activity.onStart
  Fragment.onCreateView
Fragment.onViewStateRestored
  Fragment.onStart
Activity.onRestoreInstanceState
  Activity.onResume
Fragment.onResume

以下是检查它的代码：

public class FooActivity extends FragmentActivity {

    private static final String LOG_TAG = FooActivity.class.getSimpleName() + "_TAG";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Log.i(LOG_TAG, "Activity.onCreate");
        setContentView(R.layout.activity_foo);
        if (savedInstanceState == null) {
            getSupportFragmentManager().beginTransaction()
                    .add(R.id.container, new BarFragment())
                    .commit();
        }
    }


    @Override
    protected void onPause() {
        Log.i(LOG_TAG, "Activity.onPause");
        super.onPause();
    }

    @Override
    protected void onStop() {
        Log.i(LOG_TAG, "Activity.onStop");
        super.onStop();
    }

    @Override
    protected void onDestroy() {
        Log.i(LOG_TAG, "Activity.onDestroy");
        super.onDestroy();
    }

    @Override
    protected void onResume() {
        Log.i(LOG_TAG, "Activity.onResume");
        super.onResume();
    }

    @Override
    protected void onStart() {
        Log.i(LOG_TAG, "Activity.onStart");
        super.onStart();
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        Log.i(LOG_TAG, "Activity.onConfigurationChanged");
        super.onConfigurationChanged(newConfig);
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        Log.i(LOG_TAG, "Activity.onSaveInstanceState");
        super.onSaveInstanceState(outState);
    }

    @Override
    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        Log.i(LOG_TAG, "Activity.onRestoreInstanceState");
        super.onRestoreInstanceState(savedInstanceState);
    }

    /**
     * A placeholder fragment containing a simple view.
     */
    public static class BarFragment extends Fragment {

        public BarFragment() {
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                 Bundle savedInstanceState) {
            Log.i(LOG_TAG, "Fragment.onCreateView");
            View rootView = inflater.inflate(R.layout.fragment_bar, container, false);
            return rootView;
        }

        @Override
        public void onCreate(Bundle savedInstanceState) {
            Log.i(LOG_TAG, "Fragment.onCreate");
            super.onCreate(savedInstanceState);
        }

        @Override
        public void onAttach(Activity activity) {
            Log.i(LOG_TAG, "Fragment.onAttach");
            super.onAttach(activity);
        }

        @Override
        public void onViewStateRestored(Bundle savedInstanceState) {
            Log.i(LOG_TAG, "Fragment.onViewStateRestored");
            super.onViewStateRestored(savedInstanceState);
        }

        @Override
        public void onSaveInstanceState(Bundle outState) {
            Log.i(LOG_TAG, "Fragment.onSaveInstanceState");
            super.onSaveInstanceState(outState);
        }

        @Override
        public void onResume() {
            Log.i(LOG_TAG, "Fragment.onResume");
            super.onResume();
        }

        @Override
        public void onStart() {
            Log.i(LOG_TAG, "Fragment.onStart");
            super.onStart();
        }

        @Override
        public void onConfigurationChanged(Configuration newConfig) {
            Log.i(LOG_TAG, "Fragment.onConfigurationChanged");
            super.onConfigurationChanged(newConfig);
        }

        @Override
        public void onPause() {
            Log.i(LOG_TAG, "Fragment.onPause");
            super.onPause();
        }

        @Override
        public void onStop() {
            Log.i(LOG_TAG, "Fragment.onStop");
            super.onStop();
        }

        @Override
        public void onDetach() {
            Log.i(LOG_TAG, "Fragment.onDetach");
            super.onDetach();
        }

        @Override
        public void onDestroy() {
            Log.i(LOG_TAG, "Fragment.onDestroy");
            super.onDestroy();
        }
    }
}

Answer 2

onConfigurationChanged（）方法

@Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
// Checks the orientation of the screen
if (newConfig.orientation == Configuration.ORIENTATION_LANDSCAPE) {
    Toast.makeText(this, "landscape", Toast.LENGTH_SHORT).show();
} else if (newConfig.orientation == Configuration.ORIENTATION_PORTRAIT){
    Toast.makeText(this, "portrait", Toast.LENGTH_SHORT).show();
 }  }

在AndroidManifest.xml中添加此代码

<activity android:name=".MyActivity"
      android:configChanges="orientation|keyboardHidden"
      android:label="@string/app_name">

您还可以查看这些Activity和Fragment

更改Android方向时会执行哪些Activity的生命周期回调？

2 个答案: