Question

我的Android应用程序遇到了非常令人不安的麻烦。我正在使用Fragments。每个片段都包含一个用于Portrait UI和Landscape UI的单独XML文件。

如果我从片段“InputFragment”移动到片段“OutputFragment”，如果我现在旋转设备，片段会变为“InputFragment”!!这意味着，应用程序将在轮换时返回到上一个片段！但是，这不是应该发生的事情。如果我在设备处于纵向状态时旋转设备，那么它应该调用相同片段的横向UI，反之亦然。

以下是代码。我只显示代码的结构，因为所有其他的都是变量声明和赋值等。

InputFragment.java

public class InputFragment extends Fragment {

    //Declaring variables. CODE REMOVED




    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
    {
        //Intializing instance variables. CODE REMOVED

        view = inflater.inflate(R.layout.input, container,false);



        restoreStates(savedInstanceState);

        return view;

    }

    //This method will save the instances
    @Override
    public void onSaveInstanceState(Bundle savedInstanceStateBundle) 
    {
        super.onSaveInstanceState(savedInstanceStateBundle);

        try{

        }
        catch(NullPointerException e)
        {

        }
    }

    //This method will restore the instances
    @Override 
    public void onActivityCreated(Bundle savedInstanceStateBundle)
    {
        super.onActivityCreated(savedInstanceStateBundle);

        if(savedInstanceStateBundle!=null)
        {
        }
    }

    //Action Listener for the Submit Bar
    private class SubmitButtonAction implements OnClickListener
    {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            try {
                //Put the JSON. Calling to the JSON handling class. CODE REMOVED


            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace(); 
            }

            Fragment frag = new OutputFragment();

            FragmentTransaction ft = getFragmentManager().beginTransaction();   
            ft.replace(R.id.fragment_container, frag);
            ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
            ft.addToBackStack(null);
            ft.commit();



        }

    }



    private void restoreStates(Bundle savedInstanceStateBundle)
    {
        if(savedInstanceStateBundle!=null)
        {

        }
    }




}

OutputFragment.Java

public class OutputFragment extends Fragment implements AsyncResponse{

    //Delclaring variables. CODE REMOVED


    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
    {
        //Intializing instance variables. CODE REMOVED
        view = inflater.inflate(R.layout.output, container,false);


        return view;

    }


    //ActionListener for the manual back button
    private class BackButtonAction implements OnClickListener
    {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            FragmentManager fm = getFragmentManager(); 
            fm.popBackStackImmediate();

        }

    }


    @Override
    public void processFinish(String output) {
        // TODO Auto-generated method stub
        Log.d("OUTPUT_FRAGMENT", output);

        try {





            progressDialog.dismiss();

        } catch (JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

}

MainActivity.java

    import android.os.Bundle;
    import android.app.Activity;
    import android.content.Intent;
    import android.support.v4.app.Fragment;
    import android.support.v4.app.FragmentActivity;
    import android.support.v4.app.FragmentTransaction;
    import android.view.Menu;
    import android.view.Window;

    public class MainActivity extends FragmentActivity {

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            this.requestWindowFeature(Window.FEATURE_NO_TITLE);
            setContentView(R.layout.activity_main);


            Fragment frag = new InputFragment();

            FragmentTransaction ft = getSupportFragmentManager().beginTransaction();    
            ft.replace(R.id.fragment_container, frag);
            ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
            ft.addToBackStack(null);
            ft.commit();
        }

        @Override
        public boolean onCreateOptionsMenu(Menu menu) {
            // Inflate the menu; this adds items to the action bar if it is present.
            getMenuInflater().inflate(R.menu.main, menu);
            return true;
        }



}

清单文件

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.xxx.xxx"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-permission android:name="android.permission.INTERNET" />

    <uses-sdk
        android:minSdkVersion="11"
        android:targetSdkVersion="18" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/xxx_logo"
        android:label="@string/xxx"
        android:theme="@style/AppTheme">
        <activity
            android:name="com.xxx.xxx.MainActivity"
            android:configChanges="keyboardHidden|screenLayout|orientation|screenSize"
            android:label="@string/xxx" >

        </activity>
        <activity
            android:name="com.xxx.xxx.SplashScreen"
            android:configChanges="keyboardHidden|screenLayout|orientation|screenSize"
            android:label="@string/xxx" >

            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

搜索了几个小时后，我找到了解决方案来解决这个问题。也就是说，将代码android:configChanges="keyboardHidden|screenLayout|orientation|screenSize"添加到清单文件中。

现在，Fragment不会移动到Rotation上的前一个片段，但是，它也不会加载Other布局！这意味着，如果我将手机从纵向旋转到横向，它不会加载“横向”用户界面，反之亦然！它只是试图将自己调整到视图并且它不好，因为在不加载其他相关UI的情况下，图像和所有内容都会显示得很糟糕。这里发生了什么？

Answer 1

旋转后，您的Activity将被重新创建并调用其onCreate()方法。你想要做的是检查活动是否是第一次启动，然后用InputFragment替换你的片段。在Activity第一次创建savedInstanceState为null，所以你可以这样做：

if(savedInstanceState == null) {
    // replace fragment 
}

修改

这就是您的onCreate()活动应该如何显示：

@Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); this.requestWindowFeature(Window.FEATURE_NO_TITLE); setContentView(R.layout.activity_main); if(savedInstanceState == null) { Fragment frag = new InputFragment(); FragmentTransaction ft = getSupportFragmentManager().beginTransaction(); ft.replace(R.id.fragment_container, frag); ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE); ft.addToBackStack(null); ft.commit(); } }

现在，在方向更改活动中不会替换您的片段，您不需要在Manifest中设置任何attrs

不要在旋转时加载相关的横向/纵向布局

1 个答案: