java - 单击项目时 ListView 在纵向模式下崩溃(使用 fragment )

Question

我在我的应用中使用 fragment 布局，这个应用包含一个 ListView 。单击项目将完成一些工作。在横向模式下工作正常，但如果在纵向模式下单击项目会崩溃。可能是什么问题？

这是我的代码:

MainAcitivity.java

package com.example.newfragment;

import android.content.res.Configuration;

import android.os.Bundle;

import android.support.v4.app.FragmentActivity;

import android.widget.Toast;


public class MainActivity extends FragmentActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);

        /*/ Checks the orientation of the screen
        if (newConfig.orientation == Configuration.ORIENTATION_LANDSCAPE) {
            setContentView(R.layout.activity_main);
            Toast.makeText(this, "landscape", Toast.LENGTH_SHORT).show();
        } else if (newConfig.orientation == Configuration.ORIENTATION_PORTRAIT){
            setContentView(R.layout.activity_main);
            Toast.makeText(this, "portait", Toast.LENGTH_SHORT).show();
        }*/


    }



}

MenuFragment.java //显示 ListView

    package com.example.newfragment;
    import java.io.File;
    import java.util.ArrayList;

    import android.support.v4.app.ListFragment;
    import android.os.Bundle;
    import android.os.Environment;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.ArrayAdapter;
    import android.widget.ListView;

    public class MenuFragment extends ListFragment {

    int i; 

    private String[] FilePathStrings;
    private String[] FileNameStrings;
     File[] listFile;//for photo
    String[] name = new String[] 
            { "Sri","Sud","Urmila","Amrita","Indra","Ayan",
            "Leo","Neymar","Robin","Ian","Suarez","Mesut","Bastin",
            "Rooney","Ranti","Dong Hyun","Barisich","Andrew" };

    String[] address = new String[]
            {"Dumdum","Dumdum","Dumdum","Dumdum","Lake Town",
            "Salkia","Argentina","Brazil","Netherlands"};

    String [] mobile = new String[]{"456456456","56564565","787687866",
                "645645645","5654576457","76897978978","768768567"};



    String [] photo = new String[]{};



    @Override
    public View onCreateView(LayoutInflater inflater,ViewGroup container, Bundle savedInstanceState) {
        View view =inflater.inflate(R.layout.list_fragment, container, false);
        ArrayAdapter<String> adapter = new ArrayAdapter<String>(getActivity(),
                android.R.layout.simple_list_item_1, name);
        setListAdapter(adapter);

        return view;





    }



    /////////////////////sending data to TextFragment//////////////////
    @Override
    public void onListItemClick(ListView l, View v, int position, long id) {


        ///////////accessing files from sd card///////
         File file = new  File(Environment.getExternalStorageDirectory() +"/Frag_list/");
         if (file.isDirectory()) {
            listFile = file.listFiles();

            // Create a String array for FilePathStrings
            FilePathStrings = new String[listFile.length];


            for (i = 0; i < listFile.length; i++) {
                // Get the path of the image file
                FilePathStrings[i] = listFile[i].getAbsolutePath();

            }
        }

       //////////////////////////////


        TextFragment txt = (TextFragment)getFragmentManager().findFragmentById(R.id.fragment2);
        txt.change(position,address[position],mobile[position]);
        getListView().setSelector(android.R.color.holo_blue_dark);


    }
}

TextFragment.java //用于点击项目时的操作

  package com.example.newfragment;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FilenameFilter;
import java.io.InputStream;

import android.R.string;
import android.support.v4.app.Fragment;
import android.app.Activity;
import android.content.ContentResolver;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.PixelFormat;
import android.hardware.Camera;
import android.hardware.Camera.Parameters;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;


public class TextFragment extends Fragment implements OnClickListener {
    TextView text,add;
    private ImageView img;
    Button b;
    int value;
    String mobile;
    File photo;
    private static final int CAMERA_REQUEST = 1888; 
    Camera camera;


    ////////////data received here////////////
    public void change(int txt, String txt1, String txt2 ){


        add.setText(txt1 );
        value = txt;
        mobile = txt2;

        //photo = f;
        //File image = new  File(Environment.getExternalStorageDirectory() +"/Frag_list/"+value+".jpg"); 

        /*if(photo.exists())
        {
            img.setImageBitmap(BitmapFactory.decodeFile(photo.getAbsolutePath()));
        }
        else
            img.setImageResource(R.drawable.ic_launcher);*/

    }

    @Override

    public View onCreateView(LayoutInflater inflater,ViewGroup container, Bundle savedInstanceState) {

        View view = inflater.inflate(R.layout.text_fragment, container, false);
        //text= (TextView) view.findViewById(R.id.AndroidOs);
        add= (TextView)view.findViewById(R.id.address);
        img= (ImageView)view.findViewById(R.id.img);

        //////////////////
        /*File image = new  File(Environment.getExternalStorageDirectory() +"/Frag_list/"+value+".jpg"); 
        if(image.exists())
            {

                     img.setImageBitmap(BitmapFactory.decodeFile(image.getAbsolutePath()));/////////////setting image in imageview
            }*/


        //////////////////////
        b= (Button)view.findViewById(R.id.b);

        img.setOnClickListener(this);
        b.setOnClickListener(this);



        return view;

    }



    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        if(v.equals(img))
        {
            //Toast.makeText(getContext(), "Camera", Toast.LENGTH_LONG).show();


            /*///////////camera hardware///////////
            Parameters parameters = camera.getParameters();//////////////PROBLEM: APP GETTING CRASHED WHEN USED
            parameters.setPictureSize(80, 80);
            camera.setParameters(parameters);
            camera = Camera.open();
            ///////////////////////////////////////*/



            /*Clicking and saving image to sd card*/
            //////////////////////////////////////
            File file = new File(Environment.getExternalStorageDirectory(), "Frag_list");
            file.mkdirs();

            String path = Environment.getExternalStorageDirectory() +"/Frag_list/"+value+".jpg";
            File file2= new File(path);
            Uri outputFileUri = Uri.fromFile( file2 );
            Intent intent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE );
            //intent.putExtra("android.media.action.IMAGE_CAPTURE", outputFileUri ); ///////for displaying image
            intent.putExtra( MediaStore.EXTRA_OUTPUT, outputFileUri ); //////////for saving image

            /*Bundle b = new Bundle();
            b.putString("android.media.action.IMAGE_CAPTURE", outputFileUri);*/

            startActivityForResult( intent, CAMERA_REQUEST );
            /////////////////////////////////////



        }

        if(v.equals(b))
        {
            //Toast.makeText(getContext(), "mobile:"+mobile, Toast.LENGTH_LONG).show();

            /*Calling number*/
            ////////////////////////////////////////////////
            Uri number = Uri.parse("tel:" +mobile);
            Intent callIntent = new Intent(Intent.ACTION_CALL, number);
            startActivity(callIntent);
            ////////////////////////////////////////////////

        }

    }

    ///setting image in display
    ///////////////////////////////////////////////////////////
     public void onActivityResult(int requestCode, int resultCode, Intent data) {  
            if (requestCode == CAMERA_REQUEST && resultCode == Activity.RESULT_OK) 
            {  
                /*if (data != null) {


                    File photo = new File(Environment.getExternalStorageDirectory()+"/Frag_list/"+value+".jpg");  

                    Uri imgUri=Uri.fromFile(photo);
                    img.setImageURI(imgUri);

                    /*
                    img.setImageBitmap((Bitmap) data.getExtras().get("data")); // this is image view where you want to set image
                    Log.d("camera ---- > ", "" + data.getExtras().get("data"));

                }*/

                File image = new  File(Environment.getExternalStorageDirectory() +"/Frag_list/"+value+".jpg"); 
                if(image.exists()){

                         img.setImageBitmap(BitmapFactory.decodeFile(image.getAbsolutePath()));/////////////setting image in imageview
            }

            }


        }
     ////////////////////*/


}

AndroidManifest.xml

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

    <uses-sdk
        android:minSdkVersion="14"
        android:targetSdkVersion="21" />

     <uses-permission android:name="android.permission.CAMERA" />
     <uses-feature android:name="android.hardware.camera"  android:required="false" />
     <uses-feature android:name="android.hardware.camera.autofocus" />
     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
     <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
     <uses-permission android:name="android.permission.CALL_PHONE" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        >
        <activity
            android:name=".MainActivity"
            android:configChanges="orientation" 
             >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

    </application>

</manifest>

逻辑猫

    10-05 11:07:06.480: E/AndroidRuntime(4921): FATAL EXCEPTION: main
10-05 11:07:06.480: E/AndroidRuntime(4921): java.lang.NullPointerException
10-05 11:07:06.480: E/AndroidRuntime(4921):     at com.example.newfragment.TextFragment.change(TextFragment.java:48)
10-05 11:07:06.480: E/AndroidRuntime(4921):     at com.example.newfragment.MenuFragment.onListItemClick(MenuFragment.java:85)
10-05 11:07:06.480: E/AndroidRuntime(4921):     at android.support.v4.app.ListFragment$2.onItemClick(ListFragment.java:58)
10-05 11:07:06.480: E/AndroidRuntime(4921):     at android.widget.AdapterView.performItemClick(AdapterView.java:298)
10-05 11:07:06.480: E/AndroidRuntime(4921):     at android.widget.AbsListView.performItemClick(AbsListView.java:1128)
10-05 11:07:06.480: E/AndroidRuntime(4921):     at android.widget.AbsListView$PerformClick.run(AbsListView.java:2815)
10-05 11:07:06.480: E/AndroidRuntime(4921):     at android.widget.AbsListView$1.run(AbsListView.java:3574)
10-05 11:07:06.480: E/AndroidRuntime(4921):     at android.os.Handler.handleCallback(Handler.java:800)
10-05 11:07:06.480: E/AndroidRuntime(4921):     at android.os.Handler.dispatchMessage(Handler.java:100)
10-05 11:07:06.480: E/AndroidRuntime(4921):     at android.os.Looper.loop(Looper.java:194)
10-05 11:07:06.480: E/AndroidRuntime(4921):     at android.app.ActivityThread.main(ActivityThread.java:5371)
10-05 11:07:06.480: E/AndroidRuntime(4921):     at java.lang.reflect.Method.invokeNative(Native Method)
10-05 11:07:06.480: E/AndroidRuntime(4921):     at java.lang.reflect.Method.invoke(Method.java:525)
10-05 11:07:06.480: E/AndroidRuntime(4921):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:833)
10-05 11:07:06.480: E/AndroidRuntime(4921):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
10-05 11:07:06.480: E/AndroidRuntime(4921):     at dalvik.system.NativeStart.main(Native Method)

ActivityMain.xml

    <?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <fragment
        android:id="@+id/list_Fragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_weight="1"
        class="com.example.newfragment.MenuFragment" >
    </fragment>

</LinearLayout>

ActivityMain.xml landscpae

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal"
    tools:context="com.example.newfragment.MainActivity">


    <fragment
        android:layout_height="match_parent"
        android:layout_width="0dp"
        android:layout_weight="1"
        class="com.example.newfragment.MenuFragment"
        android:id="@+id/fragment"/>
    <fragment
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="2"
        class="com.example.newfragment.TextFragment"
        android:id="@+id/fragment2"/>




</LinearLayout>

ListFragment.xml //用于 ListView

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <ListView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@android:id/list" />
</LinearLayout>

TextFragment.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent"
    android:background="#5ba4e5"
    >
    <ImageView
                android:id="@+id/img"
                android:layout_width="100dp"
                android:layout_height="100dp"
                android:layout_marginTop="20dp"
                android:layout_marginLeft="30dp"
                android:onClick="imageClick"
                android:src="@drawable/ic_launcher"
                 />

    <TableLayout
        android:id="@+id/tb"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
         >

        <TableRow>

            <TextView
                android:id="@+id/address"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Address"
                android:textColor="#ffffff"
                android:textSize="20sp"
                android:layout_marginLeft="40dp"
                android:layout_marginTop="30dp" />
        </TableRow>

        <TableRow
            android:layout_width="match_parent"
            android:layout_height="match_parent" >

            <Button
                android:id="@+id/b"
                android:layout_marginLeft="40dp"
                android:layout_marginTop="30dp"
                android:layout_span="2"
                android:background="#ffffff"
                android:text="Mobile"

                android:textColor="#000000" />
        </TableRow>
    </TableLayout>

</LinearLayout>

截图

Current situation of the portait mode after following the suggestions suggested in the answers:

更新

当前处于<​​strong>纵向模式时，我能够克服崩溃问题并在单击 ListView 中的项目后移至下一个屏幕，但 View 返回 null那里;表示我想在那里显示的内容(屏幕截图的蓝色部分)没有显示，屏幕是空白的。

这是更新后的代码:

MenuFragment.java

public class MenuFragment extends ListFragment {

    int i; 

    private String[] FilePathStrings;
    private String[] FileNameStrings;
     File[] listFile;//for photo
    String[] name = new String[] 
            { "Sri","Sud","Urmila","Amrita","Indra","Ayan",
            "Leo","Neymar","Robin","Ian","Suarez","Mesut","Bastin",
            "Rooney","Ranti","Dong Hyun","Barisich","Andrew" };

    String[] address = new String[]
            {"Dumdum","Dumdum","Dumdum","Dumdum","Lake Town",
            "Salkia","Argentina","Brazil","Netherlands"};

    String [] mobile = new String[]{"456456456","56564565","787687866",
                "645645645","5654576457","76897978978","768768567"};



    String [] photo = new String[]{};



    @Override
    public View onCreateView(LayoutInflater inflater,ViewGroup container, Bundle savedInstanceState) {
        View view =inflater.inflate(R.layout.list_fragment, container, false);
        ArrayAdapter<String> adapter = new ArrayAdapter<String>(getActivity(),
                android.R.layout.simple_list_item_1, name);
        setListAdapter(adapter);



        return view;


    }





    /////////////////////sending data to TextFragment//////////////////
    @Override
    public void onListItemClick(ListView l, View v, int position, long id) {

///////////accessing files from sd card///////
         File file = new  File(Environment.getExternalStorageDirectory() +"/Frag_list/");
         if (file.isDirectory()) {
            listFile = file.listFiles();

            // Create a String array for FilePathStrings
            FilePathStrings = new String[listFile.length];


            for (i = 0; i < listFile.length; i++) {
                // Get the path of the image file
                FilePathStrings[i] = listFile[i].getAbsolutePath();

            }
        }

         //////////////////////////////


        int orientation = getResources().getConfiguration().orientation; 
        if (Configuration.ORIENTATION_LANDSCAPE == orientation) { 
            //Do SomeThing; // Landscape




            TextFragment txt = (TextFragment)getFragmentManager().findFragmentById(R.id.fragment2);
            txt.change(position,address[position],mobile[position]);
            getListView().setSelector(android.R.color.holo_blue_dark);

        } else { 
            //Do SomeThing;  // Portrait
            //Toast.makeText(getContext(),address[position] , Toast.LENGTH_SHORT).show();

//////////////此处更新代码//////////////

        **Intent intent = new Intent(getActivity(), TextFragment2.class);
        Bundle bundle = new Bundle();
        bundle.putString("message", address[position]);
        intent.putExtras(bundle);
        getActivity().startActivity(intent);**





}

}  

TextFragment.java

public class TextFragment2 extends Activity implements OnClickListener {
    TextView text,add;
    private ImageView img;
    Button b;
    int value;
    String mobile,txt;
    File photo;
    private static final int CAMERA_REQUEST = 1888; 
    Camera camera;

 public View onCreateView(LayoutInflater inflater,ViewGroup container, Bundle savedInstanceState) {

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

        add= (TextView)view.findViewById(R.id.address);
        img= (ImageView)view.findViewById(R.id.img);

        //////////////////
        /*File image = new  File(Environment.getExternalStorageDirectory() +"/Frag_list/"+value+".jpg"); 
        if(image.exists())
            {

                     img.setImageBitmap(BitmapFactory.decodeFile(image.getAbsolutePath()));/////////////setting image in imageview
            }*/


        //////////////////////
        b= (Button)view.findViewById(R.id.b);

        img.setOnClickListener(this);
        b.setOnClickListener(this);

        //Intent intent = getActivity().getIntent();
        //String message = intent.getStringExtra("message");

////////////////////此处更新代码/////////////////

Bundle bundle= getIntent().getExtras(); txt= bundle.getString("消息");

    **add.setText(txt);**

    return view;

}



@Override
public void onClick(View v) {
    // TODO Auto-generated method stub
    if(v.equals(img))
    {
        //Toast.makeText(getContext(), "Camera", Toast.LENGTH_LONG).show();


        /*///////////camera hardware///////////
        Parameters parameters = camera.getParameters();//////////////PROBLEM: APP GETTING CRASHED WHEN USED
        parameters.setPictureSize(80, 80);
        camera.setParameters(parameters);
        camera = Camera.open();
        ///////////////////////////////////////*/



        /*Clicking and saving image to sd card*/
        //////////////////////////////////////
        File file = new File(Environment.getExternalStorageDirectory(), "Frag_list");
        file.mkdirs();

        String path = Environment.getExternalStorageDirectory() +"/Frag_list/"+value+".jpg";
        File file2= new File(path);
        Uri outputFileUri = Uri.fromFile( file2 );
        Intent intent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE );
        //intent.putExtra("android.media.action.IMAGE_CAPTURE", outputFileUri ); ///////for displaying image
        intent.putExtra( MediaStore.EXTRA_OUTPUT, outputFileUri ); //////////for saving image

        /*Bundle b = new Bundle();
        b.putString("android.media.action.IMAGE_CAPTURE", outputFileUri);*/

        startActivityForResult( intent, CAMERA_REQUEST );
        /////////////////////////////////////



    }

    if(v.equals(b))
    {
        //Toast.makeText(getContext(), "mobile:"+mobile, Toast.LENGTH_LONG).show();

        /*Calling number*/
        ////////////////////////////////////////////////
        Uri number = Uri.parse("tel:" +mobile);
        Intent callIntent = new Intent(Intent.ACTION_CALL, number);
        startActivity(callIntent);
        ////////////////////////////////////////////////

    }

}

///setting image in display
///////////////////////////////////////////////////////////
 public void onActivityResult(int requestCode, int resultCode, Intent data) {  
        if (requestCode == CAMERA_REQUEST && resultCode == Activity.RESULT_OK) 
        {  
            /*if (data != null) {


                File photo = new File(Environment.getExternalStorageDirectory()+"/Frag_list/"+value+".jpg");  

                Uri imgUri=Uri.fromFile(photo);
                img.setImageURI(imgUri);

                /*
                img.setImageBitmap((Bitmap) data.getExtras().get("data")); // this is image view where you want to set image
                Log.d("camera ---- > ", "" + data.getExtras().get("data"));

            }*/

            File image = new  File(Environment.getExternalStorageDirectory() +"/Frag_list/"+value+".jpg"); 
            if(image.exists()){

                     img.setImageBitmap(BitmapFactory.decodeFile(image.getAbsolutePath()));/////////////setting image in imageview
        }

        }


    }
 ////////////////////*/

---

破案

将 public View oncreateView 更改为 protected void onCreate! :)

public class TextFragment2 extends Activity implements OnClickListener {
    TextView text,add;
    private ImageView img;
    Button b;
    int value;
    String mobile,txt;
    File photo;
    private static final int CAMERA_REQUEST = 1888; 
    Camera camera;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.text_fragment);

        add= (TextView)findViewById(R.id.address);
        img= (ImageView)findViewById(R.id.img);

        b= (Button)findViewById(R.id.b);

        img.setOnClickListener(this);
        b.setOnClickListener(this);
        Bundle bundle= getIntent().getExtras();
        txt= bundle.getString("message");
        add.setText(txt);

    }

人像模式截图:

Answer 1

问题在这里:

TextFragment txt = (TextFragment)getFragmentManager().findFragmentById(R.id.fragment2);

您试图找到仅在 MainActivity 横向布局中的 R.id.fragment2，当您旋转到横向时它会找到 id fragment2，但是当您将设备旋转到纵向模式时找不到 id，因为它在 MainActivity 的纵向模式中不存在。