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Java 通过listactivity中的（Intent putextra）传递数据不工作

java android

Java 通过listactivity中的（Intent putextra）传递数据不工作,java,android,android-intent,Java,Android,Android Intent,单击“打开新活动”时，我的listactivity每行形成5行 我为每一个设置了单独的类（对其进行定制），所以我有5个类：as（City1、City2、City3等等） 在每一行类中，我都有许多视图，当单击“打开”自定义无限库时，其中一个视图是按钮 我想通过使用putextra intent将这个无限图库传递给5行类 但当运行应用程序时，按下按钮打开它提供的无限画廊（强制关闭） ，我在android开发方面没有什么经验 你能帮我吗？任何建议都将不胜感激，谢谢 我的代码：GalleryCity类

单击“打开新活动”时，我的listactivity每行形成5行

我为每一个设置了单独的类（对其进行定制），所以我有5个类：as（City1、City2、City3等等）

在每一行类中，我都有许多视图，当单击“打开”自定义无限库时，其中一个视图是按钮

我想通过使用putextra intent将这个无限图库传递给5行类

但当运行应用程序时，按下按钮打开它提供的无限画廊（强制关闭）

，我在android开发方面没有什么经验

你能帮我吗？任何建议都将不胜感激，谢谢

我的代码：GalleryCity类

 public class GalleryCity extends Activity {
  static String city;

  /** Called when the activity is first created. */
  @Override
  public void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);

     Boolean customTitleSupported = requestWindowFeature(Window.FEATURE_CUSTOM_TITLE); 
      // Set the layout to use
      setContentView(R.layout.main);
      if (customTitleSupported) { 
 getWindow().setFeatureInt(Window.FEATURE_CUSTOM_TITLE,R.layout.custom_title); 
    TextView tv = (TextView) findViewById(R.id.tv); 
         Typeface face=Typeface.createFromAsset(getAssets(),"BFantezy.ttf");     
         tv.setTypeface(face);
         tv.setText("My Pictures"); 
            } 

      Intent intent = getIntent(); 
      city = intent.getStringExtra("galleryimags"); 

      InfiniteGallery galleryOne = (InfiniteGallery) findViewById(R.id.galleryOne);
      galleryOne.setAdapter(new InfiniteGalleryAdapter(this)); 
      galleryOne.setSelection(galleryOne.getCount()/2);            
                     }
                     }


   class InfiniteGalleryAdapter extends BaseAdapter { 
      private Context mContext;
      public InfiniteGalleryAdapter(Context c, int[] imageIds) { 
      this.mContext = c; } 

       public int getCount() { 
      return Integer.MAX_VALUE; } 

       public Object getItem(int position) { 
      return position; } 

       public long getItemId(int position) { 
      return position; } 

    private LayoutInflater inflater=null; 
    public InfiniteGalleryAdapter(Context a) { 
       this.mContext = a; 
       inflater = (LayoutInflater)mContext.getSystemService (
            Context.LAYOUT_INFLATER_SERVICE); 
       getImagesforCity(); 
        } 

      private int[] images;
      private void getImagesforCity() {
        if(GalleryCity.city.equalsIgnoreCase("City1")){ 
         int[] imagestemp = {
               R.drawable.one_1, R.drawable.one_1, 
                R.drawable.one_1

                  }; 
        images=imagestemp;

                        }
        if(GalleryCity.city.equalsIgnoreCase("City2")){
         int[] imagestemp = {
        R.drawable.one_2, R.drawable.one_2, 
             R.drawable.one_2   }; 
       images=imagestemp;

                                  }

        if(GalleryCity.city.equalsIgnoreCase("City3")){
          int[] imagestemp = {
        R.drawable.one_3, R.drawable.one_3, 
             R.drawable.one_3   }; 
        images=imagestemp;

                       }
        if(GalleryCity.city.equalsIgnoreCase("City4")){
          int[] imagestemp = {
        R.drawable.one_4, R.drawable.one_4, 
             R.drawable.one_4   }; 
        images=imagestemp;

                         }
        if(GalleryCity.city.equalsIgnoreCase("City5")){
            int[] imagestemp = {
        R.drawable.one_5, R.drawable.one_5, 
             R.drawable.one_5   }; 
       images=imagestemp;

                          }
                   }
       public class ViewHolder{ 
      public TextView text; 
      public ImageView image; } 

      private String[] name = { "in the cafe", "im in park", "nice place", };

      public View getView(int position, View convertView, ViewGroup parent) { 
         ImageView i = getImageView(); 

             int itemPos = (position % images.length); 

        try { i.setImageResource(images[itemPos]); ((BitmapDrawable) i.getDrawable 
                     ()).setAntiAlias(true); } 

       catch (OutOfMemoryError e) { Log.e("InfiniteGalleryAdapter", "Out of memory
                    creating imageview. Using empty view.", e); } 

       View vi=convertView; 
       ViewHolder holder; 
    if(convertView==null){ 
     vi = inflater.inflate(R.layout.gallery_items, null); 
      holder=new ViewHolder(); holder.text=(TextView)vi.findViewById
                    (R.id.textView1); 
      holder.image=(ImageView)vi.findViewById(R.id.image); 
         vi.setTag(holder); } 

      else holder=(ViewHolder)vi.getTag(); 
      holder.text.setText(name[itemPos]); 

      final int stub_id=images[itemPos]; 
      holder.image.setImageResource(stub_id); 

         return vi; } 

      private ImageView getImageView() { 

        ImageView i = new ImageView(mContext); 

               return i; } 

                        }
    class InfiniteGallery extends Gallery {

   public InfiniteGallery(Context context) {
    super(context);
      init();
            }

public InfiniteGallery(Context context, AttributeSet attrs) {
    super(context, attrs);
    init();
                   }

public InfiniteGallery(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    init();
               }

private void init(){
    setSpacing(25);
    setHorizontalFadingEdgeEnabled(false);
                   }

public void setResourceImages(int[] name){
    setAdapter(new InfiniteGalleryAdapter(getContext(), name));
    setSelection((getCount() / 2));
                  }
                    }
在每一行类别（城市1、城市2、城市3等）中：

我把这个代码：

 public void handleClick(View v){


    Intent intent = new Intent(this, GalleryCity.class);
    intent.putExtra("galleryimags",city);
    startActivity(intent);                           

            }

                }
另外，请告诉我如何为每个设置不同的图像字符串名称： （城市1、城市2、城市3、城市4、城市5）类

例如：

   private String[] name = { "in the cafe", "im in park",
                                 "nice place", };
这是堆栈跟踪：

 04-20 18:29:17.421: E/AndroidRuntime(5007): FATAL EXCEPTION: main
 04-20 18:29:17.421: E/AndroidRuntime(5007): java.lang.RuntimeException: Unable to
 start activity ComponentInfo{com.test.city/com.test.city.GalleryCity}:
 java.lang.NullPointerException
 04-20 18:29:17.421: E/AndroidRuntime(5007):
 at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1651)
 04-20 18:29:17.421: E/AndroidRuntime(5007):
 at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1667)
 04-20 18:29:17.421: E/AndroidRuntime(5007): 
 at android.app.ActivityThread.access$1500(ActivityThread.java:117)
 04-20 18:29:17.421: E/AndroidRuntime(5007): 
 at android.app.ActivityThread$H.handleMessage(ActivityThread.java:935)
 04-20 18:29:17.421: E/AndroidRuntime(5007):
 at android.os.Handler.dispatchMessage(Handler.java:99)
 04-20 18:29:17.421: E/AndroidRuntime(5007): 
 at android.os.Looper.loop(Looper.java:123)
 04-20 18:29:17.421: E/AndroidRuntime(5007): 
 at android.app.ActivityThread.main(ActivityThread.java:3687)
 04-20 18:29:17.421: E/AndroidRuntime(5007): 
 at java.lang.reflect.Method.invokeNative(Native Method)
 04-20 18:29:17.421: E/AndroidRuntime(5007): 
 at java.lang.reflect.Method.invoke(Method.java:507)
 04-20 18:29:17.421: E/AndroidRuntime(5007): 
 at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:842)
 04-20 18:29:17.421: E/AndroidRuntime(5007): 
 at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
 04-20 18:29:17.421: E/AndroidRuntime(5007): 
 at dalvik.system.NativeStart.main(Native Method)
 04-20 18:29:17.421: E/AndroidRuntime(5007):
 Caused by: java.lang.NullPointerException
 04-20 18:29:17.421: E/AndroidRuntime(5007): 
 at com.test.city.InfiniteGalleryAdapter.getImagesforCity(GalleryCity.java:71)
 04-20 18:29:17.421: E/AndroidRuntime(5007): 
 at com.test.city.InfiniteGalleryAdapter.<init>(GalleryCity.java:66)
 04-20 18:29:17.421: E/AndroidRuntime(5007): 
 at com.test.city.GalleryCity.onCreate(GalleryCity.java:43)
 04-20 18:29:17.421: E/AndroidRuntime(5007): 
 at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
 04-20 18:29:17.421: E/AndroidRuntime(5007): 
 at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1615)
 04-20 18:29:17.421: E/AndroidRuntime(5007): 
    ... 11 more
应用更改后的第一件事是，我在这一部分出现红线错误：

  public void setResourceImages(int[] name){
    setAdapter(new InfiniteGalleryAdapter(getContext(), name));
    setSelection((getCount() / 2));
          }
          }
  red mark under :
     setAdapter(new InfiniteGalleryAdapter(getContext(), name));
然后更改为此（因此不会出现红线错误）：

在我运行应用程序之后，当点击打开图库的按钮时，它强制关闭

以下logcat日志如下所示：

  04-21 23:31:32.394: E/AndroidRuntime(27795): FATAL EXCEPTION: main
  04-21 23:31:32.394: E/AndroidRuntime(27795): java.lang.NullPointerException
  04-21 23:31:32.394: E/AndroidRuntime(27795): 
    at com.test.city.InfiniteGalleryAdapter.getView(GalleryCity.java:126)
  04-21 23:31:32.394: E/AndroidRuntime(27795): 
    at android.widget.AbsSpinner.onMeasure(AbsSpinner.java:192)
  04-21 23:31:32.394: E/AndroidRuntime(27795): 
   at android.view.View.measure(View.java:8366)
  04-21 23:31:32.394: E/AndroidRuntime(27795): 
   at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138)
  04-21 23:31:32.394: E/AndroidRuntime(27795): 
   at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1017)
  04-21 23:31:32.394: E/AndroidRuntime(27795): 
   at android.widget.LinearLayout.measureVertical(LinearLayout.java:386)
  04-21 23:31:32.394: E/AndroidRuntime(27795): 
   at android.widget.LinearLayout.onMeasure(LinearLayout.java:309)
  04-21 23:31:32.394: E/AndroidRuntime(27795): 
   at android.view.View.measure(View.java:8366)
  04-21 23:31:32.394: E/AndroidRuntime(27795): 
   at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138)
  04-21 23:31:32.394: E/AndroidRuntime(27795): 
   at android.widget.FrameLayout.onMeasure(FrameLayout.java:250)
  04-21 23:31:32.394: E/AndroidRuntime(27795): 
   at android.view.View.measure(View.java:8366)
  04-21 23:31:32.394: E/AndroidRuntime(27795): 
   at android.widget.LinearLayout.measureVertical(LinearLayout.java:531)
  04-21 23:31:32.394: E/AndroidRuntime(27795): 
   at android.widget.LinearLayout.onMeasure(LinearLayout.java:309)
  04-21 23:31:32.394: E/AndroidRuntime(27795): 
   at android.view.View.measure(View.java:8366)
  04-21 23:31:32.394: E/AndroidRuntime(27795): 
   at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138)
  04-21 23:31:32.394: E/AndroidRuntime(27795): 
   at android.widget.FrameLayout.onMeasure(FrameLayout.java:250)
  04-21 23:31:32.394: E/AndroidRuntime(27795): 
   at android.view.View.measure(View.java:8366)
  04-21 23:31:32.394: E/AndroidRuntime(27795): 
   at android.view.ViewRoot.performTraversals(ViewRoot.java:844)
  04-21 23:31:32.394: E/AndroidRuntime(27795): 
   at android.view.ViewRoot.handleMessage(ViewRoot.java:1865)
  04-21 23:31:32.394: E/AndroidRuntime(27795): 
   at android.os.Handler.dispatchMessage(Handler.java:99)
  04-21 23:31:32.394: E/AndroidRuntime(27795): 
   at android.os.Looper.loop(Looper.java:123)
  04-21 23:31:32.394: E/AndroidRuntime(27795): 
   at android.app.ActivityThread.main(ActivityThread.java:3687)
  04-21 23:31:32.394: E/AndroidRuntime(27795): 
   at java.lang.reflect.Method.invokeNative(Native Method)
  04-21 23:31:32.394: E/AndroidRuntime(27795): 
   at java.lang.reflect.Method.invoke(Method.java:507)
  04-21 23:31:32.394: E/AndroidRuntime(27795): 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:842)
  04-21 23:31:32.394: E/AndroidRuntime(27795): 
   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
  04-21 23:31:32.394: E/AndroidRuntime(27795): 
   at dalvik.system.NativeStart.main(Native Method)
此行中的日志cat错误：

   04-21 23:31:32.394: E/AndroidRuntime(27795): 
     at com.test.city.InfiniteGalleryAdapter.getView(GalleryCity.java:126)
与代码块中的此行匹配的代码：

     int itemPos = (position % images.length);

我认为这与你的意图无关。您可以通过调试来检查它，或者只需放入
Log.d（“intentExtra”，city）
从intent获得额外字符串后，检查它是否真的得到了它。我想是的

你需要做的是，在你的代码中没有这样的事情，为你设置一个适配器
InfiniteGallery
（这是典型的
Gallery
）的扩展），这样它就知道从哪里获取图像了

首先，您必须通过调用以下命令来实例化适配器：

InfiniteGalleryAdapter mAdapter=新的InfiniteGalleryAdapter（这是ImageID）

（
int[]imageIds
是一个ID数组，我不知道从哪里获得它）

然后通过以下方式将其设置为您的多媒体资料：

galleryOne.setAdapter（mAdapter）
更新： 请为您的CityGallery类尝试以下代码：

InfiniteGallery galleryOne = (InfiniteGallery) findViewById(R.id.galleryOne);
        galleryOne.setAdapter(initializeImages()); 
        galleryOne.setSelection(galleryOne.getCount()/2);            





    }

    private InfiniteGalleryAdapter initializeImages() {
        InfiniteGalleryAdapter galleryAdapter = null;

        String city = getIntent().getStringExtra("cityname");
        tv.setText("My "+city+" Pictures"); 

        if(city.equalsIgnoreCase("City1")){
            int[] tempimages = { R.drawable.ic_launcher, R.drawable.ic_launcher,R.drawable.ic_launcher };  
            String[] name = { "Image 1","Image 2", "Image 3"};  

            galleryAdapter=new InfiniteGalleryAdapter(this, tempimages, name);
        }else if(city.equalsIgnoreCase("City2")){
            int[] tempimages = { R.drawable.ic_launcher, R.drawable.ic_launcher,R.drawable.ic_launcher };  
            String[] name = { "Image 4","Image 5", "Image 6"};  

            galleryAdapter=new InfiniteGalleryAdapter(this, tempimages, name);


        }else if(city.equalsIgnoreCase("City3")){
            int[] tempimages = { R.drawable.ic_launcher, R.drawable.ic_launcher,R.drawable.ic_launcher };  
            String[] name = { "Image 7","Image 8", "Image 9"};  

            galleryAdapter=new InfiniteGalleryAdapter(this, tempimages, name);

        }else if(city.equalsIgnoreCase("City4")){
            int[] tempimages = { R.drawable.ic_launcher, R.drawable.ic_launcher,R.drawable.ic_launcher };  
            String[] name = { "Image 10","Image 11", "Image 12"};  

            galleryAdapter=new InfiniteGalleryAdapter(this, tempimages, name);

        }else if(city.equalsIgnoreCase("City5")){
            int[] tempimages = { R.drawable.ic_launcher, R.drawable.ic_launcher,R.drawable.ic_launcher };  
            String[] name = { "Image 13","Image 14", "Image 15"};  

            galleryAdapter=new InfiniteGalleryAdapter(this, tempimages, name);
        }
        return galleryAdapter;





    }
}

你说你有一个力接近。堆栈跟踪将是helpful@MichałK请检查post now编辑它，谢谢（不显示图像）。从日志中可以看到，您调用
新的InfiniteGalleryAdapter（this）
，因此调用InfiniteGalleryAdapter的构造函数。您有一个函数
getImagesforCity（）存在导致问题的原因。问题出现在第71行，请检查是哪一个问题。有可能您确实没有通过getExtra设置这个静态变量
city
。我告诉过你如何在我的回答中检查它。您也可以尝试硬编码
city
，例如使用
static String city=“city
”`@MichałK我将其更改为static String city=“city”；但仍然存在相同的问题抱歉，“City1”，以匹配您的equals状态。但即使使用“city”，也不应提供NPE“.com.test.city.InfiniteGalleryAdapter.getImagesforCity（GalleryCity.java:71）的堆栈跟踪部分：
告诉您第71行的GalleryCity文件有问题。你明白了吗？仔细阅读堆栈跟踪，找出NPE可能发生的位置。NPE（NullPointerException）发生在您传递null时，您应该传递其他内容。请检查post now编辑它，谢谢（不显示图像）。但是您检查了为什么要关闭强制吗？是哪一行引起的？这是某种NullPointerException吗？对我来说，很明显，你没有图像，因为你没有设置适配器（否则画廊怎么知道它应该显示什么图像？）。因此，请尝试阅读有关适配器的更多信息。如果应用您的更改，可能会在此处出现红色标记错误：public void setResourceImages（int[]name）{setAdapter（新的InfiniteGalleryAdapter（getContext（），name））；setSelection（（getCount（）/2））；我更改为：public void setResourceImages（字符串名称）{setAdapter（新的InfiniteGalleryAdapter（getContext（），name））；setSelection（（getCount（）/2））；，然后运行app get，并使用下面的日志cat强制关闭它指向：20 21:54:34.941:E/AndroidRuntime（7678）：atcom.test.city.InfiniteGalleryAdapter.getView（GalleryCity.java:126），该值等于：int-itemPos=（位置%images.length）；在这一行中跟随logcat错误：int-itemPos=（位置%images.length）；@AndroidStack:更改构造函数，如我的答案更新中所示。

     int itemPos = (position % images.length); 



Intent myIntent = new Intent();
myIntent.putExtra("key", "value");
startActivity(myIntent); 



InfiniteGallery galleryOne = (InfiniteGallery) findViewById(R.id.galleryOne);
        galleryOne.setAdapter(initializeImages()); 
        galleryOne.setSelection(galleryOne.getCount()/2);            





    }

    private InfiniteGalleryAdapter initializeImages() {
        InfiniteGalleryAdapter galleryAdapter = null;

        String city = getIntent().getStringExtra("cityname");
        tv.setText("My "+city+" Pictures"); 

        if(city.equalsIgnoreCase("City1")){
            int[] tempimages = { R.drawable.ic_launcher, R.drawable.ic_launcher,R.drawable.ic_launcher };  
            String[] name = { "Image 1","Image 2", "Image 3"};  

            galleryAdapter=new InfiniteGalleryAdapter(this, tempimages, name);
        }else if(city.equalsIgnoreCase("City2")){
            int[] tempimages = { R.drawable.ic_launcher, R.drawable.ic_launcher,R.drawable.ic_launcher };  
            String[] name = { "Image 4","Image 5", "Image 6"};  

            galleryAdapter=new InfiniteGalleryAdapter(this, tempimages, name);


        }else if(city.equalsIgnoreCase("City3")){
            int[] tempimages = { R.drawable.ic_launcher, R.drawable.ic_launcher,R.drawable.ic_launcher };  
            String[] name = { "Image 7","Image 8", "Image 9"};  

            galleryAdapter=new InfiniteGalleryAdapter(this, tempimages, name);

        }else if(city.equalsIgnoreCase("City4")){
            int[] tempimages = { R.drawable.ic_launcher, R.drawable.ic_launcher,R.drawable.ic_launcher };  
            String[] name = { "Image 10","Image 11", "Image 12"};  

            galleryAdapter=new InfiniteGalleryAdapter(this, tempimages, name);

        }else if(city.equalsIgnoreCase("City5")){
            int[] tempimages = { R.drawable.ic_launcher, R.drawable.ic_launcher,R.drawable.ic_launcher };  
            String[] name = { "Image 13","Image 14", "Image 15"};  

            galleryAdapter=new InfiniteGalleryAdapter(this, tempimages, name);
        }
        return galleryAdapter;





    }