java - 无限滚动图库的文本自定义

Question

我有基于这个例子的无限画廊:

http://blog.blundell-apps.com/infinite-scrolling-gallery/ ，一切运行正常:

确切地说，我想将文本应用到每张图片并且也能够自定义文本，如下图所示，并且每张图片的文字都与其他图片不同 strong> , 但用无限画廊还是没成功

我尝试使用以下代码，但在运行应用程序时它给了我FORCE CLOSE，

(也许我写的代码有误，但我仍在学习 JAVA 和 ANDROID 开发的初学者)。

如有任何帮助和建议，我们将不胜感激

非常感谢。

我的代码:

GALLERY_ITEM

<?xml version="1.0" encoding="utf-8"?> 
  <RelativeLayout  xmlns:android="http://schemas.android.com/apk/res/android"   
      android:id="@+id/LinearLayout01" 
      android:layout_width="fill_parent"   
      android:layout_height="fill_parent" 
      android:orientation="vertical"   
      android:gravity="center_horizontal">  
  <ImageView  
     android:id="@+id/image" 
     android:layout_height="300dp" 
     android:layout_width="fill_parent"          /> 
  <TextView   
    android:text="TextView" 
    android:id="@+id/textView1"  
    android:layout_width="fill_parent"  
    android:layout_height="fill_parent"  
    android:textColor="#B22222"    
    android:textSize="20dp"   
    android:gravity="center"   
    android:layout_margin="30dp"  
    android:layout_below="@+id/image"          />  

然后在 InfiniteScrollingGalleryActivity.java 中更改如下:

  public class InfiniteScrollingGalleryActivity extends Activity {  

     /** Called when the activity is first created. */  
   @Override 
     public void onCreate(Bundle savedInstanceState) {  
     super.onCreate(savedInstanceState);  
        // Set the layout to use   
     setContentView(R.layout.main);  

   InfiniteGallery galleryOne = (InfiniteGallery) findViewById(R.id.galleryOne); 
   galleryOne.setAdapter(new InfiniteGalleryAdapter(this));    
        }      } 

然后如下更改 InfiniteGalleryResourceAdapter.java :

 public class InfiniteGalleryAdapter extends BaseAdapter {

    /** The width of each child image */  
   private static final int G_ITEM_WIDTH = 360; 
   /** The height of each child image */  
  private static final int G_ITEM_HEIGHT = 240; 
  /** The context your gallery is running in (usually the activity) */ 
       private Context mContext;  
       private int imageWidth; 
       private int imageHeight;  
       private int[] imageIds;  

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

      public int getCount() {   
        return Integer.MAX_VALUE;     } 
      public Object getItem(int position) { 
        return position;    } 
      public long getItemId(int position) {  
        return position;    }      

      private Activity activity;   
      private  LayoutInflater inflater=null; 

   public InfiniteGalleryAdapter(Activity a) {     
      final int[] imageIds;
     activity = a;  
     inflater = (LayoutInflater)activity.getSystemService
          Context.LAYOUT_INFLATER_SERVICE);          }   
      public  class ViewHolder{    
      public TextView text;     
      public ImageView image;         }  
  public View getView(int position, View convertView, ViewGroup parent) {  
     ImageView i = getImageView();  
 try {  

   int itemPos = (position % imageIds.length); 

   i.setImageResource(imageIds[itemPos]); 

  ((BitmapDrawable) i.getDrawable()).setAntiAlias(true); }

          catch (OutOfMemoryError e) {  

    Log.e("InfiniteGalleryResourceAdapter", "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[position]);  

   final int stub_id=images[position]; 
   holder.image.setImageResource(stub_id);  
  return vi;         }

    private int[] images = {   
         R.drawable.one_1, R.drawable.one_4,  
         R.drawable.one_2, R.drawable.one_5, 
         R.drawable.one_3                    }; 

   private String[] name = {   
         "this is my car", "i love this",   
         "please hekp me", "im in park", 
         " This is nice place to visit.",          }; 


   private ImageView getImageView() {  
      setImageDimensions();  
     ImageView i = new ImageView(mContext);  
     i.setLayoutParams(new Gallery.LayoutParams(imageWidth, imageHeight)); 
     i.setScaleType(ScaleType.CENTER_INSIDE);     return i;      } 

 private void setImageDimensions() {   
      if (imageWidth == 0 || imageHeight == 0) {   
     imageWidth = AndroidUtils.convertToPix(mContext, G_ITEM_WIDTH);  
     imageHeight = AndroidUtils.convertToPix(mContext,G_ITEM_HEIGHT); 
        }         }      
           } 

这是 logcat 错误:

04-10 02:25:13.057: E/AndroidRuntime(12302): FATAL EXCEPTION: main
04-10 02:25:13.057: E/AndroidRuntime(12302): java.lang.NullPointerException
04-10 02:25:13.057: E/AndroidRuntime(12302):
at com.infinite.test.AndroidUtils.convertToPix(AndroidUtils.java:11)
04-10 02:25:13.057: E/AndroidRuntime(12302): 
at com.infinite.test.InfiniteGalleryAdapter.setImageDimensions
(InfiniteGalleryAdapter.java:131)
4-10 02:25:13.057: E/AndroidRuntime(12302):
at com.infinite.test.InfiniteGalleryAdapter.getImageView
(InfiniteGalleryAdapter.java:117)
04-10 02:25:13.057: E/AndroidRuntime(12302):
at com.infinite.test.InfiniteGalleryAdapter.getView(InfiniteGalleryAdapter.java:66)
04-10 02:25:13.057: E/AndroidRuntime(12302):
at android.widget.AbsSpinner.onMeasure(AbsSpinner.java:192)
04-10 02:25:13.057: E/AndroidRuntime(12302):
at android.view.View.measure( View.java:8366)
04-10 02:25:13.057: E/AndroidRuntime(12302):
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138)
04-10 02:25:13.057: E/AndroidRuntime(12302):
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1017)
04-10 02:25:13.057: E/AndroidRuntime(12302):
at android.widget.LinearLayout.measureVertical(LinearLayout.java:386)
04-10 02:25:13.057: E/AndroidRuntime(12302):
at android.widget.LinearLayout.onMeasure(LinearLayout.java:309)
04-10 02:25:13.057: E/AndroidRuntime(12302):
at android.view.View.measure(View.java:8366)
04-10 02:25:13.057: E/AndroidRuntime(12302):
at android.view.ViewGroup.measureChildWithMargins(viewGroup.java:3138)
04-10 02:25:13.057: E/AndroidRuntime(12302):
at android.widget.FrameLayout.onMeasure(FrameLayout.java:250)
04-10 02:25:13.057: E/AndroidRuntime(12302):
at android.view.View.measure(View.java:8366)
04-10 02:25:13.057: E/AndroidRuntime(12302):
at android.widget.LinearLayout.measureVertical(LinearLayout.java:531)
04-10 02:25:13.057: E/AndroidRuntime(12302):
at android.widget.LinearLayout.onMeasure(LinearLayout.java:309)
04-10 02:25:13.057: E/AndroidRuntime(12302):
at android.view.View.measure(View.java:8366)
04-10 02:25:13.057: E/AndroidRuntime(12302):
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138)
04-10 02:25:13.057: E/AndroidRuntime(12302):
at android.widget.FrameLayout.onMeasure(FrameLayout.java:250)
04-10 02:25:13.057: E/AndroidRuntime(12302):
at android.view.View.measure(View.java:8366)
04-10 02:25:13.057: E/AndroidRuntime(12302):
at android.view.ViewRoot.performTraversals(ViewRoot.java:844)
04-10 02:25:13.057: E/AndroidRuntime(12302):
at android.view.ViewRoot.handleMessage(ViewRoot.java:1865)
04-10 02:25:13.057: E/AndroidRuntime(12302):
at android.os.Handler.dispatchMessage(Handler.java:99)
04-10 02:25:13.057: E/AndroidRuntime(12302):
at android.os.Looper.loop(Looper.java:123)
04-10 02:25:13.057: E/AndroidRuntime(12302):
at android.app.ActivityThread.main(ActivityThread.java:3687)
04-10 02:25:13.057: E/AndroidRuntime(12302):
at java.lang.reflect.Method.invokeNative(Native Method)
04-10 02:25:13.057: E/AndroidRuntime(12302):
at java.lang.reflect.Method.invoke    (Method.java:507)
04-10 02:25:13.057: E/AndroidRuntime(12302):
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:842)
04-10 02:25:13.057: E/AndroidRuntime(12302):
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
04-10 02:25:13.057: E/AndroidRuntime(12302):
at dalvik.system.NativeStart.main(Native Method)
04-10 02:25:13.061: E/(129): Dumpstate > /data/log/dumpstate_app_error

Answer 1

问题似乎在于图像的上下文变量和位置。为您的适配器尝试以下代码:

public class InfiniteGalleryAdapter extends BaseAdapter { 
/** The width of each child image */ 
private static final int G_ITEM_WIDTH = 360;   
/** The height of each child image */  
private static final int G_ITEM_HEIGHT = 240; 
/** The context your gallery is running in (usually the activity) */   
private Context mContext;       
private int imageWidth;     
private int imageHeight;   
private int[] imageIds;    
public InfiniteGalleryAdapter(Context c, int[] imageIds) {    
    this.mContext = c;          
    this.imageIds = imageIds; }   
public int getCount() {   
    return Integer.MAX_VALUE;   
}      
public Object getItem(int position) { 
    return position;    }  
public long getItemId(int position) { 
    return position;    }       
//private Activity activity;  
private  LayoutInflater inflater=null;
public InfiniteGalleryAdapter(Context a) {  
    final int[] imageIds;  
    //activity = a;   
    this.mContext = a;   
    inflater = (LayoutInflater)mContext.getSystemService   (        Context.LAYOUT_INFLATER_SERVICE);  
}          public  class ViewHolder{ 
    public TextView text;
    public ImageView image;   
}    

private int[] images = {  
        R.drawable.one_1, R.drawable.one_4,   
        R.drawable.one_2, R.drawable.one_5,   
        R.drawable.one_3               
};    
private String[] name = {   
        "this is my car", "i love this",   
        "please hekp me", "im in park",    
        " This is nice place to visit.",  
};       
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("InfiniteGalleryResourceAdapter", "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() { 
    setImageDimensions();   

    ImageView i = new ImageView(mContext);   
    i.setLayoutParams(new Gallery.LayoutParams(imageWidth, imageHeight)); 
    i.setScaleType(ScaleType.CENTER_INSIDE);  
    return i;      }  
private void setImageDimensions() { 
    if (imageWidth == 0 || imageHeight == 0) {        
        imageWidth = AndroidUtils.convertToPix(mContext, G_ITEM_WIDTH);
        imageHeight = AndroidUtils.convertToPix(mContext,G_ITEM_HEIGHT); 
    }         }                  }