从适配器提取ArrayList值到GridView

我可以找到很多关于如何在BaseAdapter类中使用ArrayList来填充GridView的示例，但我很难通过传递正确的值。这在我刚使用光标位置时工作正常，但我现在需要使用ArrayList。据我所知，解决方案在于正确填充getItem和getItemID。哪里有错误 - 有人可以帮忙吗？相关代码如下：从适配器提取ArrayList值到GridView

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

allImages = Images.Media.EXTERNAL_CONTENT_URI; 
ArrayList<String> imageCollection = new ArrayList<String>(); 

String[] projection = { 
     MediaStore.Images.Media._ID, 
     MediaStore.Images.Media.DATA 
}; 
getCursor = getContentResolver().query(
     allImages, 
     projection, 
     null, 
     null, 
     null 
); 
columnIndex = getCursor.getColumnIndexOrThrow(projection[0]); //-- ID number. 
arrayIndex = getCursor.getColumnIndexOrThrow(projection[1]); //-- Filepath. 
imageCollection.add(String.valueOf(columnIndex)); 

GridView gridView = (GridView) findViewById(R.id.gridview); 
gridView.setAdapter(new ImageAdapter(this, imageCollection)); 
} //---End of OnCreate -- 

public class ImageAdapter extends BaseAdapter { 
    private Context context; 
    private int colCount; 
    private ArrayList<String> tempCollection; 

    public ImageAdapter(Context c, ArrayList<String> anyCollection) { 
     context = c; 
     tempCollection = anyCollection; 
     colCount = tempCollection.size(); 
    } 
    //---Returns the number of images--- 
    public int getCount() { 
     return colCount; 
    } 
    //---Returns the item--- 
    public Object getItem(int position) { 
     return tempCollection.get(position); 

    } 
    //---Returns the ID of one item. 
    public long getItemId(int position) { 
     return position; 
    } 

public View getView(int position, View convertView, ViewGroup parent) { 
    ImageView imageView; 
    if (convertView == null) { //---If it's not recycled, initialize some attributes -- 
     imageView = new ImageView(context); 
    } else { 
     imageView = (ImageView) convertView; 
    } 
    String imageID = String.valueOf(position); //--- FAILS: always 0, causing FileNotFound Exception below.!!! 
    imageView.setLayoutParams(new GridView.LayoutParams(85, 85)); 
    imageView.setScaleType(ImageView.ScaleType.CENTER_CROP); 
    imageView.setPadding(5,5,5,5); 
    imageView.setCropToPadding(true); 
    imageView.setImageURI(    //--- Now create each individual display image -- 
     Uri.withAppendedPath(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, imageID) 
    ); 
    return imageView; 
} //---End of ImageAdapter class--

来源

2015-02-06 Archdeacon

在活动中，使用下面的代码将ImageId保存到ArrayList。

if (getCursor != null) { 
    while (getCursor.moveToNext()) { 
     columnIndex = getCursor.getColumnIndexOrThrow(projection[0]); 
     imageCollection.add(String.valueOf(getCursor.getLong(columnIndex)); 
    } 
}

在ImageAdapter，getView方法，通过使用下面的代码获取图像标识：

String imageID = tempCollection.get(position);

来源

2015-02-06 11:42:11 user543

在原来的职位，我认为ArrayList中被完全填充_before_试图提取图像标识;并且仍然不清楚，所以在GetView类中没有cursor.moveToPosition指令是正确的。很抱歉，但可以在任何地方找到任何文档。上面的代码看起来很有希望，现在就试试吧。 – Archdeacon 2015-02-06 13:32:57

从适配器提取ArrayList值到GridView

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