Android GridView setItem動態檢查

Question

我有一個自定義Gridview。當Activity開始時，我想動態設置Checked和Item。我試過gridView.setItemChecked(5, true);，但它沒有奏效。我能怎麼做？

public class MainActivity extends Activity { 
    GridView gridView; 
    ArrayList<Item> gridArray = new ArrayList<Item>(); 
    CustomGridViewAdapter customGridAdapter; 

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

     //set grid view item 
     Bitmap homeIcon = BitmapFactory.decodeResource(this.getResources(), R.drawable.home); 
     Bitmap userIcon = BitmapFactory.decodeResource(this.getResources(), R.drawable.personal); 

     gridArray.add(new Item(homeIcon,"Home")); 
     gridArray.add(new Item(userIcon,"User")); 
     gridArray.add(new Item(homeIcon,"House")); 
     gridArray.add(new Item(userIcon,"Friend")); 
     gridArray.add(new Item(homeIcon,"Home")); 
     gridArray.add(new Item(userIcon,"Personal")); 
     gridArray.add(new Item(homeIcon,"Home")); 
     gridArray.add(new Item(userIcon,"User")); 
     gridArray.add(new Item(homeIcon,"Building")); 
     gridArray.add(new Item(userIcon,"User")); 
     gridArray.add(new Item(homeIcon,"Home")); 
     gridArray.add(new Item(userIcon,"xyz")); 


     gridView = (GridView) findViewById(R.id.gridView1); 
     customGridAdapter = new CustomGridViewAdapter(this, R.layout.row_grid, gridArray); 
     gridView.setAdapter(customGridAdapter); 
     gridView.setItemChecked(5, true); 
    } 

適配器

public class CustomGridViewAdapter extends ArrayAdapter<Item> { 
    Context context; 
    int layoutResourceId; 
    ArrayList<Item> data = new ArrayList<Item>(); 

    public CustomGridViewAdapter(Context context, int layoutResourceId, 
      ArrayList<Item> data) { 
     super(context, layoutResourceId, data); 
     this.layoutResourceId = layoutResourceId; 
     this.context = context; 
     this.data = data; 
    } 

    @Override 
    public View getView(int position, View convertView, ViewGroup parent) { 
     View row = convertView; 
     RecordHolder holder = null; 

     if (row == null) { 
      LayoutInflater inflater = ((Activity) context).getLayoutInflater(); 
      row = inflater.inflate(layoutResourceId, parent, false); 

      holder = new RecordHolder(); 
      holder.txtTitle = (TextView) row.findViewById(R.id.item_text); 
      holder.imageItem = (ImageView) row.findViewById(R.id.item_image); 
      row.setTag(holder); 
     } else { 
      holder = (RecordHolder) row.getTag(); 
     } 

     Item item = data.get(position); 
     holder.txtTitle.setText(item.getTitle()); 
     holder.imageItem.setImageBitmap(item.getImage()); 
     return row; 

    } 

    static class RecordHolder { 
     TextView txtTitle; 
     ImageView imageItem; 

    } 
} 

項目

public class Item { 
    Bitmap image; 
    String title; 

    public Item(Bitmap image, String title) { 
     super(); 
     this.image = image; 
     this.title = title; 
    } 
    public Bitmap getImage() { 
     return image; 
    } 
    public void setImage(Bitmap image) { 
     this.image = image; 
    } 
    public String getTitle() { 
     return title; 
    } 
    public void setTitle(String title) { 
     this.title = title; 
    } 
}  

的GridView

<GridView 
    android:id="@+id/gridView1" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:layout_margin="4dp" 
    android:columnWidth="80dp" 
    android:gravity="center" 
    android:numColumns="auto_fit" 
    android:stretchMode="columnWidth" 
    android:listSelector="@drawable/selector_" 
    android:choiceMode="singleChoice"> 
</GridView> 

Answer 1

gridView.setItemChecked(5, true);實際工作！如果你想驗證，你可以請求checked項目位置使用下面的API，將給你正確的價值（在你的情況5）。

int i = gridView.getCheckedItemPosition(); 

現在，您可能會對您選中的商品的某些視覺表示感興趣。但是，您在getView（...）中擁有的內容是TextView和ImageView，並且它們都隱式未配備檢查/取消選中功能。如果你明白地使用一些Widgets如CheckBox即implementsCheckable接口，你可以清楚地看到差異！

有一個很不錯的職位here，一定會幫助您實施。

Answer 2

如下構建您的自定義適配器類。如果您想發送一些預先選定的內容，請將其傳遞給構造函數。

class CustomListAdapter extends BaseAdapter { 
    Context context; 
    static ArrayList<Object> items; 
    ArrayList<Integer> imgTag; 

    public CustomListAdapter(Context context, ArrayList<Object> items) { 
     imgTag = new ArrayList<>(); 
     this.context = context; 
     CustomListAdapter.items = items; 
    } 

    public void set_selected(int tag) { 
     imgTag.add(tag); 
    } 

    public ArrayList<Integer> selected_items() { 
     return imgTag; 
    } 

    public void remove_all() { 
     imgTag = new ArrayList<>(); 
    } 

    public void select_all() { 
     remove_all(); 
     for (int i = 0; i < items.size(); i++) { 
      imgTag.add(i); 
     } 
    } 

    public void remove_selected(int tag) { 
     for (int i = 0; i < imgTag.size(); i++) { 
      if (tag == imgTag.get(i)) { 
       imgTag.remove(i); 
       break; 
      } 
     } 
    } 

    public boolean isSelected(int tag) { 
     for (int i = 0; i < imgTag.size(); i++) { 
      if (tag == imgTag.get(i)) { 
       return true; 
      } 
     } 
     return false; 
    } 

    @Override 
    public int getCount() { 
     return items.size(); 
    } 

    @Override 
    public View getView(int arg0, View convertView, ViewGroup arg2) { 
     ImageView img; 
     LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
     convertView = inflater.inflate(R.layout.picture_block, null); 
     if (convertView != null) { 
      if (!this.isSelected(arg0)) { 
       convertView.findViewById(R.id.check_img).setChecked(true); 
      } else { 
       convertView.findViewById(R.id.check_img).setChecked(false); 
      } 
      img = (ImageView) convertView.findViewById(R.id.original_img); 
     } else { 
      img = (ImageView) convertView.findViewById(R.id.original_img); 
      View view = img; 
      if (!this.isSelected(arg0)) { 
       convertView.findViewById(R.id.check_img).setChecked(true); 
      } else { 
       convertView.findViewById(R.id.check_img).setChecked(false); 
      } 
      img = (ImageView) view; 
     } 
     convertView.setTag(arg0); 
     img.setScaleType(ImageView.ScaleType.CENTER_CROP); 
     Ion.with(img) 
       .placeholder(R.drawable.mw_background_100x100) 
       .error(R.drawable.mw_background_100x100) 
       .load(items.get(arg0).getFile()); 
     return convertView; 
    } 

    @Override 
    public Object getItem(int position) { 
     // TODO Auto-generated method stub 
     return null; 
    } 

    @Override 
    public long getItemId(int position) { 
     // TODO Auto-generated method stub 
     return 0; 
    } 
}