使用GridView中的項目滾動背景

Question

如何使用GridView實現背景滾動？如果聽起來含糊不清，我的意思是像使用gridview實現一個書架，其中貨架圖像附加到gridview中的項目。

Answer 1

我花了很長時間才弄清楚這一點，因此對於所有嘗試這樣做的人來說，下面是我電子書閱讀器的代碼。

它基於Shelves by Romain Guy，所以他值得信任原代碼。

package net.nightwhistler.pageturner.view; 

import net.nightwhistler.pageturner.R; 
import net.nightwhistler.pageturner.library.LibraryBook; 
import net.nightwhistler.pageturner.library.QueryResult; 
import android.content.Context; 
import android.graphics.Bitmap; 
import android.graphics.BitmapFactory; 
import android.graphics.Canvas; 
import android.graphics.Rect; 
import android.util.AttributeSet; 
import android.view.KeyEvent; 
import android.widget.GridView; 

public class BookCaseView extends GridView { 

    private Bitmap background; 

    private int mShelfWidth; 
    private int mShelfHeight; 

    private QueryResult<LibraryBook> result;  

    private LibraryBook selectedBook; 

    public BookCaseView(Context context, AttributeSet attributes) { 
     super(context, attributes); 

     this.setFocusableInTouchMode(true); 
     this.setClickable(false); 

     final Bitmap shelfBackground = BitmapFactory.decodeResource(context.getResources(), 
       R.drawable.shelf_single); 
     setBackground(shelfBackground); 
     this.setFocusable(true); 
    } 

    public void setBackground(Bitmap background) { 
     this.background = background; 

     mShelfWidth = background.getWidth(); 
     mShelfHeight = background.getHeight(); 
    } 

    protected void onClick(int bookIndex) { 
     LibraryBook book = this.result.getItemAt(bookIndex); 

     this.selectedBook = book; 
     invalidate(); 
    } 

    @Override 
    protected void dispatchDraw(Canvas canvas) { 
     final int count = getChildCount(); 
     final int top = count > 0 ? getChildAt(0).getTop() : 0; 
     final int shelfWidth = mShelfWidth; 
     final int shelfHeight = mShelfHeight; 
     final int width = getWidth(); 
     final int height = getHeight(); 
     final Bitmap background = this.background; 

     for (int x = 0; x < width; x += shelfWidth) { 
      for (int y = top; y < height; y += shelfHeight) { 
       canvas.drawBitmap(background, x, y, null); 
      } 

      //This draws the top pixels of the shelf above the current one 

      Rect source = new Rect(0, mShelfHeight - top, mShelfWidth, mShelfHeight); 
      Rect dest = new Rect(x, 0, x + mShelfWidth, top);    

      canvas.drawBitmap(background, source, dest, null);    
     }   


     super.dispatchDraw(canvas); 
    } 

    @Override 
    public boolean onKeyDown(int keyCode, KeyEvent event) { 
     if (keyCode == KeyEvent.KEYCODE_BACK && this.selectedBook != null) { 
      this.selectedBook = null; 
      invalidate(); 
      return true; 
     } 

     return false; 
    } 

} 

Answer 2

我以前的回答只會添加背景，但不會讓它隨着項目滾動。你想要什麼是NightWhistler的回答:) 對不起，誤解了這個問題。

Answer 3

我所做的是在n個gridview列和我的gridview中分割我的背景圖像getView方法根據網格中的位置添加視圖背景。 它工作完美。

如果你想要的代碼只是問。