移動運算符在android中的語法錯誤

只是想知道你是否可以在android中使用移位運算符我在嘗試時遇到語法錯誤。運營商是>> < < >>>。如果它不支持它是他們的android sdk等價物？移動運算符在android中的語法錯誤

編輯：這裏是我使用的代碼。我試圖做一個像素碰撞檢測，並嘗試了這一點。

public void getBitmapData(Bitmap bitmap1, Bitmap bitmap2){ 
    int[] bitmap1Pixels; 
    int[] bitmap2Pixels; 

int bitmap1Height = bitmap1.getHeight(); 
    int bitmap1Width = bitmap1.getWidth(); 
    int bitmap2Height = bitmap1.getHeight(); 
    int bitmap2Width = bitmap1.getWidth(); 
    bitmap1Pixels = new int[bitmap1Height * bitmap1Width]; 
    bitmap2Pixels = new int[bitmap2Height * bitmap2Width]; 

    bitmap1.getPixels(bitmap1Pixels, 0, bitmap1Width, 1, 1, bitmap1Width - 1, bitmap1Height - 1); 
    bitmap2.getPixels(bitmap2Pixels, 0, bitmap2Width, 1, 1, bitmap2Width - 1, bitmap2Height - 1); 


// Find the first line where the two sprites might overlap 
    int linePlayer, lineEnemy; 
    if (ninja.getY() <= enemy.getY()) { 
     linePlayer = enemy.getY() - ninja.getY(); 
     lineEnemy = 0; 
    } else { 
     linePlayer = 0; 
     lineEnemy = ninja.getY() - enemy.getY(); 
    } 
    int line = Math.max(linePlayer, lineEnemy); 

    // Get the shift between the two 
    int x = ninja.getX() - enemy.getX(); 
    int maxLines = Math.max(bitmap1Height, bitmap2Height); 
    for (; line <= maxLines; line ++) { 
     // if width > 32, then you need a second loop here 
     long playerMask = bitmap1Pixels[linePlayer]; 
     long enemyMask = bitmap2Pixels[lineEnemy]; 
     // Reproduce the shift between the two sprites 
     if (x < 0) playerMask << (-x); 
     else enemyMask << x; 
     // If the two masks have common bits, binary AND will return != 0 
     if ((playerMask & enemyMask) != 0) { 
      // Contact! 
      Log.d("pixel collsion","we have pixel on pixel"); 
     } 

    } 



}

來源

2011-03-19 pengume

是的，可以。請發佈不起作用的代碼，否則我們無法真正幫助。 – fredley 2011-03-19 23:54:42

我用我的代碼編輯了原始問題。對不起 – pengume 2011-03-20 00:32:51

Android中使用的Java確實支持按位運算。 Here's a handy guide。

來源

2011-03-19 23:55:40 fredley

謝謝我發佈我的代碼上面。不知道爲什麼它不工作，也許你可以幫忙？ – pengume 2011-03-20 01:26:40

如果你要追加到一個字符串，除非你把算術運算括號，你會得到一個錯誤：


[email protected]:/tmp$ cat test.java 
public class test { 
public static void main(String args[]) { 
    int test = 42; 
    System.out.println("" + (test >> 1) + ", " + (test << 1) + ", " + (test >>> 1)); 
} 
} 
[email protected]:/tmp$ java test 
21, 84, 21

來源

2011-03-19 23:58:27

移動運算符在android中的語法錯誤

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