Question

我正在使用Autoscroll示例中的Apple TapDetectingImageView类。

静态分析器显示以下警告：

类别/ TapDetectingImageView.m：68：30：{68：17-68：29}：警告：

The left operand of '==' is a garbage value
         if (tapCounts[0] == 1 && tapCounts[1] == 1) {
             ~~~~~~~~~~~~ ^

以下附加代码。读取变量时，如果没有先初始化，则会发生垃圾值。但似乎tapCounts已经初始化了。

如果应用程序运行正常或我应该修改任何内容，我可以忽略它吗？

    BOOL allTouchesEnded = ([touches count] == [[event touchesForView:self] count]);

// first check for plain single/double tap, which is only possible if we haven't seen multiple touches
if (!multipleTouches) {
    UITouch *touch = [touches anyObject];
    tapLocation = [touch locationInView:self];

    if ([touch tapCount] == 1) {
        [self performSelector:@selector(handleSingleTap) withObject:nil afterDelay:DOUBLE_TAP_DELAY];
    } else if([touch tapCount] == 2) {
        [self handleDoubleTap];
    }
}   

// check for 2-finger tap if we've seen multiple touches and haven't yet ruled out that possibility
else if (multipleTouches && twoFingerTapIsPossible) {

    // case 1: this is the end of both touches at once
    if ([touches count] == 2 && allTouchesEnded) {
        int i = 0;
        int tapCounts[2]; CGPoint tapLocations[2];
        for (UITouch *touch in touches) {
            tapCounts[i]    = [touch tapCount];
            tapLocations[i] = [touch locationInView:self];
            i++;
        }
        if (tapCounts[0] == 1 && tapCounts[1] == 1) { // it's a two-finger tap if they're both single taps
            tapLocation = midpointBetweenPoints(tapLocations[0], tapLocations[1]);
            [self handleTwoFingerTap];
        }
    }

Answer 1

当创建变量但未初始化为值时会发生这种情况。在上面的代码中，您可以这样做：

int tapCounts[2];
...

但是在尝试在if语句中对它进行评估几行之前，不要将数组内容初始化为任何内容：

if( tapCounts[0] == 1 && tapCounts[1] == 1 ) {
   ....
}

编译器警告您tapCounts [0]的内容未初始化并且是垃圾。

Answer 2

这是由于tapCounts数组初始化为索引0和1的垃圾值。

请更改行：

int tapCounts[2]; CGPoint tapLocations[2];

与

int tapCounts[2] = {0,0}; CGPoint tapLocations[2] = {0,0};

这将在分析构建

时删除初始化警告

点击检测垃圾值

2 个答案: