Question

我有一个集合视图，其中每个单元格包含7个按钮（通过代码而不是故事板创建）。

它们最初是敏锐的，但如果我向上/向下滚动几次，质量会下降。

当我更改视图并返回时，锐度会恢复。

有什么想法吗？

ADDIT：

我在循环中制作这样的按钮（可以是1到7个按钮）

- (UICollectionViewCell*) collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
    static NSString *CellIdentifier = @"patientCell";
    UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:CellIdentifier forIndexPath:indexPath];
    Patient *aPt = [self.fetchedResultsController objectAtIndexPath:indexPath];
    PatientCVCell *ptCell = (PatientCVCell *) cell;
    ptCell.ptName.text = aPt.name;
    ptCell.ptRoom.text = aPt.room;
    ptCell.ptRx.text = aPt.diagnosis;

    int xPos = 20;
    NSArray *daysForRx = aPt.ofList.listDays;
    // loop through to add button for each day of Rx

    for (int i = 0; i < [daysForRx count]; i++) {
        // get the treatment day that == postition in array

        for (Treatment *t in aPt.patientRx) {
            if (t.day == daysForRx[i]) {
                //NSLog(@"%i", xPos);
                StatusButton *testButton = [StatusButton buttonWithType:UIButtonTypeCustom];
                testButton.frame = CGRectMake(xPos, 110, 28, 28);
                testButton.btnTreatment = t;
                // match status of the RX to the correct button

                if ([t.status intValue] == NotSeen) {
                    [testButton setImage:[UIImage imageNamed:@"toSee"] forState:UIControlStateNormal];
                    testButton.linkNumber = NotSeen;
                }
                else if ([t.status intValue] == SeenNotCharted) {
                    [testButton setImage:[UIImage imageNamed:@"seenNotCharted"] forState:UIControlStateNormal];
                    testButton.linkNumber = SeenNotCharted;
                }
                else if ([t.status intValue] == SeenCharted) {
                    [testButton setImage:[UIImage imageNamed:@"seenCharted"] forState:UIControlStateNormal];
                    testButton.linkNumber = SeenCharted;
                }
                else if ([t.status intValue] == NotSeeing) {
                    [testButton setImage:[UIImage imageNamed:@"notSeeing"] forState:UIControlStateNormal];
                    testButton.linkNumber = NotSeeing;
                }
                else if ([t.status intValue] == NotSeeingDC) {
                    [testButton setImage:[UIImage imageNamed:@"notSeeingDischarged"] forState:UIControlStateNormal];
                    testButton.linkNumber = NotSeeingDC;
                }
                [testButton addTarget:self action:@selector(buttonClicked:) forControlEvents:UIControlEventTouchUpInside];
                [cell addSubview:testButton];
                xPos = xPos + 36;
            }
        }
    }
    return cell;
}

图像尺寸正确，因此无需缩放图像。

在模拟器和设备上发生。

仔细观察后，图像内部是锐利的！所以这个问题与方形按钮内按钮的圆形形状的透明度有关！

Answer 1

您正在将单元格出列，然后将按钮添加到出列单元格。

这些按钮永远不会被删除。当您向上和向下滚动时，屏幕上的单元格将放在出列队列中。此时他们仍然有按钮，然后他们出列了，你添加了更多按钮。你有许多按钮在彼此之上，这就是为什么它看起来模糊，你的内存占用变大。

我会在单元格内添加按钮。将它们保存在一个数组中，以便以后删除它们。然后我会添加一个方法来设置你需要的按钮数量。像这样：

// header
@property (strong, nonatomic) NSMutableArray *buttons;

// implementation
- (void)setNumberOfButtons:(NSInteger)numberOfButtons withTarget:(id)target selector:(SEL)selector {
    // remove existing buttons from view
    [self.buttons makeObjectsPerformSelector:@selector(removeFromSuperview)];
    // "save" existing buttons in a reuse queue so you don't have to alloc init them again
    NSMutableArray *reuseQueue = self.buttons;

    self.buttons = [NSMutableArray arrayWithCapacity:numberOfButtons];
    for (NSInteger i = 0; i < numberOfButtons; i++) {
        UIButton *button = [reuseQueue lastObject];
        if (button) {
            [reuseQueue removeLastObject];
        }
        else {
            button = [UIButton buttonWithType:UIButtonTypeCustom];
            // you should always use the same target and selector for all your cells. otherwise this won't work. 
            [button addTarget:target action:selector forControlEvents:UIControlEventTouchUpInside];
        }
        [self.buttons addObject:button];
        button.frame = ....
        // don't set up images or titles. you'll do this from the collectionView dataSource method
    }
}

然后，您将在collectionView:cellForItemAtIndexPath:中设置按钮数量，并根据您的需要配置每个按钮。这些方面的东西：

- (UICollectionViewCell*) collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
    Cell *cell = ... dequeue ...
    Object *object = ... get from your backend ...
    /* configure your cell */
    if ([cell.buttons count] != object.numberOfItems) {
        // no need to remove and add buttons if the item count stays the same
        [cell setNumberOfButtons:object.numberOfItems withTarget:self selector:@selector(buttonPressed:)];
    }
    for (NSInteger i = 0; i < [object.numberOfItems count]; i++) {
        UIButton *button = cell.buttons[i];
        [button setImage:... forState:UIControlStateNormal];
    }
}

行动看起来像这样：

- (IBAction)buttonPressed:(UIButton *)sender {
    UICollectionView *collectionView;
    CGPoint buttonOriginInCollectionView = [sender convertPoint:CGPointZero toView:collectionView];
    NSIndexPath *indexPath = [collectionView indexPathForItemAtPoint:buttonOriginInCollectionView];
    NSAssert(indexPath, @"can't calculate indexPath");
    Cell *cell = [collectionView cellForItemAtIndexPath:indexPath];
    if (cell) {
        NSInteger pressedButtonIndex = [cell.buttons indexOfObject:sender];
        if (pressedButtonIndex != NSNotFound) {
            // do something
        }
    }
    else {
        // cell is offscreen?! why?
    }
}

很直接。获取indexPath，获取collectionViewCell，检查按下的按钮有哪个索引

按钮图像质量集合视图

1 个答案: