iPhone: modifying view when user shakes
I am developing an iPhone application which deletes rows from a table view when the user shakes the phone. I have created a navigation-based project. Now when the user shakes the iPhone I want the title of the navigation bar to change to "DELETE" and a delete button to appear on the navigation bar, in the same view. Otherwise, when a user selects a particular row it should move to the next view. I have written the following code but it's not working. Please help me out.
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
if (isShaked == NO)
{
//logic to move to next view goes here.
}
else
{
self.title = @"Del开发者_JAVA技巧ete Rows";
delete=[[UIBarButtonItem alloc] initWithTitle:@"Delete rows" style:
UIBarButtonItemStyleBordered target:self action:@selector(deleteItemsSelected)] ;
self.navigationItem.rightBarButtonItem=self.delete;
MyTableCell *targetCustomCell = (MyTableCell *)[tableView cellForRowAtIndexPath:indexPath];
[targetCustomCell checkAction];
[self.tempArray addObject: [myModal.listOfStates objectAtIndex:indexPath.row]];
//[delete addTarget:self action:@selector(deleteItemsSelected:) forControlEvents:UIControlEventTouchUpInside];
self.tempTableView = tableView;
}
}
-(void)deleteItemsSelected
{
[myModal.listOfStates removeObjectsInArray:tempArray];
[tempTableView reloadData];
}
checkAction
method is a custom cell method which is used to put a tickmark on the row selected.
In order for you to check if the phone's been shaken, your class will have to use the UIAccelerometerDelegate protocol.
For example:
@interface myTableViewClass : UITableView <UIAccelerometerDelegate>
Then, you need to be able to tell when the phone's been shaken (I use this in my viewDidLoad):
[[UIAccelerometer sharedAccelerometer] setDelegate:self];
[[UIAccelerometer sharedAccelerometer] setUpdateInterval:0.1];
Once the user shakes the phone, you can do your magic in this method:
- (void)accelerometer:(UIAccelerometer *)accelerometer didAccelerate:(UIAcceleration *)acceleration
{
if(fabsf(acceleration.x) > 2.2 || fabsf(acceleration.y) > 2.2 || fabsf(acceleration.z) > 2.2){
//The user has shaken the iPhone
}
}
You can obviously change the interval to check more often and change the parameters on the accelerometer:didAccelerate method to suit your needs.
Check these methods/APIs:
- (void)motionBegan:(UIEventSubtype)motion withEvent:(UIEvent *)event
- (void)motionCancelled:(UIEventSubtype)motion withEvent:(UIEvent *)event
- (void)motionEnded:(UIEventSubtype)motion withEvent:(UIEvent *)event
These are event handlers provided for motion recognition. Go through the document before using these.
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