Defines animated transitions that occur on state changes. 更多...
| import 语句： | import QtQuick |
A Transition defines the animations to be applied when a State change occurs.
例如，以下
Rectangle
has two states: the default state, and an added "moved" state. In the "moved state, the rectangle's position changes to (50, 50). The added Transition specifies that when the rectangle changes between the default and the "moved" state, any changes to the
x
and
y
properties should be animated, using an
Easing.InOutQuad
.
import QtQuick 2.0 Rectangle { id: rect width: 100; height: 100 color: "red" MouseArea { id: mouseArea anchors.fill: parent } states: State { name: "moved"; when: mouseArea.pressed PropertyChanges { target: rect; x: 50; y: 50 } } transitions: Transition { NumberAnimation { properties: "x,y"; easing.type: Easing.InOutQuad } } }
Notice the example does not require
to
and
from
values for the
NumberAnimation
. As a convenience, these properties are automatically set to the values of
x
and
y
before and after the state change; the
from
values are provided by the current values of
x
and
y
，和
to
values are provided by the
PropertyChanges
object. If you wish, you can provide
to
and
from
values anyway to override the default values.
By default, a Transition's animations are applied for any state change in the parent item. The Transition from and to values can be set to restrict the animations to only be applied when changing from one particular state to another.
Top-level animations within a transition are run in parallel. To run them sequentially, define them within a SequentialAnimation :
transitions: Transition { to: "brighter" reversible: true SequentialAnimation { PropertyAnimation { property: "x"; duration: 1000 } ColorAnimation { duration: 1000 } } }
To define multiple Transitions, specify Item::transitions as a list:
transitions: [
Transition {
from: "*"; to: "middleRight"
NumberAnimation {
properties: "x,y";
easing.type: Easing.InOutQuad;
duration: 2000;
}
},
Transition {
from: "*"; to: "bottomLeft";
NumberAnimation {
properties: "x,y";
easing.type: Easing.InOutQuad;
duration: 200;
}
},
//If any other rectangle is clicked, the icon will return
//to the start position at a slow speed and bounce.
Transition {
from: "*"; to: "*";
NumberAnimation {
easing.type: Easing.OutBounce;
properties: "x,y";
duration: 4000;
}
}
]
If multiple Transitions are specified, only a single (best-matching) Transition will be applied for any particular state change. In the example above, if the Rectangle enters a state other than
"middleRight"
or
"bottomLeft"
, the third Transition will be carried out, meaning the icon will be moved to the starting point.
If a state change has a Transition that matches the same property as a Behavior , the Transition animation overrides the Behavior for that state change.
另请参阅 Qt Quick 中的动画和过渡 , States example , Qt Quick 状态 ，和 Qt QML .
|
from : string |
|
to : string |
These properties indicate the state changes that trigger the transition.
The default values for these properties is "*" (that is, any state).
For example, the following transition has not set the
to
and
from
properties, so the animation is always applied when changing between the two states (i.e. when the mouse is pressed and released).
Rectangle { id: rect width: 100; height: 100 color: "red" MouseArea { id: mouseArea; anchors.fill: parent } states: State { name: "brighter"; when: mouseArea.pressed PropertyChanges { target: rect; color: "yellow" } } transitions: Transition { ColorAnimation { duration: 1000 } } }
If the transition was changed to this:
transitions: Transition { to: "brighter" ColorAnimation { duration: 1000 } }
The animation would only be applied when changing from the default state to the "brighter" state (i.e. when the mouse is pressed, but not on release).
多
to
and
from
values can be set by using a comma-separated string.
另请参阅 reversible .
This property holds a list of the animations to be run for this transition.
transitions: Transition { PropertyAnimation { duration: 3000 } ColorAnimation { duration: 3000 } }
The top-level animations are run in parallel. To run them sequentially, define them within a SequentialAnimation :
transitions: Transition { to: "brighter" reversible: true SequentialAnimation { PropertyAnimation { property: "x"; duration: 1000 } ColorAnimation { duration: 1000 } } }
|
enabled : bool |
This property holds whether the Transition will be run when moving from the
from
state to the
to
状态。
By default a Transition is enabled.
Note that in some circumstances disabling a Transition may cause an alternative Transition to be used in its place. In the following example, although the first Transition has been set to animate changes from "state1" to "state2", this transition has been disabled by setting
被启用
to
false
, so any such state change will actually be animated by the second Transition instead.
Item { states: [ State { name: "state1" }, State { name: "state2" } ] transitions: [ Transition { from: "state1"; to: "state2"; enabled: false }, Transition { // ... } ] }
|
reversible : bool |
This property holds whether the transition should be automatically reversed when the conditions that triggered this transition are reversed.
默认值为 false。
By default, transitions run in parallel and are applied to all state changes if the from and to states have not been set. In this situation, the transition is automatically applied when a state change is reversed, and it is not necessary to set this property to reverse the transition.
However, if a SequentialAnimation is used, or if the from or to properties have been set, this property will need to be set to reverse a transition when a state change is reverted. For example, the following transition applies a sequential animation when the mouse is pressed, and reverses the sequence of the animation when the mouse is released:
Rectangle { id: rect width: 100; height: 100 color: "steelblue" TapHandler { id: tapHandler } states: State { name: "brighter" when: tapHandler.pressed PropertyChanges { target: rect; color: "lightsteelblue"; x: 50 } } transitions: Transition { to: "brighter" reversible: true SequentialAnimation { PropertyAnimation { property: "x"; duration: 1000 } ColorAnimation { duration: 1000 } } } }
If the transition did not set the
to
and
reversible
values, then on the mouse release, the transition would play the
PropertyAnimation
先于
ColorAnimation
instead of reversing the sequence.
|
[read-only] running : bool |
This property holds whether the transition is currently running.
注意： 不像 Animation::running , this property is read only, and can not be used to control the transition.