Multimedia animation playback application
1.1 Experimental purpose
Master the use of Android multimedia animation playback
1.2 Experimental steps
1. Create an Android application and create MainActivity.
2. Add the control code in the activity_main main layout file
3. Add the animated xml file to the drawable folder
4. Add animation initialization code to MainActivity, and write frame-by-frame animation and tween animation respectively.
1.3 实验代码
1. Create a project
2. Write the initialization code for frame-by-frame animation, and add the control code in the activity_main main layout file:
2.1 Add the frame_animation.xml initialization code of the animation to the drawable folder, and place all the image files in the drawable folder.
2.2 Add imageView initialization code to MainActivity
3. Start a new project and follow the steps to complete the usage of tween animation. Add the following code to the activity_main main layout file and place the images used in the code into the drawable folder.
Add anim folder under the res folder to store animation xml files
How to edit tweened animations separately
alpha.xml
rotate.xml
scale.xml
translate.xml
tween.xml
Add the following code to MainActivity
Experimental effect
1.4 Experimental Summary
1, Frame )
Frame-by-frame animation in Android is the simple process of continuously displaying a series of images at short intervals, so that the final effect is a moving or changing object.
Before developing frame-by-frame animation, you first need to plan the animation sequence using a series of images.
2, Tween animation (Tween)
Tween animation is a way to set the start state and end state of animation, and the changes in the middle are supplemented by system calculations. Tween animation is implemented by the Animation class to achieve specific effects, including four subclasses and four variations:
1. TranslateAnimation
2. Scale(ScaleAnimation)
3. Rotate(RotateAnimation)
4, Transparency (AlphaAnimation)
It can be implemented through xml or java code.
(1)Alpha (transparency) animation
When creating a transparency animation, you need to specify the transparency at the beginning of the animation, the transparency at the end, and the duration of the animation. Transparency values range from 0.0 to 1.0.
1.0 means the transparency is completely opaque, and 0.0 means completely transparent.
(2)Scale animation
When creating a scaling animation effect, you need to specify the scaling ratio at the beginning of the animation, the scaling ratio at the end, and specify the duration of the animation. Since the scaling effect of the scaling animation is different from to the same reference point, it is also necessary to specify the scaling center point of the scaling animation.
(3)Translate (bit) moving animation
When creating a displacement animation, you need to specify the position when the animation starts, the position when it ends, and the duration of the animation.
(4)Rotate animation
When creating a rotation animation, you need to specify the rotation angle at the beginning and end of the animation.
The rotation angle and animation duration. Due to rotation animation to different points
The effects of center rotation are different, so you also need to know how to specify the "rotation axis"
coordinate of.
Property description:
android: fromDegrees
Rotation start angle, positive number indicates clockwise direction, negative number indicates counterclockwise direction.
android: toDegrees
End angle of rotation, positive number indicates clockwise direction, negative number indicates counterclockwise direction.
android: pivotX
The X coordinate of the rotation center point.
android:pivotY
The Y coordinate of the rotation center point.