我正在尝试制作一个简单的图片动画。我想让直升机的螺旋桨看起来像在转动。我有3张直升机的图片，根据动画进度，我会显示其中一张图片。问题是所有三张图片重叠在一起，而不是只有一张图片出现，从而创建动画效果。到目前为止，我所做的就是这样做，我甚至尝试通过使用canvas.drawColor（Color.BLACK）清除画布，但这将清除整个画布，这不是我想要的。
以下是我的代码：
1）在View类中：
静态类 直升机 { private long mLastUpdate; private long mProgress = 0; private final float mX; private final float mY;
private final Bitmap mHelicopter1;
private final Bitmap mHelicopter2;
private final Bitmap mHelicopter3;
private final float mRadius;
Helicopter(long mLastUpdate, float mX, float mY,
Bitmap helicopter1, Bitmap helicopter2, Bitmap helicopter3) {
this.mLastUpdate = mLastUpdate;
this.mX = mX;
this.mY = mY;
this.mHelicopter1 = helicopter1;
this.mHelicopter2 = helicopter2;
this.mHelicopter3 = helicopter3;
mRadius = ((float) mHelicopter1.getWidth()) / 2f;
}
public void update(long now) {
mProgress += (now - mLastUpdate);
if(mProgress >= 400L)
{
mProgress = 0;
}
mLastUpdate = now;
}
public void setNow(long now) {
mLastUpdate = now;
}
public void draw(Canvas canvas, Paint paint)
{
if (mProgress < 150L)
{
canvas.drawBitmap(mHelicopter1, mX - mRadius, mY - mRadius, paint);
}
else if (mProgress < 300L)
{
canvas.drawBitmap(mHelicopter2, mX - mRadius, mY - mRadius, paint);
}
else if(mProgress < 400L)
{
canvas.drawBitmap(mHelicopter3, mX - mRadius, mY - mRadius, paint);
}
}
public boolean done() {
return mProgress > 700L;
}
}
private ArrayList<Helicopter> mHelicopters = new ArrayList<Helicopter>();
2) 这是在线程的run()方法中调用的:
private void doDraw(Canvas canvas)
{
final long now = SystemClock.elapsedRealtime();
canvas.save();
for (int i = 0; i < mHelicopters.size(); i++) {
final Helicopter explosion = mHelicopters.get(i);
explosion.update(now);
}
for (int i = 0; i < mHelicopters.size(); i++) {
final Helicopter explosion = mHelicopters.get(i);
explosion.draw(canvas, mPaint);
}
canvas.restore();
}
有人能帮我吗？我在网上看了很多关于动画的例子，它们似乎总是涉及文本，而不是图片。谢谢。