本来项目是用的viewpager实现的轮播滚动，但是客户觉得轮播的效果太大众化了，于是就要我们改成渐变切换的效果。听到这需求，我最先想到是给viewpager设置切换动画，但是无论怎么设置动画，都要手动切换的时候才有效果。于是我就自定义了一个控件，利用淡入淡出动画实现了这效果，还是先上效果图，没效果图说再多也没用。
public class Gradient extends RelativeLayout {
private List<ImageView> imageViews;
private List<Animation> outAnim;//淡出动画
private List<Animation> inAnim;//淡入动画
private Context mContext;
private Handler handler = new Handler(Looper.getMainLooper());
private int couot;
private int currentIndex;//当前的页面
private LinearLayout linearLayout;
private onClickListner listner;
private long time=3000;//动画间隔时间
public Gradient(Context context) {
this(context, null);
}
public Gradient(Context context, AttributeSet attrs) {
super(context, attrs);
this.mContext = context;
}
/**
* 画点
*/
public void cratePoint() {
if (null != imageViews && imageViews.size() > 0) {
int size = imageViews.size();
linearLayout = new LinearLayout(mContext);
linearLayout.setOrientation(LinearLayout.HORIZONTAL);
linearLayout.setGravity(Gravity.CENTER);
// 添加图片
for (int i = 0; i < size; i++) {
// 设置圆点
View viewPoint = new View(mContext);
viewPoint.setBackgroundResource(R.drawable.point_background);
int weight = dip2px(mContext, 5);
LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(weight, weight);
lp.leftMargin = weight;
viewPoint.setLayoutParams(lp);
viewPoint.setEnabled(false);
linearLayout.addView(viewPoint);
}
View childAt = linearLayout.getChildAt(0);
if (null != childAt) {
childAt.setEnabled(true);
}
//添加到图片的下边
RelativeLayout.LayoutParams rlp = new RelativeLayout.LayoutParams(-1,-2);
rlp.bottomMargin = dip2px(mContext, 5);
rlp.addRule(ALIGN_PARENT_BOTTOM);
this.addView(linearLayout, rlp);
}
}
/**
* 根据手机的分辨率从 dip 的单位 转成为 px(像素)
*/
public static int dip2px(Context context, float dpValue) {
final float scale = context.getResources().getDisplayMetrics().density;
return (int) (dpValue * scale + 0.5f);
}
/**
* 设置图片
* @param imageViews
*/
public void setImageViews(List<ImageView> imageViews) {
this.imageViews = imageViews;
for (int i = 0; i < imageViews.size(); i++) {
RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(-1,-1);
addView(imageViews.get(i),layoutParams);
}
setonClick();
cratePoint();
createAnim();
start();
}
/**
* 开启动画
*/
private void start() {
final int size = imageViews.size();
handler.post(new Runnable() {
@Override
public void run() {
final int i = couot % size;
//解决点击事件的冲突
for (int j = 0; j < size; j++) {
if (j == i) {
imageViews.get(i).setClickable(true);
} else {
imageViews.get(i).setClickable(false);
}
}
if (couot < size) {
if (i == size - 1) {
ImageView imageView = imageViews.get(0);
imageView.startAnimation(outAnim.get(0));
ImageView imageView2 = imageViews.get(size - 1);
imageView2.startAnimation(inAnim.get(size - 1));
} else {
//当前的淡出,下一张淡入
ImageView imageView = imageViews.get(size - 1 - i);
imageView.startAnimation(outAnim.get(size - 1 - i));
}
} else {
if (i == size - 1) {
//当显示到最后一张的时候,要跳到第一张
ImageView imageView = imageViews.get(0);
imageView.startAnimation(outAnim.get(0));
ImageView imageView2 = imageViews.get(size - 1);
imageView2.startAnimation(inAnim.get(size - 1));
} else {
//当前的淡出,下一张淡入
ImageView imageView = imageViews.get(size - 1 - i);
imageView.startAnimation(outAnim.get(size - 1 - i));
ImageView imageView2 = imageViews.get(size - 2 - i);
imageView2.startAnimation(inAnim.get(size - 2 - i));
}
}
currentIndex = i;
linearLayout.getChildAt(currentIndex % size).setEnabled(false);
currentIndex++;
linearLayout.getChildAt(currentIndex % size).setEnabled(true);
couot++;
handler.postDelayed(this, time);
}
});
}
/**
* 创建动画
*/
private void createAnim() {
outAnim = new ArrayList<>();
inAnim = new ArrayList<>();
for (int i = 0; i < imageViews.size(); i++) {
Animation zoomOutAwayAnim = createZoomOutAwayAnim();
zoomOutAwayAnim.setFillAfter(true);
outAnim.add(zoomOutAwayAnim);
Animation zoomOutNearAnim = createZoomOutNearAnim();
zoomOutNearAnim.setFillAfter(true);
inAnim.add(zoomOutNearAnim);
}
}
/**
* 设置点击事件
*/
public void setonClick() {
for (int i = 0; i < imageViews.size(); i++) {
imageViews.get(i).setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
if (listner != null) {
listner.setonClick((currentIndex) % imageViews.size());
}
}
});
}
}
public interface onClickListner{
void setonClick(int position);
}
/**
* 设置动画播放和handler延迟时间
* @param time
*/
public void setTime(long time) {
this.time = time;
}
public void setListner(onClickListner listner) {
this.listner = listner;
}
/** 创建一个淡出缩小的动画 */
public Animation createZoomOutAwayAnim() {
AnimationSet ret;
Animation anim;
ret = new AnimationSet(false);
// 创建一个淡出的动画
anim = new AlphaAnimation(1f, 0f);
anim.setDuration(time);
anim.setInterpolator(new DecelerateInterpolator());
ret.addAnimation(anim);
// 创建一个缩小的动画
/*anim = new ScaleAnimation(1, 0, 1, 0, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);
anim.setDuration(MEDIUM);
anim.setInterpolator(new DecelerateInterpolator());
ret.addAnimation(anim);*/
return ret;
}
/** 创建一个淡入缩小的动画 */
public Animation createZoomOutNearAnim() {
AnimationSet ret;
Animation anim;
ret = new AnimationSet(false);
// 创建一个淡入的动画
anim = new AlphaAnimation(0f, 1f);
anim.setDuration(time);
anim.setInterpolator(new LinearInterpolator());
ret.addAnimation(anim);
// 创建一个缩小的动画
/*anim = new ScaleAnimation(3, 1, 3, 1, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);
anim.setDuration(MEDIUM);
anim.setInterpolator(new DecelerateInterpolator());
ret.addAnimation(anim);*/
return ret;
}
}
这个控件的使用非常简单只要在布局文件中使用我们自定义的控件，然后调用setTime设置动画切换的时间，setListener设置图片的点击事件，setImagevies设置图片就可以实现效果.考虑到内存泄漏的问题，只要在ondestry方法里面调用stop方法即可，点击下载Demo
