Android自定义ViewPager:水平滑动弹性效果，侧滑刷新加载的ViewPager

效果：

public class FlexibleViewPager extends ViewPager {
public FlexibleViewPager(Context context) {
super(context);
}

public FlexibleViewPager(Context context, AttributeSet attrs) {
super(context, attrs);
}

}

@Override
protected void onPageScrolled(int position, float offset, int offsetPixels) {//监听viewpager是否是第一页或最后一页
if (getAdapter() == null && getAdapter().getCount() == 0) {
isMoveLeft = false;
isMoveRight = false;
} else if (position == 0 && offset == 0 && offsetPixels == 0) {//当前为首页，左边能滑出
isMoveLeft = true;
} else if (position == getAdapter().getCount() - 1 && offset == 0 && offsetPixels == 0) {
isMoveRight = true;
} else {
isMoveLeft = false;
isMoveRight = false;
}
if (normal.isEmpty() || normal.top - normal.bottom == 0) {
normal.set(this.getLeft(), this.getTop(), this.getRight(), this.getBottom());//记录原来view的位置
}
super.onPageScrolled(position, offset, offsetPixels);
}

@Override
public boolean onTouchEvent(MotionEvent ev) {
switch (ev.getAction()) {
case MotionEvent.ACTION_MOVE:
if (x == 0) {
x = ev.getX();//记录位置
}
xMove = (int) (x - ev.getX()) / 2;//计算移动距离
if (isMoveLeft && xMove <= 0||isMoveRight && xMove >= 0) {//移动位置
this.layout(-xMove, normal.top, normal.right - xMove, normal.bottom);
return true;
}
break;
case MotionEvent.ACTION_UP:
if (isMoveLeft || isMoveRight) {
animation(xMove);//还原动画
}
break;
}
return super.onTouchEvent(ev);
}

附上全部代码：

/**
* Created by wcb on 2017/4/19.
*/

public class FlexibleViewPager extends ViewPager {
private static final String TAG = "FlexibleViewPager::::";
private boolean isMoveLeft = true;//左边是否能移动
private boolean isMoveRight;
private Rect normal = new Rect();//记录原来的位置
private OnRefreshListener listener;
float x = 0;//记录开始触摸的位置
int xMove = 0;//移动的距离

public FlexibleViewPager(Context context) {
super(context);
}

public FlexibleViewPager(Context context, AttributeSet attrs) {
super(context, attrs);
}

@Override
protected void onFinishInflate() {
super.onFinishInflate();
}

@Override
public boolean onTouchEvent(MotionEvent ev) {
switch (ev.getAction()) {
case MotionEvent.ACTION_MOVE:
if (x == 0) {
x = ev.getX();//记录位置
}
xMove = (int) (x - ev.getX()) / 2;//计算移动距离
Log.e(TAG, "xMove:" + xMove + "isMoveLeft:" + isMoveLeft + "isMoveRight:" + isMoveRight);
if (isMoveLeft && xMove <= 0 || isMoveRight && xMove >= 0) {//移动位置
this.layout(-xMove, normal.top, normal.right - xMove, normal.bottom);
return true;
}
break;
case MotionEvent.ACTION_UP:
if (isMoveLeft || isMoveRight) {
animation(xMove);//还原位置
}
break;
}
return super.onTouchEvent(ev);
}

@Override
protected void onPageScrolled(int position, float offset, int offsetPixels) {//监听viewpager是否是第一页或最后一页
if (getAdapter() == null && getAdapter().getCount() == 0) {
isMoveLeft = false;
isMoveRight = false;
} else if (position == 0 && offset == 0 && offsetPixels == 0) {
isMoveLeft = true;
} else if (position == getAdapter().getCount() - 1 && offset == 0 && offsetPixels == 0) {
isMoveRight = true;
} else {
isMoveLeft = false;
isMoveRight = false;
}
if (normal.isEmpty() || normal.top - normal.bottom == 0) {
normal.set(this.getLeft(), this.getTop(), this.getRight(), this.getBottom());//viewpager记录原来位置
}
super.onPageScrolled(position, offset, offsetPixels);
}

/**
* 还原动画
**/
public void animation(int moveX) {
if (listener != null) {
if (moveX > getWidth() / 6) {//滑动的距离超过屏幕的1/6才回调
listener.onLoadMore();
} else if (moveX < -getWidth() / 6) {
listener.onRefresh();
}
}
x = 0;
TranslateAnimation ta = new TranslateAnimation(this.getX(), normal.left, 0, 0);
ta.setDuration(200);
this.startAnimation(ta);
this.layout(normal.left, normal.top, normal.right, normal.bottom);
}

public void setOnRefreshListener(OnRefreshListener listener) {
this.listener = listener;
}

public interface OnRefreshListener {
void onRefresh();

void onLoadMore();
}

}