我成功地在我的 CustomViewPager 开始时创建了一个动画，它就像一个轮播。所以在这里，我的物品从左边来，然后在 3 秒内到右边。问题是它只是一个翻译，我想知道是否可以让我的浏览器从远处滚动到他的最终位置。
你有办法做到这一点吗？问候。
编辑：所以我尝试了其他方法，并创建了我的自定义 ScrollToAnimation。我成功地创造了我想要的东西，但动作并不顺畅，你能帮帮我吗？我的新代码：
import android.support.v4.view.ViewPager;
import android.view.animation.Animation;
import android.view.animation.Transformation;
import java.util.Calendar;
public class ScrollToAnimation extends Animation {
private int currentIndex = 0, nbChilds = -1, deltaT = 0;
private float fromX, toX;
private long animationStart;
private ViewPager viewpager;
public ScrollToAnimation(ViewPager viewpager, float fromX, float toX, int duration) {
this.viewpager = viewpager;
this.fromX = fromX;
this.toX = toX;
nbChilds = viewpager.getChildCount();
deltaT = duration / nbChilds;
setDuration(duration);
animationStart = Calendar.getInstance().getTimeInMillis();
}
@Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
super.applyTransformation(interpolatedTime, t);
int offset = (int) (-fromX * interpolatedTime + fromX);
viewpager.scrollTo(offset, 0);
long animationProgression = Calendar.getInstance().getTimeInMillis() - animationStart;
currentIndex = (int) (animationProgression/deltaT);
if(viewpager.getCurrentItem() != currentIndex) {
viewpager.setCurrentItem(nbChilds-currentIndex, false);
}
}
}
视图页面：
import android.content.Context;
import android.graphics.Canvas;
import android.support.v4.view.ViewPager;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.animation.Animation;
import android.view.animation.Interpolator;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
public class CarouselViewPager extends ViewPager {
private DisplayMetrics metrics;
private Animation animation;
private SpeedScroller mScroller = null;
private boolean animationNotStarted = true, leftToRight;
public CarouselViewPager(Context context) {
super(context);
postInitViewPager();
metrics = getContext().getResources().getDisplayMetrics();
}
public CarouselViewPager(Context context, AttributeSet attrs) {
super(context, attrs);
postInitViewPager();
metrics = getContext().getResources().getDisplayMetrics();
}
private void postInitViewPager() {
try {
Class<?> viewpager = ViewPager.class;
Field scroller = viewpager.getDeclaredField("mScroller");
scroller.setAccessible(true);
Field interpolator = viewpager.getDeclaredField("sInterpolator");
interpolator.setAccessible(true);
mScroller = new SpeedScroller(getContext(), (Interpolator) interpolator.get(null));
scroller.set(this, mScroller);
} catch (Exception e) {
Log.e("postInitViewPager", e.getMessage());
}
}
public void setScrollDurationFactor(double scrollFactor) {
mScroller.setScrollDurationFactor(scrollFactor);
}
@Override
public void setCurrentItem(int item, boolean smoothScroll) {
try {
Method method = ViewPager.class.getDeclaredMethod("setCurrentItemInternal", int.class, boolean.class, boolean.class, int.class);
method.setAccessible(true);
method.invoke(this, item, true, false, 1500);
} catch (Exception e) {
e.printStackTrace();
super.setCurrentItem(item, smoothScroll);
}
}
public void startAnimation(boolean leftToRight) {
animation = new ScrollToAnimation(this, ((metrics.widthPixels/2)+200)*2, 0, 2000);
animationNotStarted = false;
this.leftToRight = leftToRight;
}
private Canvas enterAnimation(final Canvas c) {
animationNotStarted = true;
startAnimation(animation);
scrollTo(0, 0);
return c;
}
@Override
protected void onDraw(Canvas canvas) {
if (!animationNotStarted) {
canvas = enterAnimation(canvas);
}
super.onDraw(canvas);
}
}
编辑2：
这里有一个截图可以帮助你理解我想要什么。实际上我有一个这样的自定义viewpager：
我想要的动画如下：
- 当我启动动画时，项目很远。
- 之后，它们从左到右（或相反）并停在所选项目上，但我希望在项目滚动时具有缩放效果。
- 由于自定义适配器，我成功创建了缩放效果
我的问题，这是当我设置当前项目时它不流畅，你知道吗？这是代码适配器
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.TextView;
import java.util.ArrayList;
public class CarouselAdapter extends FragmentPagerAdapter implements ViewPager.OnPageChangeListener {
private float scale;
private MainActivity context;
private FragmentManager fragmentManager;
private ArrayList<Entity> entities = new ArrayList<>();
private ScaledFrameLayout cur = null, next = null;
public CarouselAdapter(MainActivity context, FragmentManager fragmentManager, ArrayList<Entity> mData) {
super(fragmentManager);
this.fragmentManager = fragmentManager;
this.context = context;
this.entities = mData;
}
@Override
public Fragment getItem(int position) {
if (position == MainActivity.FIRST_PAGE) {
scale = MainActivity.BIG_SCALE;
} else {
scale = MainActivity.SMALL_SCALE;
}
Fragment fragment = CarouselFragment.newInstance(context, entities.get(position), position, scale);
return fragment;
}
@Override
public int getItemPosition(Object object) {
return super.getItemPosition(object);
}
@Override
public int getCount() {
return entities.size();
}
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
if (positionOffset >= 0f && positionOffset <= 1f) {
cur = getRootView(position);
cur.setScaleBoth(MainActivity.BIG_SCALE - MainActivity.DIFF_SCALE * positionOffset);
if (position < entities.size()-1) {
next = getRootView(position + 1);
next.setScaleBoth(MainActivity.SMALL_SCALE + MainActivity.DIFF_SCALE * positionOffset);
}
}
}
@Override
public void onPageSelected(int position) { }
@Override
public void onPageScrollStateChanged(int state) {}
private ScaledFrameLayout getRootView(int position) {
return (ScaledFrameLayout) fragmentManager.findFragmentByTag(this.getFragmentTag(position)).getView().findViewById(R.id.rootItem);
}
private String getFragmentTag(int position) {
return "android:switcher:" + context.carousel.getId() + ":" + position;
}
}
更简单的方法是在不刷新所有内容的情况下更改当前项目的当前位置，这可能吗？我的意思是没有进行任何转换，因为如您所见，我已经有了翻译，当我设置当前项目时，结果与我的滚动到偏移量发生冲突。