android - ViewFlipper 动画，在两个 ImageView 之间平滑滚动

Question

我有这段代码可以在两个 ImageViews 之间滑动

public class CaseHolder extends MainClass{

// for the next movement
public static Animation inFromLeftAnimation() {
    Animation inFromLeft = new TranslateAnimation(
            Animation.RELATIVE_TO_PARENT, -1.0f,
            Animation.RELATIVE_TO_PARENT, 0.0f,
            Animation.RELATIVE_TO_PARENT, 0.0f,
            Animation.RELATIVE_TO_PARENT, 0.0f);
    inFromLeft.setDuration(350);
    inFromLeft.setInterpolator(new AccelerateInterpolator());
    return inFromLeft;
}
// for the previous movement
public static Animation inFromRightAnimation() {

    Animation inFromRight = new TranslateAnimation(
            Animation.RELATIVE_TO_PARENT, +1.0f,
            Animation.RELATIVE_TO_PARENT, 0.0f,
            Animation.RELATIVE_TO_PARENT, 0.0f,
            Animation.RELATIVE_TO_PARENT, 0.0f);
    inFromRight.setDuration(350);
    inFromRight.setInterpolator(new AccelerateInterpolator());
    return inFromRight;
}
public static Animation outToLeftAnimation() {
    Animation outtoLeft = new TranslateAnimation(
            Animation.RELATIVE_TO_PARENT, 0.0f,
            Animation.RELATIVE_TO_PARENT, -1.0f,
            Animation.RELATIVE_TO_PARENT, 0.0f,
            Animation.RELATIVE_TO_PARENT, 0.0f);
    outtoLeft.setDuration(350);
    outtoLeft.setInterpolator(new AccelerateInterpolator());
    return outtoLeft;
}
public static Animation outToRightAnimation() {
    Animation outtoRight = new TranslateAnimation(
            Animation.RELATIVE_TO_PARENT, 0.0f,
            Animation.RELATIVE_TO_PARENT, +1.0f,
            Animation.RELATIVE_TO_PARENT, 0.0f,
            Animation.RELATIVE_TO_PARENT, 0.0f);
    outtoRight.setDuration(350);
    outtoRight.setInterpolator(new AccelerateInterpolator());
    return outtoRight;
}
TextView pcn;

TextView header;
TextView date;
ImageView right;
TextView status; 

ImageView left;
String dateFromIntent;

String pcnFromIntent;

String statusFromIntent; 

ViewFlipper vf;

float oldTouchValue;

boolean isDown;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    super.setTabBar(R.layout.caseholder);
    overridePendingTransition(R.anim.activityfade, R.anim.activityfadeout);

    vf = (ViewFlipper) findViewById(R.id.viewFlipper01);


    pcn = (TextView) findViewById(R.id.pcn);
    header = (TextView) findViewById(R.id.textView1);
    date = (TextView) findViewById(R.id.date);
    status = (TextView) findViewById(R.id.status);

    right = (ImageView) findViewById(R.id.rightF);
    left = (ImageView) findViewById(R.id.leftF);

    header.setText("Overview");
    pcnFromIntent = getIntent().getExtras().getString("pcn");
    dateFromIntent = getIntent().getExtras().getString("date");
    statusFromIntent = getIntent().getExtras().getString("status");

    date.setText("Date: " + dateFromIntent);
    pcn.setText(pcnFromIntent);
    status.setText("Status: " + statusFromIntent);

    if (getIntent().hasExtra("right")) {
        Bitmap b = BitmapFactory.decodeByteArray(getIntent()
                .getByteArrayExtra("right"), 0, getIntent()
                .getByteArrayExtra("right").length);
        right.setImageBitmap(b);
    }

    if (getIntent().hasExtra("left")) {
        Bitmap b1 = BitmapFactory.decodeByteArray(getIntent()
                .getByteArrayExtra("left"), 0, getIntent()
                .getByteArrayExtra("left").length);

        left.setImageBitmap(b1);
    }

}

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK) {
        Intent j = new Intent(getApplicationContext(), MainClass.class);
        startActivity(j);
          CaseHolder.this.finish();
             overridePendingTransition(R.anim.activityfade, R.anim.activityfadeout);
        return true;
    }
    return super.onKeyDown(keyCode, event);
}

@Override
public boolean onTouchEvent(MotionEvent touchevent) {

    switch (touchevent.getAction()) {
    case MotionEvent.ACTION_DOWN: {
        oldTouchValue = touchevent.getX();
        break;
    }
    case MotionEvent.ACTION_UP: {

        float currentX = touchevent.getX();
        if (oldTouchValue < currentX) {
            vf.setInAnimation(inFromLeftAnimation());
            vf.setOutAnimation(outToRightAnimation());
            vf.showNext();

        }
        if (oldTouchValue > currentX) {
            vf.setInAnimation(inFromRightAnimation());
            vf.setOutAnimation(outToLeftAnimation());
            vf.showPrevious();
        }
        break;
    }
    }
    return false;
}

这完全没问题，但我想要更平滑的滚动。目前，用户必须将手指从屏幕上移开，才能在 Views 之间滑动。我如何修改这段代码，以便用户可以在屏幕上滑动手指，而 ViewFlipper 将“跟随”手指的移动？

Answer 1

只需使用其适配器实现 android.support.v4.view.ViewPager，很简单。这是适配器类的代码。您只需将 View 添加到 adapter 并将 ViewPager 的 Adapter 设置为此。

public class PreferencesViewPagerAdapter extends PagerAdapter
{
    ArrayList<View> preferencesViews;

public PreferencesViewPagerAdapter(ArrayList<View> preferencesViews)
{
    this.preferencesViews = preferencesViews;
}

@Override
public Object instantiateItem(ViewGroup container, int position)
{
    ((ViewPager) container).addView(preferencesViews.get(position));
    return preferencesViews.get(position);
}

@Override
public int getCount()
{
    return preferencesViews.size();
}

@Override
public boolean isViewFromObject(View view, Object object)
{
    return view == object;
}

@Override
public void destroyItem(ViewGroup container, int position, Object view)
{
    ((ViewPager) container).removeView((View) view);
}