有什么方法可以让我们一次只滚动一个 ListView 项目。 就像当你向上滑动时它只会向上滚动一个项目而不是正常滚动类似于向下滚动只有一个项目向下移动。

请帮忙!

这是我的代码:

public class ListViewTestExample extends Activity {

    ListView listView;

    private GestureDetectorCompat mDetector;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main_list_view_test);

        mDetector = new GestureDetectorCompat(this, new MyGestureListener());
        // Grid ListView object from XML
        listView = (ListView) findViewById(R.id.list);

        mDetector = new GestureDetectorCompat(this, new MyGestureListener());
        // Defined Array values to show in ListView

        String[] values = new String[] { "Android List View",
         "Adapter implementation", "Simple List View In Android",
         "Create List View Android", "Android Example",
         "List View Source Code", "List View Array Adapter",
         "Android Example List View" };

         ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
         android.R.layout.simple_list_item_1, android.R.id.text1, values);

         listView.setAdapter(adapter);       
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    public boolean onTouchEvent(MotionEvent event) {
        this.mDetector.onTouchEvent(event);
        return super.onTouchEvent(event);
    }

    class MyGestureListener extends GestureDetector.SimpleOnGestureListener {
        Context context = getApplicationContext();

        public boolean onDown(MotionEvent event) {
                return true;
        }

        public void onLongPress(MotionEvent event) {
            Toast.makeText(context, "Long Press", Toast.LENGTH_SHORT).show();
        }

        public boolean onFling(MotionEvent event1, MotionEvent event2,
                float velocityX, float velocityY) {

            float sensitvity = 50;

            // TODO Auto-generated method stub
            if ((event1.getX() - event2.getX()) > sensitvity) {
                Toast.makeText(context, "Swipe Left", Toast.LENGTH_SHORT)
                    .show();
            } else if ((event2.getX() - event1.getX()) > sensitvity) {
                Toast.makeText(context, "Swipe Right", Toast.LENGTH_SHORT)
                    .show();
            }
            if ((event1.getY() - event2.getY()) > sensitvity) {
                if (event2.getPressure() > event1.getPressure()) {
                    Toast.makeText(context, "Swipe Up + Hold",
                            Toast.LENGTH_SHORT).show();
                } else {
                    Toast.makeText(context, "Swipe Up", Toast.LENGTH_SHORT).show();
                }
            } else if ((event2.getY() - event1.getY()) > sensitvity) {
                if (event2.getPressure() > event1.getPressure()) {
                    Toast.makeText(context, "Swipe Down + Hold",
                        Toast.LENGTH_SHORT).show();
                } else {
                    Toast.makeText(context, "Swipe Down", Toast.LENGTH_SHORT).show();
                }
            }
            return true;
        }

        public boolean onSingleTapConfirmed(MotionEvent event) {
            Toast.makeText(context, "Single Tap Confirmed", Toast.LENGTH_SHORT)
                .show();
            return true;
        }

        public boolean onDoubleTap(MotionEvent event) {
            Toast.makeText(context, "Double Tap Confirmed", Toast.LENGTH_SHORT).show();
            return true;
        }

    }

}

最佳答案

我知道这是一个旧帖子，但我已经在网上搜索过并没有真正找到解决这个问题的方法。所以我找到了适合我的解决方案。您需要制作一个自定义 ListView 并覆盖 dispatchTouchEvent 函数。我的版本检查用户是否以最小速度轻弹，以及他们是否平滑滚动到下一个项目。如果低于此速度，则检查项目是否超过一半，然后进行平滑滚动。否则返回当前项目。此代码假定项目填充 View 。

import android.content.Context;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.VelocityTracker;
import android.view.View;
import android.widget.ListView;

/**
 * Created by bradj on 11/12/13.
 */
public class SingleScrollListView extends ListView
{
    private boolean mSingleScroll = false;
    private VelocityTracker mVelocity = null;
    final private float mEscapeVelocity = 2000.0f;
    final private int mMinDistanceMoved = 20;
    private float mStartY = 0;

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

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

    public SingleScrollListView(Context context, AttributeSet attrs, int defStyle)
    {
        super(context, attrs, defStyle);
    }

    public void setSingleScroll(boolean aSingleScroll) { mSingleScroll = aSingleScroll; }
    public int getVerticalScrollOffset() { return getFirstVisiblePosition(); }

    @Override
    public boolean dispatchTouchEvent(MotionEvent aMotionEvent)
    {
        if (aMotionEvent.getAction() == MotionEvent.ACTION_DOWN)
        {
            if (mSingleScroll && mVelocity == null)
                mVelocity = VelocityTracker.obtain();
            mStartY = aMotionEvent.getY();
            return super.dispatchTouchEvent(aMotionEvent);
        }

        if (aMotionEvent.getAction() == MotionEvent.ACTION_UP)
        {
            if (mVelocity != null)
            {
                if (Math.abs(aMotionEvent.getY() - mStartY) > mMinDistanceMoved)
                {
                    mVelocity.computeCurrentVelocity(1000);
                    float velocity = mVelocity.getYVelocity();

                    if (aMotionEvent.getY() > mStartY)
                    {
                        // always lock
                        if (velocity > mEscapeVelocity)
                            smoothScrollToPosition(getFirstVisiblePosition());
                        else
                        {
                            // lock if over half way there
                            View view = getChildAt(0);
                            if (view != null)
                            {
                                if (view.getBottom() >= getHeight() / 2)
                                    smoothScrollToPosition(getFirstVisiblePosition());
                                else
                                    smoothScrollToPosition(getLastVisiblePosition());
                            }
                        }
                    }
                    else
                    {
                        if (velocity < -mEscapeVelocity)
                            smoothScrollToPosition(getLastVisiblePosition());
                        else
                        {
                            // lock if over half way there
                            View view = getChildAt(1);
                            if (view != null)
                            {
                                if (view.getTop() <= getHeight() / 2)
                                    smoothScrollToPosition(getLastVisiblePosition());
                                else
                                    smoothScrollToPosition(getFirstVisiblePosition());
                            }
                        }
                    }
                }
                mVelocity.recycle();
            }
            mVelocity = null;

            if (mSingleScroll)
            {
                if (Math.abs(aMotionEvent.getY() - mStartY) > mMinDistanceMoved)
                    return super.dispatchTouchEvent(aMotionEvent);
            }
            else
                return super.dispatchTouchEvent(aMotionEvent);
        }

        if (mSingleScroll)
        {
            if (mVelocity == null)
            {
                mVelocity = VelocityTracker.obtain();
                mStartY = aMotionEvent.getY();
            }
            mVelocity.addMovement(aMotionEvent);
        }

        return super.dispatchTouchEvent(aMotionEvent);
    }
}

所以简单的代码就变成了下面这样。 (别忘了将xml中的ListView改成SingleScrollListView)不需要手势监听。

listView = (SingleScrollListView) findViewById(R.id.list);
listView.setSingleScroll(true);

关于android - Android 中的 ListView 项目一次滚动一个，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/18822017/