Android自定义左滑删除列表 Android实现左滑删除列表功能

时间:2021-03-30 peterchen1101 人气:1

1、布局文件view_left_slide_remove.xml

包含一个RelativeLayout和TextView，RelativeLayout是实际界面，TextView是删除按钮。

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="40dp">
  <RelativeLayout
    android:id="@+id/view_content"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />
  <TextView
    android:id="@+id/tv_remove"
    android:layout_width="@dimen/left_slide_remove_width"
    android:layout_height="match_parent"
    android:layout_alignParentRight="true"
    android:gravity="center"
    android:text="删除"
    android:textSize="16sp"
    android:textColor="@color/white"
    android:background="#ffff4b30"
    android:visibility="gone"/>
</RelativeLayout>

2、自定义Adapter

LeftSlideRemoveAdapter类实现了BaseAdapter。
在getView方法中引用了view_left_slide_remove布局，提供getSubView来导入真正的布局。
OnItemRemoveListener是删除监听器。

public static abstract class LeftSlideRemoveAdapter extends BaseAdapter {
 protected Context mContext;
 private OnItemRemoveListener mListener;
 
 public LeftSlideRemoveAdapter(Context context) {
 this.mContext = context;
 }
 
 @Override
 public final View getView(final int position, View convertView, ViewGroup parent) {
 ViewHolder holder;
 if (convertView == null) {
  LayoutInflater inflater = LayoutInflater.from(mContext);
  convertView = inflater.inflate(R.layout.view_left_slide_remove, parent, false);
 
  holder = new ViewHolder();
  holder.viewContent = (RelativeLayout) convertView.findViewById(R.id.view_content);
  holder.tvRmove = (TextView) convertView.findViewById(R.id.tv_remove);
  convertView.setTag(holder);
 
  // viewChild是实际的界面
  holder.viewChild = getSubView(position, null, parent);
  holder.viewContent.addView(holder.viewChild);
 } else {
  holder = (ViewHolder) convertView.getTag();
  getSubView(position, holder.viewChild, parent);
 }
 holder.tvRmove.setOnClickListener(new View.OnClickListener(){
  @Override
  public void onClick(View v) {
  if (mListener != null) {
   mListener.onItemRemove(position);
   notifyDataSetChanged();
  }
  }
 });
 return convertView;
 }
 
 public abstract View getSubView(int position, View convertView, ViewGroup parent);
}
 
private static class ViewHolder {
 RelativeLayout viewContent;
 View viewChild;
 View tvRmove;
}
 
public static interface OnItemRemoveListener {
 public void onItemRemove(int position);
}

3、自定义左滑删除列表

在dispatchTouchEvent方法里面捕捉MotionEvent事件。
在onTouchEvent方法里面滑动界面。
VelocityTracker类记录手势。
Scroller类进行滑动操作。

public class LeftSlideRemoveListView extends ListView {
  private final static int SNAP_VELOCITY = 600;
 
  private Scroller mScroller;
  private VelocityTracker mVelocityTracker;
 
  private int mTouchSlop;
  private boolean mIsSlide = false;
  private int mDelta = 0;
  private int mDownX;
  private int mDownY;
  private int mMaxDistence;
  private int mSlidePosition = INVALID_POSITION;
  private OnItemRemoveListener adapterListener;
 
  private OnItemRemoveListener mRemoveListener = new OnItemRemoveListener() {
    @Override
    public void onItemRemove(int position) {
      if (adapterListener != null) {
        adapterListener.onItemRemove(position);
      }
      clear();
      mSlidePosition = INVALID_POSITION;
    }
  };
  private LeftSlideRemoveAdapter mRemoveAdapter;
 
  private View mCurrentContentView, mCurrentRemoveView;
 
  public LeftSlideRemoveListView(Context context) {
    this(context, null);
  }
 
  public LeftSlideRemoveListView(Context context, AttributeSet attrs) {
    super(context, attrs);
 
    mScroller = new Scroller(context);
    mTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop();
 
    mMaxDistence = context.getResources().getDimensionPixelSize(
        R.dimen.left_slide_remove_width);
  }
 
  @Override
  public boolean dispatchTouchEvent(MotionEvent ev) {
    switch (ev.getAction()) {
      case MotionEvent.ACTION_DOWN:
        addVelocityTracker(ev);
 
        if (!mScroller.isFinished()) {
          return super.dispatchTouchEvent(ev);
        }
        // 起始位置，当前position
        mDownX = (int) ev.getX();
        mDownY = (int) ev.getY();
        int position = pointToPosition(mDownX, mDownY);
        if (position == mSlidePosition) break;
 
        mSlidePosition = position;
 
        if (mSlidePosition == INVALID_POSITION ) {
          return super.dispatchTouchEvent(ev);
        }
 
        // 恢复状态
        clear();
 
        // 获取当前界面
        View childView = getChildAt(mSlidePosition - getFirstVisiblePosition());
        mCurrentContentView = childView.findViewById(R.id.view_content);
        mCurrentRemoveView = childView.findViewById(R.id.tv_remove);
 
        break;
      case MotionEvent.ACTION_MOVE:
        if (mCurrentContentView == null) break;
 
        if (Math.abs(getScrollVelocity()) > SNAP_VELOCITY
            || (Math.abs(ev.getX() - mDownX) > mTouchSlop
            && Math.abs(ev.getY() - mDownY) < mTouchSlop)) {
          // 开始滑动
          mIsSlide = true;
        }
        break;
      case MotionEvent.ACTION_UP:
        if (mCurrentContentView == null && mIsSlide) break;
 
        // 如果左滑小于4/5，按钮不显示
        if (mDelta < mMaxDistence * 4 / 5) {
          mCurrentRemoveView.setVisibility(View.GONE);
          scrollRight();
        } else if (mDelta < mMaxDistence) {
          scrollLeft();
        }
        recycleVelocityTracker();
        mIsSlide = false;
        break;
    }
 
    return super.dispatchTouchEvent(ev);
  }
 
  @Override
  public boolean onTouchEvent(MotionEvent ev) {
    if (mIsSlide && mSlidePosition != INVALID_POSITION) {
      final int action = ev.getAction();
      int x = (int) ev.getX();
      switch (action) {
        case MotionEvent.ACTION_MOVE:
          addVelocityTracker(ev);
 
          int deltaX = mDownX - x;
          mDownX = x;
 
          mDelta += deltaX;
 
          if (mDelta < 0) {
            mCurrentContentView.scrollTo(0, 0);
 
            mDelta = 0;
            mCurrentRemoveView.setVisibility(View.GONE);
          } else if (mDelta >= mMaxDistence) {
            mDelta = mMaxDistence;
            mCurrentContentView.scrollTo(mMaxDistence, 0);
            mCurrentRemoveView.setVisibility(View.VISIBLE);
            mCurrentRemoveView.setTranslationX(0);
          } else {
            mCurrentContentView.scrollBy(deltaX, 0);
            mCurrentRemoveView.setVisibility(View.VISIBLE);
            mCurrentRemoveView.setTranslationX(mMaxDistence - mDelta);
          }
          break;
      }
      return true;
    }
    return super.onTouchEvent(ev);
  }
 
  // 右滑
  private void scrollRight() {
    final int delta = mDelta;
    mScroller.startScroll(delta, 0, -delta, 0, Math.abs(delta));
    mDelta = 0;
    postInvalidate();
  }
 
  // 左滑
  private void scrollLeft() {
    final int delta = mMaxDistence - mDelta;
    mScroller.startScroll(mDelta, 0, delta, 0, Math.abs(delta));
    mDelta = mMaxDistence;
    postInvalidate();
  }
 
  @Override
  public void computeScroll() {
    if (mScroller.computeScrollOffset()) {
      mCurrentContentView.scrollTo(mScroller.getCurrX(), mScroller.getCurrY());
      mCurrentRemoveView.setTranslationX(mMaxDistence - mScroller.getCurrX());
 
      postInvalidate();
 
      if (mScroller.isFinished()) {
        mCurrentContentView.scrollTo(mDelta, 0);
        mCurrentRemoveView.setTranslationX(0);
      }
    }
  }
 
  private void addVelocityTracker(MotionEvent event) {
    if (mVelocityTracker == null) {
      mVelocityTracker = VelocityTracker.obtain();
    }
 
    mVelocityTracker.addMovement(event);
  }
 
  private int getScrollVelocity() {
    mVelocityTracker.computeCurrentVelocity(1000);
    int velocity = (int) mVelocityTracker.getXVelocity();
    return velocity;
  }
 
  private void recycleVelocityTracker() {
    if (mVelocityTracker != null) {
      mVelocityTracker.recycle();
      mVelocityTracker = null;
    }
  }
 
  private void clear() {
    if (mCurrentContentView != null) {
      mDelta = 0;
      mCurrentContentView.scrollTo(0, 0);
      mCurrentContentView = null;
 
      mCurrentRemoveView.setVisibility(View.GONE);
      mCurrentRemoveView = null;
    }
  }
 
  @Override
  public void setAdapter(ListAdapter adapter) {
    if (adapter instanceof LeftSlideRemoveAdapter) {
      super.setAdapter(adapter);
 
      mRemoveAdapter = (LeftSlideRemoveAdapter) adapter;
      mRemoveAdapter.mListener = mRemoveListener;
    } else {
      throw new IllegalArgumentException("Must be LeftSlideRemoveAdapter");
    }
  }
 
  public void setOnItemRemoveListener(OnItemRemoveListener listener) {
    adapterListener = listener;
  }
}

4、测试例子

ContractAdapter继承LeftSlideRemoveAdapter类。
LeftSlideRemoveActivity中使用LeftSlideRemoveListView类。

public class LeftSlideRemoveActivity extends Activity {
  private List<Map<String, String>> mContentList = new ArrayList<Map<String, String>>();
 
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
 
    setContentView(R.layout.activity_left_slide_remove);
 
    Map<String, String> item = new HashMap<String, String>();
    item.put("name", "Peter");
    item.put("address", "ShangHai");
    mContentList.add(item);
 
    item = new HashMap<String, String>();
    item.put("name", "Lily");
    item.put("address", "BeiJing");
    mContentList.add(item);
 
    item = new HashMap<String, String>();
    item.put("name", "Jack");
    item.put("address", "GuangZhou");
    mContentList.add(item);
 
    item = new HashMap<String, String>();
    item.put("name", "Mike");
    item.put("address", "ShengZhen");
    mContentList.add(item);
 
    LeftSlideRemoveListView lv = (LeftSlideRemoveListView) findViewById(R.id.id_listview);
    lv.setAdapter(new ContractAdapter(this));
    lv.setOnItemRemoveListener(new LeftSlideRemoveListView.OnItemRemoveListener() {
      @Override
      public void onItemRemove(int position) {
        mContentList.remove(position);
      }
    });
  }
 
  private class ContractAdapter extends LeftSlideRemoveListView.LeftSlideRemoveAdapter {
 
    public ContractAdapter(Context context) {
      super(context);
    }
 
    @Override
    public int getCount() {
      return mContentList.size();
    }
 
    @Override
    public Object getItem(int position) {
      return position;
    }
 
    @Override
    public long getItemId(int position) {
      return position;
    }
 
    @Override
    public View getSubView(int position, View convertView, ViewGroup parent) {
      ViewHolder holder;
      if (convertView == null) {
        convertView = getLayoutInflater().inflate(
            R.layout.listview_item_customdapter, parent, false);
        holder = new ViewHolder();
        holder.tvName = (TextView) convertView.findViewById(R.id.tv_name);
        holder.tvAddress = (TextView) convertView.findViewById(R.id.tv_address);
 
        convertView.setTag(holder);
      } else {
        holder = (ViewHolder) convertView.getTag();
      }
      Map<String, String> itemData = mContentList.get(position);
      holder.tvName.setText(itemData.get("name"));
      holder.tvAddress.setText(itemData.get("address"));
 
      return convertView;
    }
  }
 
  private class ViewHolder {
    TextView tvName;
    TextView tvAddress;
  }
 
}

显示如下

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