Android侧滑删除另一种实现,SwipeListView补充

前不久在在做聊天删除功能的时候使用SwipeListView进行侧滑删除有一点小问题,因为SwipeListView嵌套在Fragment内的时候,会报一个转换错误,原因是SwipeListView是基于ListView实现的SwipeListView。 针对这个问题,首先想到的就是自定义View。首先看一下实现的效果。

自定义侧滑实现

实现的思路很简单,通过对onTouchEvent方法进行重写,判断滑动的距离来实现删除按钮的显示与隐藏。核心代码如下:

package com.shihui.butler.butler.msg.view;

import android.content.Context;
import android.content.res.TypedArray;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewConfiguration;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.Scroller;

import com.shihui.butler.R;


public class SwipeListView extends ListView {

    public static int MODE_FORBID = 0;
    public static int MODE_RIGHT = 1;
    private int mode = MODE_FORBID;
    private int rightLength = 0;
    private int slidePosition;
    private int downY;
    private int downX;
    private View itemView;
    private Scroller scroller;
    private int mTouchSlop;
    private boolean canMove = false;
    private boolean isSlided = false;

    public SwipeListView(Context context) {
        this(context, null);
    }

    public SwipeListView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
        TypedArray a = context.obtainStyledAttributes(attrs,
                R.styleable.SlideMode);
        mode = a.getInt(R.styleable.SlideMode_mode, 0);
    }

    public SwipeListView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        TypedArray a = context.obtainStyledAttributes(attrs,
                R.styleable.SlideMode);
        mode = a.getInt(R.styleable.SlideMode_mode, 0);
        scroller = new Scroller(context);
        mTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop();
    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        final int action = ev.getAction();
        int lastX = (int) ev.getX();
        switch (action) {
            case MotionEvent.ACTION_DOWN:
                System.out.println("touch-->" + "down");
                if (this.mode == MODE_FORBID) {
                    return super.onTouchEvent(ev);
                }
                if (isSlided) {
                    scrollBack();
                    return false;
                }
                if (!scroller.isFinished()) {
                    return false;
                }
                downX = (int) ev.getX();
                downY = (int) ev.getY();
                slidePosition = pointToPosition(downX, downY);
                if (slidePosition == AdapterView.INVALID_POSITION) {
                    return super.onTouchEvent(ev);
                }
                itemView = getChildAt(slidePosition - getFirstVisiblePosition());
                if (this.mode == MODE_RIGHT) {
                    this.rightLength = -itemView.getPaddingRight();
                }

                break;
            case MotionEvent.ACTION_MOVE:
                System.out.println("touch-->" + "move");

                if (!canMove
                        && slidePosition != AdapterView.INVALID_POSITION
                        && (Math.abs(ev.getX() - downX) > mTouchSlop && Math.abs(ev
                        .getY() - downY) < mTouchSlop)) {
                    int offsetX = downX - lastX;
                    if (offsetX > 0 && this.mode == MODE_RIGHT) {
                        canMove = true;
                    } else {
                        canMove = false;
                    }
                    MotionEvent cancelEvent = MotionEvent.obtain(ev);
                    cancelEvent
                            .setAction(MotionEvent.ACTION_CANCEL
                                    | (ev.getActionIndex() << MotionEvent.ACTION_POINTER_INDEX_SHIFT));
                    onTouchEvent(cancelEvent);
                }
                if (canMove) {
                    requestDisallowInterceptTouchEvent(true);
                    int deltaX = downX - lastX;
                    if (deltaX > 0 && this.mode == MODE_RIGHT) {
                        itemView.scrollTo(deltaX, 0);
                    } else {
                        itemView.scrollTo(0, 0);
                    }
                    return true;
                }
            case MotionEvent.ACTION_UP:
                System.out.println("touch-->" + "up");
                if (canMove) {
                    canMove = false;
                    scrollByDistanceX();
                }
                break;
        }
        return super.onTouchEvent(ev);
    }

    private void scrollByDistanceX() {
        if (this.mode == MODE_FORBID) {
            return;
        }
        if (itemView.getScrollX() > 0 && this.mode == MODE_RIGHT) {
            if (itemView.getScrollX() >= rightLength / 2) {
                scrollLeft();
            } else {
                scrollBack();
            }
        } else {
            scrollBack();
        }

    }

    private void scrollLeft() {
        isSlided = true;
        final int delta = (rightLength - itemView.getScrollX());
        scroller.startScroll(itemView.getScrollX(), 0, delta, 0,
                Math.abs(delta));
        postInvalidate(); // 刷新itemView
    }

    private void scrollBack() {
        isSlided = false;
        scroller.startScroll(itemView.getScrollX(), 0, -itemView.getScrollX(),
                0, Math.abs(itemView.getScrollX()));
        // 刷新itemView
        postInvalidate();
    }

    @Override
    public void computeScroll() {
        if (scroller.computeScrollOffset()) {
            itemView.scrollTo(scroller.getCurrX(), scroller.getCurrY());

            postInvalidate();
        }
    }

    public void slideBack() {
        this.scrollBack();
    }

}

然后我们在界面上引入上面的SwipeListView。

<SwipeListView
            android:id="@+id/msg_listView"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:animationCache="false"
            android:divider="#E4E4E4"
            android:dividerHeight="0.5px"
            android:scrollbars="none"
            android:scrollingCache="false"
            app:mode="right"/>

在Adapter的子布局中,通过对SwipeListView滑动监听即可。 下面是Adapter的子布局方面,相关代码:

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal"
    android:background="@color/white"
    android:paddingRight="-100dp"
    >

    //...省略部分代码
         android:background="@android:color/holo_red_light"
        android:gravity="center"
        android:text="删除"
        android:textColor="@android:color/white"
        android:textSize="18sp" />
</LinearLayout>

为了实现点击删除按钮删除,我们需要在Adapter中给按钮绑定点击事件,并通过接口回传给页面进行刷新。 adapter代码

private void initItemClick(ViewHolder viewHolder, final int position) {
    viewHolder.itemDel.setOnClickListener(new View.OnClickListener() {
      @Override
      public void onClick(View view) {
        if (mRemoveListener != null)
          mRemoveListener.onRemoveItem(position);
      }
    });
  }

//声明接口监听
public void setRemoveListener(OnRemoveListener removeListener) {
    this.mRemoveListener = removeListener;
  }

  public interface OnRemoveListener {
    void onRemoveItem(int position);
  }

然后我们在Fragment中直接调用即可。

controller.getAdapter().setRemoveListener(new MsgAdapter.OnRemoveListener() {
       @Override
       public void onRemoveItem(int position) {
       //删除聊天逻辑
       
       }
     });

就写到这里吧,有任何问题欢迎留言。

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