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。