Android 实现ListView的滑动删除效果(转)

<?xml version="1.0" encoding="utf-8"?>
<merge xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >

<LinearLayout
android:id="@+id/view_content"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal" >
</LinearLayout>

<RelativeLayout
android:id="@+id/holder"
android:layout_width="120dp"
android:layout_height="match_parent"
android:clickable="true"
android:background="@drawable/holder_bg">

<TextView
android:id="@+id/delete"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:drawableLeft="@drawable/del_icon_normal"
android:layout_centerInParent="true"
android:gravity="center"
android:textColor="@color/floralwhite"
android:text="删除" />
</RelativeLayout>

</merge>

上述xml文件中，所有的view都会被放在view_content中，而holder是放置诸如删除按钮之类的东西，我们的SlideView会加载这个布局。再看SlideView.java：/**
* SlideView 继承自LinearLayout
*/
public class SlideView extends LinearLayout {

private static final String TAG = "SlideView";

private Context mContext;

// 用来放置所有view的容器
private LinearLayout mViewContent;

// 用来放置内置view的容器，比如删除 按钮
private RelativeLayout mHolder;

// 弹性滑动对象，提供弹性滑动效果
private Scroller mScroller;

// 滑动回调接口，用来向上层通知滑动事件
private OnSlideListener mOnSlideListener;

// 内置容器的宽度 单位：dp
private int mHolderWidth = 120;

// 分别记录上次滑动的坐标
private int mLastX = 0;
private int mLastY = 0;

// 用来控制滑动角度，仅当角度a满足如下条件才进行滑动：tan a = deltaX / deltaY > 2
private static final int TAN = 2;

public interface OnSlideListener {
// SlideView的三种状态：开始滑动，打开，关闭
public static final int SLIDE_STATUS_OFF = 0;
public static final int SLIDE_STATUS_START_SCROLL = 1;
public static final int SLIDE_STATUS_ON = 2;

/**
* @param view
* current SlideView
* @param status
* SLIDE_STATUS_ON, SLIDE_STATUS_OFF or
* SLIDE_STATUS_START_SCROLL
*/
public void onSlide(View view, int status);
}

public SlideView(Context context) {
super(context);
initView();
}

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

private void initView() {
mContext = getContext();
// 初始化弹性滑动对象
mScroller = new Scroller(mContext);
// 设置其方向为横向
setOrientation(LinearLayout.HORIZONTAL);
// 将slide_view_merge加载进来
View.inflate(mContext, R.layout.slide_view_merge, this);
mViewContent = (LinearLayout) findViewById(R.id.view_content);
mHolderWidth = Math.round(TypedValue.applyDimension(
TypedValue.COMPLEX_UNIT_DIP, mHolderWidth, getResources()
.getDisplayMetrics()));
}

// 设置按钮的内容，也可以设置图标啥的，我没写
public void setButtonText(CharSequence text) {
((TextView) findViewById(R.id.delete)).setText(text);
}

// 将view加入到ViewContent中
public void setContentView(View view) {
mViewContent.addView(view);
}

// 设置滑动回调
public void setOnSlideListener(OnSlideListener onSlideListener) {
mOnSlideListener = onSlideListener;
}

// 将当前状态置为关闭
public void shrink() {
if (getScrollX() != 0) {
this.smoothScrollTo(0, 0);
}
}

// 根据MotionEvent来进行滑动，这个方法的作用相当于onTouchEvent
// 如果你不需要处理滑动冲突，可以直接重命名，照样能正常工作
public void onRequireTouchEvent(MotionEvent event) {
int x = (int) event.getX();
int y = (int) event.getY();
int scrollX = getScrollX();
Log.d(TAG, "x=" + x + " y=" + y);

switch (event.getAction()) {
case MotionEvent.ACTION_DOWN: {
if (!mScroller.isFinished()) {
mScroller.abortAnimation();
}
if (mOnSlideListener != null) {
mOnSlideListener.onSlide(this,
OnSlideListener.SLIDE_STATUS_START_SCROLL);
}
break;
}
case MotionEvent.ACTION_MOVE: {
int deltaX = x - mLastX;
int deltaY = y - mLastY;
if (Math.abs(deltaX) < Math.abs(deltaY) * TAN) {
// 滑动不满足条件，不做横向滑动
break;
}

// 计算滑动终点是否合法，防止滑动越界
int newScrollX = scrollX - deltaX;
if (deltaX != 0) {
if (newScrollX < 0) {
newScrollX = 0;
} else if (newScrollX > mHolderWidth) {
newScrollX = mHolderWidth;
}
this.scrollTo(newScrollX, 0);
}
break;
}
case MotionEvent.ACTION_UP: {
int newScrollX = 0;
// 这里做了下判断，当松开手的时候，会自动向两边滑动，具体向哪边滑，要看当前所处的位置
if (scrollX - mHolderWidth * 0.75 > 0) {
newScrollX = mHolderWidth;
}
// 慢慢滑向终点
this.smoothScrollTo(newScrollX, 0);
// 通知上层滑动事件
if (mOnSlideListener != null) {
mOnSlideListener.onSlide(this,
newScrollX == 0 ? OnSlideListener.SLIDE_STATUS_OFF
: OnSlideListener.SLIDE_STATUS_ON);
}
break;
}
default:
break;
}

mLastX = x;
mLastY = y;
}

private void smoothScrollTo(int destX, int destY) {
// 缓慢滚动到指定位置
int scrollX = getScrollX();
int delta = destX - scrollX;
// 以三倍时长滑向destX，效果就是慢慢滑动
mScroller.startScroll(scrollX, 0, delta, 0, Math.abs(delta) * 3);
invalidate();
}

@Override
public void computeScroll() {
if (mScroller.computeScrollOffset()) {
scrollTo(mScroller.getCurrX(), mScroller.getCurrY());
postInvalidate();
}
}

}

上述代码做了很详细的说明，这就是滑动控件的完整代码，大家要明白的是：你所添加的view都是加在SlideView的子View : view_content中的，而不是直接加在SlideView中，只有这样我们才方便做滑动效果。接着看ListView的代码：核心就是下面这一个方法，将点击事件发送给SlideView处理。@Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN: {
int x = (int) event.getX();
int y = (int) event.getY();
//我们想知道当前点击了哪一行
int position = pointToPosition(x, y);
Log.e(TAG, "postion=" + position);
if (position != INVALID_POSITION) {
//得到当前点击行的数据从而取出当前行的item。
//可能有人怀疑，为什么要这么干？为什么不用getChildAt(position)？
//因为ListView会进行缓存，如果你不这么干，有些行的view你是得不到的。
MessageItem data = (MessageItem) getItemAtPosition(position);
mFocusedItemView = data.slideView;
Log.e(TAG, "FocusedItemView=" + mFocusedItemView);
}
}
default:
break;
}

//向当前点击的view发送滑动事件请求，其实就是向SlideView发请求
if (mFocusedItemView != null) {
mFocusedItemView.onRequireTouchEvent(event);
}

return super.onTouchEvent(event);
} 最后看Activity的代码：

public class MainActivity extends Activity implements OnItemClickListener,
OnClickListener, OnSlideListener {

private static final String TAG = "MainActivity";

private ListViewCompat mListView;

private List<MessageItem> mMessageItems = new ArrayList<MainActivity.MessageItem>();

private SlideAdapter mSlideAdapter;

// 上次处于打开状态的SlideView
private SlideView mLastSlideViewWithStatusOn;

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

private void initView() {
mListView = (ListViewCompat) findViewById(R.id.list);

for (int i = 0; i < 20; i++) {
MessageItem item = new MessageItem();
if (i % 3 == 0) {
item.iconRes = R.drawable.default_qq_avatar;
item.title = "腾讯新闻";
item.msg = "青岛爆炸满月：大量鱼虾死亡";
item.time = "晚上18:18";
} else {
item.iconRes = R.drawable.wechat_icon;
item.title = "微信团队";
item.msg = "欢迎你使用微信";
item.time = "12月18日";
}
mMessageItems.add(item);
}
mSlideAdapter = new SlideAdapter();
mListView.setAdapter(mSlideAdapter);
mListView.setOnItemClickListener(this);
}

private class SlideAdapter extends BaseAdapter {

private LayoutInflater mInflater;

SlideAdapter() {
super();
mInflater = getLayoutInflater();
}

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

@Override
public Object getItem(int position) {
return mMessageItems.get(position);
}

@Override
public long getItemId(int position) {
return position;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
SlideView slideView = (SlideView) convertView;
if (slideView == null) {
// 这里是我们的item
View itemView = mInflater.inflate(R.layout.list_item, null);

slideView = new SlideView(MainActivity.this);
// 这里把item加入到slideView
slideView.setContentView(itemView);
// 下面是做一些数据缓存
holder = new ViewHolder(slideView);
slideView.setOnSlideListener(MainActivity.this);
slideView.setTag(holder);
} else {
holder = (ViewHolder) slideView.getTag();
}
MessageItem item = mMessageItems.get(position);
item.slideView = slideView;
item.slideView.shrink();

holder.icon.setImageResource(item.iconRes);
holder.title.setText(item.title);
holder.msg.setText(item.msg);
holder.time.setText(item.time);
holder.deleteHolder.setOnClickListener(MainActivity.this);

return slideView;
}

}

public class MessageItem {
public int iconRes;
public String title;
public String msg;
public String time;
public SlideView slideView;
}

private static class ViewHolder {
public ImageView icon;
public TextView title;
public TextView msg;
public TextView time;
public ViewGroup deleteHolder;

ViewHolder(View view) {
icon = (ImageView) view.findViewById(R.id.icon);
title = (TextView) view.findViewById(R.id.title);
msg = (TextView) view.findViewById(R.id.msg);
time = (TextView) view.findViewById(R.id.time);
deleteHolder = (ViewGroup) view.findViewById(R.id.holder);
}
}

@Override
public void onItemClick(AdapterView<?> parent, View view, int position,
long id) {
// 这里处理ListItem的点击事件
Log.e(TAG, "onItemClick position=" + position);
}

@Override
public void onSlide(View view, int status) {
// 如果当前存在已经打开的SlideView，那么将其关闭
if (mLastSlideViewWithStatusOn != null
&& mLastSlideViewWithStatusOn != view) {
mLastSlideViewWithStatusOn.shrink();
}
// 记录本次处于打开状态的view
if (status == SLIDE_STATUS_ON) {
mLastSlideViewWithStatusOn = (SlideView) view;
}
}

@Override
public void onClick(View v) {
// 这里处理删除按钮的点击事件，可以删除对话
if (v.getId() == R.id.holder) {
int position = mListView.getPositionForView(v);
if (position != ListView.INVALID_POSITION) {
mMessageItems.remove(position);
mSlideAdapter.notifyDataSetChanged();
}
Log.e(TAG, "onClick v=" + v);
}
}
}