怎么在Android中实现一个左滑删除列表功能？针对这个问题，这篇文章详细介绍了相对应的分析和解答，希望可以帮助更多想解决这个问题的小伙伴找到更简单易行的方法。
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;
}
}关于怎么在Android中实现一个左滑删除列表功能问题的解答就分享到这里了，希望以上内容可以对大家有一定的帮助，如果你还有很多疑惑没有解开，可以关注亿速云行业资讯频道了解更多相关知识。
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