转载请注明来源:http://blog.csdn.net/kjunchen/article/details/51145737
在最近的项目中,我的ListView中item选项是长按删除的效果(Android的通常做法长按或点击),老板觉得这个效果不好,提出要求做类似QQ消息列表横向滑动时删除消息的效果,这种效果确实感觉挺爽的,但是我也没做过,于是就在网上搜索了一番,找到了很多例子,实现了这个效果,但在这个过程中不尽如人意,遇到一些曲折,大多数例子确实实现了效果,但是也存在一些问题没有解决,用着有问题,如item点击无效、item有点击事件时滑动item结束后执行了item的点击事件、item中有按钮时若手指按下在按钮位置时滑动无效等等,自己查了很多终于解决了这些问题,现整理如下供大家参考,如有问题请多多包含。
本博文实现思路是在滑动item的过程中修改item的leftMargin实现的。先看下最终效果:
下面就一步步来实现吧。
ListView中的item布局有讲究,最外层使用的LinearLayout,设置其orientation属性为horizontal。然后里面主要包含两个视图组件,一个是我们正常显示时的布局,另外一个是滑动时出现的视图如删除按钮。正常显示的视图初始的layout_width设置为match_parent,并且滑动时出现的视图必须指定其layout_width,不要使用match_parent或wrap_parent,否则会获取不到宽度。稍后你会明白的。看本博文完整的item布局。
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="wrap_content" android:descendantFocusability="blocksDescendants" android:orientation="horizontal">
<LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="horizontal" android:padding="8dp">
<TextView android:id="@+id/textView" android:layout_width="wrap_content" android:layout_height="wrap_content" android:textSize="18sp" android:text="text" />
<Button android:layout_marginLeft="8dp" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Button"/>
</LinearLayout>
<!--必须指定宽度-->
<TextView android:id="@+id/txtv_delete" android:layout_width="96dp" android:layout_height="match_parent" android:gravity="center" android:textSize="18sp" android:background="#e53935" android:textColor="#eeeeee" android:text="删除" />
</LinearLayout>
需要自定义ListView,继承于ListView。如:
public class SideslipListView extends ListView {
...
public SideslipListView(Context context) {
super(context);
}
public SideslipListView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public SideslipListView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
...
}
首先获取屏幕宽度。
private int mScreenWidth;//屏幕的宽度
...
// 获取屏幕宽度
WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
DisplayMetrics dm = new DisplayMetrics();
wm.getDefaultDisplay().getMetrics(dm);
mScreenWidth = dm.widthPixels;
接着重写onTouchEvent(MotionEvent ev)方法,对手指按下、移动、离开分别进行相应处理。如
@Override
public boolean onTouchEvent(MotionEvent ev) {//事件响应
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN:
performActionDown(ev);
break;
case MotionEvent.ACTION_MOVE:
performActionMove(ev);
break;
case MotionEvent.ACTION_UP:
performActionUp(ev);
break;
}
return super.onTouchEvent(ev);
}
当手指按下时我们需要获取到按下时所在的item,得到正常显示时的视图,并设置其宽度为屏幕的宽度;另外还需得到删除组件的宽度。如:
private int mDownX;//手指初次按下的X坐标
private int mDownY;//手指初次按下的Y坐标
private boolean isDeleteShow;//删除组件是否显示
private ViewGroup mPointChild;//手指按下位置的item组件
private int mDeleteWidth;//删除组件的宽度
private LinearLayout.LayoutParams mItemLayoutParams;//手指按下时所在的item的布局参数
...
private void performActionDown(MotionEvent ev) {
mDownX = (int) ev.getX();
mDownY = (int) ev.getY();
if (isDeleteShow) {
ViewGroup tmpViewGroup = (ViewGroup) getChildAt(pointToPosition(mDownX, mDownY) - getFirstVisiblePosition());
Log.i(TAG, "*********mPointChild.equals(tmpViewGroup): " + mPointChild.equals(tmpViewGroup));
if (!mPointChild.equals(tmpViewGroup)) {
turnNormal();
}
}
//获取当前的item
mPointChild = (ViewGroup) getChildAt(pointToPosition(mDownX, mDownY) - getFirstVisiblePosition());
mDeleteWidth = mPointChild.getChildAt(1).getLayoutParams().width;//获取删除组件的宽度
Log.i(TAG, "**********pointToPosition(x,y): " + pointToPosition(mDownX, mDownY)
+ ", getFirstVisiblePosition() = " + getFirstVisiblePosition()
+ ", mDeleteWidth = " + mDeleteWidth);
mItemLayoutParams = (LinearLayout.LayoutParams) mPointChild.getChildAt(0).getLayoutParams();
mItemLayoutParams.width = mScreenWidth;
mPointChild.getChildAt(0).setLayoutParams(mItemLayoutParams);
}
当手指移动时动态修改正常是显示视图组件的leftMargin,如果删除按钮没有显示,手指向左滑动删除按钮就会根据滑动的距离显示相应的可见宽度。如:
private boolean performActionMove(MotionEvent ev) {
int nowX = (int) ev.getX();
int nowY = (int) ev.getY();
int diffX = nowX - mDownX;
if (Math.abs(diffX) > Math.abs(nowY - mDownY) && Math.abs(nowY - mDownY) < 20) {
if (!isDeleteShow && nowX < mDownX) {//删除按钮未显示时向左滑
if (-diffX >= mDeleteWidth) {//如果滑动距离大于删除组件的宽度时进行偏移的最大处理
diffX = -mDeleteWidth;
}
mItemLayoutParams.leftMargin = diffX;
mPointChild.getChildAt(0).setLayoutParams(mItemLayoutParams);
isAllowItemClick = false;
} else if (isDeleteShow && nowX > mDownX) {//删除按钮显示时向右滑
if (diffX >= mDeleteWidth) {
diffX = mDeleteWidth;
}
mItemLayoutParams.leftMargin = diffX - mDeleteWidth;
mPointChild.getChildAt(0).setLayoutParams(mItemLayoutParams);
isAllowItemClick = false;
}
return true;
}
return super.onTouchEvent(ev);
}
当手指离开时,根据移动的距离判断是否显示删除按钮。如:
private void performActionUp(MotionEvent ev) {
//如果向左滑出超过隐藏的二分之一就全部显示
if (-mItemLayoutParams.leftMargin >= mDeleteWidth / 2) {
mItemLayoutParams.leftMargin = -mDeleteWidth;
isDeleteShow = true;
mPointChild.getChildAt(0).setLayoutParams(mItemLayoutParams);
} else {
turnNormal();
}
}
到这里基本上就实现了侧滑时删除按钮的显示和隐藏了。不过还有些问题。
当ListView中的item设置了点击事件时,我们左右滑动时就会触发这个点击事件,那么如何避免呢?在自定义的ListView中设置标志isAllowItemClick,当手指按下时设置其值为isAllowItemClick = true,在手指移动的过程中,若是发生左右移动,则设置其值为isAllowItemClick = false,另外向外公布方法:
public boolean isAllowItemClick() {
return isAllowItemClick;
}
当为Listview设置点击事件时这样做就可以避免了。
mSideslipListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
if (mSideslipListView.isAllowItemClick()) {
Log.i(TAG, mDataList.get(position) + "被点击了");
Toast.makeText(MainActivity.this, mDataList.get(position) + "被点击了",
Toast.LENGTH_SHORT).show();
}
}
});
这个跟Android的事件分发机制有关系,不知道可以去仔细看看查查资料。我们可以重写onInterceptTouchEvent(MotionEvent ev)这个方法来解决,若手指按下并且是左右移动时则最该Touch事件进行拦截。如:
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {//事件拦截
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN: {
isAllowItemClick = true;
//侧滑删除
mDownX = (int) ev.getX();
mDownY = (int) ev.getY();
mPointPosition = pointToPosition(mDownX, mDownY);
Log.i(TAG, "*******pointToPosition(mDownX, mDownY): " + mPointPosition);
if (mPointPosition != -1) {
if (isDeleteShow) {
ViewGroup tmpViewGroup = (ViewGroup) getChildAt(mPointPosition - getFirstVisiblePosition());
if (!mPointChild.equals(tmpViewGroup)) {
turnNormal();
}
}
//获取当前的item
mPointChild = (ViewGroup) getChildAt(mPointPosition - getFirstVisiblePosition());
mDeleteWidth = mPointChild.getChildAt(1).getLayoutParams().width;
mItemLayoutParams = (LinearLayout.LayoutParams) mPointChild.getChildAt(0).getLayoutParams();
Log.i(TAG, "*********mItemLayoutParams.height: " + mItemLayoutParams.height +
", mDeleteWidth: " + mDeleteWidth);
mItemLayoutParams.width = mScreenWidth;
mPointChild.getChildAt(0).setLayoutParams(mItemLayoutParams);
}
break;
}
case MotionEvent.ACTION_MOVE: {
int nowX = (int) ev.getX();
int nowY = (int) ev.getY();
int diffX = nowX - mDownX;
Log.i(TAG, "******dp2px(4): " + dp2px(8) + ", dp2px(8): " + dp2px(8) +
", density: " + getContext().getResources().getDisplayMetrics().density);
if (Math.abs(diffX) > dp2px(4) || Math.abs(nowY - mDownY) > dp2px(4)) {
return true;//避免子布局中有点击的控件时滑动无效
}
break;
}
}
return super.onInterceptTouchEvent(ev);
}
public float dp2px(int dp) {
return TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dp,
getContext().getResources().getDisplayMetrics());
}
到此,我们的自定义ListView基本上就搞定了。最后贴上我的自定义SideslipListView的完整源码。
package com.junkchen.toucheventtest;
import android.content.Context;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.util.Log;
import android.util.TypedValue;
import android.view.MotionEvent;
import android.view.ViewGroup;
import android.view.WindowManager;
import android.widget.LinearLayout;
import android.widget.ListView;
/** * Created by JunkChen on 2016/3/29 0029. */
public class SideslipListView extends ListView {
private static final String TAG = "SideslipListView";
private int mScreenWidth;//屏幕的宽度
private boolean isDeleteShow;//删除组件是否显示
private ViewGroup mPointChild;//手指按下位置的item组件
private int mDeleteWidth;//删除组件的宽度
private LinearLayout.LayoutParams mItemLayoutParams;//手指按下时所在的item的布局参数
private int mDownX;//手指初次按下的X坐标
private int mDownY;//手指初次按下的Y坐标
private int mPointPosition;//手指按下位置所在的item位置
private boolean isAllowItemClick;//是否允许item点击
public SideslipListView(Context context) {
super(context);
init(context);
}
public SideslipListView(Context context, AttributeSet attrs) {
super(context, attrs);
init(context);
}
public SideslipListView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init(context);
}
private void init(Context context) {
// 获取屏幕宽度
WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
DisplayMetrics dm = new DisplayMetrics();
wm.getDefaultDisplay().getMetrics(dm);
mScreenWidth = dm.widthPixels;
Log.i(TAG, "***********mScreenWidth: " + mScreenWidth);
}
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {//事件拦截
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN: {
isAllowItemClick = true;
//侧滑删除
mDownX = (int) ev.getX();
mDownY = (int) ev.getY();
mPointPosition = pointToPosition(mDownX, mDownY);
Log.i(TAG, "*******pointToPosition(mDownX, mDownY): " + mPointPosition);
if (mPointPosition != -1) {
if (isDeleteShow) {
ViewGroup tmpViewGroup = (ViewGroup) getChildAt(mPointPosition - getFirstVisiblePosition());
if (!mPointChild.equals(tmpViewGroup)) {
turnNormal();
}
}
//获取当前的item
mPointChild = (ViewGroup) getChildAt(mPointPosition - getFirstVisiblePosition());
mDeleteWidth = mPointChild.getChildAt(1).getLayoutParams().width;
mItemLayoutParams = (LinearLayout.LayoutParams) mPointChild.getChildAt(0).getLayoutParams();
Log.i(TAG, "*********mItemLayoutParams.height: " + mItemLayoutParams.height +
", mDeleteWidth: " + mDeleteWidth);
mItemLayoutParams.width = mScreenWidth;
mPointChild.getChildAt(0).setLayoutParams(mItemLayoutParams);
}
break;
}
case MotionEvent.ACTION_MOVE: {
int nowX = (int) ev.getX();
int nowY = (int) ev.getY();
int diffX = nowX - mDownX;
Log.i(TAG, "******dp2px(4): " + dp2px(8) + ", dp2px(8): " + dp2px(8) +
", density: " + getContext().getResources().getDisplayMetrics().density);
if (Math.abs(diffX) > dp2px(4) || Math.abs(nowY - mDownY) > dp2px(4)) {
return true;//避免子布局中有点击的控件时滑动无效
}
break;
}
}
return super.onInterceptTouchEvent(ev);
}
public float dp2px(int dp) {
return TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dp,
getContext().getResources().getDisplayMetrics());
}
@Override
public boolean onTouchEvent(MotionEvent ev) {//事件响应
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN:
performActionDown(ev);
break;
case MotionEvent.ACTION_MOVE:
performActionMove(ev);
break;
case MotionEvent.ACTION_UP:
performActionUp(ev);
break;
}
return super.onTouchEvent(ev);
}
private void performActionDown(MotionEvent ev) {
mDownX = (int) ev.getX();
mDownY = (int) ev.getY();
if (isDeleteShow) {
ViewGroup tmpViewGroup = (ViewGroup) getChildAt(pointToPosition(mDownX, mDownY) - getFirstVisiblePosition());
Log.i(TAG, "*********mPointChild.equals(tmpViewGroup): " + mPointChild.equals(tmpViewGroup));
if (!mPointChild.equals(tmpViewGroup)) {
turnNormal();
}
}
//获取当前的item
mPointChild = (ViewGroup) getChildAt(pointToPosition(mDownX, mDownY) - getFirstVisiblePosition());
mDeleteWidth = mPointChild.getChildAt(1).getLayoutParams().width;//获取删除组件的宽度
Log.i(TAG, "**********pointToPosition(x,y): " + pointToPosition(mDownX, mDownY)
+ ", getFirstVisiblePosition() = " + getFirstVisiblePosition()
+ ", mDeleteWidth = " + mDeleteWidth);
mItemLayoutParams = (LinearLayout.LayoutParams) mPointChild.getChildAt(0).getLayoutParams();
mItemLayoutParams.width = mScreenWidth;
mPointChild.getChildAt(0).setLayoutParams(mItemLayoutParams);
}
private boolean performActionMove(MotionEvent ev) {
int nowX = (int) ev.getX();
int nowY = (int) ev.getY();
int diffX = nowX - mDownX;
if (Math.abs(diffX) > Math.abs(nowY - mDownY) && Math.abs(nowY - mDownY) < 20) {
if (!isDeleteShow && nowX < mDownX) {//删除按钮未显示时向左滑
if (-diffX >= mDeleteWidth) {//如果滑动距离大于删除组件的宽度时进行偏移的最大处理
diffX = -mDeleteWidth;
}
mItemLayoutParams.leftMargin = diffX;
mPointChild.getChildAt(0).setLayoutParams(mItemLayoutParams);
isAllowItemClick = false;
} else if (isDeleteShow && nowX > mDownX) {//删除按钮显示时向右滑
if (diffX >= mDeleteWidth) {
diffX = mDeleteWidth;
}
mItemLayoutParams.leftMargin = diffX - mDeleteWidth;
mPointChild.getChildAt(0).setLayoutParams(mItemLayoutParams);
isAllowItemClick = false;
}
return true;
}
return super.onTouchEvent(ev);
}
private void performActionUp(MotionEvent ev) {
//如果向左滑出超过隐藏的二分之一就全部显示
if (-mItemLayoutParams.leftMargin >= mDeleteWidth / 2) {
mItemLayoutParams.leftMargin = -mDeleteWidth;
isDeleteShow = true;
mPointChild.getChildAt(0).setLayoutParams(mItemLayoutParams);
} else {
turnNormal();
}
}
/** * 转换为正常隐藏情况 */
public void turnNormal() {
mItemLayoutParams.leftMargin = 0;
mPointChild.getChildAt(0).setLayoutParams(mItemLayoutParams);
isDeleteShow = false;
}
/** * 是否允许Item点击 * * @return */
public boolean isAllowItemClick() {
return isAllowItemClick;
}
}
在布局中的使用。
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" android:gravity="center_horizontal" tools:context="com.junkchen.toucheventtest.MainActivity">
<TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerHorizontal="true" android:layout_margin="8dp" android:text="ListView item侧滑删除" />
<!--使用自定义的SideslipListView-->
<com.junkchen.toucheventtest.SideslipListView android:id="@+id/sideslipListView" android:layout_width="match_parent" android:layout_height="wrap_content">
</com.junkchen.toucheventtest.SideslipListView>
</LinearLayout>
package com.junkchen.toucheventtest;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
private static final String TAG = "MainActivity";
private SideslipListView mSideslipListView;
/** * 初始化数据 */
private ArrayList<String> mDataList = new ArrayList<String>() {
{
for (int i = 0; i < 50; i++) {
add("ListView item " + i);
}
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mSideslipListView = (SideslipListView) findViewById(R.id.sideslipListView);
mSideslipListView.setAdapter(new CustomAdapter());//设置适配器
//设置item点击事件
mSideslipListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
if (mSideslipListView.isAllowItemClick()) {
Log.i(TAG, mDataList.get(position) + "被点击了");
Toast.makeText(MainActivity.this, mDataList.get(position) + "被点击了",
Toast.LENGTH_SHORT).show();
}
}
});
//设置item长按事件
mSideslipListView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
@Override
public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
if (mSideslipListView.isAllowItemClick()) {
Log.i(TAG, mDataList.get(position) + "被长按了");
Toast.makeText(MainActivity.this, mDataList.get(position) + "被长按了",
Toast.LENGTH_SHORT).show();
return true;//返回true表示本次事件被消耗了,若返回
}
return false;
}
});
}
/** * 自定义ListView适配器 */
class CustomAdapter extends BaseAdapter {
@Override
public int getCount() {
return mDataList.size();
}
@Override
public Object getItem(int position) {
return mDataList.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder viewHolder;
if (null == convertView) {
convertView = View.inflate(MainActivity.this, R.layout.item, null);
viewHolder = new ViewHolder();
viewHolder.textView = (TextView) convertView.findViewById(R.id.textView);
viewHolder.txtv_delete = (TextView) convertView.findViewById(R.id.txtv_delete);
convertView.setTag(viewHolder);
} else {
viewHolder = (ViewHolder) convertView.getTag();
}
viewHolder.textView.setText(mDataList.get(position));
final int pos = position;
viewHolder.txtv_delete.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(MainActivity.this, mDataList.get(pos) + "被删除了",
Toast.LENGTH_SHORT).show();
mDataList.remove(pos);
notifyDataSetChanged();
mSideslipListView.turnNormal();
}
});
return convertView;
}
}
class ViewHolder {
public TextView textView;
public TextView txtv_delete;
}
}
上面这个应用就不详细介绍了,注释写得比较清楚。可以自行新建工程测试,想要完整源码请加群联系群主。
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