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這篇文章給大家介紹怎么在android中使用View實現(xiàn)一個滑動刪除效果，內容非常詳細，感興趣的小伙伴們可以參考借鑒，希望對大家能有所幫助。
實現(xiàn)功能
1、可以向左滑動,右側出現(xiàn)刪除
2、向左滑動如果刪除出現(xiàn)一大半,松手打開刪除,反之關閉刪除
3、應用場景
微信消息的刪除功能
實現(xiàn)原理
1、外面是一個ListView
2、條目是一個自定義控件繼承ViewGroup
1）、左邊一個TextView,右側屏幕外也有一個TextView
2）、所以繼承ViewGroup
實現(xiàn)步驟
1、創(chuàng)建一個SlideDeleteView類
1）.構造方法要關聯(lián)
public class SlideDelete extends ViewGroup {
private View leftView;
private View rightView;
private ViewDragHelper helper;
//第一步關聯(lián)構造方法
//第二步重寫onMeasure和onLViewayout測量子View和布局子View
public SlideDelete(Context context) {
this(context,null);
}
public SlideDelete(Context context, AttributeSet attrs) {
this(context, attrs,0);
}
public SlideDelete(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
helper = ViewDragHelper.create(this, callback);
}
}2、在布局文件中設置SlideDeleteView里面的子View
SlideDeleteView height=80
TextView
width:matchParent
height:matchparent
TextView
<com.example.movedelete.SlideDelete android:id="@+id/container" android:layout_width="match_parent" android:layout_height="80dp"> <TextView android:id="@+id/content" android:layout_width="match_parent" android:layout_height="match_parent" android:gravity="center" android:background="#33000000" android:text="第0個條目" android:textColor="#fff" android:textSize="20sp" /> <TextView android:id="@+id/delete" android:layout_width="80dp" android:layout_height="match_parent" android:background="#f00" android:gravity="center" android:text="刪除" android:textColor="#fff" android:textSize="20sp" /> </com.example.movedelete.SlideDelete>
3、重寫onMeasure,給子View進行測量
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
//對當前組合View的測量,不使用的話,也可以自己設置
measureChildren(widthMeasureSpec,heightMeasureSpec);
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}4、重寫onLayout,給子View進行布局
注意事項:要設置leftView,也要設置rightView,不要都寫成leftView了
protected void onLayout(boolean changed, int l, int t, int r, int b) {
//第一步獲取里面子View
leftView = getChildAt(0);
rightView = getChildAt(1);
//第二步給子View提供相應的布局
int leftL = 0;
int leftT = 0;
int leftR = leftView.getMeasuredWidth();
int leftB = leftView.getMeasuredHeight();
leftView.layout(leftL,leftT,leftR,leftB);
//給rightView提供相應的布局
int rightL = leftView.getMeasuredWidth();
int rightT = 0;
int rightR = leftView.getMeasuredWidth()+ rightView.getMeasuredWidth();
int rightB = rightView.getMeasuredHeight();
rightView.layout(rightL,rightT,rightR,rightB);
}5、設置View的滑動事件onTouchEvent,實現(xiàn)滑動
1）.因為要滑動,所以消費該事件返回true
2）.使用ViewDragHelper來實現(xiàn)滑動效果
注意事項:
只能實現(xiàn)leftView的滑動,右側RightView看不到所以滑動不了
只能給滑動的View設置監(jiān)聽,當滑動的時候,重新設置另一個View的布局跟著滑動
@Override
public boolean onTouchEvent(MotionEvent event) {
//1,要消費該事件,所以直接返回true
//2,使用ViewDragHelper來實現(xiàn)滑動效果
helper.processTouchEvent(event);
return true;
}6、重寫滑動事件的監(jiān)聽onViewPositionChanged解決只有l(wèi)efView滑動的問題
1）.重寫的方法是在ViewDragHelper.Callback的子實現(xiàn)類中
2）.要實現(xiàn)滑動事件,必須在tryCaptureView方法中返回true
private ViewDragHelper.Callback callback = new ViewDragHelper.Callback() {
//手勢滑動時
@Override
public boolean tryCaptureView(View child, int pointerId) {
return true;
} //監(jiān)聽控件移動狀態(tài)
@Override
public void onViewPositionChanged(View changedView, int left, int top, int dx, int dy) {
//如果左邊控件拖動,我們要讓右邊控件也重新布局
if(changedView == leftView){
rightView.layout(rightView.getLeft()+dx,0,rightView.getRight()+dx,rightView.getBottom()+dy);
}else if(changedView == rightView){
leftView.layout(leftView.getLeft()+dx,0,leftView.getRight()+dx,leftView.getBottom()+dy);
}
}7、重寫clampViewPositionHorizontal水平位置移動,解決左右越界問題
1.返回值為移動時左側滑動的距離
2.如果滑動的控件是leftView時,解決越界
3.如果滑動的控件是rightView時,解決越界
public int clampViewPositionHorizontal(View child, int left, int dx) {
//對左右越界問題的處理
if(child == leftView){
//處理兩邊的越界問題
if(left >= 0){
left = 0;
}else if(left <= -rightView.getMeasuredWidth()){
left = -rightView.getMeasuredWidth();
}
}else if(child == rightView){
//只處理右邊的越界問題,因為左側越界的時看不到該View
if(left <= leftView.getMeasuredWidth()- rightView.getMeasuredWidth()){
left = leftView.getMeasuredWidth()- rightView.getMeasuredWidth();
}else if(left >= leftView.getMeasuredWidth()){
left = leftView.getMeasuredWidth();
}
}
return left;
}8、手松開時重寫onViewReleased方法,實現(xiàn)滑動手松開時,rightView是打開還是關閉
1.使用ViewDragHelper滑動時,要調用invalidate方法,回調computeScroll方法
2.重寫computeScroll方法
1）.先判斷是否要繼承滑動
2）.使用兼容的invalidate方法來實現(xiàn)勻速滑動
@Override
public void onViewReleased(View releasedChild, float xvel, float yvel) {
//松開后,什么時候打開rightView,什么時候關閉leftView
//臨界值,rightView.getLeft() 和 屏幕的寬度-rightView.getWidth()/2
if(releasedChild == leftView){
if(rightView.getLeft() < getMeasuredWidth() - rightView.getMeasuredWidth()/2){
//使用ViewDragHelper來滑動
helper.smoothSlideViewTo(rightView,getMeasuredWidth()-rightView.getMeasuredWidth(),0);
invalidate();
}else{
helper.smoothSlideViewTo(rightView,getMeasuredWidth(),0);
invalidate();
}
}
}
//需要重寫computeScroll
@Override
public void computeScroll() {
//判斷是否要繼承滑動
if(helper.continueSettling(true)){
//invalidate();
//兼容使用
ViewCompat.postInvalidateOnAnimation(this);
}
}9、實現(xiàn)刪除rightView的點擊刪除事件
1.在listView的adapter中找到右側的rightView
2.調用rightView的點擊事件
3.刪除該條目
1）刪除集合中的數(shù)據(jù)
list.remove(position);
2）更新adapter
notifyDataSetChanged();
3）重新繪制整個條目
requestLayout();
//設置刪除的點擊事件
vh.delete.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//刪除當前的數(shù)據(jù)
list.remove(position);
notifyDataSetChanged();
//讓父容器更新下
}
});
vh.container.requestLayout();注意事項
1、在重寫onLayout方法的時候,給rightView設置布局的時候,寫成leftView一直出錯
2、在onTouchEvent中要返回true,因為要消費該事件
3、在使用ViewDragHelper.Callback時,重寫tryCaptureView時要返回true
4、在onTouchEvent中,不使用scrollby或者scrollTo,而是使用ViewDragHelper工具類,不需要判斷滑動的距離
總結
1、首先該控件是自定義View,不是組合控件,因為組合的話rightView在屏幕右側不能實現(xiàn)
2、是自定義View中的繼承ViewGroup,因為左側leftView和右側rightView都是TextView不需要自己畫
源碼
SlideDelete的源碼
package com.example.movedelete;
import android.content.Context;
import android.support.v4.view.ViewCompat;
import android.support.v4.widget.ViewDragHelper;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
/**
* Created by guixin on 2017/1/5.
*/
public class SlideDelete extends ViewGroup {
private View leftView;
private View rightView;
private ViewDragHelper helper;
//第一步關聯(lián)構造方法
//第二步重寫onMeasure和onLViewayout測量子View和布局子View
public SlideDelete(Context context) {
this(context,null);
}
public SlideDelete(Context context, AttributeSet attrs) {
this(context, attrs,0);
}
public SlideDelete(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
helper = ViewDragHelper.create(this, callback);
}
private ViewDragHelper.Callback callback = new ViewDragHelper.Callback() {
//手勢滑動時
@Override
public boolean tryCaptureView(View child, int pointerId) {
return true;
}
//拖動控件水平移動
@Override
public int clampViewPositionHorizontal(View child, int left, int dx) {
//對左右越界問題的處理
if(child == leftView){
//處理兩邊的越界問題
if(left >= 0){
left = 0;
}else if(left <= -rightView.getMeasuredWidth()){
left = -rightView.getMeasuredWidth();
}
}else if(child == rightView){
//只處理右邊的越界問題,因為左側越界的時看不到該View
if(left <= leftView.getMeasuredWidth()- rightView.getMeasuredWidth()){
left = leftView.getMeasuredWidth()- rightView.getMeasuredWidth();
}else if(left >= leftView.getMeasuredWidth()){
left = leftView.getMeasuredWidth();
}
}
return left;
}
//監(jiān)聽控件移動狀態(tài)
@Override
public void onViewPositionChanged(View changedView, int left, int top, int dx, int dy) {
//如果左邊控件拖動,我們要讓右邊控件也重新布局
if(changedView == leftView){
rightView.layout(rightView.getLeft()+dx,0,rightView.getRight()+dx,rightView.getBottom()+dy);
}else if(changedView == rightView){
leftView.layout(leftView.getLeft()+dx,0,leftView.getRight()+dx,leftView.getBottom()+dy);
}
}
//解決滑動一半松手時,View的復位
/**
*
* @param releasedChild 松開的View
* @param xvel
* @param yvel
*/
@Override
public void onViewReleased(View releasedChild, float xvel, float yvel) {
//松開后,什么時候打開rightView,什么時候關閉leftView
//臨界值,rightView.getLeft() 和 屏幕的寬度-rightView.getWidth()/2
if(releasedChild == leftView){
if(rightView.getLeft() < getMeasuredWidth() - rightView.getMeasuredWidth()/2){
//使用ViewDragHelper來滑動
helper.smoothSlideViewTo(rightView,getMeasuredWidth()-rightView.getMeasuredWidth(),0);
invalidate();
}else{
helper.smoothSlideViewTo(rightView,getMeasuredWidth(),0);
invalidate();
}
}
}
};
//需要重寫computeScroll
@Override
public void computeScroll() {
//判斷是否要繼承滑動
if(helper.continueSettling(true)){
//invalidate();
//兼容使用
ViewCompat.postInvalidateOnAnimation(this);
}
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
//對當前組合View的測量,不使用的話,也可以自己設置
measureChildren(widthMeasureSpec,heightMeasureSpec);
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
//第一步獲取里面子View
leftView = getChildAt(0);
rightView = getChildAt(1);
//第二步給子View提供相應的布局
int leftL = 0;
int leftT = 0;
int leftR = leftView.getMeasuredWidth();
int leftB = leftView.getMeasuredHeight();
leftView.layout(leftL,leftT,leftR,leftB);
//給rightView提供相應的布局
int rightL = leftView.getMeasuredWidth();
int rightT = 0;
int rightR = leftView.getMeasuredWidth()+ rightView.getMeasuredWidth();
int rightB = rightView.getMeasuredHeight();
rightView.layout(rightL,rightT,rightR,rightB);
}
//View的事件傳遞
@Override
public boolean onTouchEvent(MotionEvent event) {
//1,要消費該事件,所以直接返回true
//2,使用ViewDragHelper來實現(xiàn)滑動效果
helper.processTouchEvent(event);
return true;
}
}MainActivity.java源碼
package com.example.movedelete;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.ListView;
import com.example.movedelete.adapter.SlideDeleteAdapter;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
private ListView lv;
private ArrayList<String> list;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//初始化視圖
initView();
//初始化數(shù)據(jù)
initData();
//初始化事件
initEvent();
}
//初始化視圖
private void initView() {
lv = (ListView) findViewById(R.id.lv);
}
//初始化數(shù)據(jù)
private void initData() {
list = new ArrayList<>();
for (int i = 0; i < 20; i++) {
list.add("第"+i+"項條目");
}
}
//初始化事件
private void initEvent() {
SlideDeleteAdapter adapter = new SlideDeleteAdapter(list);
lv.setAdapter(adapter);
}
}SlideDeleteAdapter.java源碼
package com.example.movedelete.adapter;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;
import com.example.movedelete.R;
import com.example.movedelete.SlideDelete;
import java.util.ArrayList;
/**
* Created by guixin on 2017/1/5.
*/
public class SlideDeleteAdapter extends BaseAdapter{
private ArrayList<String> list;
public SlideDeleteAdapter(ArrayList<String> list) {
this.list = list;
}
@Override
public int getCount() {
return list == null ? 0 : list.size();
}
@Override
public String getItem(int position) {
return list == null ? null : list.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(final int position, View convertView, ViewGroup parent) {
ViewHolder vh;
if(convertView == null){
convertView = View.inflate(parent.getContext(), R.layout.item_slide,null);
vh = new ViewHolder(convertView);
convertView.setTag(vh);
}else{
vh = (ViewHolder) convertView.getTag();
}
vh.content.setText(list.get(position));
//設置刪除的點擊事件
vh.delete.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//刪除當前的數(shù)據(jù)
list.remove(position);
notifyDataSetChanged();
//讓父容器更新下
}
});
vh.container.requestLayout();
return convertView;
}
class ViewHolder{
private TextView content;
private TextView delete;
private SlideDelete container;
public ViewHolder(View v){
container = (SlideDelete) v.findViewById(R.id.container);
content = (TextView) v.findViewById(R.id.content);
delete = (TextView) v.findViewById(R.id.delete);
}
}
}activity_main.xml
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/activity_main" android:layout_width="match_parent" android:layout_height="match_parent"> <ListView android:id="@+id/lv" android:layout_width="match_parent" android:layout_height="match_parent"> </ListView> </RelativeLayout>
item_slide.xml
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent"> <com.example.movedelete.SlideDelete android:id="@+id/container" android:layout_width="match_parent" android:layout_height="80dp"> <TextView android:id="@+id/content" android:layout_width="match_parent" android:layout_height="match_parent" android:gravity="center" android:background="#33000000" android:text="第0個條目" android:textColor="#fff" android:textSize="20sp" /> <TextView android:id="@+id/delete" android:layout_width="80dp" android:layout_height="match_parent" android:background="#f00" android:gravity="center" android:text="刪除" android:textColor="#fff" android:textSize="20sp" /> </com.example.movedelete.SlideDelete> </LinearLayout>
關于怎么在android中使用View實現(xiàn)一個滑動刪除效果就分享到這里了，希望以上內容可以對大家有一定的幫助，可以學到更多知識。如果覺得文章不錯，可以把它分享出去讓更多的人看到。
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