跟随鸿洋大神的步伐研究代码-写一个ListView上左滑跳出popwindow删除ListItem的自定义控件 并记录下关于几个不熟悉的类的使用和解释
1.ViewConfiguration.get(context)
// 获取touchSlop （系统 滑动距离的最小值，大于该值可以认为滑动）
int touchSlop = viewConfiguration.getScaledTouchSlop();
// 获得允许执行fling （抛）的最小速度值
int minimumVelocity = viewConfiguration.getScaledMinimumFlingVelocity();
// 获得允许执行fling （抛）的最大速度值
int maximumVelocity = viewConfiguration.getScaledMaximumFlingVelocity();
// Report if the device has a permanent menu key available to the user
// （报告设备是否有用户可找到的永久的菜单按键）
// 即判断设备是否有返回、主页、菜单键等实体按键（非虚拟按键）
boolean hasPermanentMenuKey = viewConfiguration.hasPermanentMenuKey();
2.ListView中pointToPosition()
//根据触摸点的坐标计算出点击的是ListView的哪个Item
int mCurrent = pointToPosition();
//获取界面中显示可见的第一个item的下标
int firstPosition = lisView.getFirstVisiblePosition();
//获取界面中显示可见的最后一个item的下标；
int lastPosition = lisView.getLastVisiblePosition();
//获取界面显示可见的liem的列目总数
int childCount = lisView.getChildCount();
自定义控件的代码
public class QQListView extends ListView {
private static final String TAG = "QQListView";
private int xMove;//移动X坐标
private int yMove;//移动Y坐标
private int xDown;//按下X坐标
private int yDown;//按下Y坐标
private boolean isSlide;//是否移动
private int touchSlop;//最小距离
private LayoutInflater layoutInflater;
private PopupWindow popupWindow;
private int popWindowHeight;//高
private int popWindowWidth;//宽
private Button mBtn;
private int mCurrentPos;
private View mCurrentView;
private DelButtonClickListener delButtonClickListener;
public void setDelButtonClickListener(DelButtonClickListener delButtonClickListener) {
this.delButtonClickListener = delButtonClickListener;
}
public QQListView(Context context, AttributeSet attrs) {
super(context, attrs);
layoutInflater = LayoutInflater.from(context);
// 获取touchSlop （系统 滑动距离的最小值，大于该值可以认为滑动）
touchSlop = ViewConfiguration.get(context).getScaledTouchSlop();
View v = layoutInflater.inflate(R.layout.item_btn,null);
mBtn = v.findViewById(R.id.btn);
popupWindow = new PopupWindow(v, LinearLayout.LayoutParams.WRAP_CONTENT,LinearLayout.LayoutParams.WRAP_CONTENT);
popupWindow.getContentView().measure(0,0);//获取视图设置成不限制测量大小
popWindowHeight = popupWindow.getContentView().getMeasuredHeight();
popWindowWidth = popupWindow.getContentView().getMeasuredWidth();
}
@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
int action = ev.getAction();
//获取触摸的坐标
int x = (int)ev.getX();
int y = (int)ev.getY();
switch (action){
case MotionEvent.ACTION_DOWN:
xDown = x;
yDown = y;
if(popupWindow.isShowing()){
dismissPopWindow();
return false;
}
//根据触摸点的坐标计算出点击的是ListView的哪个Item
mCurrentPos = pointToPosition(xDown,yDown);
/**
*childCount 12说明屏幕上只能显示12个数据
* first = 2;mCurrentPos = 5;last = 13;就会截取显示的数据为数组这样下标就会被重新定义0-11；
* getChildAt(3) //这就是重新定数组只有的下标
*/
mCurrentView = getChildAt(mCurrentPos - getFirstVisiblePosition());
break;
case MotionEvent.ACTION_MOVE:
xMove = x;
yMove = y;
int dx = xMove - xDown;
int dy = yMove - yDown;
//移动最终的点小于按下的点说名是向左滑动 并且 移动最终的点-按下的点 肯定是 负值 所以要 绝对值一下
//既然是向左滑动 那上下的移动就不能超过 滑动的移动范围
if(xMove < xDown && Math.abs(dx) > touchSlop && Math.abs(dy) <touchSlop ){
isSlide = true;
}
break;
}
return super.dispatchTouchEvent(ev);
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
int action = ev.getAction();
if(isSlide){
switch (action){
case MotionEvent.ACTION_MOVE:
int location[] = new int[2];
mCurrentView.getLocationOnScreen(location);
popupWindow.update();
popupWindow.showAtLocation(mCurrentView, Gravity.TOP|Gravity.LEFT
,location[0]+mCurrentView.getWidth(),
location[1]+mCurrentView.getHeight()/2-popWindowHeight/2);
mBtn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View view) {
if(delButtonClickListener != null){
delButtonClickListener.clickHappend(mCurrentPos);
popupWindow.dismiss();
}
}
});
break;
case MotionEvent.ACTION_UP:
isSlide = false;
break;
}
return true;
}
return super.onTouchEvent(ev);
}
private void dismissPopWindow()
{
if (popupWindow != null && popupWindow.isShowing())
{
popupWindow.dismiss();
}
}
public interface DelButtonClickListener{
public void clickHappend(int position);
}
}
mainActivity
public class MainActivity extends AppCompatActivity {
private QQListView listView;
private ArrayAdapter<String> mAdapter;
private List<String> mDatas;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
init();
dealDelInterface();
}
public void init() {
listView = findViewById(R.id.listView);
mDatas = new ArrayList<String>(Arrays.asList("HelloWorld", "Welcome", "Java", "Android", "Servlet", "Struts",
"Hibernate", "Spring", "HTML5", "Javascript", "Lucene"));
mAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, mDatas);
listView.setAdapter(mAdapter);
}
public void dealDelInterface() {
listView.setDelButtonClickListener(new QQListView.DelButtonClickListener() {
@Override
public void clickHappend(int position) {
Toast.makeText(MainActivity.this, position + " : " + mAdapter.getItem(position), Toast.LENGTH_SHORT).show();
mAdapter.remove(mAdapter.getItem(position));
}
});
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Toast.makeText(MainActivity.this, position + " : " + mAdapter.getItem(position), Toast.LENGTH_SHORT).show();
}
});
}
}
anim-pupop_enter/pupop_exit
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
<scale android:fromXScale="0.6" android:toXScale="1.0"
android:fromYScale="0.6" android:toYScale="1.0" android:pivotX="50%"
android:pivotY="50%" android:duration="1000" />
<alpha android:interpolator="@android:anim/decelerate_interpolator"
android:fromAlpha="0.0" android:toAlpha="1.0" android:duration="1000" />
</set>
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
<scale
android:fromXScale="1.0"
android:toXScale="0.5"
android:fromYScale="1.0"
android:toYScale="0.5"
android:pivotX="50%"
android:pivotY="50%"
android:duration="500" />
<alpha
android:interpolator="@android:anim/accelerate_interpolator"
android:fromAlpha="1.0"
android:toAlpha="0.0"
android:duration="500" />
</set>
values-styles
<?xml version="1.0" encoding="utf-8"?>
<resources>
<style name="PopupAnimation" parent="android:Animation" mce_bogus="1">
<item name="android:windowEnterAnimation">@anim/popup_enter</item>
<item name="android:windowExitAnimation">@anim/popup_exit</item>
</style>
</resources>
item_btn.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical" >
<Button
android:id="@+id/btn"
android:layout_width="70dp"
android:singleLine="true"
android:layout_height="wrap_content"
android:text="删除"
android:textColor="#ffffff"
android:paddingLeft="15dp"
android:paddingRight="15dp"
android:layout_alignParentRight="true"
android:layout_centerVertical="true"
android:layout_marginRight="15dp"
/>
</LinearLayout>
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<com.example.threeapp.QQListView
android:id="@+id/listView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
</RelativeLayout>
