税务专业就业前景,20121115新闻联播,好吃得要死的拉面
很久以前，发现qq有一个很有趣的功能，就是未读消息的红点是可以拖拽的，而且在任何地方都可以随意拖拽，并且有一个弹性的动画，非常有趣，而且也是一个非常方便的功能，于是总想仿制一个，虽说仿制，但也只是他的拖拽功能，弹性效果还是能力有限。
不多说 先上效果
一个自定义的view 使用方式也很简单
<com.weizhenbin.show.widget.vanishview android:layout_width="30dp" android:layout_height="30dp" android:text="5" android:layout_alignparentbottom="true" android:gravity="center" android:textcolor="#fff" android:id="@+id/vv" android:layout_marginbottom="35dp" android:layout_marginleft="80dp" android:background="@drawable/shape_red_bg"/>
然后先看下源码
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**
* created by weizhenbin on 16/6/1.
* <p/>
* 一个可以随意拖动的view
*/
public class vanishview extends textview {
private context context;
/**窗口管理器*/
private windowmanager windowmanager;
/**用来存储镜像的imageview*/
private imageview iv;
/** 状态栏高度*/
private int statusheight = 0;
/**按下的坐标x 相对于view自身*/
private int dx = 0;
/**按下的坐标y 相对于view自身*/
private int dy = 0;
/**镜像bitmap*/
private bitmap tmp;
/**按下的坐标x 相对于屏幕*/
private float downx = 0;
/**按下的坐标y 相对于屏幕*/
private float downy = 0;
/**属性动画 用于回弹效果*/
private valueanimator animator;
/**窗口参数*/
private windowmanager.layoutparams mwindowlayoutparams;
/**接口对象*/
private onlistener listener;
public vanishview(context context) {
super(context);
init(context);
}
public vanishview(context context, attributeset attrs) {
super(context, attrs);
init(context);
}
public vanishview(context context, attributeset attrs, int defstyleattr) {
super(context, attrs, defstyleattr);
init(context);
}
private void init(context context) {
this.context = context;
windowmanager = ((activity) context).getwindowmanager();
statusheight = getstatusheight(context);
}
@override
public boolean ontouchevent(motionevent event) {
switch (event.getaction()) {
case motionevent.action_down:
dx = (int) event.getx();
dy = (int) event.gety();
downx = event.getrawx();
downy = event.getrawy();
addwindow(context, event.getrawx(), event.getrawy());
setvisibility(invisible);
break;
case motionevent.action_move:
mwindowlayoutparams.x = (int) (event.getrawx() - dx);
mwindowlayoutparams.y = (int) (event.getrawy() - statusheight - dy);
windowmanager.updateviewlayout(iv, mwindowlayoutparams);
break;
case motionevent.action_up:
int distance=distance(new mypoint(event.getrawx(), event.getrawy()), new mypoint(downx, downy));
if(distance<400) {
scroll(new mypoint(event.getrawx(), event.getrawy()), new mypoint(downx, downy));
}else {
if(listener!=null){
listener.ondismiss();
}
windowmanager.removeview(iv);
}
break;
}
return true;
}
/**
* 构建一个窗口 用于存放和移动镜像
* */
private void addwindow(context context, float downx, float dowmy) {
mwindowlayoutparams = new windowmanager.layoutparams();
mwindowlayoutparams.width = windowmanager.layoutparams.wrap_content;
mwindowlayoutparams.height = windowmanager.layoutparams.wrap_content;
iv = new imageview(context);
mwindowlayoutparams.format = pixelformat.rgba_8888;
mwindowlayoutparams.gravity = gravity.top | gravity.left;
mwindowlayoutparams.x = (int) (downx - dx);
mwindowlayoutparams.y = (int) (dowmy - statusheight - dy);
//获取view的镜像bitmap
this.setdrawingcacheenabled(true);
tmp = bitmap.createbitmap(this.getdrawingcache());
//释放缓存
this.destroydrawingcache();
iv.setimagebitmap(tmp);
windowmanager.addview(iv, mwindowlayoutparams);
}
/**
* 使用属性动画 实现缓慢回弹效果
* */
private void scroll(mypoint start, mypoint end) {
animator = valueanimator.ofobject(new mytypeevaluator(), start, end);
animator.setduration(200);
animator.addupdatelistener(new valueanimator.animatorupdatelistener() {
@override
public void onanimationupdate(valueanimator animation) {
mypoint point = (mypoint) animation.getanimatedvalue();
mwindowlayoutparams.x = (int) (point.x - dx);
mwindowlayoutparams.y = (int) (point.y - statusheight - dy);
windowmanager.updateviewlayout(iv, mwindowlayoutparams);
}
});
animator.addlistener(new animatorlisteneradapter() {
@override
public void onanimationend(animator animation) {
super.onanimationend(animation);
windowmanager.removeview(iv);
setvisibility(visible);
}
});
animator.start();
}
/**
* 计算两点的距离
*/
private int distance(mypoint point1, mypoint point2) {
int distance = 0;
if (point1 != null && point2 != null) {
float dx = point1.x - point2.x;
float dy = point1.y - point2.y;
distance = (int) math.sqrt(dx * dx + dy * dy);
}
return distance;
}
/**
* 获取状态栏的高度
*/
private static int getstatusheight(context context) {
int statusheight = 0;
rect localrect = new rect();
((activity) context).getwindow().getdecorview().getwindowvisibledisplayframe(localrect);
statusheight = localrect.top;
if (0 == statusheight) {
class<?> localclass;
try {
localclass = class.forname("com.android.internal.r$dimen");
object localobject = localclass.newinstance();
int i5 = integer.parseint(localclass.getfield("status_bar_height").get(localobject).tostring());
statusheight = context.getresources().getdimensionpixelsize(i5);
} catch (exception e) {
e.printstacktrace();
}
}
return statusheight;
}
class mypoint {
float x;
float y;
public mypoint(float x, float y) {
this.x = x;
this.y = y;
}
@override
public string tostring() {
return "mypoint{" +
"x=" + x +
", y=" + y +
'}';
}
}
class mytypeevaluator implements typeevaluator<mypoint> {
@override
public mypoint evaluate(float fraction, mypoint startvalue, mypoint endvalue) {
mypoint point = startvalue;
point.x = startvalue.x + fraction * (endvalue.x - startvalue.x);
point.y = startvalue.y + fraction * (endvalue.y - startvalue.y);
return point;
}
}
/**事件回调借口*/
public interface onlistener{
void ondismiss();
}
public void setlistener(onlistener listener) {
this.listener = listener;
}
实现这一功能其实也不难，这个功能涉及到以下几个知识点
使用windowmanager添加一个view
使用valueanimator属性动画实现回弹效果
getx和getrawx,gety和getrawy的区别
1.使用windowmanager添加一个view
/**
* 构建一个窗口 用于存放和移动镜像
* */
private void addwindow(context context, float downx, float dowmy) {
mwindowlayoutparams = new windowmanager.layoutparams();
mwindowlayoutparams.width = windowmanager.layoutparams.wrap_content;
mwindowlayoutparams.height = windowmanager.layoutparams.wrap_content;
iv = new imageview(context);
mwindowlayoutparams.format = pixelformat.rgba_8888;
mwindowlayoutparams.gravity = gravity.top | gravity.left;
mwindowlayoutparams.x = (int) (downx - dx);
mwindowlayoutparams.y = (int) (dowmy - statusheight - dy);
//获取view的镜像bitmap
this.setdrawingcacheenabled(true);
tmp = bitmap.createbitmap(this.getdrawingcache());
//释放缓存
this.destroydrawingcache();
iv.setimagebitmap(tmp);
windowmanager.addview(iv, mwindowlayoutparams);
}
这一步是为了投影一个镜像来达到拖动view的一个假像效果，使用imageview来显示。这里为了使投影没用偏移需要了解getx getrawx gety getrawy的区别
getx和gety 是相对于view自身的，getrawx和getrawy是像对屏幕的，这里还要扣除掉状态栏的高度。
2.移动
windowmanager.updateviewlayout(iv, mwindowlayoutparams);
3.使用valueanimator属性动画实现回弹效果
这里自定义了typeevaluator实现点的位移动画
class mytypeevaluator implements typeevaluator<mypoint> {
@override
public mypoint evaluate(float fraction, mypoint startvalue, mypoint endvalue) {
mypoint point = startvalue;
point.x = startvalue.x + fraction * (endvalue.x - startvalue.x);
point.y = startvalue.y + fraction * (endvalue.y - startvalue.y);
return point;
}
}
/**
* 使用属性动画 实现缓慢回弹效果
* */
private void scroll(mypoint start, mypoint end) {
animator = valueanimator.ofobject(new mytypeevaluator(), start, end);
animator.setduration(200);
animator.addupdatelistener(new valueanimator.animatorupdatelistener() {
@override
public void onanimationupdate(valueanimator animation) {
mypoint point = (mypoint) animation.getanimatedvalue();
mwindowlayoutparams.x = (int) (point.x - dx);
mwindowlayoutparams.y = (int) (point.y - statusheight - dy);
windowmanager.updateviewlayout(iv, mwindowlayoutparams);
}
});
animator.addlistener(new animatorlisteneradapter() {
@override
public void onanimationend(animator animation) {
super.onanimationend(animation);
windowmanager.removeview(iv);
setvisibility(visible);
}
});
animator.start();
}
通过属性动画实现一个回弹效果
4.触发消失的时机
/**
* 计算两点的距离
*/
private int distance(mypoint point1, mypoint point2) {
int distance = 0;
if (point1 != null && point2 != null) {
float dx = point1.x - point2.x;
float dy = point1.y - point2.y;
distance = (int) math.sqrt(dx * dx + dy * dy);
}
return distance;
}
计算两点之间的距离来触发一个回调事件。
int distance=distance(new mypoint(event.getrawx(), event.getrawy()), new mypoint(downx, downy));
if(distance<400) {
scroll(new mypoint(event.getrawx(), event.getrawy()), new mypoint(downx, downy));
}else {
if(listener!=null){
listener.ondismiss();
}
windowmanager.removeview(iv);
}
代码分析就到这里，实现这个功能的核心代码都在这里。
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