android自带的seekbar是水平的，要垂直的，必须自己写一个类，继承seekbar。
一个简单的垂直seekbar的例子：
（但是它其实是存在一些问题的。不过要是满足基本需要还是可以凑合的）
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package com.example.helloverticalseekbar;
import android.content.context;
import android.graphics.canvas;
import android.util.attributeset;
import android.view.motionevent;
import android.widget.seekbar;
public class verticalseekbar extends seekbar
{
public verticalseekbar(context context, attributeset attrs, int defstyle)
{
super(context, attrs, defstyle);
}
public verticalseekbar(context context, attributeset attrs)
{
super(context, attrs);
}
public verticalseekbar(context context)
{
super(context);
}
@override
protected void onsizechanged(int w, int h, int oldw, int oldh)
{
super.onsizechanged(h, w, oldh, oldw);
}
@override
protected synchronized void onmeasure(int widthmeasurespec,
int heightmeasurespec)
{
super.onmeasure(heightmeasurespec, widthmeasurespec);
setmeasureddimension(getmeasuredheight(), getmeasuredwidth());
}
@override
protected synchronized void ondraw(canvas canvas)
{
canvas.rotate(-90);
canvas.translate(-getheight(), 0);
super.ondraw(canvas);
}
@override
public boolean ontouchevent(motionevent event)
{
if (!isenabled())
{
return false;
}
switch (event.getaction())
{
case motionevent.action_down:
case motionevent.action_move:
case motionevent.action_up:
setprogress(getmax()
- (int) (getmax() * event.gety() / getheight()));
onsizechanged(getwidth(), getheight(), 0, 0);
break;
case motionevent.action_cancel:
break;
}
return true;
}
}
demo中加上一个水平seekbar作为对比，代码如下：
activity：
helloseekbaractivity
package com.example.helloverticalseekbar;
import android.os.bundle;
import android.app.activity;
import android.util.log;
import android.view.menu;
import android.widget.seekbar;
import android.widget.textview;
import android.widget.seekbar.onseekbarchangelistener;
public class helloseekbaractivity extends activity
{
private seekbar horiseekbar = null;
private textview horitext = null;
private verticalseekbar verticalseekbar = null;
private textview verticaltext = null;
@override
protected void oncreate(bundle savedinstancestate)
{
log.d(appconstants.log_tag, "oncreate");
super.oncreate(savedinstancestate);
setcontentview(r.layout.activity_hello_seek_bar);
horiseekbar = (seekbar) findviewbyid(r.id.horiseekbar);
horitext = (textview)findviewbyid(r.id.horitext);
horiseekbar.setonseekbarchangelistener(horiseekbarlistener);
verticalseekbar = (verticalseekbar)findviewbyid(r.id.verticalseekbar);
verticaltext = (textview)findviewbyid(r.id.verticaltext);
verticalseekbar.setonseekbarchangelistener(verticalseekbarchangelistener);
}
@override
public boolean oncreateoptionsmenu(menu menu)
{
getmenuinflater().inflate(r.menu.hello_seek_bar, menu);
return true;
}
private onseekbarchangelistener horiseekbarlistener = new onseekbarchangelistener()
{
@override
public void onstoptrackingtouch(seekbar seekbar)
{
}
@override
public void onstarttrackingtouch(seekbar seekbar)
{
}
@override
public void onprogresschanged(seekbar seekbar, int progress,
boolean fromuser)
{
log.d(appconstants.log_tag, "horizontal seekbar --> onprogresschanged");
horitext.settext(integer.tostring(progress));
}
};
private onseekbarchangelistener verticalseekbarchangelistener = new onseekbarchangelistener()
{
@override
public void onstoptrackingtouch(seekbar seekbar)
{
}
@override
public void onstarttrackingtouch(seekbar seekbar)
{
}
@override
public void onprogresschanged(seekbar seekbar, int progress,
boolean fromuser)
{
log.d(appconstants.log_tag, "vertical seekbar --> onprogresschanged");
verticaltext.settext(integer.tostring(progress));
}
};
}
布局：
activity_hello_seek_bar.xml
<relativelayout 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:paddingbottom="@dimen/activity_vertical_margin" android:paddingleft="@dimen/activity_horizontal_margin" android:paddingright="@dimen/activity_horizontal_margin" android:paddingtop="@dimen/activity_vertical_margin" tools:context=".helloseekbaractivity" > <textview android:id="@+id/mytextview" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignparenttop="true" android:text="@string/hello_world" /> <seekbar android:id="@+id/horiseekbar" android:layout_width="match_parent" android:layout_height="20dp" android:layout_below="@id/mytextview" /> <textview android:id="@+id/horitext" android:layout_width="wrap_content" android:layout_height="20dp" android:layout_below="@id/horiseekbar" android:text="horizontal" /> <com.example.helloverticalseekbar.verticalseekbar android:id="@+id/verticalseekbar" android:layout_width="wrap_content" android:layout_height="200dp" android:layout_below="@id/horitext" /> <textview android:id="@+id/verticaltext" android:layout_width="wrap_content" android:layout_height="20dp" android:layout_below="@id/verticalseekbar" android:text="vertical" /> </relativelayout>
运行截图：
一个改进版的seekbar
package com.example.helloverticalseekbarv2;
import android.content.context;
import android.graphics.canvas;
import android.graphics.rect;
import android.graphics.drawable.drawable;
import android.util.attributeset;
import android.view.motionevent;
import android.view.view;
import android.view.viewconfiguration;
import android.view.viewgroup;
import android.view.viewparent;
import android.widget.seekbar;
public class verticalseekbar extends seekbar
{
private boolean misdragging;
private float mtouchdowny;
private int mscaledtouchslop;
private boolean isinscrollingcontainer = false;
public boolean isinscrollingcontainer()
{
return isinscrollingcontainer;
}
public void setinscrollingcontainer(boolean isinscrollingcontainer)
{
this.isinscrollingcontainer = isinscrollingcontainer;
}
/**
* on touch, this offset plus the scaled value from the position of the
* touch will form the progress value. usually 0.
*/
float mtouchprogressoffset;
public verticalseekbar(context context, attributeset attrs, int defstyle)
{
super(context, attrs, defstyle);
mscaledtouchslop = viewconfiguration.get(context).getscaledtouchslop();
}
public verticalseekbar(context context, attributeset attrs)
{
super(context, attrs);
}
public verticalseekbar(context context)
{
super(context);
}
@override
protected void onsizechanged(int w, int h, int oldw, int oldh)
{
super.onsizechanged(h, w, oldh, oldw);
}
@override
protected synchronized void onmeasure(int widthmeasurespec,
int heightmeasurespec)
{
super.onmeasure(heightmeasurespec, widthmeasurespec);
setmeasureddimension(getmeasuredheight(), getmeasuredwidth());
}
@override
protected synchronized void ondraw(canvas canvas)
{
canvas.rotate(-90);
canvas.translate(-getheight(), 0);
super.ondraw(canvas);
}
@override
public boolean ontouchevent(motionevent event)
{
if (!isenabled())
{
return false;
}
switch (event.getaction())
{
case motionevent.action_down:
if (isinscrollingcontainer())
{
mtouchdowny = event.gety();
}
else
{
setpressed(true);
invalidate();
onstarttrackingtouch();
tracktouchevent(event);
attemptclaimdrag();
onsizechanged(getwidth(), getheight(), 0, 0);
}
break;
case motionevent.action_move:
if (misdragging)
{
tracktouchevent(event);
}
else
{
final float y = event.gety();
if (math.abs(y - mtouchdowny) > mscaledtouchslop)
{
setpressed(true);
invalidate();
onstarttrackingtouch();
tracktouchevent(event);
attemptclaimdrag();
}
}
onsizechanged(getwidth(), getheight(), 0, 0);
break;
case motionevent.action_up:
if (misdragging)
{
tracktouchevent(event);
onstoptrackingtouch();
setpressed(false);
}
else
{
// touch up when we never crossed the touch slop threshold
// should
// be interpreted as a tap-seek to that location.
onstarttrackingtouch();
tracktouchevent(event);
onstoptrackingtouch();
}
onsizechanged(getwidth(), getheight(), 0, 0);
// progressbar doesn't know to repaint the thumb drawable
// in its inactive state when the touch stops (because the
// value has not apparently changed)
invalidate();
break;
}
return true;
}
private void tracktouchevent(motionevent event)
{
final int height = getheight();
final int top = getpaddingtop();
final int bottom = getpaddingbottom();
final int available = height - top - bottom;
int y = (int) event.gety();
float scale;
float progress = 0;
// 下面是最小值
if (y > height - bottom)
{
scale = 0.0f;
}
else if (y < top)
{
scale = 1.0f;
}
else
{
scale = (float) (available - y + top) / (float) available;
progress = mtouchprogressoffset;
}
final int max = getmax();
progress += scale * max;
setprogress((int) progress);
}
/**
* this is called when the user has started touching this widget.
*/
void onstarttrackingtouch()
{
misdragging = true;
}
/**
* this is called when the user either releases his touch or the touch is
* canceled.
*/
void onstoptrackingtouch()
{
misdragging = false;
}
private void attemptclaimdrag()
{
viewparent p = getparent();
if (p != null)
{
p.requestdisallowintercepttouchevent(true);
}
}
@override
public synchronized void setprogress(int progress)
{
super.setprogress(progress);
onsizechanged(getwidth(), getheight(), 0, 0);
}
}
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