SeekBar的使用和竖向的SeekBar

这是实现的几个seekbar的效果图，大家可以先看看：

第一个seekbar是以提供的bitmap为背景，然后进度条是透明的效果

<SeekBar
        android:id="@+id/horiSeekBar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" 
        android:progressDrawable="@drawable/seekbar_progress_example"/>

对应的图片drawable xml

<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
     <item android:id="@android:id/background">
        <bitmap android:src="@drawable/seekbarbackground"/>
    item>
    <item android:id="@android:id/progress">
        <clip>
            <shape>
            <solid android:color="@color/transparent" />
        shape>
        clip>
    item>


layer-list>

第二个seekbar是以自己的shape为背景的，有进度条效果，同时添加一个thumb拖动条

"@+id/horiSeekBar02"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/horiText" 
        android:thumb="@drawable/switch_thumb"
        android:progressDrawable="@drawable/progress_two"/>

对应progress的图片xml

<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >
   <item android:id="@android:id/background">
            <shape>
            <solid android:color="@color/grey_eee" />

            <corners android:radius="5dp" />
        shape>
    item>

   <item android:id="@android:id/secondaryProgress">
       <clip> 
       <shape>
            <solid android:color="@color/green" />

            <corners android:radius="5dp" />
        shape>
        clip>
    item>

layer-list>

---

下面要说的是这个竖向的seekbar，大致的思想就和网上很多写的一样，自定义一个verticalseekbar控件继承seekbar，在绘画的时候把canvas画布旋转90度，同时在onTouchEvent方法里，把拖动时需要的参数，由X变成Y。
我们在设置该控件的背景图片的时候发现，根本不起作用，或者说图片没有达到我们旋转的效果。因此我在onMeasure和onDraw方法里，去主动测量和绘制背景图片，达到我们预想的效果。

protected synchronized void onMeasure(int widthMeasureSpec,
            int heightMeasureSpec) {

        Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.seekbarbackground);

        int heightMeasure = MeasureSpec.makeMeasureSpec(bitmap.getHeight(), MeasureSpec.EXACTLY);
        int widthtMeasure = MeasureSpec.makeMeasureSpec(bitmap.getWidth(), MeasureSpec.EXACTLY);

        super.onMeasure(heightMeasure, widthtMeasure);

        setMeasuredDimension(heightMeasure, widthtMeasure);
    }

    @Override
    protected synchronized void onDraw(Canvas canvas) {

        canvas.rotate(-90);
        canvas.translate(-getHeight(), 0);
        super.onDraw(canvas);


        Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.seekbarbackground);
        Paint paint = new Paint();
        canvas.drawBitmap(bitmap, 0,0, paint);
    }

    @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);

    }

demo下载链接：http://download.csdn.net/detail/yus201120/9872161