垂直的seekbar

看下效果：

  



  1 package org.qianyukun.core.views;
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
{
    Drawable mThumb;
    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(0, -getWidth());
        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);
//                    System.out.println(event.getY());
                    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)
                    {
                        System.out.println("mScaledTouchSlop "+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;
        
        if (y > height - bottom)
        {
            scale = 1.0f;
        }
        else if (y < top)
        {
            scale = 0.0f;
        }
        else
        {
            scale = (float) (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);

    }

    @Override
    public void setThumb(Drawable thumb) {
        super.setThumb(thumb);
        mThumb = thumb;
    }
    public Drawable getSeekBarThumb() {
        return mThumb;
    }

}

最近在做PDF文档的浏览，文档右侧有一个垂直的透明的滑动块，来快速定位文档位置和显示当前页面的位置。

由于原生的seekbar是水平的，所以需要可自定义View了。虽然View的自定义这块，了解的不够深，但是够用了。

实现方式：继承SeekBar，在onDrow（）中将画布旋转，然后平移到能够显示的位置。添加滑动事件。

mPageSlider = new VerticalSeekBar(context);
        mPageSlider.setThumb(getResources().getDrawable(
                R.drawable.pdfseekbarthum));//添加thumb样式
        mPageSlider.setProgressDrawable(getResources().getDrawable(
                R.drawable.seek_progress));//添加进度条样式
        mPageSlider.setBackgroundResource(R.color.toolbar);
        mPageSlider.setThumbOffset(0);//这句比较重要，使thumb显示完整

记录每一行代码，滴水穿石！