VerticalSeekbar.java

package com.justwayward.reader.view.epubview;

import android.content.Context;
import android.graphics.Canvas;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.ViewConfiguration;
import android.view.ViewParent;
import android.widget.SeekBar;

import com.justwayward.reader.ui.fragment.EPubReaderFragment;

/**
 * @author yuyh.
 * @date 2016/12/13.
 */
public class VerticalSeekbar extends SeekBar {

    private EPubReaderFragment fragment;

    private boolean mIsDragging;
    private float mTouchDownY;
    private int mScaledTouchSlop;
    private boolean isInScrollingContainer = false;
    private OnSeekBarChangeListener mOnSeekBarChangeListener;

    public boolean isInScrollingContainer() {
        return isInScrollingContainer;
    }

    public void setInScrollingContainer(boolean isInScrollingContainer) {
        this.isInScrollingContainer = isInScrollingContainer;
    }
    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);

        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);

                    invalidate();
                    onStartTrackingTouch();
                    trackTouchEvent(event);
                    attemptClaimDrag();

                    onSizeChanged(getWidth(), getHeight(), 0, 0);
                }
                if (fragment != null) {
                    fragment.removeCallback();
                }
                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 {
                    onStartTrackingTouch();
                    trackTouchEvent(event);
                    onStopTrackingTouch();

                }
                onSizeChanged(getWidth(), getHeight(), 0, 0);
                invalidate();

                if (fragment != null) {
                    fragment.startCallback();
                }

                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 = 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);
        // 便于监听用户触摸改变进度
        mOnSeekBarChangeListener.onProgressChanged(this, (int) progress, true);

    }

    void onStartTrackingTouch() {
        mIsDragging = true;
    }

    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);
    }

    public void setOnSeekBarChangeListener(OnSeekBarChangeListener l) {
        mOnSeekBarChangeListener = l;
        super.setOnSeekBarChangeListener(mOnSeekBarChangeListener);
    }

    public void setFragment(EPubReaderFragment fragment) {
        this.fragment = fragment;
    }
}