android开发之做一个竖着的seekbar

/*
 * Copyright (C) 2006 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package android.widget;
import android.content.Context;
import android.util.AttributeSet;
/**
 * A SeekBar is an extension of ProgressBar that adds a draggable thumb. The user can touch
 * the thumb and drag left or right to set the current progress level or use the arrow keys.
 * Placing focusable widgets to the left or right of a SeekBar is discouraged. 
 * <p>
 * Clients of the SeekBar can attach a {@link SeekBar.OnSeekBarChangeListener} to
 * be notified of the user's actions.
 *
 * @attr ref android.R.styleable#SeekBar_thumb
 */
public class SeekBar extends AbsSeekBar {
    /**
     * A callback that notifies clients when the progress level has been
     * changed. This includes changes that were initiated by the user through a
     * touch gesture or arrow key/trackball as well as changes that were initiated
     * programmatically.
     */
    public interface OnSeekBarChangeListener {
        
        /**
         * Notification that the progress level has changed. Clients can use the fromUser parameter
         * to distinguish user-initiated changes from those that occurred programmatically.
         * 
         * @param seekBar The SeekBar whose progress has changed
         * @param progress The current progress level. This will be in the range 0..max where max
         *        was set by {@link ProgressBar#setMax(int)}. (The default value for max is 100.)
         * @param fromUser True if the progress change was initiated by the user.
         */
        void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser);
    
        /**
         * Notification that the user has started a touch gesture. Clients may want to use this
         * to disable advancing the seekbar. 
         * @param seekBar The SeekBar in which the touch gesture began
         */
        void onStartTrackingTouch(SeekBar seekBar);
        
        /**
         * Notification that the user has finished a touch gesture. Clients may want to use this
         * to re-enable advancing the seekbar. 
         * @param seekBar The SeekBar in which the touch gesture began
         */
        void onStopTrackingTouch(SeekBar seekBar);
    }
    private OnSeekBarChangeListener mOnSeekBarChangeListener;
    
    public SeekBar(Context context) {
        this(context, null);
    }
    
    public SeekBar(Context context, AttributeSet attrs) {
        this(context, attrs, com.android.internal.R.attr.seekBarStyle);
    }
    public SeekBar(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }
    @Override
    void onProgressRefresh(float scale, boolean fromUser) {
        super.onProgressRefresh(scale, fromUser);
        if (mOnSeekBarChangeListener != null) {
            mOnSeekBarChangeListener.onProgressChanged(this, getProgress(), fromUser);
        }
    }
    /**
     * Sets a listener to receive notifications of changes to the SeekBar's progress level. Also
     * provides notifications of when the user starts and stops a touch gesture within the SeekBar.
     * 
     * @param l The seek bar notification listener
     * 
     * @see SeekBar.OnSeekBarChangeListener
     */
    public void setOnSeekBarChangeListener(OnSeekBarChangeListener l) {
        mOnSeekBarChangeListener = l;
    }
    
    @Override
    void onStartTrackingTouch() {
        if (mOnSeekBarChangeListener != null) {
            mOnSeekBarChangeListener.onStartTrackingTouch(this);
        }
    }
    
    @Override
    void onStopTrackingTouch() {
        if (mOnSeekBarChangeListener != null) {
            mOnSeekBarChangeListener.onStopTrackingTouch(this);
        }
    }
    
}

/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package android.widget;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.view.KeyEvent;
import android.view.MotionEvent;
public abstract class AbsSeekBar extends ProgressBar {
    private Drawable mThumb;
    private int mThumbOffset;
    
    /**
     * On touch, this offset plus the scaled value from the position of the
     * touch will form the progress value. Usually 0.
     */
    float mTouchProgressOffset;
    /**
     * Whether this is user seekable.
     */
    boolean mIsUserSeekable = true;
    /**
     * On key presses (right or left), the amount to increment/decrement the
     * progress.
     */
    private int mKeyProgressIncrement = 1;
    
    private static final int NO_ALPHA = 0xFF;
    private float mDisabledAlpha;
    
    public AbsSeekBar(Context context) {
        super(context);
    }
    public AbsSeekBar(Context context, AttributeSet attrs) {
        super(context, attrs);
    }
    public AbsSeekBar(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        TypedArray a = context.obtainStyledAttributes(attrs,
                com.android.internal.R.styleable.SeekBar, defStyle, 0);
        Drawable thumb = a.getDrawable(com.android.internal.R.styleable.SeekBar_thumb);
        setThumb(thumb);
        int thumbOffset =
                a.getDimensionPixelOffset(com.android.internal.R.styleable.SeekBar_thumbOffset, 0);
        setThumbOffset(thumbOffset);
        a.recycle();
        a = context.obtainStyledAttributes(attrs,
                com.android.internal.R.styleable.Theme, 0, 0);
        mDisabledAlpha = a.getFloat(com.android.internal.R.styleable.Theme_disabledAlpha, 0.5f);
        a.recycle();
    }
    /**
     * Sets the thumb that will be drawn at the end of the progress meter within the SeekBar
     * 
     * @param thumb Drawable representing the thumb
     */
    public void setThumb(Drawable thumb) {
        if (thumb != null) {
            thumb.setCallback(this);
        }
        mThumb = thumb;
        invalidate();
    }
    /**
     * @see #setThumbOffset(int)
     */
    public int getThumbOffset() {
        return mThumbOffset;
    }
    /**
     * Sets the thumb offset that allows the thumb to extend out of the range of
     * the track.
     * 
     * @param thumbOffset The offset amount in pixels.
     */
    public void setThumbOffset(int thumbOffset) {
        mThumbOffset = thumbOffset;
        invalidate();
    }
    /**
     * Sets the amount of progress changed via the arrow keys.
     * 
     * @param increment The amount to increment or decrement when the user
     *            presses the arrow keys.
     */
    public void setKeyProgressIncrement(int increment) {
        mKeyProgressIncrement = increment < 0 ? -increment : increment;
    }
    /**
     * Returns the amount of progress changed via the arrow keys.
     * <p>
     * By default, this will be a value that is derived from the max progress.
     * 
     * @return The amount to increment or decrement when the user presses the
     *         arrow keys. This will be positive.
     */
    public int getKeyProgressIncrement() {
        return mKeyProgressIncrement;
    }
    
    @Override
    public synchronized void setMax(int max) {
        super.setMax(max);
        if ((mKeyProgressIncrement == 0) || (getMax() / mKeyProgressIncrement > 20)) {
            // It will take the user too long to change this via keys, change it
            // to something more reasonable
            setKeyProgressIncrement(Math.max(1, Math.round((float) getMax() / 20)));
        }
    }
    @Override
    protected boolean verifyDrawable(Drawable who) {
        return who == mThumb || super.verifyDrawable(who);
    }
    @Override
    protected void drawableStateChanged() {
        super.drawableStateChanged();
        
        Drawable progressDrawable = getProgressDrawable();
        if (progressDrawable != null) {
            progressDrawable.setAlpha(isEnabled() ? NO_ALPHA : (int) (NO_ALPHA * mDisabledAlpha));
        }
        
        if (mThumb != null && mThumb.isStateful()) {
            int[] state = getDrawableState();
            mThumb.setState(state);
        }
    }
    
    @Override
    void onProgressRefresh(float scale, boolean fromUser) { 
        Drawable thumb = mThumb;
        if (thumb != null) {
            setThumbPos(getWidth(), thumb, scale, Integer.MIN_VALUE);
            /*
             * Since we draw translated, the drawable's bounds that it signals
             * for invalidation won't be the actual bounds we want invalidated,
             * so just invalidate this whole view.
             */
            invalidate();
        }
    }
    
    
    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        Drawable d = getCurrentDrawable();
        Drawable thumb = mThumb;
        int thumbHeight = thumb == null ? 0 : thumb.getIntrinsicHeight();
        // The max height does not incorporate padding, whereas the height
        // parameter does
        int trackHeight = Math.min(mMaxHeight, h - mPaddingTop - mPaddingBottom);
        
        int max = getMax();
        float scale = max > 0 ? (float) getProgress() / (float) max : 0;
        
        if (thumbHeight > trackHeight) {
            if (thumb != null) {
                setThumbPos(w, thumb, scale, 0);
            }
            int gapForCenteringTrack = (thumbHeight - trackHeight) / 2;
            if (d != null) {
                // Canvas will be translated by the padding, so 0,0 is where we start drawing
                d.setBounds(0, gapForCenteringTrack, 
                        w - mPaddingRight - mPaddingLeft, h - mPaddingBottom - gapForCenteringTrack
                        - mPaddingTop);
            }
        } else {
            if (d != null) {
                // Canvas will be translated by the padding, so 0,0 is where we start drawing
                d.setBounds(0, 0, w - mPaddingRight - mPaddingLeft, h - mPaddingBottom
                        - mPaddingTop);
            }
            int gap = (trackHeight - thumbHeight) / 2;
            if (thumb != null) {
                setThumbPos(w, thumb, scale, gap);
            }
        }
    }
    /**
     * @param gap If set to {@link Integer#MIN_VALUE}, this will be ignored and
     */
    private void setThumbPos(int w, Drawable thumb, float scale, int gap) {
        int available = w - mPaddingLeft - mPaddingRight;
        int thumbWidth = thumb.getIntrinsicWidth();
        int thumbHeight = thumb.getIntrinsicHeight();
        available -= thumbWidth;
        // The extra space for the thumb to move on the track
        available += mThumbOffset * 2;
        int thumbPos = (int) (scale * available);
        int topBound, bottomBound;
        if (gap == Integer.MIN_VALUE) {
            Rect oldBounds = thumb.getBounds();
            topBound = oldBounds.top;
            bottomBound = oldBounds.bottom;
        } else {
            topBound = gap;
            bottomBound = gap + thumbHeight;
        }
        
        // Canvas will be translated, so 0,0 is where we start drawing
        thumb.setBounds(thumbPos, topBound, thumbPos + thumbWidth, bottomBound);
    }
    
    @Override
    protected synchronized void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        if (mThumb != null) {
            canvas.save();
            // Translate the padding. For the x, we need to allow the thumb to
            // draw in its extra space
            canvas.translate(mPaddingLeft - mThumbOffset, mPaddingTop);
            mThumb.draw(canvas);
            canvas.restore();
        }
    }
    @Override
    protected synchronized void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        Drawable d = getCurrentDrawable();
        int thumbHeight = mThumb == null ? 0 : mThumb.getIntrinsicHeight();
        int dw = 0;
        int dh = 0;
        if (d != null) {
            dw = Math.max(mMinWidth, Math.min(mMaxWidth, d.getIntrinsicWidth()));
            dh = Math.max(mMinHeight, Math.min(mMaxHeight, d.getIntrinsicHeight()));
            dh = Math.max(thumbHeight, dh);
        }
        dw += mPaddingLeft + mPaddingRight;
        dh += mPaddingTop + mPaddingBottom;
        
        setMeasuredDimension(resolveSize(dw, widthMeasureSpec),
                resolveSize(dh, heightMeasureSpec));
    }
    
    @Override
    public boolean onTouchEvent(MotionEvent event) {
        if (!mIsUserSeekable || !isEnabled()) {
            return false;
        }
        
        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                setPressed(true);
                onStartTrackingTouch();
                trackTouchEvent(event);
                break;
                
            case MotionEvent.ACTION_MOVE:
                trackTouchEvent(event);
                attemptClaimDrag();
                break;
                
            case MotionEvent.ACTION_UP:
                trackTouchEvent(event);
                onStopTrackingTouch();
                setPressed(false);
                break;
                
            case MotionEvent.ACTION_CANCEL:
                onStopTrackingTouch();
                setPressed(false);
                break;
        }
        return true;
    }
    private void trackTouchEvent(MotionEvent event) {
        final int width = getWidth();
        final int available = width - mPaddingLeft - mPaddingRight;
        int x = (int)event.getX();
        float scale;
        float progress = 0;
        if (x < mPaddingLeft) {
            scale = 0.0f;
        } else if (x > width - mPaddingRight) {
            scale = 1.0f;
        } else {
            scale = (float)(x - mPaddingLeft) / (float)available;
            progress = mTouchProgressOffset;
        }
        
        final int max = getMax();
        progress += scale * max;
        
        setProgress((int) progress, true);
    }
    /**
     * Tries to claim the user's drag motion, and requests disallowing any
     * ancestors from stealing events in the drag.
     */
    private void attemptClaimDrag() {
        if (mParent != null) {
            mParent.requestDisallowInterceptTouchEvent(true);
        }
    }
    
    /**
     * This is called when the user has started touching this widget.
     */
    void onStartTrackingTouch() {
    }
    /**
     * This is called when the user either releases his touch or the touch is
     * canceled.
     */
    void onStopTrackingTouch() {
    }
    /**
     * Called when the user changes the seekbar's progress by using a key event.
     */
    void onKeyChange() {
    }
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        int progress = getProgress();
        
        switch (keyCode) {
            case KeyEvent.KEYCODE_DPAD_LEFT:
                if (progress <= 0) break;
                setProgress(progress - mKeyProgressIncrement, true);
                onKeyChange();
                return true;
        
            case KeyEvent.KEYCODE_DPAD_RIGHT:
                if (progress >= getMax()) break;
                setProgress(progress + mKeyProgressIncrement, true);
                onKeyChange();
                return true;
        }
        return super.onKeyDown(keyCode, event);
    }
}