android应用程序中带有项目符号的幻灯片

Question

如何从 daimajia.slider 中删除这个黑色部分和描述 或者是否有其他替代方法可以仅使用带有子弹的滑块。

Answer 1

是的，您可以制作只有项目符号而没有文字的幻灯片。

使用ViewPager制作幻灯片

屏幕幻灯片是整个屏幕到另一个屏幕之间的过渡，并且 在设置向导或幻灯片等 UI 中很常见。本课 向您展示如何使用由 支持库。 ViewPagers 可以自动为屏幕幻灯片制作动画。

要添加点，请使用 Jake Wharton 的 ViewPagerIndicator 库并使用它提供的 CirclePageIndicator。完成！

Answer 2

您可以在下面的类中使用 viewpager。

CirclePageIndicator.java

public class CirclePageIndicator extends View implements PageIndicator {
    private static final int INVALID_POINTER = -1;

    private float mRadius;
    private final Paint mPaintPageFill = new Paint(ANTI_ALIAS_FLAG);
    private final Paint mPaintStroke = new Paint(ANTI_ALIAS_FLAG);
    private final Paint mPaintFill = new Paint(ANTI_ALIAS_FLAG);
    private ViewPager mViewPager;
    private ViewPager.OnPageChangeListener mListener;
    private int mCurrentPage;
    private int mSnapPage;
    private float mPageOffset;
    private int mScrollState;
    private int mOrientation;
    private boolean mCentered;
    private boolean mSnap;

    private int mTouchSlop;
    private float mLastMotionX = -1;
    private int mActivePointerId = INVALID_POINTER;
    private boolean mIsDragging;


    public CirclePageIndicator(Context context) {
        this(context, null);
    }

    public CirclePageIndicator(Context context, AttributeSet attrs) {
        this(context, attrs, R.attr.vpiCirclePageIndicatorStyle);
    }

    public CirclePageIndicator(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        if (isInEditMode()) return;

        //Load defaults from resources
        final Resources res = getResources();
        final int defaultPageColor = res.getColor(R.color.default_circle_indicator_page_color);
        //default_circle_indicator_fill_color
        final int defaultFillColor = res.getColor(R.color.holo_blue_dark);
        final int defaultOrientation = res.getInteger(R.integer.default_circle_indicator_orientation);
        final int defaultStrokeColor = res.getColor(R.color.default_circle_indicator_stroke_color);
        final float defaultStrokeWidth = res.getDimension(R.dimen.default_circle_indicator_stroke_width);
        final float defaultRadius = res.getDimension(R.dimen.default_circle_indicator_radius);
        final boolean defaultCentered = res.getBoolean(R.bool.default_circle_indicator_centered);
        final boolean defaultSnap = res.getBoolean(R.bool.default_circle_indicator_snap);

        //Retrieve styles attributes
        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.CirclePageIndicator, defStyle, 0);

        mCentered = a.getBoolean(R.styleable.CirclePageIndicator_centered, defaultCentered);
        mOrientation = a.getInt(R.styleable.CirclePageIndicator_android_orientation, defaultOrientation);
        mPaintPageFill.setStyle(Style.FILL);
        mPaintPageFill.setColor(a.getColor(R.styleable.CirclePageIndicator_pageColor, defaultPageColor));
        mPaintStroke.setStyle(Style.STROKE);
        mPaintStroke.setColor(a.getColor(R.styleable.CirclePageIndicator_strokeColor, defaultStrokeColor));
        mPaintStroke.setStrokeWidth(a.getDimension(R.styleable.CirclePageIndicator_strokeWidth, defaultStrokeWidth));
        mPaintFill.setStyle(Style.FILL);
        mPaintFill.setColor(a.getColor(R.styleable.CirclePageIndicator_fillColor, defaultFillColor));
        mRadius = a.getDimension(R.styleable.CirclePageIndicator_radius, defaultRadius);
        mSnap = a.getBoolean(R.styleable.CirclePageIndicator_snap, defaultSnap);

        Drawable background = a.getDrawable(R.styleable.CirclePageIndicator_android_background);
        if (background != null) {
            setBackgroundDrawable(background);
        }

        a.recycle();

        final ViewConfiguration configuration = ViewConfiguration.get(context);
        mTouchSlop = ViewConfigurationCompat.getScaledPagingTouchSlop(configuration);
    }


    public void setCentered(boolean centered) {
        mCentered = centered;
        invalidate();
    }

    public boolean isCentered() {
        return mCentered;
    }

    public void setPageColor(int pageColor) {
        mPaintPageFill.setColor(pageColor);
        invalidate();
    }

    public int getPageColor() {
        return mPaintPageFill.getColor();
    }

    public void setFillColor(int fillColor) {
        mPaintFill.setColor(fillColor);
        invalidate();
    }

    public int getFillColor() {
        return mPaintFill.getColor();
    }

    public void setOrientation(int orientation) {
        switch (orientation) {
        case HORIZONTAL:
        case VERTICAL:
            mOrientation = orientation;
            requestLayout();
            break;

        default:
            throw new IllegalArgumentException("Orientation must be either HORIZONTAL or VERTICAL.");
        }
    }

    public int getOrientation() {
        return mOrientation;
    }

    public void setStrokeColor(int strokeColor) {
        mPaintStroke.setColor(strokeColor);
        invalidate();
    }

    public int getStrokeColor() {
        return mPaintStroke.getColor();
    }

    public void setStrokeWidth(float strokeWidth) {
        mPaintStroke.setStrokeWidth(strokeWidth);
        invalidate();
    }

    public float getStrokeWidth() {
        return mPaintStroke.getStrokeWidth();
    }

    public void setRadius(float radius) {
        mRadius = radius;
        invalidate();
    }

    public float getRadius() {
        return mRadius;
    }

    public void setSnap(boolean snap) {
        mSnap = snap;
        invalidate();
    }

    public boolean isSnap() {
        return mSnap;
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        if (mViewPager == null) {
            return;
        }
        final int count = mViewPager.getAdapter().getCount();
        if (count == 0) {
            return;
        }

        if (mCurrentPage >= count) {
            setCurrentItem(count - 1);
            return;
        }

        int longSize;
        int longPaddingBefore;
        int longPaddingAfter;
        int shortPaddingBefore;
        if (mOrientation == HORIZONTAL) {
            longSize = getWidth();
            longPaddingBefore = getPaddingLeft();
            longPaddingAfter = getPaddingRight();
            shortPaddingBefore = getPaddingTop();
        } else {
            longSize = getHeight();
            longPaddingBefore = getPaddingTop();
            longPaddingAfter = getPaddingBottom();
            shortPaddingBefore = getPaddingLeft();
        }

        final float threeRadius = mRadius * 3;
        final float shortOffset = shortPaddingBefore + mRadius;
        float longOffset = longPaddingBefore + mRadius;
        if (mCentered) {
            longOffset += ((longSize - longPaddingBefore - longPaddingAfter) / 2.0f) - ((count * threeRadius) / 2.0f);
        }

        float dX;
        float dY;

        float pageFillRadius = mRadius;
        if (mPaintStroke.getStrokeWidth() > 0) {
            pageFillRadius -= mPaintStroke.getStrokeWidth() / 2.0f;
        }

        //Draw stroked circles
        for (int iLoop = 0; iLoop < count; iLoop++) {
            float drawLong = longOffset + (iLoop * threeRadius);
            if (mOrientation == HORIZONTAL) {
                dX = drawLong;
                dY = shortOffset;
            } else {
                dX = shortOffset;
                dY = drawLong;
            }
            // Only paint fill if not completely transparent
            if (mPaintPageFill.getAlpha() > 0) {
                canvas.drawCircle(dX, dY, pageFillRadius, mPaintPageFill);
            }

            // Only paint stroke if a stroke width was non-zero
            if (pageFillRadius != mRadius) {
                canvas.drawCircle(dX, dY, mRadius, mPaintStroke);
            }
        }

        //Draw the filled circle according to the current scroll
        float cx = (mSnap ? mSnapPage : mCurrentPage) * threeRadius;
        if (!mSnap) {
            cx += mPageOffset * threeRadius;
        }
        if (mOrientation == HORIZONTAL) {
            dX = longOffset + cx;
            dY = shortOffset;
        } else {
            dX = shortOffset;
            dY = longOffset + cx;
        }
        canvas.drawCircle(dX, dY, mRadius, mPaintFill);
    }

    public boolean onTouchEvent(android.view.MotionEvent ev) {
        if (super.onTouchEvent(ev)) {
            return true;
        }
        if ((mViewPager == null) || (mViewPager.getAdapter().getCount() == 0)) {
            return false;
        }

        final int action = ev.getAction() & MotionEventCompat.ACTION_MASK;
        switch (action) {
        case MotionEvent.ACTION_DOWN:
            mActivePointerId = MotionEventCompat.getPointerId(ev, 0);
            mLastMotionX = ev.getX();
            break;

        case MotionEvent.ACTION_MOVE: {
            final int activePointerIndex = MotionEventCompat.findPointerIndex(ev, mActivePointerId);
            final float x = MotionEventCompat.getX(ev, activePointerIndex);
            final float deltaX = x - mLastMotionX;

            if (!mIsDragging) {
                if (Math.abs(deltaX) > mTouchSlop) {
                    mIsDragging = true;
                }
            }

            if (mIsDragging) {
                mLastMotionX = x;
                if (mViewPager.isFakeDragging() || mViewPager.beginFakeDrag()) {
                    mViewPager.fakeDragBy(deltaX);
                }
            }

            break;
        }

        case MotionEvent.ACTION_CANCEL:
        case MotionEvent.ACTION_UP:
            if (!mIsDragging) {
                final int count = mViewPager.getAdapter().getCount();
                final int width = getWidth();
                final float halfWidth = width / 2f;
                final float sixthWidth = width / 6f;

                if ((mCurrentPage > 0) && (ev.getX() < halfWidth - sixthWidth)) {
                    if (action != MotionEvent.ACTION_CANCEL) {
                        mViewPager.setCurrentItem(mCurrentPage - 1);
                    }
                    return true;
                } else if ((mCurrentPage < count - 1) && (ev.getX() > halfWidth + sixthWidth)) {
                    if (action != MotionEvent.ACTION_CANCEL) {
                        mViewPager.setCurrentItem(mCurrentPage + 1);
                    }
                    return true;
                }
            }

            mIsDragging = false;
            mActivePointerId = INVALID_POINTER;
            if (mViewPager.isFakeDragging()) mViewPager.endFakeDrag();
            break;

        case MotionEventCompat.ACTION_POINTER_DOWN: {
            final int index = MotionEventCompat.getActionIndex(ev);
            mLastMotionX = MotionEventCompat.getX(ev, index);
            mActivePointerId = MotionEventCompat.getPointerId(ev, index);
            break;
        }

        case MotionEventCompat.ACTION_POINTER_UP:
            final int pointerIndex = MotionEventCompat.getActionIndex(ev);
            final int pointerId = MotionEventCompat.getPointerId(ev, pointerIndex);
            if (pointerId == mActivePointerId) {
                final int newPointerIndex = pointerIndex == 0 ? 1 : 0;
                mActivePointerId = MotionEventCompat.getPointerId(ev, newPointerIndex);
            }
            mLastMotionX = MotionEventCompat.getX(ev, MotionEventCompat.findPointerIndex(ev, mActivePointerId));
            break;
        }

        return true;
    }

    @Override
    public void setViewPager(ViewPager view) {
        if (mViewPager == view) {
            return;
        }
        if (mViewPager != null) {
            mViewPager.setOnPageChangeListener(null);
        }
        if (view.getAdapter() == null) {
            throw new IllegalStateException("ViewPager does not have adapter instance.");
        }
        mViewPager = view;
        mViewPager.setOnPageChangeListener(this);
        invalidate();
    }

    @Override
    public void setViewPager(ViewPager view, int initialPosition) {
        setViewPager(view);
        setCurrentItem(initialPosition);
    }

    @Override
    public void setCurrentItem(int item) {
        if (mViewPager == null) {
            throw new IllegalStateException("ViewPager has not been bound.");
        }
        mViewPager.setCurrentItem(item);
        mCurrentPage = item;
        invalidate();
    }

    @Override
    public void notifyDataSetChanged() {
        invalidate();
    }

    @Override
    public void onPageScrollStateChanged(int state) {
        mScrollState = state;

        if (mListener != null) {
            mListener.onPageScrollStateChanged(state);
        }
    }

    @Override
    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
        mCurrentPage = position;
        mPageOffset = positionOffset;
        invalidate();

        if (mListener != null) {
            mListener.onPageScrolled(position, positionOffset, positionOffsetPixels);
        }
    }

    @Override
    public void onPageSelected(int position) {
        if (mSnap || mScrollState == ViewPager.SCROLL_STATE_IDLE) {
            mCurrentPage = position;
            mSnapPage = position;
            invalidate();
        }

        if (mListener != null) {
            mListener.onPageSelected(position);
        }
    }

    @Override
    public void setOnPageChangeListener(ViewPager.OnPageChangeListener listener) {
        mListener = listener;
    }

    /*
     * (non-Javadoc)
     *
     * @see android.view.View#onMeasure(int, int)
     */
     @Override
     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
         if (mOrientation == HORIZONTAL) {
             setMeasuredDimension(measureLong(widthMeasureSpec), measureShort(heightMeasureSpec));
         } else {
             setMeasuredDimension(measureShort(widthMeasureSpec), measureLong(heightMeasureSpec));
         }
     }

     /**
      * Determines the width of this view
      *
      * @param measureSpec
      *            A measureSpec packed into an int
      * @return The width of the view, honoring constraints from measureSpec
      */
     private int measureLong(int measureSpec) {
         int result;
         int specMode = MeasureSpec.getMode(measureSpec);
         int specSize = MeasureSpec.getSize(measureSpec);

         if ((specMode == MeasureSpec.EXACTLY) || (mViewPager == null)) {
             //We were told how big to be
             result = specSize;
         } else {
             //Calculate the width according the views count
             final int count = mViewPager.getAdapter().getCount();
             result = (int)(getPaddingLeft() + getPaddingRight()
                     + (count * 2 * mRadius) + (count - 1) * mRadius + 1);
             //Respect AT_MOST value if that was what is called for by measureSpec
             if (specMode == MeasureSpec.AT_MOST) {
                 result = Math.min(result, specSize);
             }
         }
         return result;
     }

     /**
      * Determines the height of this view
      *
      * @param measureSpec
      *            A measureSpec packed into an int
      * @return The height of the view, honoring constraints from measureSpec
      */
     private int measureShort(int measureSpec) {
         int result;
         int specMode = MeasureSpec.getMode(measureSpec);
         int specSize = MeasureSpec.getSize(measureSpec);

         if (specMode == MeasureSpec.EXACTLY) {
             //We were told how big to be
             result = specSize;
         } else {
             //Measure the height
             result = (int)(2 * mRadius + getPaddingTop() + getPaddingBottom() + 1);
             //Respect AT_MOST value if that was what is called for by measureSpec
             if (specMode == MeasureSpec.AT_MOST) {
                 result = Math.min(result, specSize);
             }
         }
         return result;
     }

     @Override
     public void onRestoreInstanceState(Parcelable state) {
         SavedState savedState = (SavedState)state;
         super.onRestoreInstanceState(savedState.getSuperState());
         mCurrentPage = savedState.currentPage;
         mSnapPage = savedState.currentPage;
         requestLayout();
     }

     @Override
     public Parcelable onSaveInstanceState() {
         Parcelable superState = super.onSaveInstanceState();
         SavedState savedState = new SavedState(superState);
         savedState.currentPage = mCurrentPage;
         return savedState;
     }

     static class SavedState extends BaseSavedState {
         int currentPage;

         public SavedState(Parcelable superState) {
             super(superState);
         }

         private SavedState(Parcel in) {
             super(in);
             currentPage = in.readInt();
         }

         @Override
         public void writeToParcel(Parcel dest, int flags) {
             super.writeToParcel(dest, flags);
             dest.writeInt(currentPage);
         }

         @SuppressWarnings("UnusedDeclaration")
         public static final Parcelable.Creator<SavedState> CREATOR = new Parcelable.Creator<SavedState>() {
             @Override
             public SavedState createFromParcel(Parcel in) {
                 return new SavedState(in);
             }

             @Override
             public SavedState[] newArray(int size) {
                 return new SavedState[size];
             }
         };
     }
}

在你的 xml 中使用这个类：

 <android.support.v4.view.ViewPager
            android:id="@+id/view_pager"
            android:layout_width="fill_parent"
            android:layout_height="220dp" />

        <com.example.support.CirclePageIndicator
            android:id="@+id/indicator"
            android:layout_width="fill_parent"
            android:layout_height="20dp"
            android:layout_below="@+id/view_pager"
            android:layout_marginTop="10dp" />