Java tutorial
/* * Copyright (C) 2012 Jake Wharton * * 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 com.cyou.cma.clockscreen.widget; import android.content.Context; import android.content.res.Resources; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.drawable.Drawable; import android.os.Parcel; import android.os.Parcelable; import android.support.v4.view.ViewConfigurationCompat; import android.support.v4.view.ViewPager; import android.util.AttributeSet; import android.util.FloatMath; import android.view.View; import android.view.ViewConfiguration; import com.cynad.cma.locker.R; /** * Draws a line for each page. The current page line is colored differently than * the unselected page lines. */ public class LinePageIndicator extends View implements PageIndicator { private static final int INVALID_POINTER = -1; private final Paint mPaintUnselected = new Paint(Paint.ANTI_ALIAS_FLAG); private final Paint mPaintSelected = new Paint(Paint.ANTI_ALIAS_FLAG); private ViewPager mViewPager; private ViewPager.OnPageChangeListener mListener; private int mCurrentPage; private boolean mCentered = true; private float mLineWidth; private float mGapWidth; // private Bitmap mBitmapUnselected, mBitmapSelected; private Drawable mDrawableUnselected, mDrawableSelected; private int mTouchSlop; private float mLastMotionX = -1; private int mActivePointerId = INVALID_POINTER; private boolean mIsDragging; public LinePageIndicator(Context context) { this(context, null); } public LinePageIndicator(Context context, AttributeSet attrs) { this(context, attrs, -1); } public LinePageIndicator(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); if (isInEditMode()) return; final Resources res = getResources(); mDrawableUnselected = res.getDrawable(R.drawable.indicator_normal); mDrawableSelected = res.getDrawable(R.drawable.indicator_selected); // Load defaults from resources final int defaultSelectedColor = res.getColor(R.color.default_line_indicator_selected_color); final int defaultUnselectedColor = res.getColor(R.color.default_line_indicator_unselected_color); final float defaultLineWidth = res.getDimension(R.dimen.default_line_indicator_line_width); final float defaultGapWidth = res.getDimension(R.dimen.default_line_indicator_gap_width); final float defaultStrokeWidth = res.getDimension(R.dimen.default_line_indicator_stroke_width); final boolean defaultCentered = res.getBoolean(R.bool.default_line_indicator_centered); // Retrieve styles attributes // TypedArray a = context.obtainStyledAttributes(attrs, // R.styleable.LinePageIndicator, defStyle, 0); mCentered = defaultCentered; mLineWidth = defaultLineWidth; mGapWidth = defaultGapWidth; setStrokeWidth(defaultStrokeWidth); mPaintUnselected.setColor(defaultUnselectedColor); mPaintSelected.setColor(defaultSelectedColor); // Drawable background = a // .getDrawable(R.styleable.LinePageIndicator_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 setUnselectedColor(int unselectedColor) { mPaintUnselected.setColor(unselectedColor); invalidate(); } public int getUnselectedColor() { return mPaintUnselected.getColor(); } public void setSelectedColor(int selectedColor) { mPaintSelected.setColor(selectedColor); invalidate(); } public int getSelectedColor() { return mPaintSelected.getColor(); } public void setLineWidth(float lineWidth) { mLineWidth = lineWidth; invalidate(); } public float getLineWidth() { return mLineWidth; } public void setStrokeWidth(float lineHeight) { mPaintSelected.setStrokeWidth(lineHeight); mPaintUnselected.setStrokeWidth(lineHeight); invalidate(); } public float getStrokeWidth() { return mPaintSelected.getStrokeWidth(); } public void setGapWidth(float gapWidth) { mGapWidth = gapWidth; invalidate(); } public float getGapWidth() { return mGapWidth; } @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; } final float lineWidthAndGap = mDrawableSelected.getIntrinsicWidth() + mGapWidth; final float indicatorWidth = (count * lineWidthAndGap) - mGapWidth; final float paddingLeft = getPaddingLeft(); final float paddingRight = getPaddingRight(); float horizontalOffset = paddingLeft; if (mCentered) { horizontalOffset += (getWidth() / 2.0f - indicatorWidth / 2.0f); } // Draw stroked circles for (int i = 0; i < count; i++) { Drawable drawable = null; if (i == mCurrentPage) { drawable = getResources().getDrawable(R.drawable.indicator_selected); } else { drawable = getResources().getDrawable(R.drawable.indicator_normal); } final int right = (int) horizontalOffset + drawable.getIntrinsicWidth(); drawable.setBounds((int) horizontalOffset, 0, right, drawable.getIntrinsicHeight()); horizontalOffset += drawable.getIntrinsicWidth() + mGapWidth; ; drawable.draw(canvas); } } @Override public void setViewPager(ViewPager viewPager) { if (mViewPager == viewPager) { return; } if (mViewPager != null) { // Clear us from the old pager. mViewPager.setOnPageChangeListener(null); } if (viewPager.getAdapter() == null) { // throw new IllegalStateException( // "ViewPager does not have adapter instance."); return; } mViewPager = viewPager; 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."); return; } mViewPager.setCurrentItem(item); mCurrentPage = item; invalidate(); } @Override public void notifyDataSetChanged() { invalidate(); } @Override public void onPageScrollStateChanged(int state) { if (mListener != null) { mListener.onPageScrollStateChanged(state); } } @Override public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { if (mListener != null) { mListener.onPageScrolled(position, positionOffset, positionOffsetPixels); } } @Override public void onPageSelected(int position) { mCurrentPage = position; invalidate(); if (mListener != null) { mListener.onPageSelected(position); } } @Override public void setOnPageChangeListener(ViewPager.OnPageChangeListener listener) { mListener = listener; } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { setMeasuredDimension(measureWidth(widthMeasureSpec), mDrawableSelected.getIntrinsicHeight()); } /** * 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 measureWidth(int measureSpec) { float 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 = getPaddingLeft() + getPaddingRight() + (count * mLineWidth) + ((count - 1) * mGapWidth); // Respect AT_MOST value if that was what is called for by // measureSpec if (specMode == MeasureSpec.AT_MOST) { result = Math.min(result, specSize); } } return (int) FloatMath.ceil(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 measureHeight(int measureSpec) { float 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 = mPaintSelected.getStrokeWidth() + getPaddingTop() + getPaddingBottom(); // Respect AT_MOST value if that was what is called for by // measureSpec if (specMode == MeasureSpec.AT_MOST) { result = Math.min(result, specSize); } } return (int) FloatMath.ceil(result); } @Override public void onRestoreInstanceState(Parcelable state) { SavedState savedState = (SavedState) state; super.onRestoreInstanceState(savedState.getSuperState()); mCurrentPage = 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]; } }; } }