v4/java/android/support/v4/view/PagerTabStrip.java - platform/frameworks/support.git - Git at Google

 /*
  * Copyright (C) 2012 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.support.v4.view;

 import android.content.Context;
 import android.graphics.Canvas;
 import android.graphics.Paint;
 import android.graphics.Rect;
 import android.graphics.drawable.Drawable;
 import android.support.annotation.ColorRes;
 import android.support.annotation.DrawableRes;
 import android.util.AttributeSet;
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.ViewConfiguration;

 /**
  * PagerTabStrip is an interactive indicator of the current, next,
  * and previous pages of a {@link ViewPager}. It is intended to be used as a
  * child view of a ViewPager widget in your XML layout.
  * Add it as a child of a ViewPager in your layout file and set its
  * android:layout_gravity to TOP or BOTTOM to pin it to the top or bottom
  * of the ViewPager. The title from each page is supplied by the method
  * {@link PagerAdapter#getPageTitle(int)} in the adapter supplied to
  * the ViewPager.
  *
  * <p>For a non-interactive indicator, see {@link PagerTitleStrip}.</p>
  */
 public class PagerTabStrip extends PagerTitleStrip {
     private static final String TAG = "PagerTabStrip";

     private static final int INDICATOR_HEIGHT = 3; // dp
     private static final int MIN_PADDING_BOTTOM = INDICATOR_HEIGHT + 3; // dp
     private static final int TAB_PADDING = 16; // dp
     private static final int TAB_SPACING = 32; // dp
     private static final int MIN_TEXT_SPACING = TAB_SPACING + TAB_PADDING * 2; // dp
     private static final int FULL_UNDERLINE_HEIGHT = 1; // dp
     private static final int MIN_STRIP_HEIGHT = 32; // dp

     private int mIndicatorColor;
     private int mIndicatorHeight;

     private int mMinPaddingBottom;
     private int mMinTextSpacing;
     private int mMinStripHeight;

     private int mTabPadding;

     private final Paint mTabPaint = new Paint();
     private final Rect mTempRect = new Rect();

     private int mTabAlpha = 0xFF;

     private boolean mDrawFullUnderline = false;
     private boolean mDrawFullUnderlineSet = false;
     private int mFullUnderlineHeight;

     private boolean mIgnoreTap;
     private float mInitialMotionX;
     private float mInitialMotionY;
     private int mTouchSlop;

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

     public PagerTabStrip(Context context, AttributeSet attrs) {
         super(context, attrs);

         mIndicatorColor = mTextColor;
         mTabPaint.setColor(mIndicatorColor);

         // Note: this follows the rules for Resources#getDimensionPixelOffset/Size:
         //       sizes round up, offsets round down.
         final float density = context.getResources().getDisplayMetrics().density;
         mIndicatorHeight = (int) (INDICATOR_HEIGHT * density + 0.5f);
         mMinPaddingBottom = (int) (MIN_PADDING_BOTTOM * density + 0.5f);
         mMinTextSpacing = (int) (MIN_TEXT_SPACING * density);
         mTabPadding = (int) (TAB_PADDING * density + 0.5f);
         mFullUnderlineHeight = (int) (FULL_UNDERLINE_HEIGHT * density + 0.5f);
         mMinStripHeight = (int) (MIN_STRIP_HEIGHT * density + 0.5f);
         mTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop();

         // Enforce restrictions
         setPadding(getPaddingLeft(), getPaddingTop(), getPaddingRight(), getPaddingBottom());
         setTextSpacing(getTextSpacing());

         setWillNotDraw(false);

         mPrevText.setFocusable(true);
         mPrevText.setOnClickListener(new OnClickListener() {
             @Override
             public void onClick(View v) {
                 mPager.setCurrentItem(mPager.getCurrentItem() - 1);
             }
         });

         mNextText.setFocusable(true);
         mNextText.setOnClickListener(new OnClickListener() {
             @Override
             public void onClick(View v) {
                 mPager.setCurrentItem(mPager.getCurrentItem() + 1);
             }
         });

         if (getBackground() == null) {
             mDrawFullUnderline = true;
         }
     }

     /**
      * Set the color of the tab indicator bar.
      *
      * @param color Color to set as an 0xRRGGBB value. The high byte (alpha) is ignored.
      */
     public void setTabIndicatorColor(int color) {
         mIndicatorColor = color;
         mTabPaint.setColor(mIndicatorColor);
         invalidate();
     }

     /**
      * Set the color of the tab indicator bar from a color resource.
      *
      * @param resId Resource ID of a color resource to load
      */
     public void setTabIndicatorColorResource(@ColorRes int resId) {
         setTabIndicatorColor(getContext().getResources().getColor(resId));
     }

     /**
      * @return The current tab indicator color as an 0xRRGGBB value.
      */
     public int getTabIndicatorColor() {
         return mIndicatorColor;
     }

     @Override
     public void setPadding(int left, int top, int right, int bottom) {
         if (bottom < mMinPaddingBottom) {
             bottom = mMinPaddingBottom;
         }
         super.setPadding(left, top, right, bottom);
     }

     @Override
     public void setTextSpacing(int textSpacing) {
         if (textSpacing < mMinTextSpacing) {
             textSpacing = mMinTextSpacing;
         }
         super.setTextSpacing(textSpacing);
     }

     @Override
     public void setBackgroundDrawable(Drawable d) {
         super.setBackgroundDrawable(d);
         if (!mDrawFullUnderlineSet) {
             mDrawFullUnderline = d == null;
         }
     }

     @Override
     public void setBackgroundColor(int color) {
         super.setBackgroundColor(color);
         if (!mDrawFullUnderlineSet) {
             mDrawFullUnderline = (color & 0xFF000000) == 0;
         }
     }

     @Override
     public void setBackgroundResource(@DrawableRes int resId) {
         super.setBackgroundResource(resId);
         if (!mDrawFullUnderlineSet) {
             mDrawFullUnderline = resId == 0;
         }
     }

     /**
      * Set whether this tab strip should draw a full-width underline in the
      * current tab indicator color.
      *
      * @param drawFull true to draw a full-width underline, false otherwise
      */
     public void setDrawFullUnderline(boolean drawFull) {
         mDrawFullUnderline = drawFull;
         mDrawFullUnderlineSet = true;
         invalidate();
     }

     /**
      * Return whether or not this tab strip will draw a full-width underline.
      * This defaults to true if no background is set.
      *
      * @return true if this tab strip will draw a full-width underline in the
      * current tab indicator color.
      */
     public boolean getDrawFullUnderline() {
         return mDrawFullUnderline;
     }

     @Override
     int getMinHeight() {
         return Math.max(super.getMinHeight(), mMinStripHeight);
     }

     @Override
     public boolean onTouchEvent(MotionEvent ev) {
         final int action = ev.getAction();
         if (action != MotionEvent.ACTION_DOWN && mIgnoreTap) {
             return false;
         }

         // Any tap within touch slop to either side of the current item
         // will scroll to prev/next.
         final float x = ev.getX();
         final float y = ev.getY();
         switch (action) {
             case MotionEvent.ACTION_DOWN:
                 mInitialMotionX = x;
                 mInitialMotionY = y;
                 mIgnoreTap = false;
                 break;

             case MotionEvent.ACTION_MOVE:
                 if (Math.abs(x - mInitialMotionX) > mTouchSlop ||
                         Math.abs(y - mInitialMotionY) > mTouchSlop) {
                     mIgnoreTap = true;
                 }
                 break;

             case MotionEvent.ACTION_UP:
                 if (x < mCurrText.getLeft() - mTabPadding) {
                     mPager.setCurrentItem(mPager.getCurrentItem() - 1);
                 } else if (x > mCurrText.getRight() + mTabPadding) {
                     mPager.setCurrentItem(mPager.getCurrentItem() + 1);
                 }
                 break;
         }

         return true;
     }

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

         final int height = getHeight();
         final int bottom = height;
         final int left = mCurrText.getLeft() - mTabPadding;
         final int right = mCurrText.getRight() + mTabPadding;
         final int top = bottom - mIndicatorHeight;

         mTabPaint.setColor(mTabAlpha << 24 | (mIndicatorColor & 0xFFFFFF));
         canvas.drawRect(left, top, right, bottom, mTabPaint);

         if (mDrawFullUnderline) {
             mTabPaint.setColor(0xFF << 24 | (mIndicatorColor & 0xFFFFFF));
             canvas.drawRect(getPaddingLeft(), height - mFullUnderlineHeight,
                     getWidth() - getPaddingRight(), height, mTabPaint);
         }
     }

     @Override
     void updateTextPositions(int position, float positionOffset, boolean force) {
         final Rect r = mTempRect;
         int bottom = getHeight();
         int left = mCurrText.getLeft() - mTabPadding;
         int right = mCurrText.getRight() + mTabPadding;
         int top = bottom - mIndicatorHeight;

         r.set(left, top, right, bottom);

         super.updateTextPositions(position, positionOffset, force);
         mTabAlpha = (int) (Math.abs(positionOffset - 0.5f) * 2 * 0xFF);

         left = mCurrText.getLeft() - mTabPadding;
         right = mCurrText.getRight() + mTabPadding;
         r.union(left, top, right, bottom);

         invalidate(r);
     }
 }
	/*
	* Copyright (C) 2012 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.support.v4.view;

	import android.content.Context;
	import android.graphics.Canvas;
	import android.graphics.Paint;
	import android.graphics.Rect;
	import android.graphics.drawable.Drawable;
	import android.support.annotation.ColorRes;
	import android.support.annotation.DrawableRes;
	import android.util.AttributeSet;
	import android.view.MotionEvent;
	import android.view.View;
	import android.view.ViewConfiguration;

	/**
	* PagerTabStrip is an interactive indicator of the current, next,
	* and previous pages of a {@link ViewPager}. It is intended to be used as a
	* child view of a ViewPager widget in your XML layout.
	* Add it as a child of a ViewPager in your layout file and set its
	* android:layout_gravity to TOP or BOTTOM to pin it to the top or bottom
	* of the ViewPager. The title from each page is supplied by the method
	* {@link PagerAdapter#getPageTitle(int)} in the adapter supplied to
	* the ViewPager.
	*
	* <p>For a non-interactive indicator, see {@link PagerTitleStrip}.</p>
	*/
	public class PagerTabStrip extends PagerTitleStrip {
	private static final String TAG = "PagerTabStrip";

	private static final int INDICATOR_HEIGHT = 3; // dp
	private static final int MIN_PADDING_BOTTOM = INDICATOR_HEIGHT + 3; // dp
	private static final int TAB_PADDING = 16; // dp
	private static final int TAB_SPACING = 32; // dp
	private static final int MIN_TEXT_SPACING = TAB_SPACING + TAB_PADDING * 2; // dp
	private static final int FULL_UNDERLINE_HEIGHT = 1; // dp
	private static final int MIN_STRIP_HEIGHT = 32; // dp

	private int mIndicatorColor;
	private int mIndicatorHeight;

	private int mMinPaddingBottom;
	private int mMinTextSpacing;
	private int mMinStripHeight;

	private int mTabPadding;

	private final Paint mTabPaint = new Paint();
	private final Rect mTempRect = new Rect();

	private int mTabAlpha = 0xFF;

	private boolean mDrawFullUnderline = false;
	private boolean mDrawFullUnderlineSet = false;
	private int mFullUnderlineHeight;

	private boolean mIgnoreTap;
	private float mInitialMotionX;
	private float mInitialMotionY;
	private int mTouchSlop;

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

	public PagerTabStrip(Context context, AttributeSet attrs) {
	super(context, attrs);

	mIndicatorColor = mTextColor;
	mTabPaint.setColor(mIndicatorColor);

	// Note: this follows the rules for Resources#getDimensionPixelOffset/Size:
	// sizes round up, offsets round down.
	final float density = context.getResources().getDisplayMetrics().density;
	mIndicatorHeight = (int) (INDICATOR_HEIGHT * density + 0.5f);
	mMinPaddingBottom = (int) (MIN_PADDING_BOTTOM * density + 0.5f);
	mMinTextSpacing = (int) (MIN_TEXT_SPACING * density);
	mTabPadding = (int) (TAB_PADDING * density + 0.5f);
	mFullUnderlineHeight = (int) (FULL_UNDERLINE_HEIGHT * density + 0.5f);
	mMinStripHeight = (int) (MIN_STRIP_HEIGHT * density + 0.5f);
	mTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop();

	// Enforce restrictions
	setPadding(getPaddingLeft(), getPaddingTop(), getPaddingRight(), getPaddingBottom());
	setTextSpacing(getTextSpacing());

	setWillNotDraw(false);

	mPrevText.setFocusable(true);
	mPrevText.setOnClickListener(new OnClickListener() {
	@Override
	public void onClick(View v) {
	mPager.setCurrentItem(mPager.getCurrentItem() - 1);
	}
	});

	mNextText.setFocusable(true);
	mNextText.setOnClickListener(new OnClickListener() {
	@Override
	public void onClick(View v) {
	mPager.setCurrentItem(mPager.getCurrentItem() + 1);
	}
	});

	if (getBackground() == null) {
	mDrawFullUnderline = true;
	}
	}

	/**
	* Set the color of the tab indicator bar.
	*
	* @param color Color to set as an 0xRRGGBB value. The high byte (alpha) is ignored.
	*/
	public void setTabIndicatorColor(int color) {
	mIndicatorColor = color;
	mTabPaint.setColor(mIndicatorColor);
	invalidate();
	}

	/**
	* Set the color of the tab indicator bar from a color resource.
	*
	* @param resId Resource ID of a color resource to load
	*/
	public void setTabIndicatorColorResource(@ColorRes int resId) {
	setTabIndicatorColor(getContext().getResources().getColor(resId));
	}

	/**
	* @return The current tab indicator color as an 0xRRGGBB value.
	*/
	public int getTabIndicatorColor() {
	return mIndicatorColor;
	}

	@Override
	public void setPadding(int left, int top, int right, int bottom) {
	if (bottom < mMinPaddingBottom) {
	bottom = mMinPaddingBottom;
	}
	super.setPadding(left, top, right, bottom);
	}

	@Override
	public void setTextSpacing(int textSpacing) {
	if (textSpacing < mMinTextSpacing) {
	textSpacing = mMinTextSpacing;
	}
	super.setTextSpacing(textSpacing);
	}

	@Override
	public void setBackgroundDrawable(Drawable d) {
	super.setBackgroundDrawable(d);
	if (!mDrawFullUnderlineSet) {
	mDrawFullUnderline = d == null;
	}
	}

	@Override
	public void setBackgroundColor(int color) {
	super.setBackgroundColor(color);
	if (!mDrawFullUnderlineSet) {
	mDrawFullUnderline = (color & 0xFF000000) == 0;
	}
	}

	@Override
	public void setBackgroundResource(@DrawableRes int resId) {
	super.setBackgroundResource(resId);
	if (!mDrawFullUnderlineSet) {
	mDrawFullUnderline = resId == 0;
	}
	}

	/**
	* Set whether this tab strip should draw a full-width underline in the
	* current tab indicator color.
	*
	* @param drawFull true to draw a full-width underline, false otherwise
	*/
	public void setDrawFullUnderline(boolean drawFull) {
	mDrawFullUnderline = drawFull;
	mDrawFullUnderlineSet = true;
	invalidate();
	}

	/**
	* Return whether or not this tab strip will draw a full-width underline.
	* This defaults to true if no background is set.
	*
	* @return true if this tab strip will draw a full-width underline in the
	* current tab indicator color.
	*/
	public boolean getDrawFullUnderline() {
	return mDrawFullUnderline;
	}

	@Override
	int getMinHeight() {
	return Math.max(super.getMinHeight(), mMinStripHeight);
	}

	@Override
	public boolean onTouchEvent(MotionEvent ev) {
	final int action = ev.getAction();
	if (action != MotionEvent.ACTION_DOWN && mIgnoreTap) {
	return false;
	}

	// Any tap within touch slop to either side of the current item
	// will scroll to prev/next.
	final float x = ev.getX();
	final float y = ev.getY();
	switch (action) {
	case MotionEvent.ACTION_DOWN:
	mInitialMotionX = x;
	mInitialMotionY = y;
	mIgnoreTap = false;
	break;

	case MotionEvent.ACTION_MOVE:
	if (Math.abs(x - mInitialMotionX) > mTouchSlop \|\|
	Math.abs(y - mInitialMotionY) > mTouchSlop) {
	mIgnoreTap = true;
	}
	break;

	case MotionEvent.ACTION_UP:
	if (x < mCurrText.getLeft() - mTabPadding) {
	mPager.setCurrentItem(mPager.getCurrentItem() - 1);
	} else if (x > mCurrText.getRight() + mTabPadding) {
	mPager.setCurrentItem(mPager.getCurrentItem() + 1);
	}
	break;
	}

	return true;
	}

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

	final int height = getHeight();
	final int bottom = height;
	final int left = mCurrText.getLeft() - mTabPadding;
	final int right = mCurrText.getRight() + mTabPadding;
	final int top = bottom - mIndicatorHeight;

	mTabPaint.setColor(mTabAlpha << 24 \| (mIndicatorColor & 0xFFFFFF));
	canvas.drawRect(left, top, right, bottom, mTabPaint);

	if (mDrawFullUnderline) {
	mTabPaint.setColor(0xFF << 24 \| (mIndicatorColor & 0xFFFFFF));
	canvas.drawRect(getPaddingLeft(), height - mFullUnderlineHeight,
	getWidth() - getPaddingRight(), height, mTabPaint);
	}
	}

	@Override
	void updateTextPositions(int position, float positionOffset, boolean force) {
	final Rect r = mTempRect;
	int bottom = getHeight();
	int left = mCurrText.getLeft() - mTabPadding;
	int right = mCurrText.getRight() + mTabPadding;
	int top = bottom - mIndicatorHeight;

	r.set(left, top, right, bottom);

	super.updateTextPositions(position, positionOffset, force);
	mTabAlpha = (int) (Math.abs(positionOffset - 0.5f) * 2 * 0xFF);

	left = mCurrText.getLeft() - mTabPadding;
	right = mCurrText.getRight() + mTabPadding;
	r.union(left, top, right, bottom);

	invalidate(r);
	}
	}