Android example source code file (RotateDrawable.java)

This example Android source code file (RotateDrawable.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

android, bad, constantstate, drawable, drawing, graphics, ioexception, max_level, no, override, paint, resources, rotatedrawable, rotatestate, runnable, typedvalue, ui, util, xmlpullparser, xmlpullparserexception

The RotateDrawable.java Android example source code

/*
 * 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.graphics.drawable;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;

import android.graphics.Canvas;
import android.graphics.ColorFilter;
import android.graphics.Rect;
import android.content.res.Resources;
import android.content.res.TypedArray;
import android.util.TypedValue;
import android.util.AttributeSet;
import android.util.Log;

import java.io.IOException;

/**
 * <p>A Drawable that can rotate another Drawable based on the current level
 * value. The start and end angles of rotation can be controlled to map any
 * circular arc to the level values range.</p>
 *
 * <p>It can be defined in an XML file with the <rotate> element.

 *
 * @attr ref android.R.styleable#RotateDrawable_visible
 * @attr ref android.R.styleable#RotateDrawable_fromDegrees
 * @attr ref android.R.styleable#RotateDrawable_toDegrees
 * @attr ref android.R.styleable#RotateDrawable_pivotX
 * @attr ref android.R.styleable#RotateDrawable_pivotY
 * @attr ref android.R.styleable#RotateDrawable_drawable
 */
public class RotateDrawable extends Drawable implements Drawable.Callback {
    private static final float MAX_LEVEL = 10000.0f;

    private RotateState mState;
    private boolean mMutated;

    /**
     * <p>Create a new rotating drawable with an empty state.

     */
    public RotateDrawable() {
        this(null, null);
    }

    /**
     * <p>Create a new rotating drawable with the specified state. A copy of
     * this state is used as the internal state for the newly created
     * drawable.</p>
     *
     * @param rotateState the state for this drawable
     */
    private RotateDrawable(RotateState rotateState, Resources res) {
        mState = new RotateState(rotateState, this, res);
    }

    public void draw(Canvas canvas) {
        int saveCount = canvas.save();

        Rect bounds = mState.mDrawable.getBounds();

        int w = bounds.right - bounds.left;
        int h = bounds.bottom - bounds.top;

        final RotateState st = mState;
        
        float px = st.mPivotXRel ? (w * st.mPivotX) : st.mPivotX;
        float py = st.mPivotYRel ? (h * st.mPivotY) : st.mPivotY;

        canvas.rotate(st.mCurrentDegrees, px, py);

        st.mDrawable.draw(canvas);

        canvas.restoreToCount(saveCount);
    }

    /**
     * Returns the drawable rotated by this RotateDrawable.
     */
    public Drawable getDrawable() {
        return mState.mDrawable;
    }

    @Override
    public int getChangingConfigurations() {
        return super.getChangingConfigurations()
                | mState.mChangingConfigurations
                | mState.mDrawable.getChangingConfigurations();
    }
    
    public void setAlpha(int alpha) {
        mState.mDrawable.setAlpha(alpha);
    }

    public void setColorFilter(ColorFilter cf) {
        mState.mDrawable.setColorFilter(cf);
    }

    public int getOpacity() {
        return mState.mDrawable.getOpacity();
    }

    public void invalidateDrawable(Drawable who) {
        if (mCallback != null) {
            mCallback.invalidateDrawable(this);
        }
    }

    public void scheduleDrawable(Drawable who, Runnable what, long when) {
        if (mCallback != null) {
            mCallback.scheduleDrawable(this, what, when);
        }
    }

    public void unscheduleDrawable(Drawable who, Runnable what) {
        if (mCallback != null) {
            mCallback.unscheduleDrawable(this, what);
        }
    }

   @Override
    public boolean getPadding(Rect padding) {
        return mState.mDrawable.getPadding(padding);
    }

    @Override
    public boolean setVisible(boolean visible, boolean restart) {
        mState.mDrawable.setVisible(visible, restart);
        return super.setVisible(visible, restart);
    }

    @Override
    public boolean isStateful() {
        return mState.mDrawable.isStateful();
    }
    
    @Override
    protected boolean onStateChange(int[] state) {
        boolean changed = mState.mDrawable.setState(state);
        onBoundsChange(getBounds());
        return changed;
    }

    @Override
    protected boolean onLevelChange(int level) {
        mState.mDrawable.setLevel(level);
        onBoundsChange(getBounds());

        mState.mCurrentDegrees = mState.mFromDegrees +
                (mState.mToDegrees - mState.mFromDegrees) *
                        ((float) level / MAX_LEVEL);

        invalidateSelf();
        return true;
    }

    @Override
    protected void onBoundsChange(Rect bounds) {
        mState.mDrawable.setBounds(bounds.left, bounds.top,
                bounds.right, bounds.bottom);
    }

    @Override
    public int getIntrinsicWidth() {
        return mState.mDrawable.getIntrinsicWidth();
    }

    @Override
    public int getIntrinsicHeight() {
        return mState.mDrawable.getIntrinsicHeight();
    }

    @Override
    public ConstantState getConstantState() {
        if (mState.canConstantState()) {
            mState.mChangingConfigurations = super.getChangingConfigurations();
            return mState;
        }
        return null;
    }

    @Override
    public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs)
            throws XmlPullParserException, IOException {

        TypedArray a = r.obtainAttributes(attrs,
                com.android.internal.R.styleable.RotateDrawable);

        super.inflateWithAttributes(r, parser, a,
                com.android.internal.R.styleable.RotateDrawable_visible);
        
        TypedValue tv = a.peekValue(com.android.internal.R.styleable.RotateDrawable_pivotX);
        boolean pivotXRel;
        float pivotX;
        if (tv == null) {
            pivotXRel = true;
            pivotX = 0.5f;
        } else {
            pivotXRel = tv.type == TypedValue.TYPE_FRACTION;
            pivotX = pivotXRel ? tv.getFraction(1.0f, 1.0f) : tv.getFloat();
        }
        
        tv = a.peekValue(com.android.internal.R.styleable.RotateDrawable_pivotY);
        boolean pivotYRel;
        float pivotY;
        if (tv == null) {
            pivotYRel = true;
            pivotY = 0.5f;
        } else {
            pivotYRel = tv.type == TypedValue.TYPE_FRACTION;
            pivotY = pivotYRel ? tv.getFraction(1.0f, 1.0f) : tv.getFloat();
        }

        float fromDegrees = a.getFloat(
                com.android.internal.R.styleable.RotateDrawable_fromDegrees, 0.0f);
        float toDegrees = a.getFloat(
                com.android.internal.R.styleable.RotateDrawable_toDegrees, 360.0f);

        toDegrees = Math.max(fromDegrees, toDegrees);

        int res = a.getResourceId(
                com.android.internal.R.styleable.RotateDrawable_drawable, 0);
        Drawable drawable = null;
        if (res > 0) {
            drawable = r.getDrawable(res);
        }

        a.recycle();
        
        int outerDepth = parser.getDepth();
        int type;
        while ((type = parser.next()) != XmlPullParser.END_DOCUMENT &&
               (type != XmlPullParser.END_TAG || parser.getDepth() > outerDepth)) {

            if (type != XmlPullParser.START_TAG) {
                continue;
            }

            if ((drawable = Drawable.createFromXmlInner(r, parser, attrs)) == null) {
                Log.w("drawable", "Bad element under <rotate>: "
                        + parser .getName());
            }
        }

        if (drawable == null) {
            Log.w("drawable", "No drawable specified for <rotate>");
        }

        mState.mDrawable = drawable;
        mState.mPivotXRel = pivotXRel;
        mState.mPivotX = pivotX;
        mState.mPivotYRel = pivotYRel;
        mState.mPivotY = pivotY;
        mState.mFromDegrees = mState.mCurrentDegrees = fromDegrees;
        mState.mToDegrees = toDegrees;

        if (drawable != null) {
            drawable.setCallback(this);
        }
    }

    @Override
    public Drawable mutate() {
        if (!mMutated && super.mutate() == this) {
            mState.mDrawable.mutate();
            mMutated = true;
        }
        return this;
    }

    /**
     * <p>Represents the state of a rotation for a given drawable. The same
     * rotate drawable can be invoked with different states to drive several
     * rotations at the same time.</p>
     */
    final static class RotateState extends Drawable.ConstantState {
        Drawable mDrawable;

        int mChangingConfigurations;
        
        boolean mPivotXRel;
        float mPivotX;
        boolean mPivotYRel;
        float mPivotY;

        float mFromDegrees;
        float mToDegrees;

        float mCurrentDegrees;

        private boolean mCanConstantState;
        private boolean mCheckedConstantState;        

        public RotateState(RotateState source, RotateDrawable owner, Resources res) {
            if (source != null) {
                if (res != null) {
                    mDrawable = source.mDrawable.getConstantState().newDrawable(res);
                } else {
                    mDrawable = source.mDrawable.getConstantState().newDrawable();
                }
                mDrawable.setCallback(owner);
                mPivotXRel = source.mPivotXRel;
                mPivotX = source.mPivotX;
                mPivotYRel = source.mPivotYRel;
                mPivotY = source.mPivotY;
                mFromDegrees = mCurrentDegrees = source.mFromDegrees;
                mToDegrees = source.mToDegrees;
                mCanConstantState = mCheckedConstantState = true;
            }
        }

        @Override
        public Drawable newDrawable() {
            return new RotateDrawable(this, null);
        }
        
        @Override
        public Drawable newDrawable(Resources res) {
            return new RotateDrawable(this, res);
        }
        
        @Override
        public int getChangingConfigurations() {
            return mChangingConfigurations;
        }

        public boolean canConstantState() {
            if (!mCheckedConstantState) {
                mCanConstantState = mDrawable.getConstantState() != null;
                mCheckedConstantState = true;
            }

            return mCanConstantState;
        }
    }
}