Java tutorial
/* * 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.view.animation; import android.content.Context; import android.content.res.TypedArray; import android.util.AttributeSet; /** * An animation that controls the rotation of an object. This rotation takes * place in the X-Y plane. You can specify the point to use for the center of * the rotation, where (0,0) is the top left point. If not specified, (0,0) is * the default rotation point. * */ public class RotateAnimation extends Animation { private float mFromDegrees; private float mToDegrees; private int mPivotXType = ABSOLUTE; private int mPivotYType = ABSOLUTE; private float mPivotXValue = 0.0f; private float mPivotYValue = 0.0f; private float mPivotX; private float mPivotY; /** * Constructor used when a RotateAnimation is loaded from a resource. * * @param context Application context to use * @param attrs Attribute set from which to read values */ public RotateAnimation(Context context, AttributeSet attrs) { super(context, attrs); TypedArray a = context.obtainStyledAttributes(attrs, com.android.internal.R.styleable.RotateAnimation); mFromDegrees = a.getFloat(com.android.internal.R.styleable.RotateAnimation_fromDegrees, 0.0f); mToDegrees = a.getFloat(com.android.internal.R.styleable.RotateAnimation_toDegrees, 0.0f); Description d = Description .parseValue(a.peekValue(com.android.internal.R.styleable.RotateAnimation_pivotX)); mPivotXType = d.type; mPivotXValue = d.value; d = Description.parseValue(a.peekValue(com.android.internal.R.styleable.RotateAnimation_pivotY)); mPivotYType = d.type; mPivotYValue = d.value; a.recycle(); initializePivotPoint(); } /** * Constructor to use when building a RotateAnimation from code. * Default pivotX/pivotY point is (0,0). * * @param fromDegrees Rotation offset to apply at the start of the * animation. * * @param toDegrees Rotation offset to apply at the end of the animation. */ public RotateAnimation(float fromDegrees, float toDegrees) { mFromDegrees = fromDegrees; mToDegrees = toDegrees; mPivotX = 0.0f; mPivotY = 0.0f; } /** * Constructor to use when building a RotateAnimation from code * * @param fromDegrees Rotation offset to apply at the start of the * animation. * * @param toDegrees Rotation offset to apply at the end of the animation. * * @param pivotX The X coordinate of the point about which the object is * being rotated, specified as an absolute number where 0 is the left * edge. * @param pivotY The Y coordinate of the point about which the object is * being rotated, specified as an absolute number where 0 is the top * edge. */ public RotateAnimation(float fromDegrees, float toDegrees, float pivotX, float pivotY) { mFromDegrees = fromDegrees; mToDegrees = toDegrees; mPivotXType = ABSOLUTE; mPivotYType = ABSOLUTE; mPivotXValue = pivotX; mPivotYValue = pivotY; initializePivotPoint(); } /** * Constructor to use when building a RotateAnimation from code * * @param fromDegrees Rotation offset to apply at the start of the * animation. * * @param toDegrees Rotation offset to apply at the end of the animation. * * @param pivotXType Specifies how pivotXValue should be interpreted. One of * Animation.ABSOLUTE, Animation.RELATIVE_TO_SELF, or * Animation.RELATIVE_TO_PARENT. * @param pivotXValue The X coordinate of the point about which the object * is being rotated, specified as an absolute number where 0 is the * left edge. This value can either be an absolute number if * pivotXType is ABSOLUTE, or a percentage (where 1.0 is 100%) * otherwise. * @param pivotYType Specifies how pivotYValue should be interpreted. One of * Animation.ABSOLUTE, Animation.RELATIVE_TO_SELF, or * Animation.RELATIVE_TO_PARENT. * @param pivotYValue The Y coordinate of the point about which the object * is being rotated, specified as an absolute number where 0 is the * top edge. This value can either be an absolute number if * pivotYType is ABSOLUTE, or a percentage (where 1.0 is 100%) * otherwise. */ public RotateAnimation(float fromDegrees, float toDegrees, int pivotXType, float pivotXValue, int pivotYType, float pivotYValue) { mFromDegrees = fromDegrees; mToDegrees = toDegrees; mPivotXValue = pivotXValue; mPivotXType = pivotXType; mPivotYValue = pivotYValue; mPivotYType = pivotYType; initializePivotPoint(); } /** * Called at the end of constructor methods to initialize, if possible, values for * the pivot point. This is only possible for ABSOLUTE pivot values. */ private void initializePivotPoint() { if (mPivotXType == ABSOLUTE) { mPivotX = mPivotXValue; } if (mPivotYType == ABSOLUTE) { mPivotY = mPivotYValue; } } @Override protected void applyTransformation(float interpolatedTime, Transformation t) { float degrees = mFromDegrees + ((mToDegrees - mFromDegrees) * interpolatedTime); float scale = getScaleFactor(); if (mPivotX == 0.0f && mPivotY == 0.0f) { t.getMatrix().setRotate(degrees); } else { t.getMatrix().setRotate(degrees, mPivotX * scale, mPivotY * scale); } } @Override public void initialize(int width, int height, int parentWidth, int parentHeight) { super.initialize(width, height, parentWidth, parentHeight); mPivotX = resolveSize(mPivotXType, mPivotXValue, width, parentWidth); mPivotY = resolveSize(mPivotYType, mPivotYValue, height, parentHeight); } }