Android ValueAnimator和ObjectAnimator的高级用法（代码实现）
16lz
2021-01-23
参考文章：http://blog.csdn.net/guolin_blog/article/details/43816093
一、ValueAnimator的高级用法
1.MainActivity.java
public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); //两个Point对象，现在需要将Point1通过动画平滑过度到Point2 Point point1 = new Point(0, 0); Point point2 = new Point(300, 300); ValueAnimator anim = ValueAnimator.ofObject(new PointEvaluator(), point1, point2); anim.setDuration(5000); anim.start(); } }2.MyAnimView.java
public class MyAnimView extends View { public static final float RADIUS = 50f; private Point currentPoint; private Paint mPaint; public MyAnimView(Context context, AttributeSet attrs) { super(context, attrs); mPaint = new Paint(Paint.ANTI_ALIAS_FLAG); mPaint.setColor(Color.BLUE); } @Override protected void onDraw(Canvas canvas) { if (currentPoint == null) { currentPoint = new Point(RADIUS, RADIUS); drawCircle(canvas); startAnimation(); } else { drawCircle(canvas); } } private void drawCircle(Canvas canvas) { float x = currentPoint.getX(); float y = currentPoint.getY(); canvas.drawCircle(x, y, RADIUS, mPaint); } private void startAnimation() { Point startPoint = new Point(RADIUS, RADIUS); Point endPoint = new Point(getWidth() - RADIUS, getHeight() - RADIUS); ValueAnimator anim = ValueAnimator.ofObject(new PointEvaluator(), startPoint, endPoint); anim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() { @Override public void onAnimationUpdate(ValueAnimator animation) { currentPoint = (Point) animation.getAnimatedValue(); invalidate(); } }); anim.setDuration(5000); anim.start(); } } 3.Point.java
public class Point { private float x; private float y; public Point(float x, float y) { this.x = x; this.y = y; } public float getX() { return x; } public float getY() { return y; } } 4.PointEvaluator.java
public class PointEvaluator implements TypeEvaluator{ @Override public Object evaluate(float fraction, Object startValue, Object endValue) { Point startPoint = (Point) startValue; Point endPoint = (Point) endValue; float x = startPoint.getX() + fraction * (endPoint.getX() - startPoint.getX()); float y = startPoint.getY() + fraction * (endPoint.getY() - startPoint.getY()); Point point = new Point(x, y); return point; } } 5.布局文件：activity_main.xml
二、ObjectAnimator的高级用法
1.MainActivity.java
public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); //两个Point对象，现在需要将Point1通过动画平滑过度到Point2 Point point1 = new Point(0, 0); Point point2 = new Point(300, 300); ValueAnimator anim = ValueAnimator.ofObject(new PointEvaluator(), point1, point2); anim.setDuration(5000); anim.start(); }}2.Point.java
public class Point { private float x; private float y; public Point(float x, float y) { this.x = x; this.y = y; } public float getX() { return x; } public float getY() { return y; } } 3.MyAnimView.java
import android.animation.AnimatorSet;import android.animation.ObjectAnimator;import android.animation.ValueAnimator;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.util.AttributeSet;import android.view.View;public class MyAnimView extends View { public static final float RADIUS = 50f; private Point currentPoint; private Paint mPaint; public MyAnimView(Context context, AttributeSet attrs) { super(context, attrs); mPaint = new Paint(Paint.ANTI_ALIAS_FLAG); mPaint.setColor(Color.BLUE); } @Override protected void onDraw(Canvas canvas) { if (currentPoint == null) { currentPoint = new Point(RADIUS, RADIUS); drawCircle(canvas); startAnimation(); } else { drawCircle(canvas); } } private void drawCircle(Canvas canvas) { float x = currentPoint.getX(); float y = currentPoint.getY(); canvas.drawCircle(x, y, RADIUS, mPaint); } /*private void startAnimation() { Point startPoint = new Point(RADIUS, RADIUS); Point endPoint = new Point(getWidth() - RADIUS, getHeight() - RADIUS); ValueAnimator anim = ValueAnimator.ofObject(new PointEvaluator(), startPoint, endPoint); anim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() { @Override public void onAnimationUpdate(ValueAnimator animation) { currentPoint = (Point) animation.getAnimatedValue(); invalidate(); } }); anim.setDuration(5000); anim.start(); } */ private void startAnimation() { Point startPoint = new Point(RADIUS, RADIUS); Point endPoint = new Point(getWidth() - RADIUS, getHeight() - RADIUS); ValueAnimator anim = ValueAnimator.ofObject(new PointEvaluator(), startPoint, endPoint); anim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() { @Override public void onAnimationUpdate(ValueAnimator animation) { currentPoint = (Point) animation.getAnimatedValue(); invalidate(); } }); //从蓝色到红色的动画过度，历时5秒 ObjectAnimator anim2 = ObjectAnimator.ofObject(this, "color", new ColorEvaluator(), "#0000FF", "#FF0000"); AnimatorSet animSet = new AnimatorSet(); animSet.play(anim).with(anim2); animSet.setDuration(5000); animSet.start(); } private String color; public String getColor() { return color; } public void setColor(String color) { this.color = color; mPaint.setColor(Color.parseColor(color)); invalidate(); } } 4.PointEvaluator.java
public class PointEvaluator implements TypeEvaluator{ @Override public Object evaluate(float fraction, Object startValue, Object endValue) { Point startPoint = (Point) startValue; Point endPoint = (Point) endValue; float x = startPoint.getX() + fraction * (endPoint.getX() - startPoint.getX()); float y = startPoint.getY() + fraction * (endPoint.getY() - startPoint.getY()); Point point = new Point(x, y); return point; } } 5.ColorEvaluator.java
public class ColorEvaluator implements TypeEvaluator { private int mCurrentRed = -1; private int mCurrentGreen = -1; private int mCurrentBlue = -1; @Override public Object evaluate(float fraction, Object startValue, Object endValue) { String startColor = (String) startValue; String endColor = (String) endValue; int startRed = Integer.parseInt(startColor.substring(1, 3), 16); int startGreen = Integer.parseInt(startColor.substring(3, 5), 16); int startBlue = Integer.parseInt(startColor.substring(5, 7), 16); int endRed = Integer.parseInt(endColor.substring(1, 3), 16); int endGreen = Integer.parseInt(endColor.substring(3, 5), 16); int endBlue = Integer.parseInt(endColor.substring(5, 7), 16); // 初始化颜色的值 if (mCurrentRed == -1) { mCurrentRed = startRed; } if (mCurrentGreen == -1) { mCurrentGreen = startGreen; } if (mCurrentBlue == -1) { mCurrentBlue = startBlue; } // 计算初始颜色和结束颜色之间的差值 int redDiff = Math.abs(startRed - endRed); int greenDiff = Math.abs(startGreen - endGreen); int blueDiff = Math.abs(startBlue - endBlue); int colorDiff = redDiff + greenDiff + blueDiff; if (mCurrentRed != endRed) { mCurrentRed = getCurrentColor(startRed, endRed, colorDiff, 0, fraction); } else if (mCurrentGreen != endGreen) { mCurrentGreen = getCurrentColor(startGreen, endGreen, colorDiff, redDiff, fraction); } else if (mCurrentBlue != endBlue) { mCurrentBlue = getCurrentColor(startBlue, endBlue, colorDiff, redDiff + greenDiff, fraction); } // 将计算出的当前颜色的值组装返回 String currentColor = "#" + getHexString(mCurrentRed) + getHexString(mCurrentGreen) + getHexString(mCurrentBlue); return currentColor; } /** * 根据fraction值来计算当前的颜色。 */ private int getCurrentColor(int startColor, int endColor, int colorDiff, int offset, float fraction) { int currentColor; if (startColor > endColor) { currentColor = (int) (startColor - (fraction * colorDiff - offset)); if (currentColor < endColor) { currentColor = endColor; } } else { currentColor = (int) (startColor + (fraction * colorDiff - offset)); if (currentColor > endColor) { currentColor = endColor; } } return currentColor; } /** * 将10进制颜色值转换成16进制。 */ private String getHexString(int value) { String hexString = Integer.toHexString(value); if (hexString.length() == 1) { hexString = "0" + hexString; } return hexString; } } 6.布局文件：activity_main.xml
更多相关文章
- 优化布局在Android–减少过度渲染
- Android 自定义布局对话框避免全屏的设置
- Android RecyclerView网格布局的学习
- android中的一个属性动画，可以显示更多的一个案例
- android 改变bitmap颜色
- android动态布局：用java代码实现LinearLayout以及TextView
- Android TextView设置一个或多个关键字的颜色
- android里，addContentView()动态增加view控件，并实现控件的顶部，中
- Android中动态设置布局高度一致