屬性動畫實戰

實戰一：翻轉動畫

 自定義view：

package com.test.animation.view;

import android.content.Context;
import android.graphics.Camera;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.View;


import com.test.animation.Utils;

import androidx.annotation.Nullable;

public class FancyFlipView extends View {
    private static final float PADDING = Utils.dpToPixel(100);
    private static final float IMAGE_WIDTH = Utils.dpToPixel(200);

    Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
    Camera camera = new Camera();

    float topFlip = 0;
    float bottomFlip = 0;
    float flipRotation = 0;

    public FancyFlipView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
    }

    {
        camera.setLocation(0, 0, Utils.getZForCamera()); // -8 = -8 * 72
    }

    public float getTopFlip() {
        return topFlip;
    }

    public void setTopFlip(float topFlip) {
        this.topFlip = topFlip;
        invalidate();
    }

    public float getBottomFlip() {
        return bottomFlip;
    }

    public void setBottomFlip(float bottomFlip) {
        this.bottomFlip = bottomFlip;
        invalidate();
    }

    public float getFlipRotation() {
        return flipRotation;
    }

    public void setFlipRotation(float flipRotation) {
        this.flipRotation = flipRotation;
        invalidate();
    }

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

        // 繪製上半部分
        canvas.save();
        canvas.translate(PADDING + IMAGE_WIDTH / 2, PADDING + IMAGE_WIDTH / 2);
        canvas.rotate(-flipRotation);
        camera.save();
        camera.rotateX(topFlip);
        camera.applyToCanvas(canvas);
        camera.restore();
        canvas.clipRect(- IMAGE_WIDTH, - IMAGE_WIDTH, IMAGE_WIDTH, 0);
        canvas.rotate(flipRotation);
        canvas.translate(- (PADDING + IMAGE_WIDTH / 2), - (PADDING + IMAGE_WIDTH / 2));
        canvas.drawBitmap(Utils.getAvatar(getResources(), (int) IMAGE_WIDTH), PADDING, PADDING, paint);
        canvas.restore();

        // 繪製下半部分
        canvas.save();
        canvas.translate(PADDING + IMAGE_WIDTH / 2, PADDING + IMAGE_WIDTH / 2);
        canvas.rotate(-flipRotation);
        camera.save();
        camera.rotateX(bottomFlip);
        camera.applyToCanvas(canvas);
        camera.restore();
        canvas.clipRect(- IMAGE_WIDTH, 0, IMAGE_WIDTH, IMAGE_WIDTH);
        canvas.rotate(flipRotation);
        canvas.translate(- (PADDING + IMAGE_WIDTH / 2), - (PADDING + IMAGE_WIDTH / 2));
        canvas.drawBitmap(Utils.getAvatar(getResources(), (int) IMAGE_WIDTH), PADDING, PADDING, paint);
        canvas.restore();
    }
}

使用：

/**
         * 自定義屬性動畫集合
         */
        ObjectAnimator bottomFlipAnimator = ObjectAnimator.ofFloat(view, "bottomFlip", 45);
        bottomFlipAnimator.setDuration(1500);

        ObjectAnimator flipRotationAnimator = ObjectAnimator.ofFloat(view, "flipRotation", 270);
        flipRotationAnimator.setDuration(1500);

        ObjectAnimator topFlipAnimator = ObjectAnimator.ofFloat(view, "topFlip", - 45);
        topFlipAnimator.setDuration(1500);

        AnimatorSet animatorSet = new AnimatorSet();
        animatorSet.playSequentially(bottomFlipAnimator, flipRotationAnimator, topFlipAnimator);
        animatorSet.setStartDelay(1000);
        animatorSet.start();

 

實戰二：自定義插值器練習，文字變化插值器

/**
         * 自定義文字變換插值器
         */
        ObjectAnimator animator = ObjectAnimator.ofObject(view, "province", new ProvinceEvaluator(), "澳門特別行政區");
        animator.setDuration(10000);
        animator.start();

class ProvinceEvaluator implements TypeEvaluator<String> {
        @Override
        public String evaluate(float fraction, String startValue, String endValue) {
            // 北京市      上海市       fraction 0.5f
            int startIndex = ProvinceUtil.provinces.indexOf(startValue);
            int endIndex = ProvinceUtil.provinces.indexOf(endValue);
            int index = (int) (startIndex + (endIndex - startIndex) * fraction);
            return ProvinceUtil.provinces.get(index);
        }
    }

package com.test.animation.view;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.View;

import com.test.animation.Utils;

import androidx.annotation.Nullable;

public class ProvinceView extends View {
    Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);

    String province = "北京市";

    public String getProvince() {
        return province;
    }

    public void setProvince(String province) {
        this.province = province;
        invalidate();
    }

    public ProvinceView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
    }

    {
//        setLayerType(LAYER_TYPE_SOFTWARE, null);
        setLayerType(LAYER_TYPE_HARDWARE, null);
//        setLayerType(LAYER_TYPE_NONE, null);
        paint.setTextSize(Utils.dpToPixel(60));
        paint.setTextAlign(Paint.Align.CENTER);
    }

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

        canvas.drawText(province, getWidth() / 2, getHeight() / 2, paint);
    }
}