// ======================= A. 推薦方案：屬性動畫 + cameraDistance =======================
// 文件：res/layout/activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/root"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:foregroundGravity="center">
 
    <ImageView
        android:id="@+id/ivSpin"
        android:layout_width="220dp"
        android:layout_height="220dp"
        android:scaleType="centerCrop"
        android:src="@drawable/sample" />
 
    <!-- 可加控制按鈕/文本，這里省略 -->
</FrameLayout>
 
// 文件：java/com/example/rotate3d/MainActivity.java
package com.example.rotate3d;
 
import android.animation.ObjectAnimator;
import android.animation.ValueAnimator;
import android.os.Bundle;
import android.util.TypedValue;
import android.view.animation.LinearInterpolator;
import android.widget.ImageView;
 
import androidx.appcompat.app.AppCompatActivity;
 
public class MainActivity extends AppCompatActivity {
 
    private ImageView ivSpin;
    private ObjectAnimator spinAnimatorY;
    private ObjectAnimator spinAnimatorX;
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ivSpin = findViewById(R.id.ivSpin);
 
        // 1) 設置相機距離（越大透視越弱；數(shù)值過小會導致透視夸張/變形）
        // 建議：以屏幕密度為基準放大；經驗值：8000f ~ 20000f（按像素 * density）
        float density = getResources().getDisplayMetrics().density;
        ivSpin.setCameraDistance(12000 * density); // 試著改大/改小感受透視差別
 
        // 2) 繞Y軸無限旋轉（可換成 rotationX）
        spinAnimatorY = ObjectAnimator.ofFloat(ivSpin, "rotationY", 0f, 360f);
        spinAnimatorY.setDuration(3000); // 一圈3秒
        spinAnimatorY.setRepeatCount(ValueAnimator.INFINITE);
        spinAnimatorY.setInterpolator(new LinearInterpolator());
        spinAnimatorY.start();
 
        // 如需切換成繞X軸旋轉，改用下面這段（示例先不啟動）
        spinAnimatorX = ObjectAnimator.ofFloat(ivSpin, "rotationX", 0f, 360f);
        spinAnimatorX.setDuration(3000);
        spinAnimatorX.setRepeatCount(ValueAnimator.INFINITE);
        spinAnimatorX.setInterpolator(new LinearInterpolator());
 
        // 可依據(jù)交互，在按鈕點擊時：spinAnimatorY.pause()/resume()/cancel()
    }
 
    @Override
    protected void onPause() {
        super.onPause();
        if (spinAnimatorY != null && spinAnimatorY.isRunning()) {
            spinAnimatorY.pause();
        }
    }
 
    @Override
    protected void onResume() {
        super.onResume();
        if (spinAnimatorY != null && spinAnimatorY.isPaused()) {
            spinAnimatorY.resume();
        }
    }
}
 
 
// ======================= B. 進階方案：自定義 View + Camera/Matrix =======================
// 亮點：可精細控制透視與局部翻轉；適合卡片翻頁、上半/下半獨立翻轉等
// 文件：java/com/example/rotate3d/Rotate3DImageView.java
package com.example.rotate3d;
 
import android.animation.ValueAnimator;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.Camera;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.RectF;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.view.View;
import android.view.animation.LinearInterpolator;
import androidx.annotation.Nullable;
 
public class Rotate3DImageView extends View {
 
    public static final int AXIS_Y = 0;
    public static final int AXIS_X = 1;
 
    private Drawable drawable;
    private Bitmap bitmap;
    private final Camera camera = new Camera();
    private final Matrix matrix = new Matrix();
    private float degree = 0f;  // 當前角度
    private int axis = AXIS_Y;  // 旋轉軸，默認Y
    private float cameraZ = -12_000f; // 相機Z，負值表示遠離屏幕（像素維度）
    private boolean autoStart = true;
    private long duration = 3000L;
 
    private ValueAnimator animator;
 
    public Rotate3DImageView(Context context) { this(context, null); }
    public Rotate3DImageView(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }
    public Rotate3DImageView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        if (attrs != null) {
            TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.Rotate3DImageView);
            axis = a.getInt(R.styleable.Rotate3DImageView_axis, AXIS_Y);
            cameraZ = a.getFloat(R.styleable.Rotate3DImageView_cameraZ, -12000f);
            autoStart = a.getBoolean(R.styleable.Rotate3DImageView_autoStart, true);
            duration = a.getInt(R.styleable.Rotate3DImageView_durationMs, 3000);
            a.recycle();
        }
        setWillNotDraw(false);
        setLayerType(LAYER_TYPE_HARDWARE, null); // 也可嘗試 SOFTWARE 處理某些機型的Camera兼容
    }
 
    public void setImageDrawable(Drawable d) {
        this.drawable = d;
        if (d instanceof BitmapDrawable) {
            bitmap = ((BitmapDrawable) d).getBitmap();
        } else {
            bitmap = null;
        }
        requestLayout();
        invalidate();
    }
 
    public void setImageResource(int resId) {
        setImageDrawable(getResources().getDrawable(resId));
    }
 
    public void setAxis(int axis) {
        this.axis = axis;
        invalidate();
    }
 
    public void setDegree(float degree) {
        this.degree = degree;
        invalidate();
    }
 
    public void setCameraZ(float z) {
        this.cameraZ = z;
        invalidate();
    }
 
    public void setDuration(long durationMs) {
        this.duration = durationMs;
        if (animator != null) animator.setDuration(durationMs);
    }
 
    private void ensureAnimator() {
        if (animator != null) return;
        animator = ValueAnimator.ofFloat(0f, 360f);
        animator.setInterpolator(new LinearInterpolator());
        animator.setDuration(duration);
        animator.setRepeatCount(ValueAnimator.INFINITE);
        animator.addUpdateListener(a -> {
            degree = (float) a.getAnimatedValue();
            invalidate();
        });
    }
 
    @Override protected void onAttachedToWindow() {
        super.onAttachedToWindow();
        if (autoStart) start();
    }
 
    @Override protected void onDetachedFromWindow() {
        super.onDetachedFromWindow();
        stop();
    }
 
    public void start() {
        ensureAnimator();
        if (!animator.isStarted()) animator.start();
    }
 
    public void pause() {
        if (animator != null && animator.isRunning()) animator.pause();
    }
 
    public void resumeAnim() {
        if (animator != null && animator.isPaused()) animator.resume();
    }
 
    public void stop() {
        if (animator != null) {
            animator.cancel();
        }
    }
 
    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        int w = resolveSize(
                drawable == null ? 200 : Math.max(drawable.getIntrinsicWidth(), 1),
                widthMeasureSpec);
        int h = resolveSize(
                drawable == null ? 200 : Math.max(drawable.getIntrinsicHeight(), 1),
                heightMeasureSpec);
        setMeasuredDimension(w, h);
        if (drawable != null) {
            drawable.setBounds(0, 0, w, h);
        }
    }
 
    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        if (drawable == null) return;
 
        final int cx = getWidth() / 2;
        final int cy = getHeight() / 2;
 
        // 保存畫布狀態(tài)
        int saveCount = canvas.save();
 
        matrix.reset();
        camera.save();
 
        // 設置相機位置（Z 軸），單位是像素。負值遠離屏幕，絕對值越大透視越弱
        // Camera#translate(0, 0, z) 不同廠商實現(xiàn)略有差異，必要時可按密度縮放
        camera.translate(0, 0, cameraZ);
 
        if (axis == AXIS_Y) {
            camera.rotateY(degree);
        } else {
            camera.rotateX(degree);
        }
        camera.getMatrix(matrix);
        camera.restore();
 
        // 將旋轉中心平移到控件中心（Camera/Matrix 默認以(0,0)為中心）
        matrix.preTranslate(-cx, -cy);
        matrix.postTranslate(cx, cy);
 
        // 應用矩陣到畫布
        canvas.concat(matrix);
 
        // 繪制圖片
        drawable.draw(canvas);
 
        // 恢復畫布
        canvas.restoreToCount(saveCount);
    }
}
 
 
// ======================= 自定義屬性聲明 =======================
// 文件：res/values/attrs.xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="Rotate3DImageView">
        <!-- 0: Y軸；1: X軸 -->
        <attr name="axis" format="enum">
            <enum name="y" value="0"/>
            <enum name="x" value="1"/>
        </attr>
        <!-- Camera Z 位置（像素），負值表示遠離屏幕，絕對值越大透視越弱 -->
        <attr name="cameraZ" format="float"/>
        <!-- 自動開始動畫 -->
        <attr name="autoStart" format="boolean"/>
        <!-- 周期(毫秒) -->
        <attr name="durationMs" format="integer"/>
    </declare-styleable>
</resources>
 
// ======================= 使用自定義 View 的布局示例 =======================
// 文件：res/layout/activity_custom.xml
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:foregroundGravity="center">
 
    <com.example.rotate3d.Rotate3DImageView
        android:id="@+id/iv3d"
        android:layout_width="240dp"
        android:layout_height="240dp"
        app:axis="y"
        app:cameraZ="-12000"
        app:autoStart="true"
        app:durationMs="2800" />
</FrameLayout>
 
// 文件：java/com/example/rotate3d/CustomActivity.java
package com.example.rotate3d;
 
import android.os.Bundle;
import androidx.appcompat.app.AppCompatActivity;
 
public class CustomActivity extends AppCompatActivity {
    @Override protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_custom);
 
        Rotate3DImageView v = findViewById(R.id.iv3d);
        v.setImageResource(R.drawable.sample);
        // 也可在代碼里切換軸/時長/相機Z
        // v.setAxis(Rotate3DImageView.AXIS_X);
        // v.setCameraZ(-16000f);
        // v.setDuration(3500);
    }
}