Android中實現圖片平移、縮放、旋轉同步進行

前言

之前因為項目需求，其中使用到了圖片的單擊顯示取消，圖片平移縮放功能，昨天突然想再加上圖片的旋轉功能，在網上看了很多相關的例子，可是沒看到能同時實現我想要的功能的。
需求：
（1）圖片平移、縮放、旋轉等一系列操作後，圖片需要自動居中顯示。
（2）圖片旋轉後選自動水平顯示或者垂直顯示
（3）圖片在放大縮小的同時都能旋轉

Demo實現部分效果截圖

Demo主要代碼

MainActivity.java

package com.practice.noyet.rotatezoomimageview;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.graphics.RectF;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.view.MotionEvent;
import android.view.View;
import android.widget.ImageView;

import com.ypy.eventbus.EventBus;

import java.io.File;
import java.math.BigDecimal;

/**
 * package: com.practice.noyet.rotatezoomimageview
 * Created by noyet on 2015/11/11.
 */
public class MainActivity extends Activity implements View.OnTouchListener {

    private ImageView mImageView;

    private PointF point0 = new PointF();
    private PointF pointM = new PointF();

    private final int NONE = 0;
    /**
     * 平移
     */
    private final int DRAG = 1;
    /**
     * 旋轉、縮放
     */
    private final int ZOOM = 2;
    /**
     * 設定事件模式
     */
    private int mode = NONE;
    /**
     * 圖片縮放矩陣
     */
    private Matrix matrix = new Matrix();
    /**
     * 保存觸摸前的圖片縮放矩陣
     */
    private Matrix savedMatrix = new Matrix();
    /**
     * 保存觸點移動過程中的圖片縮放矩陣
     */
    private Matrix matrix1 = new Matrix();
    /**
     * 屏幕高度
     */
    private int displayHeight;
    /**
     * 屏幕寬度
     */
    private int displayWidth;
    /**
     * 最小縮放比例
     */
    protected float minScale = 1f;
    /**
     * 最大縮放比例
     */
    protected float maxScale = 3f;
    /**
     * 當前縮放比例
     */
    protected float currentScale = 1f;
    /**
     * 多點觸摸2個觸摸點間的起始距離
     */
    private float oldDist;
    /**
     * 多點觸摸時圖片的起始角度
     */
    private float oldRotation = 0;
    /**
     * 旋轉角度
     */
    protected float rotation = 0;
    /**
     * 圖片初始寬度
     */
    private int imgWidth;
    /**
     * 圖片初始高度
     */
    private int imgHeight;
    /**
     * 設置單點觸摸退出圖片顯示時，單點觸摸的靈敏度（可針對不同手機單獨設置）
     */
    protected final int MOVE_MAX = 2;
    /**
     * 單點觸摸時手指觸發的‘MotionEvent.ACTION_MOVE’次數
     */
    private int fingerNumMove = 0;

    private Bitmap bm;
    /**
     * 保存matrix縮放比例
     */
    private float matrixScale= 1;
    /*private String imagePath;*/

    /**
     * 顯示被存入緩存中的網絡圖片
     *
     * @param event 觀察者事件
     */
    public void onEventMainThread(CustomEventBus event) {
        if (event == null) {
            return;
        }
        if (event.type == CustomEventBus.EventType.SHOW_PICTURE) {
            bm = (Bitmap) event.obj;
            showImage();
        }
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        initData();
    }

    public void initData() {
        // TODO Auto-generated method stub
        bm = BitmapFactory.decodeResource(getResources(), R.drawable.alipay);
        DisplayMetrics dm = getResources().getDisplayMetrics();
        displayWidth = dm.widthPixels;
        displayHeight = dm.heightPixels;
        mImageView = (ImageView) findViewById(R.id.image_view);
        mImageView.setOnTouchListener(this);
        showImage();

        //顯示網絡圖片時使用
        /*File file = MainApplication.getInstance().getImageCache()
                .getDiskCache().get(圖片路徑);
        if (!file.exists()) {
            Toast.makeText(this, 圖片路徑錯誤, Toast.LENGTH_SHORT).show();
        } else {
            new MyTask().execute(file);
        }*/
    }

    @Override
    public boolean onTouch(View view, MotionEvent event) {
        ImageView imageView = (ImageView) view;
        switch (event.getAction() & MotionEvent.ACTION_MASK) {
            case MotionEvent.ACTION_DOWN:
                savedMatrix.set(matrix);
                point0.set(event.getX(), event.getY());
                mode = DRAG;
                System.out.println(MotionEvent--ACTION_DOWN);
                break;
            case MotionEvent.ACTION_POINTER_DOWN:
                oldDist = spacing(event);
                oldRotation = rotation(event);
                savedMatrix.set(matrix);
                setMidPoint(pointM, event);
                mode = ZOOM;
                System.out.println(MotionEvent--ACTION_POINTER_DOWN--- + oldRotation);
                break;
            case MotionEvent.ACTION_UP:
                if (mode == DRAG && (fingerNumMove <= MOVE_MAX)) {
                    MainActivity.this.finish();
                }
                checkView();
                centerAndRotate();
                imageView.setImageMatrix(matrix);
                System.out.println(MotionEvent--ACTION_UP);
                fingerNumMove = 0;
                break;
            case MotionEvent.ACTION_POINTER_UP:
                mode = NONE;
                System.out.println(MotionEvent--ACTION_POINTER_UP);
                break;
            case MotionEvent.ACTION_MOVE:
                operateMove(event);
                imageView.setImageMatrix(matrix1);
                fingerNumMove++;
                System.out.println(MotionEvent--ACTION_MOVE);
                break;

        }
        return true;
    }

    @Override
    protected void onDestroy() {
        // TODO Auto-generated method stub
        super.onDestroy();
        if (bm != null && !bm.isRecycled()) {
            bm.recycle(); // 回收圖片所占的內存
            System.gc(); // 提醒系統及時回收
        }
    }

    /**
     * 顯示圖片
     */
    private void showImage() {
        imgWidth = bm.getWidth();
        imgHeight = bm.getHeight();
        mImageView.setImageBitmap(bm);
        matrix.setScale(1, 1);
        centerAndRotate();
        mImageView.setImageMatrix(matrix);
    }

    /**
     * 觸點移動時的操作
     *
     * @param event 觸摸事件
     */
    private void operateMove(MotionEvent event) {
        matrix1.set(savedMatrix);
        switch (mode) {
            case DRAG:
                matrix1.postTranslate(event.getX() - point0.x, event.getY() - point0.y);
                break;
            case ZOOM:
                rotation = rotation(event) - oldRotation;
                float newDist = spacing(event);
                float scale = newDist / oldDist;
                currentScale = (scale > 3.5f) ? 3.5f : scale;
                System.out.println(縮放倍數--- + currentScale);
                System.out.println(旋轉角度--- + rotation);
                /** 縮放 */
                matrix1.postScale(currentScale, currentScale, pointM.x, pointM.y);
                /** 旋轉 */
                matrix1.postRotate(rotation, displayWidth / 2, displayHeight / 2);
                break;
        }
    }

    /**
     * 兩個觸點的距離
     *
     * @param event 觸摸事件
     * @return float
     */
    private float spacing(MotionEvent event) {
        float x = event.getX(0) - event.getX(1);
        float y = event.getY(0) - event.getY(1);
        return (float) Math.sqrt(x * x + y * y);
    }

    /**
     * 獲取旋轉角度
     */
    private float rotation(MotionEvent event) {
        double delta_x = (event.getX(0) - event.getX(1));
        double delta_y = (event.getY(0) - event.getY(1));
        double radians = Math.atan2(delta_y, delta_x);
        return (float) Math.toDegrees(radians);
    }

    /**
     * 兩個觸點的中間坐標
     *
     * @param pointM 中間坐標
     * @param event  觸摸事件
     */
    private void setMidPoint(PointF pointM, MotionEvent event) {
        float x = event.getX(0) + event.getY(1);
        float y = event.getY(0) + event.getY(1);
        pointM.set(x / 2, y / 2);
    }

    /**
     * 檢查約束條件(縮放倍數)
     */
    private void checkView() {
        if (currentScale > 1) {
            if (currentScale * matrixScale > maxScale) {
                matrix.postScale(maxScale / matrixScale, maxScale / matrixScale, pointM.x, pointM.y);
                matrixScale = maxScale;
            } else {
                matrix.postScale(currentScale, currentScale, pointM.x, pointM.y);
                matrixScale *= currentScale;
            }
        } else {
            if (currentScale * matrixScale < minScale) {
                matrix.postScale(minScale / matrixScale, minScale / matrixScale, pointM.x, pointM.y);
                matrixScale = minScale;
            } else {
                matrix.postScale(currentScale, currentScale, pointM.x, pointM.y);
                matrixScale *= currentScale;
            }
        }
    }

    /**
     * 圖片居中顯示、判斷旋轉角度 小於（90 * x + 45）度圖片旋轉（90 * x）度 大於則旋轉（90 * (x+1)）
     */
    private void centerAndRotate() {
        RectF rect = new RectF(0, 0, imgWidth, imgHeight);
        matrix.mapRect(rect);
        float width = rect.width();
        float height = rect.height();
        float dx = 0;
        float dy = 0;

        if (width < displayWidth) {
            dx = displayWidth / 2 - width / 2 - rect.left;
        } else if (rect.left > 0) {
            dx = -rect.left;
        } else if (rect.right < displayWidth) {
            dx = displayWidth - rect.right;
        }

        if (height < displayHeight) {
            dy = displayHeight / 2 - height / 2 - rect.top;
        } else if (rect.top > 0) {
            dy = -rect.top;
        } else if (rect.bottom < displayHeight) {
            dy = displayHeight - rect.bottom;
        }

        matrix.postTranslate(dx, dy);

        if (rotation != 0) {
            int rotationNum = (int) (rotation / 90);
            float rotationAvai = new BigDecimal(rotation % 90).setScale(1, BigDecimal.ROUND_HALF_UP).floatValue();
            float realRotation = 0;
            if (rotation > 0) {
                realRotation = rotationAvai > 45 ? (rotationNum + 1) * 90 : rotationNum * 90;
            } else if (rotation < 0) {
                realRotation = rotationAvai < -45 ? (rotationNum - 1) * 90 : rotationNum * 90;
            }
            System.out.println(realRotation:  + realRotation);
            matrix.postRotate(realRotation, displayWidth / 2, displayHeight / 2);
            rotation = 0;
        }
    }

    /**
     * 顯示網絡圖片時使用
     */
    private class MyTask extends AsyncTask {

        Bitmap bitmap;
        String path;
        int scale = 1;
        long size;

        @Override
        protected Bitmap doInBackground(File... params) {
            // TODO Auto-generated method stub
            try {
                size = params[0].length();
                path = params[0].getAbsolutePath();
                BitmapFactory.Options options = new BitmapFactory.Options();
                options.inJustDecodeBounds = true;
                BitmapFactory.decodeFile(path, options);
                scale = calculateInSampleSize(options, displayWidth,
                        displayHeight);
                options.inJustDecodeBounds = false;
                options.inSampleSize = scale;
                bitmap = BitmapFactory.decodeFile(path, options);
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            return bitmap;
        }

        @Override
        protected void onPostExecute(Bitmap result) {
            // TODO Auto-generated method stub
            EventBus.getDefault().post(
                    new CustomEventBus(CustomEventBus.EventType.SHOW_PICTURE, result));
        }

        /**
         * 獲取圖片縮放比例
         *
         * @param paramOptions Options
         * @param paramInt1    寬
         * @param paramInt2    高
         * @return int
         */
        private int calculateInSampleSize(BitmapFactory.Options paramOptions,
                                          int paramInt1, int paramInt2) {
            int i = paramOptions.outHeight;
            int j = paramOptions.outWidth;
            int k = 1;
            if ((i > paramInt2) || (j > paramInt1)) {
                int m = Math.round(i / paramInt2);
                int n = Math.round(j / paramInt1);
                k = m < n ? n : m;
            }
            return k;
        }
    }
}

CustomEventBus.java
package com.practice.noyet.rotatezoomimageview;

/**
 * package: com.practice.noyet.rotatezoomimageview
 * Created by noyet on 2015/11/11.
 */
public class CustomEventBus {

    public EventType type;
    public Object obj;

    public CustomEventBus(EventType type, Object obj) {
        this.type = type;
        this.obj = obj;
    }

    enum EventType {
        SHOW_PICTURE
    }
}