android 图片操作(缩放移动) 实例代码

<?xml version="1.0" encoding="utf-8"?>
<linearlayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="match_parent"
  android:layout_height="match_parent">
    <framelayout
        android:layout_height="fill_parent"
        android:layout_width="fill_parent">
        <imageview
            android:id="@+id/view_img"
            android:layout_height="fill_parent"
            android:layout_width="fill_parent"
            android:background="@drawable/camera_gray"/>
        <imagebutton
            android:id="@+id/view_close"
            android:layout_height="wrap_content"
            android:layout_width="wrap_content"
            android:layout_gravity="top|left"
            android:layout_margin="5dip"/>
        <imagebutton
            android:id="@+id/view_del"
            android:layout_height="wrap_content"
            android:layout_width="wrap_content"
            android:layout_gravity="top|right"
            android:layout_margin="5dip"/>
        <imagebutton
            android:id="@+id/view_narrow"
            android:layout_height="wrap_content"
            android:layout_width="wrap_content"
            android:layout_gravity="bottom|center_horizontal"
            android:layout_marginright="10dip"/>
        <imagebutton
            android:id="@+id/view_amplification"
            android:layout_height="wrap_content"
            android:layout_width="wrap_content"
            android:layout_gravity="bottom|center_horizontal"
            android:layout_marginleft="10dip"/>
    </framelayout>
</linearlayout>

package com.kotei.lbs.anthurium.lawcases;

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.bundle;
import android.util.displaymetrics;
import android.util.floatmath;
import android.util.log;
import android.view.motionevent;
import android.view.view;
import android.view.window;
import android.view.view.ontouchlistener;
import android.widget.imageview;
import android.widget.imageview.scaletype;

/**
 * 查看图片的操作
 * @author hongj
 */
public class galleryviewtouch extends activity  {
    private imageview iv;
     private bitmap bitmap=null;
        matrix matrix = new matrix();
        matrix savedmatrix = new matrix();
        displaymetrics dm;
        float minscaler;// 最小缩放比例
        static final float max_scale = 4f;// 最大缩放比例
        static final int none = 0;// 初始状态
        static final int drag = 1;// 拖动
        static final int zoom = 2;// 缩放
        int mode = none;
        pointf prev = new pointf();
        pointf mid = new pointf();
        float dist = 1f;
    /** called when the activity is first created. */
    @override
    public void oncreate(bundle savedinstancestate) {
        super.oncreate(savedinstancestate);
        requestwindowfeature(window.feature_no_title);
        setcontentview(r.layout.view_show);
        dm = new displaymetrics();
        getwindowmanager().getdefaultdisplay().getmetrics(dm);// 获取分辨率
        bitmap=bitmapfactory.decoderesource(getresources(), r.drawable.bottom_layout_background);
        iv=(imageview)findviewbyid(r.id.view_img);
        iv.setimagebitmap(bitmap);
        iv.setontouchlistener(new imagetouch(bitmap,dm.widthpixels,dm.heightpixels,iv));

    }

    class imagetouch implements ontouchlistener {
        private imageview iv;
         private bitmap bitmap=null;
            matrix matrix = new matrix();
            matrix savedmatrix = new matrix();
            int dmwidth,dmheight;
            float minscaler;// 最小缩放比例
            static final float max_scale = 4f;// 最大缩放比例
            static final int none = 0;// 初始状态
            static final int drag = 1;// 拖动
            static final int zoom = 2;// 缩放
            int mode = none;
            pointf prev = new pointf();
            pointf mid = new pointf();
            float dist = 1f;
            imagetouch(bitmap bitmap,int width,int height,imageview iv){
                this.bitmap= bitmap;
                this.dmwidth=width;
                this.dmheight=height;
                this.iv=iv;
                initimage();
            }
            public void initimage(){
                if (dmwidth < bitmap.getwidth()|| dmheight < bitmap.getheight()) {

                    minzoom();
                    center();
                    iv.setimagematrix(matrix);
                } else {
                    iv.setscaletype(scaletype.center);
                }
            }
        @override

        public boolean ontouch(view v, motionevent event) {
             switch (event.getaction() & motionevent.action_mask) {
                // 主点按下
                case motionevent.action_down:
                    log.d("system.out", "action_down");
                    savedmatrix.set(matrix);
                    prev.set(event.getx(), event.gety());
                    mode = drag;
                    break; // 副点按下
                case motionevent.action_pointer_down:
                    log.d("system.out", "action_pointer_down");
                    dist = spacing(event); // 如果连续两点距离大于10，则判定为多点模式
                    if (spacing(event) > 10f) {
                        savedmatrix.set(matrix);
                        midpoint(mid, event);
                        mode = zoom;
                    }
                    break;
                case motionevent.action_up:
                case motionevent.action_pointer_up:
                    mode = none;
                    break;
                case motionevent.action_move:
                    if (mode == drag) {
                        matrix.set(savedmatrix);
                        matrix.posttranslate(event.getx() - prev.x, event.gety()
                                - prev.y);

                    } else if (mode == zoom) {
                        float newdist = spacing(event);
                        if (newdist > 10f) {
                            matrix.set(savedmatrix);
                            float tscale = newdist / dist;
                            matrix.postscale(tscale, tscale, mid.x, mid.y);
                        }
                    }
                    break;
                }

                iv.setimagematrix(matrix);
                if(mode!=none)
               checkview();

                return true;
        }
         private void checkview() {
                float p[] = new float[9];
                matrix.getvalues(p);
                if (mode == zoom) {
                    if (p[0] < minscaler) {
                        matrix.setscale(minscaler, minscaler);
                    }
                    if (p[0] > max_scale) {
                        matrix.set(savedmatrix);
                    }
                }
                center();
            }

         public void minzoom() {
                log.i("test", bitmap.getwidth()+"");
                log.i("test", bitmap.getheight()+"");
                minscaler = math.min(
                        (float) dmwidth / (float) bitmap.getwidth(),
                        (float) dmheight / (float) bitmap.getheight());
                if (minscaler < 1.0) {
                    matrix.postscale(minscaler, minscaler);
                }
            }
          protected void center(boolean horizontal, boolean vertical) {
                matrix m = new matrix();
                m.set(matrix);
                rectf rect = new rectf(0, 0, bitmap.getwidth(), bitmap.getheight());
                m.maprect(rect);
                float height = rect.height();
                float width = rect.width();
                log.d("system.out",rect.top+"************"+ rect.bottom);
                float deltax = 0, deltay = 0;
                if (vertical) { // 图片小于屏幕大小，则居中显示。大于屏幕，上方留空则往上移，下方留空则往下移

                    int screenheight = dmheight;
                    if (height < screenheight) {
                        deltay = (screenheight - height) / 2 - rect.top;
                    } else if (rect.top > 0) {
                        deltay = -rect.top;
                    } else if (rect.bottom < screenheight) {
                        deltay = iv.getheight() - rect.bottom;
                    }
                    //deltay-=50;
                }
                if (horizontal) {
                    int screenwidth = dmwidth;
                    if (width < screenwidth) {
                        deltax = (screenwidth - width) / 2 - rect.left;
                    } else if (rect.left > 0) {
                        deltax = -rect.left;
                    } else if (rect.right < screenwidth) {
                        deltax = screenwidth - rect.right;
                    }
                }
                matrix.posttranslate(deltax, deltay);
            }
         public void center() {
                center(true, true);
            }
         private float spacing(motionevent event) {
                float x = event.getx(0) - event.getx(1);
                float y = event.gety(0) - event.gety(1);
                return floatmath.sqrt(x * x + y * y);
            }

            /** * 两点的中点 */
            private void midpoint(pointf point, motionevent event) {
                float x = event.getx(0) + event.getx(1);
                float y = event.gety(0) + event.gety(1);
                point.set(x / 2, y / 2);
            }
    }
}