图片操作(缩放移动)

<?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);
}
}
}