安卓图片（ImageView）：展示大图、双击放大、触摸放大缩小、滑动切换、长按保存等

背景：由于项目中需要做一个图片展示功能，大概就是在一个页面中有一个listview或者recyclerview的布局，然后item中有图文混排，点击图片后能看大图，并且能触摸放大，双击放大，触摸缩小，多张图片的话还可以滑动切换，长按图片还可以保存到本地等操作，然后就开始按着需求设计功能，由于网上也有很多类似demo，简直满坑满谷，所以就不在介绍各种原理及实现方法，功能很简单，代码也很easy,主要就是依赖photoView开源代码完成，各位看官就将就一下吧：
&＃8211; 1.怎样展示大图
&＃8211; 2.自定义imageview
&＃8211; 3.多张图片滑动
&＃8211; 4.长按保存，取消

1.首先点击图片后要展示当前所点击的图片大图，用什么承载这张图片呢，这里我用的是dialog,下面po出代码，注释很详细，放心阅读：
/** * 点击图片后，调用该展示大图方法 * @param mPosition */

public void showPictureDialog(final int mPosition) {
//创建dialog
mDialog = new Dialog(this, R.style.PictureDialog);
final Window window1 = mDialog.getWindow() ;
WindowManager m = getWindowManager();
Display d = m.getDefaultDisplay(); // 获取屏幕宽、高用
WindowManager.LayoutParams p = window1.getAttributes(); // 获取对话框当前的参数值
p.height = (int) (d.getHeight() * 1.0); // 改变的是dialog框在屏幕中的位置而不是大小
p.width = (int) (d.getWidth() * 1.0); // 宽度设置为屏幕
window1.setAttributes(p);
View inflate = View.inflate(QuestionDetailsActivity.this, R.layout.picture_dialog, null);//该layout在后面po出
int screenWidth = getResources().getDisplayMetrics().widthPixels;
ViewGroup.LayoutParams layoutParams = new ViewGroup.LayoutParams(screenWidth, ViewGroup.LayoutParams.MATCH_PARENT);
mDialog.setContentView(inflate, layoutParams);
pager = (ViewPagerFixed) inflate.findViewById(R.id.gallery01);
pager.setOnPageChangeListener(pageChangeListener);
PicturePageAdapter adapter = new PicturePageAdapter((ArrayList) mListPicPath, this);
pager.setAdapter(adapter);
pager.setPageMargin(0);
pager.setCurrentItem(mPosition); window1.setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
mDialog.setOnKeyListener(new DialogOnKeyListener());
mDialog.show();
adapter.setOnPictureClickListener(new PicturePageAdapter.OnPictureClickListener() {
@Override
public void OnClick() { window1.clearFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
mDialog.dismiss();
}
});
//长按图片保存
adapter.setOnPictureLongClickListener(new PicturePageAdapter.OnPictureLongClickListener() {
@Override
public void OnLongClick() {
//展示保存取消dialog
showPicDialog();
}
});
}


//展示保存取消dialog
private void showPicDialog() {
homeWorkDialog = new SavePicDialog(QuestionDetailsActivity.this);
homeWorkDialog.setOnClickListener(new SavePicDialog.onClickListener() {
@Override
public void onConfirm() {
//启动图片下载线程
if (pager != null){
onDownLoad(mListPicPath.get(pager.getCurrentItem()));
}
Toast.makeText(QuestionDetailsActivity.this,"保存成功!",Toast.LENGTH_SHORT).show();
homeWorkDialog.dismiss();
}
@Override
public void onCancle() {
homeWorkDialog.dismiss();
}
});
Window dialogWindow = homeWorkDialog.getWindow();
dialogWindow.setGravity( Gravity.BOTTOM);
WindowManager.LayoutParams lp = dialogWindow.getAttributes();
lp.y = 0;
dialogWindow.setAttributes(lp);
homeWorkDialog.show();
}

//上面style
<style name="PictureDialog" parent="android:style/Theme.Translucent.NoTitleBar.Fullscreen"> <item name="android:background">#00000000item> <item name="android:windowBackground">@android:color/transparent "android:windowNoTitle">true "android:windowIsFloating">true style>
//上面picture_dialog布局

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent">
<com.XXX.ViewPagerFixed android:id="@+id/gallery01" android:layout_width="match_parent" android:layout_height="match_parent">
com.XXX.ViewPagerFixed>
RelativeLayout>

/** * Created by ml on 17/6/30. */
public class PicturePageAdapter extends PagerAdapter {
private ArrayList mListUrls;
private SparseArray mViews = new SparseArray<>();
private Context mContext;
private int size;
private OnPictureClickListener mOnPictureClickListener;
private OnPictureLongClickListener mOnPictureLongClickListener;
public PicturePageAdapter(ArrayList listUrls, Context context) {
mCOntext= context;
mListUrls = listUrls;
size = mListUrls == null ? 0 : mListUrls.size();
}
public SparseArray getData(){
return this.mViews;
}
public int getCount() {
return size;
}
public int getItemPosition(Object object) {
return POSITION_NONE;
}
public void destroyItem(ViewGroup arg0, int arg1, Object arg2) {
arg0.removeView(mViews.get(arg1));
}
public void finishUpdate(View arg0) {
}
public Object instantiateItem(ViewGroup arg0, int arg1) {
View view = mViews.get(arg1);
if(view == null){
//引入photoView
PhotoView img = new PhotoView(mContext);
try {
img.setBackgroundColor(0xff000000);
//Glide需要自己去引入了
Glide
.with(mContext)
.load(mListUrls.get(arg1))
.into(img);
img.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));
img.setOnPhotoTapListener(new PhotoViewAttacher.OnPhotoTapListener() {
@Override
public void onPhotoTap(View view, float x, float y) {
if (mOnPictureClickListener != null) {
mOnPictureClickListener.OnClick();
}
}
});
//设置长按图片监听
img.setOnLongClickListener(new View.OnLongClickListener() {
@Override
public boolean onLongClick(View v) {
if (mOnPictureLongClickListener != null) {
mOnPictureLongClickListener.OnLongClick();
}
return false;
}
});
mViews.put(arg1,img);
view = img;
} catch (Exception e) {
e.printStackTrace();
}
}
((ViewPagerFixed) arg0).addView(view);
return view;
}
public boolean isViewFromObject(View arg0, Object arg1) {
return arg0 == arg1;
}
/** * 图片监听接口 */
public interface OnPictureClickListener{
void OnClick();
}
/** * 设置图片监听 * @param onPictureClickListener */
public void setOnPictureClickListener(OnPictureClickListener onPictureClickListener){
mOnPictureClickListener= onPictureClickListener;
}
/** * 长按图片监听接口 */
public interface OnPictureLongClickListener{
void OnLongClick();
}
/** * 设置长按图片监听 * @param onPictureLongClickListener */
public void setOnPictureLongClickListener(OnPictureLongClickListener onPictureLongClickListener){
mOnPictureLongClickListener= onPictureLongClickListener;
}
}

//自定义viewpager类
public class ViewPagerFixed extends android.support.v4.view.ViewPager {
public ViewPagerFixed(Context context) {
super(context);}
public ViewPagerFixed(Context context, AttributeSet attrs) {
super(context, attrs);}
@Override
public boolean onTouchEvent(MotionEvent ev) {
try {
return super.onTouchEvent(ev);
} catch (IllegalArgumentException ex) {
ex.printStackTrace();
}
return false;
}
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
try {
return super.onInterceptTouchEvent(ev);
} catch (IllegalArgumentException ex) {
ex.printStackTrace();
}
return false;
}
}
希望大家静下心来整理，也给自己增加理解，或者发现不好的地方，指出来，咱们一起进步，完善

好了，这样就结束了，谢谢大家浏览使用，也欢迎提出问题，一起进步！