标签：instant 项目 解耦 接口隔离 适合 sdn bottom setimage offset
大图查看器是许多app的常用功能，主要使用场景是用户点击图片，然后启动一个新界面来展示图片的完整尺寸，并能通过手势移动图片以及放大缩小。当然，上面说的是最基本的功能，实际使用中还要包括：如果是本地图片应该可以移除，如果是网络图片，应提供一个保存到本地的功能等。
本文为什么叫封装一个大图查看器，而不是叫做编写一个大图查看器呢？因为大图查看器的最核心功能，展示图片以及手势操控我们使用了一个开源库来完成，这个开源库叫做subsampling-scale-image-view，这个开源库非常靠谱，使用也非常简单，我记得知乎的Android app中也是使用了这个库。这个库的Github地址是：subsampling-scale-image-view。
我先把我做出来的效果图展示出来：
首先第一张是：
然后来看第二张：
两张界面截图展示的是同一张图片，但区别在于，第一张图片右下角有一个下载的图标，对应的是查看网络图片这种方式（大家都需要保存网络图片这个功能）；而第二张图片右下角没有了图标，而右上角有一个垃圾桶的图标，用来进行移除操作，想象一下，本来查看的就是本地图片，那用户也就不用再保存它一次了，而移除操作在很多实际使用场景中有效，比如说在微信中，你想发朋友圈，你选择了一几张本地照片以后进行大图浏览，而这时候你发现其中几张不太好，想移除它，于是为了用户方便，应该给用户一个在大图查看器中进行移除的方法。
<style name="Dialog_Fullscreen">
<item name="android:windowFullscreen">true</item>
<item name="android:windowNoTitle">true</item>
</style>这就是全屏Dialog的实现方式。接下来，定义Dialog的布局：<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@android:color/black">
<android.support.v4.view.ViewPager
android:id="@+id/scale_image_view_pager"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<ImageView
android:id="@+id/scale_image_close"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_alignParentStart="true"
android:padding="24dp"
android:src="@drawable/ic_clear_white_24dp"
tools:ignore="ContentDescription"/>
<ImageView
android:id="@+id/scale_image_delete"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_alignParentEnd="true"
android:padding="24dp"
android:src="@drawable/ic_delete_white_24dp"
tools:ignore="ContentDescription"/>
<ImageView
android:id="@+id/scale_image_save"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentEnd="true"
android:padding="24dp"
android:src="@drawable/ic_file_download_white_24dp"
tools:ignore="ContentDescription"/>
<TextView
android:id="@+id/scale_image_count"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_alignParentBottom="true"
android:layout_marginBottom="32dp"
android:textSize="16sp"
android:textColor="@android:color/white"/>
</RelativeLayout>public class ScaleImageView {
private static final byte URLS = 0;
private static final byte FILES = 1;
private byte status;
private Activity activity;
private List<String> urls;
private List<File> files;
private List<File> downloadFiles;
private int selectedPosition;
private Dialog dialog;
private ImageView delete;
private ImageView download;
private TextView imageCount;
private ViewPager viewPager;
private List<View> views;
private MyPagerAdapter adapter;
private OnDeleteItemListener listener;
private int startPosition;
public ScaleImageView(Activity activity) {
this.activity = activity;
init();
}
public void setOnDeleteItemListener(OnDeleteItemListener listener) {
this.listener = listener;
}
private void init() {
RelativeLayout relativeLayout = (RelativeLayout) activity.getLayoutInflater().inflate(R.layout.dialog_scale_image, null);
ImageView close = (ImageView) relativeLayout.findViewById(R.id.scale_image_close);
delete = (ImageView) relativeLayout.findViewById(R.id.scale_image_delete);
download = (ImageView) relativeLayout.findViewById(R.id.scale_image_save);
imageCount = (TextView) relativeLayout.findViewById(R.id.scale_image_count);
viewPager = (ViewPager) relativeLayout.findViewById(R.id.scale_image_view_pager);
dialog = new Dialog(activity, R.style.Dialog_Fullscreen);
dialog.setContentView(relativeLayout);
close.setOnClickListener(v -> dialog.dismiss());
delete.setOnClickListener(v -> {
int size = views.size();
files.remove(selectedPosition);
if (listener != null) {
listener.onDelete(selectedPosition);
}
viewPager.removeView(views.remove(selectedPosition));
if (selectedPosition != size) {
int position = selectedPosition + 1;
String text = position + "/" + views.size();
imageCount.setText(text);
}
adapter.notifyDataSetChanged();
});
download.setOnClickListener(v -> {
try {
MediaStore.Images.Media.insertImage(activity.getContentResolver(),
downloadFiles.get(selectedPosition).getAbsolutePath(),
downloadFiles.get(selectedPosition).getName(), null);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
Snackbar.make(viewPager, "图片保存成功", Snackbar.LENGTH_SHORT).show();
});
viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
selectedPosition = position;
String text = ++position + "/" + views.size();
imageCount.setText(text);
}
@Override
public void onPageScrollStateChanged(int state) {
}
});
}
}
首先，我们关注一下最上面三行定义的几个变量，URLS和FILES两个常量分别表示网络查看模式和本地查看模式，而status则用来标示现在查看器处于哪个模式下。public interface OnDeleteItemListener {
void onDelete(int position);
} public void setUrls(List<String> urls, int startPosition) {
if (this.urls == null) {
this.urls = new ArrayList<>();
} else {
this.urls.clear();
}
this.urls.addAll(urls);
status = URLS;
delete.setVisibility(View.GONE);
if (downloadFiles == null) {
downloadFiles = new ArrayList<>();
} else {
downloadFiles.clear();
}
this.startPosition = startPosition++;
String text = startPosition + "/" + urls.size();
imageCount.setText(text);
}
public void setFiles(List<File> files, int startPosition) {
if (this.files == null) {
this.files = new LinkedList<>();
} else {
this.files.clear();
}
this.files.addAll(files);
status = FILES;
download.setVisibility(View.GONE);
this.startPosition = startPosition++;
String text = startPosition + "/" + files.size();
imageCount.setText(text);
}public void create() {
dialog.show();
views = new ArrayList<>();
adapter = new MyPagerAdapter(views, dialog);
if (status == URLS) {
for (String url : urls) {
FrameLayout frameLayout = (FrameLayout) activity.getLayoutInflater().inflate(R.layout.view_scale_image, null);
SubsamplingScaleImageView imageView = (SubsamplingScaleImageView) frameLayout.findViewById(R.id.scale_image_view);
views.add(frameLayout);
IOThread.getSingleThread().execute(() -> {
File downLoadFile;
try {
downLoadFile = Glide.with(activity).load(url).downloadOnly(Target.SIZE_ORIGINAL, Target.SIZE_ORIGINAL).get();
downloadFiles.add(downLoadFile);
activity.runOnUiThread(() -> imageView.setImage(ImageSource.uri(Uri.fromFile(downLoadFile))));
} catch (Exception e) {
e.printStackTrace();
}
});
}
viewPager.setAdapter(adapter);
} else if (status == FILES) {
for (File file : files) {
FrameLayout frameLayout = (FrameLayout) activity.getLayoutInflater().inflate(R.layout.view_scale_image, null);
SubsamplingScaleImageView imageView = (SubsamplingScaleImageView) frameLayout.findViewById(R.id.scale_image_view);
views.add(frameLayout);
imageView.setImage(ImageSource.uri(Uri.fromFile(file)));
}
viewPager.setAdapter(adapter);
}
viewPager.setCurrentItem(startPosition);
}private static class MyPagerAdapter extends PagerAdapter {
private List<View> views;
private Dialog dialog;
MyPagerAdapter(List<View> views, Dialog dialog) {
this.views = views;
this.dialog = dialog;
}
@Override
public Object instantiateItem(ViewGroup container, int position) {
container.addView(views.get(position));
return views.get(position);
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
if (position == 0 && views.size() == 0) {
dialog.dismiss();
return;
}
if (position == views.size()) {
container.removeView(views.get(--position));
} else {
container.removeView(views.get(position));
}
}
@Override
public int getCount() {
return views.size();
}
@Override
public boolean isViewFromObject(View view, Object object) {
return view == object;
}
@Override
public int getItemPosition(Object object) {
return POSITION_NONE;
}
}<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<com.davemorrissey.labs.subscaleview.SubsamplingScaleImageView
android:id="@+id/scale_image_view"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</FrameLayout>ScaleImageView scaleImageView = new ScaleImageView(activity); scaleImageView.setUrls(urls, position); scaleImageView.create();
ScaleImageView scaleImageView = new ScaleImageView(activity); scaleImageView.setFiles(files, position); scaleImageView.setOnDeleteItemListener(deletePosition -> adapter.removeItem(deletePosition)); scaleImageView.create();
public class ScaleImageView {
private static final byte URLS = 0;
private static final byte FILES = 1;
private byte status;
private Activity activity;
private List<String> urls;
private List<File> files;
private List<File> downloadFiles;
private int selectedPosition;
private Dialog dialog;
private ImageView delete;
private ImageView download;
private TextView imageCount;
private ViewPager viewPager;
private List<View> views;
private MyPagerAdapter adapter;
private OnDeleteItemListener listener;
private int startPosition;
public ScaleImageView(Activity activity) {
this.activity = activity;
init();
}
public void setUrls(List<String> urls, int startPosition) {
if (this.urls == null) {
this.urls = new ArrayList<>();
} else {
this.urls.clear();
}
this.urls.addAll(urls);
status = URLS;
delete.setVisibility(View.GONE);
if (downloadFiles == null) {
downloadFiles = new ArrayList<>();
} else {
downloadFiles.clear();
}
this.startPosition = startPosition++;
String text = startPosition + "/" + urls.size();
imageCount.setText(text);
}
public void setFiles(List<File> files, int startPosition) {
if (this.files == null) {
this.files = new LinkedList<>();
} else {
this.files.clear();
}
this.files.addAll(files);
status = FILES;
download.setVisibility(View.GONE);
this.startPosition = startPosition++;
String text = startPosition + "/" + files.size();
imageCount.setText(text);
}
public void setOnDeleteItemListener(OnDeleteItemListener listener) {
this.listener = listener;
}
private void init() {
RelativeLayout relativeLayout = (RelativeLayout) activity.getLayoutInflater().inflate(R.layout.dialog_scale_image, null);
ImageView close = (ImageView) relativeLayout.findViewById(R.id.scale_image_close);
delete = (ImageView) relativeLayout.findViewById(R.id.scale_image_delete);
download = (ImageView) relativeLayout.findViewById(R.id.scale_image_save);
imageCount = (TextView) relativeLayout.findViewById(R.id.scale_image_count);
viewPager = (ViewPager) relativeLayout.findViewById(R.id.scale_image_view_pager);
dialog = new Dialog(activity, R.style.Dialog_Fullscreen);
dialog.setContentView(relativeLayout);
close.setOnClickListener(v -> dialog.dismiss());
delete.setOnClickListener(v -> {
int size = views.size();
files.remove(selectedPosition);
if (listener != null) {
listener.onDelete(selectedPosition);
}
viewPager.removeView(views.remove(selectedPosition));
if (selectedPosition != size) {
int position = selectedPosition + 1;
String text = position + "/" + views.size();
imageCount.setText(text);
}
adapter.notifyDataSetChanged();
});
download.setOnClickListener(v -> {
try {
MediaStore.Images.Media.insertImage(activity.getContentResolver(),
downloadFiles.get(selectedPosition).getAbsolutePath(),
downloadFiles.get(selectedPosition).getName(), null);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
Snackbar.make(viewPager, "图片保存成功", Snackbar.LENGTH_SHORT).show();
});
viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
selectedPosition = position;
String text = ++position + "/" + views.size();
imageCount.setText(text);
}
@Override
public void onPageScrollStateChanged(int state) {
}
});
}
public void create() {
dialog.show();
views = new ArrayList<>();
adapter = new MyPagerAdapter(views, dialog);
if (status == URLS) {
for (String url : urls) {
FrameLayout frameLayout = (FrameLayout) activity.getLayoutInflater().inflate(R.layout.view_scale_image, null);
SubsamplingScaleImageView imageView = (SubsamplingScaleImageView) frameLayout.findViewById(R.id.scale_image_view);
views.add(frameLayout);
IOThread.getSingleThread().execute(() -> {
File downLoadFile;
try {
downLoadFile = Glide.with(activity).load(url).downloadOnly(Target.SIZE_ORIGINAL, Target.SIZE_ORIGINAL).get();
downloadFiles.add(downLoadFile);
activity.runOnUiThread(() -> imageView.setImage(ImageSource.uri(Uri.fromFile(downLoadFile))));
} catch (Exception e) {
e.printStackTrace();
}
});
}
viewPager.setAdapter(adapter);
} else if (status == FILES) {
for (File file : files) {
FrameLayout frameLayout = (FrameLayout) activity.getLayoutInflater().inflate(R.layout.view_scale_image, null);
SubsamplingScaleImageView imageView = (SubsamplingScaleImageView) frameLayout.findViewById(R.id.scale_image_view);
views.add(frameLayout);
imageView.setImage(ImageSource.uri(Uri.fromFile(file)));
}
viewPager.setAdapter(adapter);
}
viewPager.setCurrentItem(startPosition);
}
private static class MyPagerAdapter extends PagerAdapter {
private List<View> views;
private Dialog dialog;
MyPagerAdapter(List<View> views, Dialog dialog) {
this.views = views;
this.dialog = dialog;
}
@Override
public Object instantiateItem(ViewGroup container, int position) {
container.addView(views.get(position));
return views.get(position);
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
if (position == 0 && views.size() == 0) {
dialog.dismiss();
return;
}
if (position == views.size()) {
container.removeView(views.get(--position));
} else {
container.removeView(views.get(position));
}
}
@Override
public int getCount() {
return views.size();
}
@Override
public boolean isViewFromObject(View view, Object object) {
return view == object;
}
@Override
public int getItemPosition(Object object) {
return POSITION_NONE;
}
}
public interface OnDeleteItemListener {
void onDelete(int position);
}
}标签：instant 项目 解耦 接口隔离 适合 sdn bottom setimage offset
原文地址：http://blog.csdn.net/qq_28899635/article/details/71552072
