「这是我参与11月更文挑战的第12天，活动详情查看：2021最后一次更文挑战」
实现原理
自定义PopupWindow+RecyclerView+TouchImageView
PopupWindow与AlertDialog的区别
最关键的区别是AlertDialog不能指定显示位置，只能默认显示在屏幕最中间（当然也可以通过设置WindowManager参数来改变位置）。而PopupWindow是可以指定显示位置的，十分灵活。
要生成一个PopupWindow最基本的三个条件是一定要设置的：
View contentView，int width, int height ；
少任意一个就不可能弹出来
PictureBrowsing
PictureBrowsing的布局文件
view_image.xml
<?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"
>
<View
android:id="@+id/bg"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#000"
android:alpha="0"
/>
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
<TextView
android:id="@+id/tv_savePicture"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="right"
android:layout_alignParentStart="true"
android:textColor="@color/white"
android:layout_marginTop="26dp"
android:layout_marginRight="16dp"
android:paddingLeft="15dp"
android:paddingRight="15dp"
android:paddingTop="4dp"
android:paddingBottom="4dp"
android:text="保存图片"
android:textSize="19dp"
android:background="@drawable/bg_operator"
/>
<ImageView
android:id="@+id/cover"
android:layout_width="0dp"
android:layout_height="0dp"
/>
</FrameLayout>
重写PopupWindow里面放入一个横向的RecyclerView
完整代码比较简单，主要就是RecyclerView的使用
public class PictureBrowsing extends PopupWindow {
private Context mContext;//上下文
private View mParent;
private View mBg;//背景图片
private RecyclerView mRecyclerView;
private ImageView mCover;//当前的图面
private List<PictureBean> mList;
private int mPosition;//当前的图面的位置
private ActionListener mActionListener; //自定义点击接口
private int recyclerViewCurrentPosition = -1; // RecyclerView当前前位置
private TextView savePicture;//保存图片
//构造函数
public PictureBrowsing(Context context, View parent, List<PictureBean> bean) {
mContext = context;
mParent = parent;
mList = new ArrayList<>();
mList .addAll( bean);
mPosition = 1;
//设置布局
setContentView(initView());
//设置布局宽高
setWidth(ViewGroup.LayoutParams.MATCH_PARENT);
setHeight(ViewGroup.LayoutParams.MATCH_PARENT);
//背景
setBackgroundDrawable(new ColorDrawable());
//点击外面销毁弹窗
setOutsideTouchable(true);
setClippingEnabled(false);
setFocusable(true);
//销毁事件监听
setOnDismissListener(new OnDismissListener() {
@Override
public void onDismiss() {
if (mActionListener != null) {
mActionListener.onImageDialogDismiss();
}
mActionListener = null;
mRecyclerView = null;
}
});
}
//初始化RecyclerView
private View initView() {
View v = LayoutInflater.from(mContext).inflate(R.layout.view_image, null);
mBg = v.findViewById(R.id.bg);
mRecyclerView = v.findViewById(R.id.recyclerView);
mRecyclerView.setHasFixedSize(true);
mRecyclerView.setLayoutManager(new LinearLayoutManager(mContext, LinearLayoutManager.HORIZONTAL, false));
mCover = v.findViewById(R.id.cover);
//适配器
PictureBrowsingAdapter adapter = new PictureBrowsingAdapter(mContext, mList);
adapter.setActionListener(new PictureBrowsingAdapter.ActionListener() {
@Override
public void onImageClick() {
dismiss();
}
});
mRecyclerView.setAdapter(adapter);
if (mPosition >= 0 && mPosition < mList.size()) {
mRecyclerView.scrollToPosition(mPosition);
}
return v;
}
public int getRecyclerViewCurrentPosition() {
return recyclerViewCurrentPosition;
}
public void show() {
//PopupWindow弹出位置
showAtLocation(mParent, Gravity.BOTTOM, 0, 0);
}
public void setActionListener(ActionListener actionListener) {
mActionListener = actionListener;
}
//自定义点击接口
public interface ActionListener {
void onImageDialogDismiss();
}
PictureBrowsingAdapter
public class PictureBrowsingAdapter extends RecyclerView.Adapter<PictureBrowsingAdapter.Vh> {
private Context mContext;
private List<PictureBean> mList;//简单封装的实体类
private LayoutInflater mInflater;//布局填充器
private View.OnClickListener mOnClickListener;//点击监听
private ActionListener mActionListener; //自定义点击接口
//传参_list
public PictureBrowsingAdapter(Context context, List<PictureBean> list) {
mContext=context;
mList = new ArrayList<>();
mList.addAll( list);
mInflater = LayoutInflater.from(context);
//销毁弹窗的点击事件，模仿微信，点击图片返回聊天界面
mOnClickListener = new View.OnClickListener() {
@Override
public void onClick(View v) {
if(!ClickUtil.canClick()){
return;
}
if (mActionListener != null) {
mActionListener.onImageClick();
}
}
};
}
@NonNull
@Override
public Vh onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
return new Vh(mInflater.inflate(R.layout.item_im_chat_img, parent, false));
}
@Override
public void onBindViewHolder(@NonNull Vh vh, int position) {
vh.setData(mList.get(position).getPicture());
}
@Override
public int getItemCount() {
return mList.size();
}
@Override
public void onAttachedToRecyclerView(@NonNull RecyclerView recyclerView) {
PagerSnapHelper pagerSnapHelper = new PagerSnapHelper();
pagerSnapHelper.attachToRecyclerView(recyclerView);
}
class Vh extends RecyclerView.ViewHolder {
//初始化ImageView
ImageView mImg;
public Vh(View itemView) {
super(itemView);
mImg =itemView.findViewById(R.id.MyZoomImageView);
mImg.setOnClickListener(mOnClickListener);
}
//设置图片
void setData(Bitmap bean) {
mImg.setImageBitmap(bean);
}
}
public void setActionListener(ActionListener actionListener) {
mActionListener = actionListener;
}
public interface ActionListener {
void onImageClick();
}
}
条目的布局就一个ImageView
item_im_chat_img
<?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"
android:background="#000"
>
<ImageView
android:id="@+id/MyZoomImageView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:src="@mipmap/ic_3"
/>
</FrameLayout>
使用方法
PictureBrowsing mChatImageDialog = new PictureBrowsing(this, v,list);
mChatImageDialog.show();
