Android自定义View实现多图片选择控件

前言

相信很多朋友在开发中都会遇到图片上传的情况，尤其是多图上传，最经典的莫过于微信的图片选择了。所有很多情况下会使用到多图选择，所以就有了这篇文章，今天抽点时间写了个控件。
 •支持自定义选择图片的样式
 •支持设置图片选择数量
 •支持图片预览，删除
 •支持图片拍照

先来看看效果

实现分析

假如不定义控件，我们要实现这样一个功能，无非是写个GridView在item点击的时候去显示图片进行选择，在返回界面的时候进行GridView的数据刷新。我们把这些逻辑写在我们自定义的GridView中，就成了一个新的控件。

1、GridView的效果展示，逻辑实现。

public class ImagePickerView extends GridView{

 //图片选择数量
 int maxImageSize = 9;

 //添加item布局
 private int noImgResource;

 //列选择数量
 private int columnNumber = 3;

 Activity context;
 ImagesAdapter adapter;

 List<String> imageList;//图片选择list

 private static final int TYPE_SHOW_ADD = 0;
 private static final int TYPE_NO_SHOW_ADD = 1;

 private boolean isShowAdd = true;

 int imageGridSize;

 public void setNoImgResource(int noImgResource) {
 this.noImgResource = noImgResource;
 }

 public void setColumnNumber(int columnNumber) {
 if (columnNumber>5){
  columnNumber = 5;
 }
 this.columnNumber = columnNumber;
 this.setNumColumns(columnNumber);
 }

 public void setShowAdd(boolean showAdd) {
 isShowAdd = showAdd;
 }

 public void setImageList(List<String> imageList) {
 this.imageList = imageList;
 adapter.setImageList(imageList);
 }

 public List<String> getImageList() {
 return imageList;
 }

 public ImagePickerView(Context context) {
 this(context,null);
 }

 public ImagePickerView(Context context, AttributeSet attrs) {
 this(context,attrs,0);
 }

 /**
 * 初始化ImagePickerView的一些信息
 * @param context
 * @param attrs
 * @param defStyle
 */
 public ImagePickerView(Context context, AttributeSet attrs, int defStyle) {
 super(context, attrs, defStyle);
 this.context = (Activity) context;
 adapter = new ImagesAdapter();
 this.setAdapter(adapter);
 if (imageList==null){
  imageList = new ArrayList<>();
 }
 this.setNumColumns(columnNumber);
 this.setVerticalSpacing(10);
 this.setHorizontalSpacing(10);
 imageGridSize = (this.context.getWindowManager().getDefaultDisplay().getWidth() - Util.dp2px(context, 2) * 2) / columnNumber;
 }

 /**
 * 提供给外部调用用来再Activity返回时获取图片信息
 * @param requestCode
 * @param resultCode
 * @param data
 */
 public void onActivityResult(int requestCode, int resultCode, Intent data) {

 if (data!=null&& !TextUtils.isEmpty(data.getStringExtra("photoPath"))){//拍照
  imageList.add(data.getStringExtra("photoPath"));
 }else if (data!=null&&data.getSerializableExtra("images")!=null){//图片选择
  imageList = (List<String>) data.getSerializableExtra("images");
 }else{
  List<ImageItem> list = AndroidImagePicker.getInstance().getSelectedImages();
  for (int i=0;i<list.size();i++){
  imageList.add(list.get(i).path);
  }
 }
 AndroidImagePicker.getInstance().setSelectLimit(maxImageSize-imageList.size());
 adapter.setImageList(imageList);
 }

 class ImagesAdapter extends BaseAdapter {

 List<String> imageList;

 public ImagesAdapter() {
  this.imageList = new ArrayList();
 }

 public void setImageList(List<String> imageList) {
  this.imageList = imageList;
  notifyDataSetChanged();
 }

 @Override
 public int getCount() {
  if (isShowAdd){
  if (imageList == null || imageList.isEmpty()) {
   return 1;
  }
  if (imageList.size() >= maxImageSize) {
   return maxImageSize;
  }
  return imageList.size() + 1;
  }
  if (imageList.size() >= maxImageSize) {
  return maxImageSize;
  }
  return imageList.size()+1;
 }

 @Override
 public String getItem(int position) {
  if (isShowAdd){
  if (position==imageList.size()){
   return null;
  }
  return imageList.get(position-1);
  }
  return imageList.get(position);
 }

 @Override
 public long getItemId(int position) {
  return 0;
 }

 @Override
 public int getViewTypeCount() {
  return 2;
 }

 @Override
 public int getItemViewType(int position) {
  if (isShowAdd){
  return position==imageList.size()?TYPE_SHOW_ADD:TYPE_NO_SHOW_ADD;
  }else{
  return TYPE_NO_SHOW_ADD;
  }
 }

 @Override
 public View getView(final int position, View convertView, ViewGroup parent) {
  int itemViewType = getItemViewType(position);
  if(itemViewType == TYPE_SHOW_ADD){//当前item为添加图片item
  if (noImgResource!=0){//加载用户的添加item布局
   convertView = LayoutInflater.from(context).inflate(noImgResource, parent, false);
  }else {//默认的添加item布局
   convertView = LayoutInflater.from(context).inflate(R.layout.grid_item_camera, parent, false);
  }
  convertView.setTag(null);
  convertView.setOnClickListener(new View.OnClickListener() {
   @Override
   public void onClick(View v) {//点击选择图片
   Intent intent = new Intent(context, ImagesGridActivity.class);//图片选择
   Activity activity = context;
   activity.startActivityForResult(intent,1001);
   }
  });
  }else{//普通item，加载图片，并对item设置点击进行预览
  final ViewHolder holder;
  if(convertView == null){
   convertView = LayoutInflater.from(context).inflate(R.layout.image_grid_item, null);
   holder = new ViewHolder();
   holder.ivPic = (SimpleDraweeView)convertView.findViewById(R.id.iv_thumb);
   holder.cbPanel = convertView.findViewById(R.id.thumb_check_panel);
   convertView.setTag(holder);
  }else{
   holder = (ViewHolder) convertView.getTag();
  }
  convertView.setOnClickListener(new OnClickListener() {
   @Override
   public void onClick(View v) {//将选择的图片与当前postion传过去。
   Intent intent = new Intent(context, PreviewDelActivity.class);
   intent.putExtra("images", (Serializable) imageList);
   intent.putExtra("position",position);
   context.startActivityForResult(intent,1002);
   }
  });
  ImageRequestBuilder requestBuilder = ImageRequestBuilder.newBuilderWithSource(
   Uri.parse(String.format("file://%s", imageList.get(position))))
   .setResizeOptions(new ResizeOptions(imageGridSize, imageGridSize))
   .setAutoRotateEnabled(true);
  PipelineDraweeController controller = (PipelineDraweeController) Fresco.newDraweeControllerBuilder()
   .setOldController(holder.ivPic.getController())
   .setImageRequest(requestBuilder.build())
   .build();
  holder.ivPic.setController(controller);
  }
  return convertView;
 }
 }

 class ViewHolder{
 SimpleDraweeView ivPic;
 View cbPanel;
 }
}

代码比较简单，都加了注释。在view的初始化方法中获取一些信息和GridView的展示信息，并且设置适配器关联。

在GridView的 item中设置了点击事件，并且提供给外部用来刷新数据的onActivityResult方法。

大家看上面的代码应该就明白了。

2、图片预览和删除

这一步很简单，获取到传过来的imageList和postion对图片进行展示，在点击删除的时候remove掉imageList对应的数据，并且刷新viewPager

直接上代码

public class PreviewDelActivity extends AppCompatActivity implements View.OnClickListener {

 private static final String TAG = ImagePreviewActivity.class.getSimpleName();

 TextView mTitleCount;
 TextView mBtnOk;
 private ImageView backBtn;

 List<String> mImageList;

 int mShowItemPosition = 0;

 ViewPager mViewPager;

 TouchImageAdapter mAdapter ;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_preview_del);

 mImageList = (List<String>) getIntent().getSerializableExtra("images");
 mShowItemPosition = getIntent().getIntExtra("position",0);

 mBtnOk = (TextView) findViewById(R.id.btn_del);
 backBtn = (ImageView) findViewById(R.id.btn_backpress);
 mBtnOk.setOnClickListener(this);
 backBtn.setOnClickListener(this);

 mTitleCount = (TextView) findViewById(R.id.tv_title_count);
 mTitleCount.setText(mShowItemPosition+1+"/" + mImageList.size());// 图片数量和当前图片信息展示

 initView();

 AndroidImagePicker.getInstance().clearSelectedImages();
 }

 private void initView() {
 mViewPager = (ViewPager)findViewById(R.id.viewpager);
 mAdapter = new TouchImageAdapter(getSupportFragmentManager());
 mViewPager.setAdapter(mAdapter);
 mViewPager.setCurrentItem(mShowItemPosition, false);//设置显示当前的图片
 mViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
  @Override
  public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

  }

  @Override
  public void onPageSelected(int position) {
  mTitleCount.setText(position+1+"/" + mImageList.size());//滑动viewPager时更新显示信息
  }

  @Override
  public void onPageScrollStateChanged(int state) {

  }
 });
 }

 @Override
 public void onClick(View v) {
 int i = v.getId();
 if (i == R.id.btn_del) {//删除按钮点击
  mAdapter.remove(mViewPager.getCurrentItem());//
  mTitleCount.setText(mViewPager.getCurrentItem()+1+"/" + mImageList.size());
  if (mImageList.size()==0){
  Intent intent = new Intent();
  intent.putExtra("images", (Serializable) mImageList);
  setResult(RESULT_OK,intent);
  finish();
  }
 }else if (i==R.id.btn_backpress){//返回
  Intent intent = new Intent();
  intent.putExtra("images", (Serializable) mImageList);
  setResult(RESULT_OK,intent);
  finish();
 }
 }

 @Override
 public boolean onKeyDown(int keyCode, KeyEvent event) {
 if (keyCode==KeyEvent.KEYCODE_BACK){
  Intent intent = new Intent();
  intent.putExtra("images", (Serializable) mImageList);
  setResult(RESULT_OK,intent);
  finish();
  return true;
 }
 return super.onKeyDown(keyCode, event);
 }

 class TouchImageAdapter extends FragmentStatePagerAdapter {
 public TouchImageAdapter(FragmentManager fm) {
  super(fm);
 }

 @Override
 public int getCount() {
  return mImageList.size();
 }

 public void remove(int position){
  mImageList.remove(position);
  notifyDataSetChanged();
 }

 @Override
 public int getItemPosition(Object object) {
  return POSITION_NONE;
 }

 @Override
 public Fragment getItem(int position) {
  SinglePreviewFragment fragment = new SinglePreviewFragment();
  Bundle bundle = new Bundle();
  bundle.putSerializable(SinglePreviewFragment.KEY_URL, mImageList.get(position));
  fragment.setArguments(bundle);
  return fragment;
 }

 }

 @SuppressLint("ValidFragment")
 private class SinglePreviewFragment extends Fragment {
 public static final String KEY_URL = "key_url";
 private PhotoDraweeView photoDraweeView;
 private String url;

 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  Bundle bundle = getArguments();

  url = (String) bundle.getSerializable(KEY_URL);
  Log.i(TAG, "=====current show image path:" + url);

  photoDraweeView = new PhotoDraweeView(getActivity());
  photoDraweeView.setBackgroundColor(0xff000000);
  ViewGroup.LayoutParams params = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,ViewGroup.LayoutParams.MATCH_PARENT);
  photoDraweeView.setLayoutParams(params);

  photoDraweeView.setOnPhotoTapListener(new OnPhotoTapListener() {
  @Override
  public void onPhotoTap(View view, float x, float y) {
   getActivity().finish();
  }
  });
  if (!url.startsWith("http://") && !url.startsWith("https://")) {
  url = "file://"+url;
  }

  ImageRequestBuilder requestBuilder = ImageRequestBuilder.newBuilderWithSource(
   Uri.parse(url))
   .setResizeOptions(new ResizeOptions(768,1280))
   .setAutoRotateEnabled(true);

  PipelineDraweeControllerBuilder controller = Fresco.newDraweeControllerBuilder();
  controller.setOldController(photoDraweeView.getController());
  controller.setImageRequest(requestBuilder.build());
  controller.setControllerListener(new BaseControllerListener<ImageInfo>() {
  @Override
  public void onFinalImageSet(String id, ImageInfo imageInfo, Animatable animatable) {
   super.onFinalImageSet(id, imageInfo, animatable);
   if (imageInfo == null) {
   return;
   }
   photoDraweeView.update(imageInfo.getWidth(), imageInfo.getHeight());
  }
  });
  photoDraweeView.setController(controller.build());
 }

 @Override
 public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
  return photoDraweeView;
 }

 }

}

相信大家都能看懂上面代码，用ViewPager对图片进行加载，在点击回退和删除完图片的时候把ImageList传回去。
这样在onActivityResult中获取到imageList，刷新adapter，gridview就重新渲染了。

使用

1、布局中引入ImagePickerView

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:paddingBottom="@dimen/activity_vertical_margin"
 android:paddingLeft="@dimen/activity_horizontal_margin"
 android:paddingRight="@dimen/activity_horizontal_margin"
 android:paddingTop="@dimen/activity_vertical_margin"
 android:orientation="vertical"
 tools:context="com.qiangyu.test.imagepickerviewdemo.MainActivity">
 <com.redare.imagepicker.widget.ImagePickerView
 android:id="@+id/imagePicker"
 android:layout_width="match_parent"
 android:layout_height="wrap_content">
 </com.redare.imagepicker.widget.ImagePickerView>

 <Button
 android:id="@+id/commit_btn"
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:text="提交"/>
</LinearLayout>

2、在Activity中获得ImagePickerView,并且在onActivityResult方法中调用ImagePickerView数据刷新方法
imagePicker.onActivityResult(requestCode,resultCode,data);

3、获取选择图片的路径
调用imagePicker.getImageList()即返回图片选择的List

下面是一段代码示例

public class MainActivity extends AppCompatActivity {

 private ImagePickerView imagePicker;

 private Button commitBtn;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 Fresco.initialize(this);

 imagePicker = (ImagePickerView) findViewById(R.id.imagePicker);
 commitBtn = (Button) findViewById(R.id.commit_btn);
 commitBtn.setOnClickListener(new View.OnClickListener() {
  @Override
  public void onClick(View v) {
  for (int i=0;i<imagePicker.getImageList().size();i++){
   Log.d("yqy",imagePicker.getImageList().get(i));
  }
  }
 });
 imagePicker.setNoImgResource(R.layout.add_img);//自定义imagePicker add item样式
 imagePicker.setColumnNumber(5);//设置显示5列

 }

 @Override
 protected void onActivityResult(int requestCode, int resultCode, Intent data) {
 imagePicker.onActivityResult(requestCode,resultCode,data);
 }
}

结语

看了ImagePickerView的实现，是不是发现一个自定义控件其实也很简单。在我们做自定义控件的时候，其实大部分情况只是在Android系统提供的功能上多加一点我们的需求而已。站在巨人的肩膀上，才可以看的更远嘛。

关于图片加载和图片选择本文没有提及，图片加载我参考了文章，感兴趣的朋友可以去github查看，https://github.com/easonline/AndroidImagePicker。我在自己的Demo中对源码做了修改，并统一使用了Fresco加载图片。

有需要参考源码的同学请参考：源码下载

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持我们。