Android PhotoPicker 自定义图片选择器

我们来先看效果图

Paste_Image.png 20170814133628.gif

概述

关于手机图片加载器，在当今像素随随便便破千万的时代，一张图片占据的内存都相当可观，作为高大尚程序猿的我们，有必要掌握图片的压缩，缓存等处理，以到达纵使你有万张照片，纵使你的像素再高，我们也能正确的显示所有的图片。

简单描述一下

1.显示手机上所有的图片
2.选中时候图片变暗。
3.可多选

实现

  <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
  compile 'com.android.support:recyclerview-v7:26.0.0-alpha1'
  compile 'com.github.bumptech.glide:glide:3.6.1'

这里我们没有写6.0获取权限 自行代码获取

1.既然我们需要显示手机上的所有图片，那么我们首先就需要拿到手机上的所有图片地址,当然这个过程在子线程理的，当 获取完成后通过handler发送完成消息

private void getImages() {

    new Thread(new Runnable() {
        @Override
        public void run() {
            fileNames = new ArrayList();
            Cursor cursor = getContentResolver().query(
                    MediaStore.Images.Media.EXTERNAL_CONTENT_URI, null, null, null, null);
            if (cursor == null) {
                Log.i(TAG, "run: 空");
                return;
            }
            while (cursor.moveToNext()) {
                //获取图片的地址
                byte[] data = cursor.getBlob(cursor.getColumnIndex(MediaStore.Images.Media.DATA));
                fileNames.add(new String(data, 0, data.length - 1));
                Log.i(TAG, "run: " + new String(data, 0, data.length - 1));
            }
            mHandler.sendMessage(mHandler.obtainMessage());
            cursor.close();
        }
    }).start();
}



Handler mHandler = new Handler() {
    @Override
    public void handleMessage(Message msg) {
        Log.i(TAG, "handleMessage: 完成");
        mRv.setAdapter(mPhotoPickerAdapter = new PhotoPickerAdapter(fileNames));
    }
};

---

2.这个时候我们已经有了所有图片的地址接下来我们需要显示图片了，我们看到效果，每行有3个，并且条目之间是有间距的，我这里使用的是RecyclerView，

@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_photo);
    mRv = findViewById(R.id.rv);
    mRv.setLayoutManager(new GridLayoutManager(this, 3));
    mRv.addItemDecoration(new SpaceItemDecoration(5));
    getImages();
}





public class SpaceItemDecoration extends RecyclerView.ItemDecoration {
    private  int  space;
    public SpaceItemDecoration(int space) {
        this.space = space;
    }
  /**这里定义的间距*/
    @Override
 public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
        outRect.left = space;
        outRect.right = space;
        outRect.bottom = space;
        outRect.top = space;
    }
}

---

3.这个时候我们RecyclerView 基本配置配置完成。接下来我们看下adapter,从下列代码我们可以看到，我这里直接采用的是谷歌推荐的图片加载Glide加载图片的，图片选中的时候调用setAlpha 设置透明度。
这里提供了一个getImages 方法。 取到所有的已经选中图片的地址；

public class PhotoPickerAdapter extends RecyclerView.Adapter<PhotoPickerAdapter.MyViewHolder> {
    private ArrayList<String> images;
    private ArrayList<Boolean> cb;
    private Context mContext;
    public PhotoPickerAdapter(ArrayList<String> images){
        this.images=images;
        cb=new ArrayList<>();
        for (int i = 0; i < images.size(); i++) {
            cb.add(false);
        }
    }

    public ArrayList<String> getImages(){
        ArrayList<String> strings =new ArrayList<>();
        for (int i = 0; i < cb.size(); i++) {
            if(cb.get(i)){
                strings.add(images.get(i));
            }
        }
        return strings;
    }
    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        mContext=parent.getContext();
        MyViewHolder holder = new MyViewHolder(LayoutInflater.from(
                mContext).inflate(R.layout.photo_item, parent,
                false));
        return holder;
    }

    @Override
    public void onBindViewHolder(final MyViewHolder holder, final int position) {
        Glide.with(mContext)
                .load(images.get(position))
                .crossFade()
                .into(holder.iv);

        holder.cb.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton compoundButton, boolean b) {
                cb.set(position,b);
                holder.iv.setAlpha(cb.get(position)==true?0.5f:1f);
            }
        });
        holder.cb.setChecked(cb.get(position));
        holder.iv.setAlpha(cb.get(position)==true?0.5f:1f);

    }

    @Override
    public int getItemCount() {
        return images.size();
    }

    public class MyViewHolder extends RecyclerView.ViewHolder{
        public ImageView iv;
        public CheckBox cb;
        public MyViewHolder(View itemView) {
            super(itemView);
            iv=itemView.findViewById(R.id.iv);
            cb=itemView.findViewById(R.id.cb);
        }

    }

}

完整代码

PhotoPickerActivity

public class PhotoPickerActivity extends Activity implements View.OnClickListener {
    private static final String TAG = "PhotoPickerActivity";
    private ArrayList<String> fileNames;
    private PhotoPickerAdapter mPhotoPickerAdapter;
    Handler mHandler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            Log.i(TAG, "handleMessage: 完成");
            mRv.setAdapter(mPhotoPickerAdapter = new PhotoPickerAdapter(fileNames));
        }
    };
    private RecyclerView mRv;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_photo);
        mRv = findViewById(R.id.rv);
        mRv.setLayoutManager(new GridLayoutManager(this, 3));
        mRv.addItemDecoration(new SpaceItemDecoration(5));
        getImages();
    }


    private void getImages() {

        new Thread(new Runnable() {
            @Override
            public void run() {
                fileNames = new ArrayList();
                Cursor cursor = getContentResolver().query(
                        MediaStore.Images.Media.EXTERNAL_CONTENT_URI, null, null, null, null);
                if (cursor == null) {
                    Log.i(TAG, "run: 空");
                    return;
                }
                while (cursor.moveToNext()) {
                    //获取图片的地址
                    byte[] data = cursor.getBlob(cursor.getColumnIndex(MediaStore.Images.Media.DATA));
                    fileNames.add(new String(data, 0, data.length - 1));
                    Log.i(TAG, "run: " + new String(data, 0, data.length - 1));
                }
                mHandler.sendMessage(mHandler.obtainMessage());
                cursor.close();
            }
        }).start();
    }
    @Override
    public void onClick(View view) {
        switch (view.getId()) {
            case R.id.confirm:
                StringBuffer stringBuffer = new StringBuffer();
                stringBuffer.append("选中的图片"+"\r\n");
                ArrayList<String> arrayList = mPhotoPickerAdapter.getImages();
                for (int i = 0; i < arrayList.size(); i++) {
                    String  s=arrayList.get(i);
                    String[]  strs=  s.split("/");
                    stringBuffer.append(strs[strs.length-1]+"\r\n");
                }
                Toast.makeText(PhotoPickerActivity.this,stringBuffer.toString(),Toast.LENGTH_SHORT).show();
                break;
        }
    }
}

activity_photo

<?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">


    <android.support.v7.widget.RecyclerView
        android:layout_weight="1"
        android:background="#272727"
        android:id="@+id/rv"
        android:layout_width="match_parent"
        android:layout_height="match_parent">
    </android.support.v7.widget.RecyclerView>

    <RelativeLayout
        android:background="@android:color/white"
        android:layout_width="match_parent"
        android:layout_height="40dp">
        <TextView
            android:onClick="onClick"
            android:id="@+id/confirm"
            android:background="#0094ff"
            android:layout_alignParentRight="true"
            android:layout_margin="5dp"
            android:text="确定"
            android:textColor="#844200"
            android:gravity="center"
            android:textSize="14sp"
            android:layout_width="60dp"
            android:layout_height="match_parent"/>
    </RelativeLayout>
</LinearLayout>

SpaceItemDecoration

public class SpaceItemDecoration extends RecyclerView.ItemDecoration {
    private  int  space;
    public SpaceItemDecoration(int space) {
        this.space = space;
    }

    @Override
    public void getItemOffsets(Rect outRect, View view,
                               RecyclerView parent, RecyclerView.State state) {
        outRect.left = space;
        outRect.right = space;
        outRect.bottom = space;

        // Add top margin only for the first item to avoid double space between items
       // if(parent.getChildPosition(view) != 0)
            outRect.top = space;
    }
}

PhotoPickerAdapter

public class PhotoPickerAdapter extends RecyclerView.Adapter<PhotoPickerAdapter.MyViewHolder> {
    private ArrayList<String> images;
    private ArrayList<Boolean> cb;
    private Context mContext;
    public PhotoPickerAdapter(ArrayList<String> images){
        this.images=images;
        cb=new ArrayList<>();
        for (int i = 0; i < images.size(); i++) {
            cb.add(false);
        }
    }

    public ArrayList<String> getImages(){
        ArrayList<String> strings =new ArrayList<>();
        for (int i = 0; i < cb.size(); i++) {
            if(cb.get(i)){
                strings.add(images.get(i));
            }
        }
        return strings;
    }
    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        mContext=parent.getContext();
        MyViewHolder holder = new MyViewHolder(LayoutInflater.from(
                mContext).inflate(R.layout.photo_item, parent,
                false));
        return holder;
    }

    @Override
    public void onBindViewHolder(final MyViewHolder holder, final int position) {
        Glide.with(mContext)
                .load(images.get(position))
                .crossFade()
                .into(holder.iv);

        holder.cb.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton compoundButton, boolean b) {
                cb.set(position,b);
                holder.iv.setAlpha(cb.get(position)==true?0.5f:1f);
            }
        });
        holder.cb.setChecked(cb.get(position));
        holder.iv.setAlpha(cb.get(position)==true?0.5f:1f);

    }

    @Override
    public int getItemCount() {
        return images.size();
    }

    public class MyViewHolder extends RecyclerView.ViewHolder{
        public ImageView iv;
        public CheckBox cb;
        public MyViewHolder(View itemView) {
            super(itemView);
            iv=itemView.findViewById(R.id.iv);
            cb=itemView.findViewById(R.id.cb);
        }

    }

}

photo_item

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="vertical"
              android:descendantFocusability="blocksDescendants"
              android:layout_width="match_parent"
              android:layout_height="120dp">
    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <ImageView
            android:scaleType="centerCrop"
            android:id="@+id/iv"
            android:layout_width="match_parent"
            android:layout_height="120dp"/>
        <CheckBox
            android:layout_marginTop="5dp"
            android:layout_marginRight="5dp"
            android:layout_alignParentRight="true"
            android:id="@+id/cb"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"/>
    </RelativeLayout>

</LinearLayout>