Android PicSelector图片选择器小功能

本文实例为大家分享了Android实现图片选择器小功能的具体代码，供大家参考，具体内容如下

效果预览

实现

需要用到的库

compile 'com.squareup.picasso:picasso:2.3.2'
compile 'com.android.support:appcompat-v7:26.1.0'

图片选择器大概思路：

- 使用Content Provider获取存储器中的图片文件路径，以及所在文件夹，并存储到相应List中
- 使用RecyclerView制作网格视图，并用Picasso加载图片，holder.itemView.setOnClickListener来监听图片是否被选中
- 使用Spinner制作文件夹选择器，然后setOnItemSelectedListener来监听当前选择的文件夹，并如改变文件夹，则重新获取该

文件夹的图片，adapter.notifyDataSetChanged()更换网格视图中图片。

- 选择图片完毕后，返回图片路径数组到前一个onActivityResult中，并显示。

图片简易预览器大概思路：

- 采用Gallery显示图片选择器中选中图片的缩略图
- ImageView中显示当前图片的大图，并且使用OnTouchListener,Matrix和Bitmap实现图片放缩

PicSelectorActivity图片选择器代码

public class PicSelectorActivity extends AppCompatActivity {
    private RecyclerView rvPic;
    public List<Map<String, Object>> imgList;//存储显示的图片信息
    public static List<Map<String, Object>> imgSelectList;//存储选择的图片信息
    private List<Map<String, String>> pathList;//存储文件夹信息
    private Spinner spFolder;//文件夹Spinner
    private RecyclerView.Adapter<PicViewHolder> adapter;
    private int MAX_NUM = 9;//选择图片数
    private int SPAN_COUNT = 4;//GridLayout 列数
    private  int SELECT_OK = 0x1001;//resultCode
    private final static String SELECT_IMAGES = "select_images";
    private final static String ALL_IMAGES = Environment.getExternalStorageDirectory().getAbsolutePath();

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_picselector);
        //设置需选择的图片数
        MAX_NUM = getIntent().getIntExtra("selectPicNum", 9);
        SELECT_OK=getIntent().getIntExtra("selectOk", 0x1001);
        initView();
    }

    private void initView() {

        //初始化变量
        imgList = new ArrayList<>();
        imgSelectList = new ArrayList<>();
        pathList = new ArrayList<>();
        Map<String, String> map = new HashMap<>();
        map.put("name",  "所有图片");
        map.put("path", ALL_IMAGES);
        pathList.add(map);

        rvPic = findViewById(R.id.rv_picselector);
        GridLayoutManager manager = new GridLayoutManager(this, SPAN_COUNT);
        rvPic.setLayoutManager(manager);
       searchImage();
        if (imgList.size() > 0) {
            adapter = new RecyclerView.Adapter<PicViewHolder>() {
                @Override
                public PicViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
                    View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.rvitem_picselector, parent, false);
                    PicViewHolder holder = new PicViewHolder(view);
                    return holder;
                }

                @Override
                public void onBindViewHolder(final PicViewHolder holder, final int position) {
                        final String path = String.valueOf(imgList.get(position).get("path"));
                        Picasso.with(PicSelectorActivity.this)
                                .load("file://" + path)
                                .placeholder(R.drawable.ic_picselector_image_default)
                                .into(holder.imgPic);
                        holder.cbPic.setChecked(false);
                        holder.itemView.setOnClickListener(new View.OnClickListener() {
                            @Override
                            public void onClick(View v) {
                                if (!holder.cbPic.isChecked()) {
                                    if (imgSelectList.size() <= 8 && imgSelectList.size() >= 0) {
                                        holder.cbPic.setChecked(true);
                                        Map<String, Object> info = imgList.get(position);
                                        imgSelectList.add(info);
                                    }
                                } else {
                                    if (imgSelectList.size() <= 9 && imgSelectList.size() >= 1) {
                                        holder.cbPic.setChecked(false);
                                        Map<String, Object> info = imgList.get(position);
                                        imgSelectList.remove(info);
                                    }
                                }
                                setTitle(imgSelectList.size() + "/" + MAX_NUM);
                            }
                        });
                }

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

            rvPic.setAdapter(adapter);
            //文件夹spinner
            spFolder = findViewById(R.id.sp_picselector_folder);
            SimpleAdapter folderAdapter = new SimpleAdapter(this, pathList, R.layout.spitem_picselector_folder, new String[]{"name"}, new int[]{R.id.tv_picselector_folder_spitem});
            spFolder.setMinimumWidth(WindowManager.LayoutParams.MATCH_PARENT);
            spFolder.setAdapter(folderAdapter);
            spFolder.setSelection(0);
            spFolder.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
                @Override
                public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                    searchImage(pathList.get(position).get("path"));

                    adapter.notifyDataSetChanged();
                }

                @Override
                public void onNothingSelected(AdapterView<?> parent) {

                }
            });
        }
    }

    private void searchImage(){
        Cursor cursor = getContentResolver().query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, null, null, null, null);
        imgList.clear();
        imgSelectList.clear();
        setTitle("0/" + MAX_NUM);
        if (cursor != null) {
            while (cursor.moveToNext()) {
                String filePath = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DATA));//图片地址
                //图片所在文件夹
                File parent = new File(new File(filePath).getParent());
                Map<String, String> info = new HashMap<>();
                info.put("name", parent.getName());
                info.put("path", parent.getAbsolutePath());
                if (!pathList.contains(info)) {
                    pathList.add(info);
                }

                    Map<String, Object> picInfo = new HashMap<>();
                    picInfo.put("parent",parent.getAbsolutePath());
                    picInfo.put("path", filePath);
                    imgList.add(picInfo);

            }//while (cursor.moveToNext())
        }// if (cursor != null)
        cursor.close();
    }
    private void searchImage(String path) {
        Cursor cursor = getContentResolver().query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, null, null, null, null);
        imgList.clear();
        imgSelectList.clear();
        setTitle("0/" + MAX_NUM);
        if (cursor != null) {
            while (cursor.moveToNext()) {
                String filePath = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DATA));//图片地址
                //图片所在文件夹
                File parent = new File(new File(filePath).getParent());
                //添加图片信息
                if(parent.getAbsolutePath().contains(path)){
                    Map<String, Object> picInfo = new HashMap<>();
                    picInfo.put("parent",parent.getAbsolutePath());
                    picInfo.put("path", filePath);
                    imgList.add(picInfo);
                }
            }//while (cursor.moveToNext())
        }// if (cursor != null)
        cursor.close();

    }
    //预览图片
    public void picShow(View view){
        if(imgSelectList.size()>0) {
            Intent intent = new Intent(this, PicSelectorShowActivity.class);
            startActivity(intent);
        }else {
            Toast.makeText(this,"请选择预览图片",Toast.LENGTH_SHORT).show();
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.menu_picselector, menu);
        return super.onCreateOptionsMenu(menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int i1 = item.getItemId();
        if (i1 == android.R.id.home) {
            this.finish();

        } else if (i1 == R.id.action_picselector_ok) {
            Intent data = new Intent();
            String[] selectImages = new String[imgSelectList.size()];
            for (int i = 0; i < imgSelectList.size(); i++) {
                selectImages[i] = String.valueOf(imgSelectList.get(i).get("path"));
            }
            data.putExtra(SELECT_IMAGES, selectImages);
            setResult(SELECT_OK, data);
            this.finish();

        }
        return super.onOptionsItemSelected(item);
    }
    //RecyclerView.ViewHolder
    static class PicViewHolder extends RecyclerView.ViewHolder {
        ImageView imgPic;
        CheckBox cbPic;

        public PicViewHolder(View itemView) {
            super(itemView);
            imgPic = itemView.findViewById(R.id.img_picselector_rvitem);
            cbPic = itemView.findViewById(R.id.cb_picselector_rvitem);
        }
    }
}

PicSelectorShowActivity简易图片预览器

public class PicSelectorShowActivity extends AppCompatActivity {
    private Gallery gv;
    private ImageView imageView;
    private String path;
    private List<Map<String, Object>> imgSelectList;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_picselector_show);
        getSupportActionBar().setHomeButtonEnabled(true);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);

        imgSelectList = PicSelectorActivity.imgSelectList;
        path = String.valueOf(imgSelectList.get(0).get("path"));
        setTitle(1 + "/" + imgSelectList.size());
imageView = findViewById(R.id.pv_picselector);

        imageView.setImageBitmap(BitmapFactory.decodeFile(path));
        imageView.setScaleType(ImageView.ScaleType.FIT_CENTER);
        imageView.setOnTouchListener(new TouchListener());

 gv = findViewById(R.id.gv_picselector);
        gv.setAdapter(new BaseAdapter() {
            @Override
            public int getCount() {
                return imgSelectList.size();
            }

            @Override
            public Object getItem(int position) {
                return position;
            }

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

            @Override
            public View getView(int position, View convertView, ViewGroup parent) {

                PicViewHolder holder;
                if (convertView == null) {
                    convertView = LayoutInflater.from(PicSelectorShowActivity.this).inflate(R.layout.gitem_picselector, parent, false);
                    holder = new PicViewHolder(convertView);
                    convertView.setTag(holder);
                } else {
                    holder = (PicViewHolder) convertView.getTag();
                }
                holder.imgPic.setImageBitmap(BitmapFactory.decodeFile(String.valueOf(imgSelectList.get(position).get("path"))));
                return convertView;
            }
        });
        gv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                imageView.setImageBitmap(BitmapFactory.decodeFile(String.valueOf(imgSelectList.get(position).get("path"))));
                imageView.setScaleType(ImageView.ScaleType.FIT_CENTER);
                setTitle((position+1) + "/" + imgSelectList.size());
            }
        });

    }

    class PicViewHolder {
        ImageView imgPic;

        public PicViewHolder(View itemView) {
            imgPic = itemView.findViewById(R.id.img_picselector_gitem);
        }
    }

    private final class TouchListener implements View.OnTouchListener {

        /**
         * 记录是拖拉照片模式还是放大缩小照片模式
         */
        private int mode = 0;// 初始状态
        /**
         * 拖拉照片模式
         */
        private static final int MODE_DRAG = 1;
        /**
         * 放大缩小照片模式
         */
        private static final int MODE_ZOOM = 2;

        /**
         * 用于记录开始时候的坐标位置
         */
        private PointF startPoint = new PointF();
        /**
         * 用于记录拖拉图片移动的坐标位置
         */
        private Matrix matrix = new Matrix();
        /**
         * 用于记录图片要进行拖拉时候的坐标位置
         */
        private Matrix currentMatrix = new Matrix();

        /**
         * 两个手指的开始距离
         */
        private float startDis;
        /**
         * 两个手指的中间点
         */
        private PointF midPoint;

        @Override
        public boolean onTouch(View v, MotionEvent event) {
            /** 通过与运算保留最后八位 MotionEvent.ACTION_MASK = 255 */
            imageView.setScaleType(ImageView.ScaleType.MATRIX);
            switch (event.getAction() & MotionEvent.ACTION_MASK) {
                // 手指压下屏幕
                case MotionEvent.ACTION_DOWN:
                    mode = MODE_DRAG;
                    // 记录ImageView当前的移动位置
                    currentMatrix.set(imageView.getImageMatrix());
                    startPoint.set(event.getX(), event.getY());
                    break;
                // 手指在屏幕上移动，改事件会被不断触发
                case MotionEvent.ACTION_MOVE:
                    // 拖拉图片
                    if (mode == MODE_DRAG) {
                        float dx = event.getX() - startPoint.x; // 得到x轴的移动距离
                        float dy = event.getY() - startPoint.y; // 得到x轴的移动距离
                        // 在没有移动之前的位置上进行移动
                        matrix.set(currentMatrix);
                        matrix.postTranslate(dx, dy);
                    }
                    // 放大缩小图片
                    else if (mode == MODE_ZOOM) {
                        float endDis = distance(event);// 结束距离
                        if (endDis > 10f) { // 两个手指并拢在一起的时候像素大于10
                            float scale = endDis / startDis;// 得到缩放倍数
                            matrix.set(currentMatrix);
                            matrix.postScale(scale, scale, midPoint.x, midPoint.y);
                        }
                    }
                    break;
                // 手指离开屏幕
                case MotionEvent.ACTION_UP:
                    // 当触点离开屏幕，但是屏幕上还有触点(手指)
                case MotionEvent.ACTION_POINTER_UP:
                    mode = 0;
                    break;
                // 当屏幕上已经有触点(手指)，再有一个触点压下屏幕
                case MotionEvent.ACTION_POINTER_DOWN:
                    mode = MODE_ZOOM;
                    /** 计算两个手指间的距离 */
                    startDis = distance(event);
                    /** 计算两个手指间的中间点 */
                    if (startDis > 10f) { // 两个手指并拢在一起的时候像素大于10
                        midPoint = mid(event);
                        //记录当前ImageView的缩放倍数
                        currentMatrix.set(imageView.getImageMatrix());
                    }
                    break;
            }

            imageView.setImageMatrix(matrix);
            return true;
        }

        /**
         * 计算两个手指间的距离
         */
        private float distance(MotionEvent event) {
            float dx = event.getX(1) - event.getX(0);
            float dy = event.getY(1) - event.getY(0);
            /** 使用勾股定理返回两点之间的距离 */
            return (float) Math.sqrt(dx * dx + dy * dy);
        }

        /**
         * 计算两个手指间的中间点
         */
        private PointF mid(MotionEvent event) {
            float midX = (event.getX(1) + event.getX(0)) / 2;
            float midY = (event.getY(1) + event.getY(0)) / 2;
            return new PointF(midX, midY);
        }

    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if (item.getItemId() == android.R.id.home) {
            this.finish();
        }
        return super.onOptionsItemSelected(item);
    }
}

Module使用

导入后

private final static int SELECT_OK = 0x1001;//ResultCode RequestCode
private final static String SELECT_IMAGES = "select_images";//在Bundle data中的Extra名字
private String[] selectImages;//接收选中图片路径数组

//打开图片选择器
Intent intent = new Intent(MainActivity.this, com.xld.picselector.PicSelectorActivity.class);
startActivityForResult(intent,SELECT_OK);

//获取选中图片路径数组
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == SELECT_OK && resultCode == SELECT_OK) {
selectImages = data.getStringArrayExtra(SELECT_IMAGES);
....
}
}

githut地址

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。