本文實例為大家分享了Android實現圖片選擇器小功能的具體代碼，供大家參考，具體內容如下

需要用到的庫

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

圖片選擇器大概思路：

- 使用Content Provider獲取存儲器中的圖片文件路徑，以及所在文件夾，并存儲到相應List中- 使用RecyclerView制作網格視圖，并用Picasso加載圖片，holder.itemView.setOnClickListener來監聽圖片是否被選中- 使用Spinner制作文件夾選擇器，然后setOnItemSelectedListener來監聽當前選擇的文件夾，并如改變文件夾，則重新獲取該

文件夾的圖片，adapter.notifyDataSetChanged()更換網格視圖中圖片。

- 選擇圖片完畢后，返回圖片路徑數組到前一個onActivityResult中，并顯示。

圖片簡易預覽器大概思路：

- 采用Gallery顯示圖片選擇器中選中圖片的縮略圖- ImageView中顯示當前圖片的大圖，并且使用OnTouchListener,Matrix和Bitmap實現圖片放縮

PicSelectorActivity圖片選擇器代碼

public class PicSelectorActivity extends AppCompatActivity { private RecyclerView rvPic; public List<Map<String, Object>> imgList;//存儲顯示的圖片信息 public static List<Map<String, Object>> imgSelectList;//存儲選擇的圖片信息 private List<Map<String, String>> pathList;//存儲文件夾信息 private Spinner spFolder;//文件夾Spinner private RecyclerView.Adapter<PicViewHolder> adapter; private int MAX_NUM = 9;//選擇圖片數 private int SPAN_COUNT = 4;//GridLayout 列數 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);//設置需選擇的圖片數MAX_NUM = getIntent().getIntExtra('selectPicNum', 9);SELECT_OK=getIntent().getIntExtra('selectOk', 0x1001);initView(); } private void initView() {//初始化變量imgList = new ArrayList<>();imgSelectList = new ArrayList<>();pathList = new ArrayList<>();Map<String, String> map = new HashMap<>();map.put('name', '所有圖片');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>() {@Overridepublic 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;}@Overridepublic 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); }});}@Overridepublic int getItemCount() { return imgList.size();} }; rvPic.setAdapter(adapter); //文件夾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() {@Overridepublic void onItemSelected(AdapterView<?> parent, View view, int position, long id) { searchImage(pathList.get(position).get('path')); adapter.notifyDataSetChanged();}@Overridepublic 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));//圖片地址//圖片所在文件夾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));//圖片地址//圖片所在文件夾File parent = new File(new File(filePath).getParent());//添加圖片信息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(); } //預覽圖片 public void picShow(View view){if(imgSelectList.size()>0) { Intent intent = new Intent(this, PicSelectorShowActivity.class); startActivity(intent);}else { Toast.makeText(this,'請選擇預覽圖片',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簡易圖片預覽器

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 {/** * 記錄是拖拉照片模式還是放大縮小照片模式 */private int mode = 0;// 初始狀態/** * 拖拉照片模式 */private static final int MODE_DRAG = 1;/** * 放大縮小照片模式 */private static final int MODE_ZOOM = 2;/** * 用于記錄開始時候的坐標位置 */private PointF startPoint = new PointF();/** * 用于記錄拖拉圖片移動的坐標位置 */private Matrix matrix = new Matrix();/** * 用于記錄圖片要進行拖拉時候的坐標位置 */private Matrix currentMatrix = new Matrix();/** * 兩個手指的開始距離 */private float startDis;/** * 兩個手指的中間點 */private PointF midPoint;@Overridepublic boolean onTouch(View v, MotionEvent event) { /** 通過與運算保留最后八位 MotionEvent.ACTION_MASK = 255 */ imageView.setScaleType(ImageView.ScaleType.MATRIX); switch (event.getAction() & MotionEvent.ACTION_MASK) {// 手指壓下屏幕case MotionEvent.ACTION_DOWN: mode = MODE_DRAG; // 記錄ImageView當前的移動位置 currentMatrix.set(imageView.getImageMatrix()); startPoint.set(event.getX(), event.getY()); break;// 手指在屏幕上移動，改事件會被不斷觸發case MotionEvent.ACTION_MOVE: // 拖拉圖片 if (mode == MODE_DRAG) {float dx = event.getX() - startPoint.x; // 得到x軸的移動距離float dy = event.getY() - startPoint.y; // 得到x軸的移動距離// 在沒有移動之前的位置上進行移動matrix.set(currentMatrix);matrix.postTranslate(dx, dy); } // 放大縮小圖片 else if (mode == MODE_ZOOM) {float endDis = distance(event);// 結束距離if (endDis > 10f) { // 兩個手指并攏在一起的時候像素大于10 float scale = endDis / startDis;// 得到縮放倍數 matrix.set(currentMatrix); matrix.postScale(scale, scale, midPoint.x, midPoint.y);} } break;// 手指離開屏幕case MotionEvent.ACTION_UP: // 當觸點離開屏幕，但是屏幕上還有觸點(手指)case MotionEvent.ACTION_POINTER_UP: mode = 0; break;// 當屏幕上已經有觸點(手指)，再有一個觸點壓下屏幕case MotionEvent.ACTION_POINTER_DOWN: mode = MODE_ZOOM; /** 計算兩個手指間的距離 */ startDis = distance(event); /** 計算兩個手指間的中間點 */ if (startDis > 10f) { // 兩個手指并攏在一起的時候像素大于10midPoint = mid(event);//記錄當前ImageView的縮放倍數currentMatrix.set(imageView.getImageMatrix()); } break; } imageView.setImageMatrix(matrix); return true;}/** * 計算兩個手指間的距離 */private float distance(MotionEvent event) { float dx = event.getX(1) - event.getX(0); float dy = event.getY(1) - event.getY(0); /** 使用勾股定理返回兩點之間的距離 */ return (float) Math.sqrt(dx * dx + dy * dy);}/** * 計算兩個手指間的中間點 */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

導入后

private final static int SELECT_OK = 0x1001;//ResultCode RequestCodeprivate final static String SELECT_IMAGES = 'select_images';//在Bundle data中的Extra名字private String[] selectImages;//接收選中圖片路徑數組//打開圖片選擇器Intent intent = new Intent(MainActivity.this, com.xld.picselector.PicSelectorActivity.class);startActivityForResult(intent,SELECT_OK);//獲取選中圖片路徑數組@Overrideprotected 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);....}}

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以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持好吧啦網。