/** * 1、實現原理:用戶打開相冊或相機選擇相片后,相片經過壓縮并設置在控件上,圖片在本地sd卡存一份(如果有的話,沒有則內部存儲,所以還 * 需要判斷用戶是否掛載了sd卡),然后在服務器上存儲一份該圖片,當下次再次啟動應用時,會默認去sd卡加載該圖片,如果本地沒有,再會去聯網請求 * 2、使用了picasso框架以及自定義BitmapUtils工具類 * 3、記得加上相關權限 * <uses-permission android:name="android.permission.INTERNET"></uses-permission> <uses-permission android:name="android.permission.CAMERA"/> <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission> * */public class MainActivity extends AppCompatActivity implements View.OnClickListener {  private ImageView iv;//要設置的頭像  private Button btn_photo;//調用相冊按鈕  private Button btn_camera;//調用相機按鈕  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    iv=(ImageView) findViewById(R.id.iv);    btn_photo = (Button) findViewById(R.id.btn_photo);    btn_camera = (Button) findViewById(R.id.btn_camera);    btn_photo.setOnClickListener(this);    btn_camera.setOnClickListener(this);  }  @Override  public void onClick(View v) {    switch (v.getId()) {      case R.id.btn_photo://打開系統相冊        Intent intent=new Intent(Intent.ACTION_PICK, MediaStore.Images.Media.EXTERNAL_CONTENT_URI);        startActivityForResult(intent,100);        break;      case R.id.btn_camera://打開系統相機        Intent intent2=new Intent(MediaStore.ACTION_IMAGE_CAPTURE);        startActivityForResult(intent2,200);        break;    }  }  @RequiresApi(api = Build.VERSION_CODES.KITKAT)  @Override  protected void onActivityResult(int requestCode, int resultCode, Intent data) {    super.onActivityResult(requestCode, resultCode, data);    if(requestCode==100&&resultCode==RESULT_OK&&data!=null){//系統相冊      Uri imageData = data.getData();      String path=getPath(imageData);      Bitmap bitmap = BitmapFactory.decodeFile(path);      Bitmap bitmap1 = BitmapUtils.zoom(bitmap, iv.getWidth(), iv.getHeight());      Bitmap bitmap2 = BitmapUtils.circleBitmap(bitmap1);      //加載顯示      iv.setImageBitmap(bitmap2);      //bitmap圖片上傳到服務器......      //bitmap圖片保存到本地      saveImage(bitmap2);    }else if(requestCode==200&&resultCode==RESULT_OK&&data!=null){//系統相機      Bitmap bitmap = (Bitmap) data.getExtras().get("data");      BitmapUtils.zoom(bitmap,iv.getWidth(),iv.getHeight());      bitmap=BitmapUtils.circleBitmap(bitmap);      //加載顯示      iv.setImageBitmap(bitmap);      //bitmap圖片上傳到服務器......      //bitmap圖片保存到本地      saveImage(bitmap);    }  }  /**   * 數據的存儲。（5種）   * Bimap:內存層面的圖片對象。   *   * 存儲--->內存：   *   BitmapFactory.decodeFile(String filePath);   *   BitmapFactory.decodeStream(InputStream is);   * 內存--->存儲：   *   bitmap.compress(Bitmap.CompressFormat.PNG,100,OutputStream os);   */  private void saveImage(Bitmap bitmap) {    File filesDir;    if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){//判斷sd卡是否掛載      //路徑1：storage/sdcard/Android/data/包名/files      filesDir = this.getExternalFilesDir("");    }else{//手機內部存儲      //路徑：data/data/包名/files      filesDir = this.getFilesDir();    }    FileOutputStream fos = null;    try {      File file = new File(filesDir,"icon.png");      fos = new FileOutputStream(file);      bitmap.compress(Bitmap.CompressFormat.PNG, 100,fos);    } catch (FileNotFoundException e) {      e.printStackTrace();    }finally{      if(fos != null){        try {          fos.close();        } catch (IOException e) {          e.printStackTrace();        }      }    }  }  //如果本地有,就不需要再去聯網去請求  private boolean readImage() {    File filesDir;    if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){//判斷sd卡是否掛載      //路徑1：storage/sdcard/Android/data/包名/files      filesDir = getExternalFilesDir("");    }else{//手機內部存儲      //路徑：data/data/包名/files      filesDir = getFilesDir();    }    File file = new File(filesDir,"icon.png");    if(file.exists()){      //存儲--->內存      Bitmap bitmap = BitmapFactory.decodeFile(file.getAbsolutePath());      iv.setImageBitmap(bitmap);      return true;    }    return false;  }  @RequiresApi(api = Build.VERSION_CODES.KITKAT)  private String getPath(Uri uri) {    int sdkVersion = Build.VERSION.SDK_INT;    //高于4.4.2的版本    if (sdkVersion >= 19) {      Log.e("TAG", "uri auth: " + uri.getAuthority());      if (isExternalStorageDocument(uri)) {        String docId = DocumentsContract.getDocumentId(uri);        String[] split = docId.split(":");        String type = split[0];        if ("primary".equalsIgnoreCase(type)) {          return Environment.getExternalStorageDirectory() + "/" + split[1];        }      } else if (isDownloadsDocument(uri)) {        final String id = DocumentsContract.getDocumentId(uri);        final Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"),            Long.valueOf(id));        return getDataColumn(this, contentUri, null, null);      } else if (isMediaDocument(uri)) {        final String docId = DocumentsContract.getDocumentId(uri);        final String[] split = docId.split(":");        final String type = split[0];        Uri contentUri = null;        if ("image".equals(type)) {          contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;        } else if ("video".equals(type)) {          contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;        } else if ("audio".equals(type)) {          contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;        }        final String selection = "_id=?";        final String[] selectionArgs = new String[]{split[1]};        return getDataColumn(this, contentUri, selection, selectionArgs);      } else if (isMedia(uri)) {        String[] proj = {MediaStore.Images.Media.DATA};        Cursor actualimagecursor = this.managedQuery(uri, proj, null, null, null);        int actual_image_column_index = actualimagecursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);        actualimagecursor.moveToFirst();        return actualimagecursor.getString(actual_image_column_index);      }    } else if ("content".equalsIgnoreCase(uri.getScheme())) {      // Return the remote address      if (isGooglePhotosUri(uri))        return uri.getLastPathSegment();      return getDataColumn(this, uri, null, null);    }    // File    else if ("file".equalsIgnoreCase(uri.getScheme())) {      return uri.getPath();    }    return null;  }  /**   * uri路徑查詢字段   *   * @param context   * @param uri   * @param selection   * @param selectionArgs   * @return   */  public static String getDataColumn(Context context, Uri uri, String selection, String[] selectionArgs) {    Cursor cursor = null;    final String column = "_data";    final String[] projection = {column};    try {      cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs, null);      if (cursor != null && cursor.moveToFirst()) {        final int index = cursor.getColumnIndexOrThrow(column);        return cursor.getString(index);      }    } finally {      if (cursor != null)        cursor.close();    }    return null;  }  private boolean isExternalStorageDocument(Uri uri) {    return "com.android.externalstorage.documents".equals(uri.getAuthority());  }  public static boolean isDownloadsDocument(Uri uri) {    return "com.android.providers.downloads.documents".equals(uri.getAuthority());  }  public static boolean isMediaDocument(Uri uri) {    return "com.android.providers.media.documents".equals(uri.getAuthority());  }  public static boolean isMedia(Uri uri) {    return "media".equals(uri.getAuthority());  }  /**   * @param uri The Uri to check.   * @return Whether the Uri authority is Google Photos.   */  public static boolean isGooglePhotosUri(Uri uri) {    return "com.google.android.apps.photos.content".equals(uri.getAuthority());  }  /**   * 判斷本地是否有該圖片,沒有則去聯網請求   * */  @Override  protected void onResume() {    super.onResume();    if(readImage()){      return;    }  }}//BitmapUtils工具類public class BitmapUtils { /**   * 該方法用于將圖片進行圓形處理   * */  public static Bitmap circleBitmap(Bitmap source){    //默認只對寬進行處理    int width=source.getWidth();    Bitmap bitmap=Bitmap.createBitmap(width,width,Bitmap.Config.ARGB_8888);    Canvas canvas=new Canvas(bitmap);    Paint paint=new Paint();    //設置抗鋸齒    paint.setAntiAlias(true);    canvas.drawCircle(width/2,width/2,width/2,paint);    paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));    canvas.drawBitmap(source,0,0,paint);    return bitmap;  }  /**   * 該方法用于圖片壓縮處理,注意width、height參數的類型必須是float   * */  public static Bitmap zoom(Bitmap source,float width,float height){    Matrix matrix=new Matrix();    //圖片進行壓縮處理    matrix.postScale(width/source.getWidth(),height/source.getHeight());    Bitmap bitmap = Bitmap.createBitmap(source, 0, 0, source.getWidth(), source.getHeight(), matrix, false);    return bitmap;  }}