读取系统的图片

Intent intent = new Intent("android.intent.action.PICK");

   intent.setType("image/*");
   startActivityForResult(intent, 0);
   @Override

   protected void onActivityResult(int requestCode, int resultCode, Intent data) {

      if(resultCode == Activity.RESULT_OK) {
         Uri uri = data.getData();         
         iv.setImageURI(uri);
      }
   }