1.

 //開啟系統相簿

Intent intent = new Intent(
        Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
startActivityForResult(intent, Code.REQUEST_CODE);

2.

//接收選擇的圖片
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if(Code.REQUEST_CODE 
 
== requestCode && Activity.RESULT_OK == resultCode && null != data){
        Uri selectImageUri  = data.getData();
        String[] filePathColumn = new String[]{MediaStore.Images.Media.DATA};//要查詢的列
Cursor cursor = getContentResolver().query(selectImageUri,filePathColumn,null,null,null
 
);
        String pirPath = null;
        while(cursor.moveToNext()){
            pirPath = cursor.getString(cursor.getColumnIndex(filePathColumn[0]));//所選擇的圖片路徑
}
        cursor.close();

}