Android自定义dialog

public void onActivityResult(int requestCode, int resultCode,
            final Intent data) {
        if (RESULT_OK == resultCode && 1 == requestCode) {
            // 在代码中声明一个layout
            LayoutInflater inflater = getLayoutInflater();
            //R.layout.dialog为一个layout布局
            View layout = inflater.inflate(R.layout.dialog,
                    (ViewGroup) findViewById(R.id.dialog));

            Builder mydialog = new AlertDialog.Builder(ImChoose.this);
            //将mydialog设置为layout布局
            mydialog.setView(layout);
            iv = (ImageView) layout.findViewById(R.id.iv);
            uri = data.getData();
            ContentResolver cr = this.getContentResolver();
            try {
                bm = BitmapFactory.decodeStream(cr.openInputStream(uri));
                iv.setImageBitmap(bm);
            } catch (FileNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            mydialog.setPositiveButton("确定", new OnClickListener() {

                @Override
                public void onClick(DialogInterface dialog, int which) {
                    // TODO Auto-generated method stub
                    // iv1.setImageURI(uri);
                    iv1.setImageBitmap(bm);
                }

            });

            // 设置重写重新选择键
            mydialog.setNeutralButton("重新选择", new OnClickListener() {

                @Override
                public void onClick(DialogInterface dialog, int which) {
                    // TODO Auto-generated method stub
                    Intent intent = new Intent();
                    intent.setType("image/*");
                    intent.setAction(intent.ACTION_GET_CONTENT);
                    startActivityForResult(intent, 1);

                }
            });
            mydialog.setNegativeButton("取消", new OnClickListener() {

                @Override
                public void onClick(DialogInterface dialog, int which) {
                    // TODO Auto-generated method stub
                    Toast.makeText(ImChoose.this, "cancel", Toast.LENGTH_SHORT)
                            .show();

                }
            });

            mydialog.create();
            mydialog.show();
        }
        super.onActivityResult(requestCode, resultCode, data);
    }