Android 简单文字提示

        new Thread(new Runnable() {
            @Override
            public void run() {
                mActivity.runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        Toast.makeText(mActivity, "开始下载", Toast.LENGTH_SHORT).show();
                    }
                });
            }
        }).start();