AlertDialog.Builder builder = new AlertDialog.Builder(DialogActivity.this,AlertDialog.THEME_TRADITIONAL);//傳統主題

AlertDialog.Builder builder = new AlertDialog.Builder(DialogActivity.this,AlertDialog.THEME_HOLO_DARK);//使用深色背景 主題 AlertDialog.Builder builder = new AlertDialog.Builder(DialogActivity.this,AlertDialog.THEME_HOLO_LIGHT);//使用淺色背景 主題
AlertDialog.Builder builder = new AlertDialog.Builder(DialogActivity.this,AlertDialog.THEME_DEVICE_DEFAULT_DARK);//使用預設裝置 深色主題 AlertDialog.Builder builder = new AlertDialog.Builder(DialogActivity.this,AlertDialog.THEME_DEVICE_DEFAULT_LIGHT);//使用預設裝置 淺色主題

//自定義佈局 
View layout = getActivity().getLayoutInflater().inflate(R.layout.mydialog,null); AlertDialog.Builder dialog = new AlertDialog.Builder(DialogActivity.this,AlertDialog.THEME_DEVICE_DEFAULT_DARK); final AlertDialog dialog = builder.create(); dialog.setView(layout); //透明 Window window = dialog.getWindow();  WindowManager.LayoutParams lp = window.getAttributes(); lp.alpha = 0.9f; window.setAttributes(lp); 。。。 dialog.show();