可以通过设置对话框的宽度来解决该问题。以下代码示例将对话框的宽度设置为屏幕宽度的80％：

//创建对话框
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage("This dialog is too narrow!");
builder.setPositiveButton("OK", null);
AlertDialog dialog = builder.create();

//获取设备屏幕宽度
DisplayMetrics metrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(metrics);
int screenWidth = metrics.widthPixels;

//设置对话框宽度为屏幕宽度的80%
WindowManager.LayoutParams params = new WindowManager.LayoutParams();
params.copyFrom(dialog.getWindow().getAttributes());
params.width = (int) (screenWidth * 0.8);
dialog.getWindow().setAttributes(params);

dialog.show();