DialogFragment封装

android的弹框大概有：PopupWindow,Dialog,DialogFragment

Android官方推荐使用DialogFragment来代替传统的Dialog ，可以让它具有更高的可复用性（降低耦合）和更好的便利性，
主要是继承Fragment的优点和缺点：
优点：fragment的生命周期管理和碎片化
缺点：fragment的一些坑，参考传送门

PopupWindow更合适相对控件位置弹出，更容易设置指定显示的位置，网上说：
Dialog是非阻塞式对话框，而PopupWindow是阻塞式对话框，
这里我使用时候发现，就算PopupWindow弹出来了，后续toast和dialog还能弹出来，当前页面的其他控件也能响应
PopupWindow能不能屏蔽屏幕的点击事件，主要是如下设置：

// 设置popupWindow获得焦点  
popupWindow.setTouchable(true);  
// 设置popupWindow以外的区域可点击，点击后空白处，对话框消失  
popupWindow.setOutsideTouchable(true);

关于PopupWindow，会另开一篇，接下来写一些简单的DialogFragment封装：

public class BaseDialogFragment extends DialogFragment {

    private String mDialogName;

    /**
     * 监听弹出窗是否被取消
     */
    private OnDialogCancelListener mCancelListener;
    /**
     * 回调获得需要显示的dialog
     */
    private OnCallDialog mOnCallDialog;

    public interface OnDialogCancelListener {
        void onCancel();
    }

    public interface OnCallDialog {
        Dialog getDialog(Context context);
    }

    public static BaseDialogFragment newInstance(OnCallDialog dialog, boolean cancelable,String dialogName)
    {
        return newInstance(dialog, cancelable,dialogName, null);
    }


    public static BaseDialogFragment newInstance(OnCallDialog dialog, boolean cancelable,String dialogName, OnDialogCancelListener cancelListener)
    {
        BaseDialogFragment instance = new BaseDialogFragment();
        instance.setCancelable(cancelable);
        instance.mCancelListener = cancelListener;
        instance.mOnCallDialog = dialog;
        instance.mDialogName = dialogName;
        return instance;
    }

    @NonNull
    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState)
    {
        if (null == mOnCallDialog) {
            super.onCreateDialog(savedInstanceState);
        }
        return mOnCallDialog.getDialog(getActivity());
    }

    /**
     *
     * @param activity
     */
    public void show(FragmentActivity activity)
    {
        Fragment prev = activity.getSupportFragmentManager().findFragmentByTag(mDialogName);
        if (prev == null) {
            FragmentTransaction ft = activity.getSupportFragmentManager().beginTransaction();
            ft.add(this, mDialogName);
            ft.commitAllowingStateLoss();
//            show(activity.getSupportFragmentManager(), mDialogName);
        }
    }

    @Override
    public void onCancel(DialogInterface dialog)
    {
        super.onCancel(dialog);
        if (mCancelListener != null) {
            mCancelListener.onCancel();
        }
    }
}

这里通过dialogName来标识dialog的唯一性，避免创建多种相同的dialog。
使用commitAllowingStateLoss()方法提交，避免产生异常：Can not perform this action after onSaveInstanceState
但是这样也放弃了fragment状态的恢复。该异常产生的原因：在你离开当前Activity等情况下，
系统会调用onSaveInstanceState()帮你保存当前Activity的状态、数据等，
直到再回到该Activity之前（onResume()之前），你执行Fragment事务，
就会抛出该异常！（一般是其他Activity的回调让当前页面执行事务的情况，会引发该问题）

具体的Dialog：

public class LoadingDialog extends Dialog {

    public static void showDialog(FragmentActivity activity,boolean cancelable)
    {
        BaseDialogFragment fragment = BaseDialogFragment.newInstance(new BaseDialogFragment.OnCallDialog() {
            @Override
            public Dialog getDialog(Context context)
            {
                return new LoadingDialog(context);
            }
        },cancelable,LoadingDialog.class.getName());
        fragment.show(activity);
    }

    public static void disDialog(FragmentActivity activity)
    {
        if(activity != null)
        {
            Fragment prev = activity.getSupportFragmentManager()
                    .findFragmentByTag(LoadingDialog.class.getName());
            if (prev != null) {
                ((DialogFragment) prev).dismissAllowingStateLoss();
            }
        }
    }

    private Context mContext;
    private AnimationDrawable animationDrawable;
    public LoadingDialog(@NonNull Context context)
    {
        this(context, R.style.loadding_dialog);
    }

    public LoadingDialog(@NonNull Context context, @StyleRes int themeResId)
    {
        super(context, themeResId);
        mContext = context;
    }

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        ImageView imageView = new ImageView(mContext);
        imageView.setBackgroundResource(R.drawable.bg_loading);
        imageView.setImageResource(R.drawable.loading);
        int padding = DeviceUtil.dip2px(mContext,10);
        int width = DeviceUtil.dip2px(mContext,120);
        imageView.setPadding(padding,padding,padding,padding);
        animationDrawable = (AnimationDrawable) imageView.getDrawable();
        ViewGroup.LayoutParams layoutParams = new ViewGroup.LayoutParams(width
                ,width);
        setContentView(imageView,layoutParams);
        animationDrawable.start();

        setOnDismissListener(new OnDismissListener() {
            @Override
            public void onDismiss(DialogInterface dialog)
            {
                if(animationDrawable != null)
                {
                    animationDrawable.stop();
                }
            }
        });
    }
}

可以看到dialog和DialogFragment是很分离的，感觉像是套了一层，dialog也可以直接使用。