使用DialogFragment代替传统Dialog

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Android 3.0 引入的基于Fragment的DialogFragment，DialogFragment让dialog也变成了碎片，用于在Activity的内容之上展示一个模态的对话框。
官方推荐使用 DialogFragment 来代替 Dialog ，可以具有更高的可复用性（降低耦合），当旋转屏幕和按下后退键时可以更好的管理其声明周期，和Fragment有着基本一致的声明周期，同时也具有和Fragment一样的优点。

为什么要使用DialogFragment

1、当横竖屏切换时，DialogFragment会自动重建，而AlertDialog没有这样的能力。

如当屏幕方向发生变化，会导致Activity重建，之前显示的AlertDialog对话框就会消失。若要使对话框重建，需手动处理。
在onSaveInstanceState中

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@Override
protected void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    if (dialog != null && dialog.isShowing()) {
        outState.putBoolean("DIALOG_SHOWN", true);
    }else{
        outState.putBoolean("DIALOG_SHOWN", false);
    }
}

在onCreate中

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@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    
    if (savedInstanceState != null) {
        boolean isShown = savedInstanceState.getBoolean("DIALOG_SHOWN");
        if (isShown) {
            AlertDialog dialog = new AlertDialog.Builder(this).setTitle("Dialog")
                    .setMessage("this is a dialog").show();
        }
    }
}

onDestroy()中

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/**
 * 在Activity销毁之前，确保对话框以关闭，否则会有Android leaked window异常信息
 */
@Override
protected void onDestroy() {
    super.onDestroy();
    if(dialog != null && dialog.isShowing())
        dialog.dismiss();
}

若使用DialogFragment来管理对话框，当旋转屏幕的时候，DialogFragment的对话框将会由FragmentManager自动重建

2、DialogFragment更灵活、松耦合性
DialogFragment可以很灵活的当做普通Fragment使用，在onCreateView中很方便的自定义布局

创建DialogFragment两种方式

1、重写 onCreateDialog
一般用于创建替代传统的 Dialog 对话框的场景。

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@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
    AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
	// AlertDialog.Builder builder = new AlertDialog.Builder(getActivity(), R.style.CustomDialog);
    builder.setTitle("title")
           .setMessage("this is a dialog")
           .setPositiveButton("ok", null)
           .setNegativeButton("cancel", null)
           .setCancelable(false);
    return builder.create();
}

or

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@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
	AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
	// AlertDialog.Builder builder = new AlertDialog.Builder(getActivity(), R.style.CustomDialog);
	LayoutInflater inflater = getActivity().getLayoutInflater();  
    View view = inflater.inflate(R.layout.fragment_dialog, null);  
    builder.setView(view) 
 	// Do Someting
    return builder.create();
}

or

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@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
	LayoutInflater inflater = getActivity().getLayoutInflater();
    View view = inflater.inflate(R.layout.fragment_dialog, null);
	Dialog dialog = new Dialog(getActivity());
  	// Dialog dialog = new Dialog(getActivity(), R.style.CustomDialog);
    dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
    dialog.setContentView(view);
    dialog.setCanceledOnTouchOutside(true);
    //Do something
    Window window = dialog.getWindow();
    window.setBackgroundDrawableResource(R.color.transparent);
    WindowManager.LayoutParams wlp = window.getAttributes();
    wlp.gravity = Gravity.BOTTOM;
    wlp.width = WindowManager.LayoutParams.MATCH_PARENT;
    wlp.height = WindowManager.LayoutParams.WRAP_CONTENT;
    window.setAttributes(wlp);
    return dialog;
}

2、重写 onCreateView
一般用于创建自定义及复杂内容弹窗的场景。

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public class CustomDialogFragment extends DialogFragment {	
	public static CustomDialogFragment newInstance(String title) {
		CustomDialogFragment frag = new CustomDialogFragment();
		Bundle args = new Bundle();
		args.putString("title", title);
		frag.setArguments(args);
		return frag;
	}
	@Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
    	super.onCreate(savedInstanceState);
    	setStyle(DialogFragment.STYLE_NO_TITLE, R.style.CustomDialog);
    }
	@Override
	public View onCreateView(LayoutInflater inflater, ViewGroup container,
			Bundle savedInstanceState) {
		View rootView = inflater.inflate(R.layout.fragment_custom_dialog, container, false);
        // Do Someting
        return rootView;
	}
}

DialogFragment的管理

1、DialogFactory

可建立一个工厂类对项目中大量的Dialog进行管理

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public class DialogFactory {
    private static final String DIALOG_PROGRESS_TAG = "progress";
    private static final String DIALOG_ACTION_SHEET_TAG = "action_sheet";
    private static final String DIALOG_CONFIRM_TAG = "confirm";
    private FragmentManager mFragmentManager;
    public DialogFactory(FragmentManager fragmentManager) {
        this.mFragmentManager = fragmentManager;
    }
    public void showProgressDialog(String message, boolean isCancelable) {
        if (mFragmentManager != null) {
            removeDialogWithTag(DIALOG_PROGRESS_TAG);
            ProgressDialogFragment progressDialogFragment = ProgressDialogFragment.newInstance(message, isCancelable);
            progressDialogFragment.show(mFragmentManager, DIALOG_PROGRESS_TAG);
            mFragmentManager.executePendingTransactions();
        }
    }
    public void dismissProgressDialog() {
        Fragment fragment = mFragmentManager.findFragmentByTag(DIALOG_PROGRESS_TAG);
        if (null != fragment) {
            ((ProgressDialogFragment) fragment).dismiss();
            mFragmentManager.beginTransaction().remove(fragment).commit();
        }
    }
    
    private void removeDialogWithTag(String dialogTag){
        Fragment fragment = mFragmentManager.findFragmentByTag(dialogTag);
        if (null != fragment) {
            mFragmentManager.beginTransaction().remove(fragment).commit();
        }
    }
}

2、链式编程

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public class ConfirmDialogFragment extends BaseDialogFragment {
    public interface IDialogClickListener {
        void onClick(ConfirmDialogFragment dialog);
    }
    private IDialogClickListener mPositiveClickListener;
    private IDialogClickListener mNegativeClickListener;
    public static class Builder {
        private Bundle bundle;
        private Activity context;
        private IDialogClickListener okClickListener;
        private IDialogClickListener cancelClickListener;
        public Builder(Activity context) {
            bundle = new Bundle();
            this.context = context;
        }
        public Builder setTitle(String title) {
            putTitle(bundle, title);
            return this;
        }
        public Builder setTitle(int titleId) {
            return setTitle(context.getString(titleId));
        }
        public Builder setMessage(String msg) {
            putMessage(bundle, msg);
            return this;
        }
        public Builder setMessage(int msgId) {
            return setMessage(context.getString(msgId));
        }
        public Builder setPositiveButton(int textId, IDialogClickListener l) {
            bundle.putString("ok", context.getString(textId));
            okClickListener = l;
            return this;
        }
        public Builder setNegativeButton(int textId, IDialogClickListener l) {
            bundle.putString("cancel", context.getString(textId));
            cancelClickListener = l;
            return this;
        }
        public Builder setCancelable(boolean cancelable) {
            putCancelable(bundle, cancelable);
            return this;
        }
        public Builder setCancelableOutside(boolean cancelable) {
            putCancelableOutside(bundle, cancelable);
            return this;
        }
        public ConfirmDialogFragment show() {
            ConfirmDialogFragment dialog = new ConfirmDialogFragment();
            dialog.setArguments(bundle);
            dialog.mPositiveClickListener = okClickListener;
            dialog.mNegativeClickListener = cancelClickListener;
            dialog.show(context.getFragmentManager(), "");
            return dialog;
        }
    }
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        getDialog().requestWindowFeature(Window.FEATURE_NO_TITLE);
        View view = inflater.inflate(R.layout.fragment_dialog_confirm, container, false);
        //...
        return view;
    }
}

使用时

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new ConfirmDialogFragment.Builder(MainActivity.this)
                .setTitle(R.string.dialog_title)
                .setMessage(R.string.dialog_message)
                .setPositiveButton(R.string.sure, new ConfirmDialogFragment.IDialogClickListener() {
                    @Override
                    public void onClick(ConfirmDialogFragment dialog) {
                        dialog.dismiss();
                    }
                })
                .setNegativeButton(R.string.cancel, new ConfirmDialogFragment.IDialogClickListener() {
                    @Override
                    public void onClick(ConfirmDialogFragment dialog) {
                        dialog.dismiss();
                    }
                })
                .setCancelable(false)
                .setCancelableOutside(false)
                .show();