Android的DialogFragment与对话框
Googlebuild议我们使用DialogFragment而不是使用Fragments API的简单Dialog ，但是使用隔离的DialogFragment作为简单的Yes-No确认消息框是荒谬的。 这种情况下的最佳做法是什么？
是的，使用DialogFragment和onCreateDialog您可以简单地使用AlertDialog构build器创build一个带有Yes / No确认button的简单AlertDialog 。 根本不是很多代码。
关于在你的片段中处理事件，会有不同的方式做，但我只是在我的Fragment定义一个消息Handler ，通过它的构造函数将它传递到DialogFragment ，然后将消息传递回我的片段的处理程序作为适用于各种点击事件。 再次采取各种方式，但下面的工作对我来说。
在对话框中保存一条消息，并在构造函数中实例化它：
private Message okMessage; ... okMessage = handler.obtainMessage(MY_MSG_WHAT, MY_MSG_OK);
在对话框中实现onClickListener ，然后根据需要调用处理程序：
public void onClick(..... if (which == DialogInterface.BUTTON_POSITIVE) { final Message toSend = Message.obtain(okMessage); toSend.sendToTarget(); } }
编辑
作为Message可以parcelable，你可以将其保存在onSaveInstanceState并恢复它
outState.putParcelable("okMessage", okMessage);
然后在onCreate
if (savedInstanceState != null) { okMessage = savedInstanceState.getParcelable("okMessage"); }
您可以创build通用的DialogFragment子类，如YesNoDialog和OkDialog，并传入标题和消息，如果您在应用程序中使用对话。
public class YesNoDialog extends DialogFragment { public static final String ARG_TITLE = "YesNoDialog.Title"; public static final String ARG_MESSAGE = "YesNoDialog.Message"; public YesNoDialog() { } @Override public Dialog onCreateDialog(Bundle savedInstanceState) { Bundle args = getArguments(); String title = args.getString(ARG_TITLE); String message = args.getString(ARG_MESSAGE); return new AlertDialog.Builder(getActivity()) .setTitle(title) .setMessage(message) .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { getTargetFragment().onActivityResult(getTargetRequestCode(), Activity.RESULT_OK, null); } }) .setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { getTargetFragment().onActivityResult(getTargetRequestCode(), Activity.RESULT_CANCELED, null); } }) .create(); } }
然后使用以下命令来调用它：
DialogFragment dialog = new YesNoDialog(); Bundle args = new Bundle(); args.putString(YesNoDialog.ARG_TITLE, title); args.putString(YesNoDialog.ARG_MESSAGE, message); dialog.setArguments(args); dialog.setTargetFragment(this, YES_NO_CALL); dialog.show(getFragmentManager(), "tag");
并在onActivityResult处理结果。
我会build议使用DialogFragment 。
当然，创build一个“是/否”对话框是相当复杂的，因为它应该是相当简单的任务，但是用Dialog创build一个类似的对话框也是非常复杂的。
（活动生命周期使其变得复杂 – 您必须让Activitypipe理对话框的生命周期 – 并且无法将自定义参数（例如自定义消息）传递给Activity.showDialog如果使用8以下的API级别）
好的是，你通常可以很容易地在DialogFragment之上build立自己的抽象。
在AlertDialog上使用DialogFragment：
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自引入API级别13以来 ：
来自Activity的showDialog方法已被弃用 。 在代码的其他地方调用一个对话框是不可取的，因为你将不得不自己pipe理对话框（例如方向改变）。
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差异DialogFragment – AlertDialog
他们差别很大吗？ 从Android参考有关DialogFragment ：
DialogFragment是一个片段，它显示一个对话窗口，并在其活动窗口之上浮动。 这个片段包含一个Dialog对象，它根据片段的状态适当地显示它。 对话框的控制（决定何时显示，隐藏，解除）应该通过这里的API完成，而不是直接调用对话框。
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其他说明
- 由于具有不同屏幕尺寸的设备的多样性，碎片是Android框架中的自然演变。
- 支持库中提供了DialogFragments和Fragments，使得该类可以在所有当前使用的Android版本中使用。
带有生成器模式的通用AlertDialogFragment
在我的项目中，我已经使用AlertDialog.Builder 了很多，然后才发现它有问题。 但是，我不想在我的应用程序的任何地方改变那么多的代码。 另外，我实际上是将OnClickListeners作为匿名类传递OnClickListeners它们（也就是说，在使用setPositiveButton() ， setNegativeButton()等）时，而不是实现数以千计的callback方法来在对话框片段和持有者片段，在我看来，这会导致非常混乱和复杂的代码。 特别是，如果在一个片段中有多个不同的对话框，那么需要在callback实现中区分当前显示的对话框。
因此，我组合了不同的方法来创build一个通用的AlertDialogFragment辅助类，它可以像 AlertDialog 一样 AlertDialog ：
解
（ 请注意 ，我在我的代码中使用Java 8 lambdaexpression式，因此如果您尚未使用lambdaexpression式，则可能需要更改部分代码。）
/** * Helper class for dialog fragments to show a {@link AlertDialog}. It can be used almost exactly * like a {@link AlertDialog.Builder} * <p /> * Creation Date: 22.03.16 * * @author felix, http://flx-apps.com/ */ public class AlertDialogFragment extends DialogFragment { protected FragmentActivity activity; protected Bundle args; protected String tag = AlertDialogFragment.class.getSimpleName(); @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); activity = getActivity(); args = getArguments(); } @NonNull @Override public Dialog onCreateDialog(Bundle savedInstanceState) { Dialog dialog = setDialogDefaults(new AlertDialog.Builder(getActivity())).create(); if (args.containsKey("gravity")) { dialog.getWindow().getAttributes().gravity = args.getInt("gravity"); } dialog.setOnShowListener(d -> { if (dialog != null && dialog.findViewById((android.R.id.message)) != null) { ((TextView) dialog.findViewById(android.R.id.message)).setMovementMethod(LinkMovementMethod.getInstance()); } }); return dialog; } @Nullable @Override public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) { return super.onCreateView(inflater, container, savedInstanceState); } @Override public void onDismiss(DialogInterface dialog) { super.onDismiss(dialog); if (args.containsKey("onDismissListener")) { Parcelable onDismissListener = args.getParcelable("onDismissListener"); if (onDismissListener != null && onDismissListener instanceof ParcelableOnDismissListener) { ((ParcelableOnDismissListener) onDismissListener).onDismiss(this); } } } /** * Sets default dialog properties by arguments which were set using {@link #builder(FragmentActivity)} */ protected AlertDialog.Builder setDialogDefaults(AlertDialog.Builder builder) { args = getArguments(); activity = getActivity(); if (args.containsKey("title")) { builder.setTitle(args.getCharSequence("title")); } if (args.containsKey("message")) { CharSequence message = args.getCharSequence("message"); builder.setMessage(message); } if (args.containsKey("viewId")) { builder.setView(getActivity().getLayoutInflater().inflate(args.getInt("viewId"), null)); } if (args.containsKey("positiveButtonText")) { builder.setPositiveButton(args.getCharSequence("positiveButtonText"), (dialog, which) -> { onButtonClicked("positiveButtonListener", which); }); } if (args.containsKey("negativeButtonText")) { builder.setNegativeButton(args.getCharSequence("negativeButtonText"), (dialog, which) -> { onButtonClicked("negativeButtonListener", which); }); } if (args.containsKey("neutralButtonText")) { builder.setNeutralButton(args.getCharSequence("neutralButtonText"), (dialog, which) -> { onButtonClicked("neutralButtonListener", which); }); } if (args.containsKey("items")) { builder.setItems(args.getStringArray("items"), (dialog, which) -> { onButtonClicked("itemClickListener", which); }); } // @formatter:off // FIXME this a pretty hacky workaround: we don't want to show the dialog if onClickListener of one of the dialog's button click listener were lost // the problem is, that there is no (known) solution for parceling a OnClickListener in the long term (only for state changes like orientation change, // but not if the Activity was completely lost) if ( (args.getParcelable("positiveButtonListener") != null && !(args.getParcelable("positiveButtonListener") instanceof ParcelableOnClickListener)) || (args.getParcelable("negativeButtonListener") != null && !(args.getParcelable("negativeButtonListener") instanceof ParcelableOnClickListener)) || (args.getParcelable("neutralButtonListener") != null && !(args.getParcelable("neutralButtonListener") instanceof ParcelableOnClickListener)) || (args.getParcelable("itemClickListener") != null && !(args.getParcelable("itemClickListener") instanceof ParcelableOnClickListener)) ) { new DebugMessage("Forgot onClickListener. Needs to be dismissed.") .logLevel(DebugMessage.LogLevel.VERBOSE) .show(); try { dismissAllowingStateLoss(); } catch (NullPointerException | IllegalStateException ignored) {} } // @formatter:on return builder; } public interface OnDismissListener { void onDismiss(AlertDialogFragment dialogFragment); } public interface OnClickListener { void onClick(AlertDialogFragment dialogFragment, int which); } protected void onButtonClicked(String buttonKey, int which) { ParcelableOnClickListener parcelableOnClickListener = getArguments().getParcelable(buttonKey); if (parcelableOnClickListener != null) { parcelableOnClickListener.onClick(this, which); } } // region Convenience Builder Pattern class almost similar to AlertDialog.Builder // ============================================================================================= public AlertDialogFragment builder(FragmentActivity activity) { this.activity = activity; this.args = new Bundle(); return this; } public AlertDialogFragment addArguments(Bundle bundle) { args.putAll(bundle); return this; } public AlertDialogFragment setTitle(int titleStringId) { return setTitle(activity.getString(titleStringId)); } public AlertDialogFragment setTitle(CharSequence title) { args.putCharSequence("title", title); return this; } public AlertDialogFragment setMessage(int messageStringId) { return setMessage(activity.getString(messageStringId)); } public AlertDialogFragment setMessage(CharSequence message) { args.putCharSequence("message", message); return this; } public AlertDialogFragment setPositiveButton(int textStringId, OnClickListener onClickListener) { return setPositiveButton(activity.getString(textStringId), onClickListener); } public AlertDialogFragment setPositiveButton(CharSequence text, AlertDialogFragment.OnClickListener onClickListener) { args.putCharSequence("positiveButtonText", text); args.putParcelable("positiveButtonListener", createParcelableOnClickListener(onClickListener)); return this; } public AlertDialogFragment setNegativeButton(int textStringId, AlertDialogFragment.OnClickListener onClickListener) { return setNegativeButton(activity.getString(textStringId), onClickListener); } public AlertDialogFragment setNegativeButton(CharSequence text, AlertDialogFragment.OnClickListener onClickListener) { args.putCharSequence("negativeButtonText", text); args.putParcelable("negativeButtonListener", createParcelableOnClickListener(onClickListener)); return this; } public AlertDialogFragment setNeutralButton(int textStringId, AlertDialogFragment.OnClickListener onClickListener) { return setNeutralButton(activity.getString(textStringId), onClickListener); } public AlertDialogFragment setNeutralButton(CharSequence text, AlertDialogFragment.OnClickListener onClickListener) { args.putCharSequence("neutralButtonText", text); args.putParcelable("neutralButtonListener", createParcelableOnClickListener(onClickListener)); return this; } public AlertDialogFragment setOnDismissListener(OnDismissListener onDismissListener) { if (onDismissListener == null) { return this; } Parcelable p = new ParcelableOnDismissListener() { @Override public void onDismiss(AlertDialogFragment dialogFragment) { onDismissListener.onDismiss(dialogFragment); } }; args.putParcelable("onDismissListener", p); return this; } public AlertDialogFragment setItems(String[] items, AlertDialogFragment.OnClickListener onClickListener) { args.putStringArray("items", items); args.putParcelable("itemClickListener", createParcelableOnClickListener(onClickListener)); return this; } public AlertDialogFragment setView(int viewId) { args.putInt("viewId", viewId); return this; } public AlertDialogFragment setGravity(int gravity) { args.putInt("gravity", gravity); return this; } public AlertDialogFragment setTag(String tag) { this.tag = tag; return this; } public AlertDialogFragment create() { setArguments(args); return AlertDialogFragment.this; } public AlertDialogFragment show() { create(); try { super.show(activity.getSupportFragmentManager(), tag); } catch (IllegalStateException e1) { /** * this whole part is used in order to attempt to show the dialog if an * {@link IllegalStateException} was thrown (it's kinda comparable to * {@link FragmentTransaction#commitAllowingStateLoss()} * So you can remove all those dirty hacks if you are sure that you are always * properly showing dialogs in the right moments */ new DebugMessage("got IllegalStateException attempting to show dialog. trying to hack around.") .logLevel(DebugMessage.LogLevel.WARN) .exception(e1) .show(); try { Field mShownByMe = DialogFragment.class.getDeclaredField("mShownByMe"); mShownByMe.setAccessible(true); mShownByMe.set(this, true); Field mDismissed = DialogFragment.class.getDeclaredField("mDismissed"); mDismissed.setAccessible(true); mDismissed.set(this, false); } catch (Exception e2) { new DebugMessage("error while showing dialog") .exception(e2) .logLevel(DebugMessage.LogLevel.ERROR) .show(); } FragmentTransaction transaction = activity.getSupportFragmentManager().beginTransaction(); transaction.add(this, tag); transaction.commitAllowingStateLoss(); // FIXME hacky and unpredictable workaround } return AlertDialogFragment.this; } @Override public int show(FragmentTransaction transaction, String tag) { throw new NoSuchMethodError("Please use AlertDialogFragment.show()!"); } @Override public void show(FragmentManager manager, String tag) { throw new NoSuchMethodError("Please use AlertDialogFragment.show()!"); } protected ParcelableOnClickListener createParcelableOnClickListener(AlertDialogFragment.OnClickListener onClickListener) { if (onClickListener == null) { return null; } return new ParcelableOnClickListener() { @Override public void onClick(AlertDialogFragment dialogFragment, int which) { onClickListener.onClick(dialogFragment, which); } }; } /** * Parcelable OnClickListener (can be remembered on screen rotation) */ public abstract static class ParcelableOnClickListener extends ResultReceiver implements AlertDialogFragment.OnClickListener { public static final Creator<ResultReceiver> CREATOR = ResultReceiver.CREATOR; ParcelableOnClickListener() { super(null); } @Override public abstract void onClick(AlertDialogFragment dialogFragment, int which); } /** * Parcelable OnDismissListener (can be remembered on screen rotation) */ public abstract static class ParcelableOnDismissListener extends ResultReceiver implements AlertDialogFragment.OnDismissListener { public static final Creator<ResultReceiver> CREATOR = ResultReceiver.CREATOR; ParcelableOnDismissListener() { super(null); } @Override public abstract void onDismiss(AlertDialogFragment dialogFragment); } // ============================================================================================= // endregion }
用法
// showing a normal alert dialog with state loss on configuration changes (like device rotation) new AlertDialog.Builder(getActivity()) .setTitle("Are you sure? (1)") .setMessage("Do you really want to do this?") .setPositiveButton("Yes", (dialog, which) -> Toast.makeText(getContext(), "Yes clicked", Toast.LENGTH_SHORT).show()) .setNegativeButton("Cancel", null) .show(); // showing a dialog fragment using the helper class with no state loss on configuration changes new AlertDialogFragment.builder(getActivity()) .setTitle("Are you sure? (2)") .setMessage("Do you really want to do this?") .setPositiveButton("Yes", (dialog, which) -> Toast.makeText(getContext(), "Yes clicked", Toast.LENGTH_SHORT).show()) .setNegativeButton("Cancel", null) .show();
我在这里发布这个不仅是为了分享我的解决scheme，还因为我想问你的意见：这种方法在某种程度上是合法的还是有问题的？
