Android中Activity源码中是如何对对话框Dialog进行处理的

       各位童鞋，对于Android而言，离开Activity，基本上就无从谈起开发，那么亲们对于Activity的实现原理熟悉么？反正我在没有看源码之前是不熟悉的，下面，咱们一起按照老规矩，一起来看一下Activity的源码吧。这一篇文章主要讲解的是Activity如何对对话框Dialog进行实现统一管理的。

      首先我们看到的是这样一个类：

 private static class ManagedDialog {
        Dialog mDialog;
        Bundle mArgs;
    }
    private SparseArray<ManagedDialog> mManagedDialogs;

    接下来我们需要看的一个方法是restoreManagedDialogs，也就是说是恢复被管理的Dialog的状态。

 private void restoreManagedDialogs(Bundle savedInstanceState) {
        final Bundle b = savedInstanceState.getBundle(SAVED_DIALOGS_TAG);
        if (b == null) {
            return;
        }
        final int[] ids = b.getIntArray(SAVED_DIALOG_IDS_KEY);
        final int numDialogs = ids.length;
        mManagedDialogs = new SparseArray<ManagedDialog>(numDialogs);
        for (int i = 0; i < numDialogs; i++) {
            final Integer dialogId = ids[i];
            Bundle dialogState = b.getBundle(savedDialogKeyFor(dialogId));
            if (dialogState != null) {
                final ManagedDialog md = new ManagedDialog();
                md.mArgs = b.getBundle(savedDialogArgsKeyFor(dialogId));
                md.mDialog = createDialog(dialogId, dialogState, md.mArgs);
                if (md.mDialog != null) {
                    mManagedDialogs.put(dialogId, md);
                    onPrepareDialog(dialogId, md.mDialog, md.mArgs);
                    md.mDialog.onRestoreInstanceState(dialogState);
                }
            }
        }
    }

创建Dialog会回调到下面的方法体中来：

private Dialog createDialog(Integer dialogId, Bundle state, Bundle args) {
        final Dialog dialog = onCreateDialog(dialogId, args);
        if (dialog == null) {
            return null;
        }
        dialog.dispatchOnCreate(state);
        return dialog;
    }

有了前面的恢复，就必然有现在的存储Dialog的状态的数据：

private void saveManagedDialogs(Bundle outState) {
        if (mManagedDialogs == null) {
            return;
        }
        final int numDialogs = mManagedDialogs.size();
        if (numDialogs == 0) {
            return;
        }
        Bundle dialogState = new Bundle();
        int[] ids = new int[mManagedDialogs.size()];
        for (int i = 0; i < numDialogs; i++) {
            final int key = mManagedDialogs.keyAt(i);
            ids[i] = key;
            final ManagedDialog md = mManagedDialogs.valueAt(i);
            dialogState.putBundle(savedDialogKeyFor(key), md.mDialog.onSaveInstanceState());
            if (md.mArgs != null) {
                dialogState.putBundle(savedDialogArgsKeyFor(key), md.mArgs);
            }
        }
        dialogState.putIntArray(SAVED_DIALOG_IDS_KEY, ids);
        outState.putBundle(SAVED_DIALOGS_TAG, dialogState);
    }

if (mManagedDialogs != null) {
            final int numDialogs = mManagedDialogs.size();
            for (int i = 0; i < numDialogs; i++) {
                final ManagedDialog md = mManagedDialogs.valueAt(i);
                if (md.mDialog.isShowing()) {
                    md.mDialog.dismiss();
                }
            }
            mManagedDialogs = null;
        }

     关于Activity中的Dialog的管理就讲到这里，希望大家能够有所收获。