来自另一个类的AlertDialog调用

Question

我正在尝试从同一个文件中的另一个类调用我的alertdialog。我在哪里错了？只是试图扩展AlertDialog，但我不知道如何做到这一点，我不想在我的公共主类，尝试和工作，但我需要在可分离的类，如果这是可能的。

class MyDialog extends AlertDialog {
public static Context context;
public static int theme;
protected MyDialog(Context context, int theme) {
    super(context, theme);
    MyDialog.context = context;

    theme = THEME_HOLO_DARK;
    MyDialog.theme = theme;
}

public void onCreateAlertDialog() {
    AlertDialog.Builder alertDialog = new AlertDialog.Builder(context);
    alertDialog.setTitle("Auto Start")
    .setMessage("Start playing after: 30 sec")
    .setIcon(R.drawable.info)
    .setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int id) {
            Toast.makeText(context, "Auto start cancaled!", Toast.LENGTH_SHORT).show();
            dialog.cancel();
            }
        }
    );
    alertDialog.show();
}
}

我从主类这样称呼它：

Context context = MyDialog.context;
int i = MyDialog.theme;
MyDialog md = new MyDialog(context, i);
md.onCreateAlertDialog();

Answer 1

我认为它来自你没有初始化它的上下文变量。 您应该从您正在调用对话框的活动中获取它：

class MyActivity extends Activity{
    ...
    Context context = this;
    MyDialog md = new MyDialog(context, i);
    ...
}

Answer 2

您正在使用AlertDialog.Builder，它在构建时始终会返回AlertDialog类的实例。您必须覆盖静态构建器以返回类的实例，但这实际上是不可能的。

您想要做的是扩展Dialog类并创建您自己的AlertDialog实现，如HoloEverywhere库中所示。

https://github.com/ChristopheVersieux/HoloEverywhere/blob/master/library/src/com/WazaBe/HoloEverywhere/app/AlertDialog.java

public class AlertDialog extends Dialog implements DialogInterface {
    public static class Builder {
        private final AlertController.AlertParams P;

        public Builder(Context context) {
            this(context, resolveDialogTheme(context, 0));
        }

        public Builder(Context context, int theme) {
            P = new AlertController.AlertParams(new ContextThemeWrapper(
                    context, resolveDialogTheme(context, theme)));
            P.mTheme = theme;
        }

        public AlertDialog create() {
            final AlertDialog dialog = new AlertDialog(P.mContext, P.mTheme);
            P.apply(dialog.mAlert);
            dialog.setCancelable(P.mCancelable);
            if (P.mCancelable) {
                dialog.setCanceledOnTouchOutside(true);
            }
            dialog.setOnCancelListener(P.mOnCancelListener);
            if (P.mOnKeyListener != null) {
                dialog.setOnKeyListener(P.mOnKeyListener);
            }
            return dialog;
        }

        public Context getContext() {
            return P.mContext;
        }

        public Builder setAdapter(final ListAdapter adapter,
                final OnClickListener listener) {
            P.mAdapter = adapter;
            P.mOnClickListener = listener;
            return this;
        }

        public Builder setCancelable(boolean cancelable) {
            P.mCancelable = cancelable;
            return this;
        }

        public Builder setCheckedItem(int checkedItem) {
            P.mCheckedItem = checkedItem;
            return this;
        }

        public Builder setCursor(final Cursor cursor,
                final OnClickListener listener, String labelColumn) {
            P.mCursor = cursor;
            P.mLabelColumn = labelColumn;
            P.mOnClickListener = listener;
            return this;
        }

        public Builder setCustomTitle(View customTitleView) {
            P.mCustomTitleView = customTitleView;
            return this;
        }

        public Builder setIcon(Drawable icon) {
            P.mIcon = icon;
            return this;
        }

        public Builder setIcon(int iconId) {
            P.mIconId = iconId;
            return this;
        }

        public Builder setIconAttribute(int attrId) {
            TypedValue out = new TypedValue();
            P.mContext.getTheme().resolveAttribute(attrId, out, true);
            P.mIconId = out.resourceId;
            return this;
        }

        public Builder setInverseBackgroundForced(boolean useInverseBackground) {
            P.mForceInverseBackground = useInverseBackground;
            return this;
        }

        public Builder setItems(CharSequence[] items,
                final OnClickListener listener) {
            P.mItems = items;
            P.mOnClickListener = listener;
            return this;
        }

        public Builder setItems(int itemsId, final OnClickListener listener) {
            P.mItems = P.mContext.getResources().getTextArray(itemsId);
            P.mOnClickListener = listener;
            return this;
        }

        public Builder setMessage(CharSequence message) {
            P.mMessage = message;
            return this;
        }

        public Builder setMessage(int messageId) {
            P.mMessage = P.mContext.getText(messageId);
            return this;
        }

        public Builder setMultiChoiceItems(CharSequence[] items,
                boolean[] checkedItems,
                final OnMultiChoiceClickListener listener) {
            P.mItems = items;
            P.mOnCheckboxClickListener = listener;
            P.mCheckedItems = checkedItems;
            P.mIsMultiChoice = true;
            return this;
        }

        public Builder setMultiChoiceItems(Cursor cursor,
                String isCheckedColumn, String labelColumn,
                final OnMultiChoiceClickListener listener) {
            P.mCursor = cursor;
            P.mOnCheckboxClickListener = listener;
            P.mIsCheckedColumn = isCheckedColumn;
            P.mLabelColumn = labelColumn;
            P.mIsMultiChoice = true;
            return this;
        }

        public Builder setMultiChoiceItems(int itemsId, boolean[] checkedItems,
                final OnMultiChoiceClickListener listener) {
            P.mItems = P.mContext.getResources().getTextArray(itemsId);
            P.mOnCheckboxClickListener = listener;
            P.mCheckedItems = checkedItems;
            P.mIsMultiChoice = true;
            return this;
        }

        public Builder setNegativeButton(CharSequence text,
                final OnClickListener listener) {
            P.mNegativeButtonText = text;
            P.mNegativeButtonListener = listener;
            return this;
        }

        public Builder setNegativeButton(int textId,
                final OnClickListener listener) {
            P.mNegativeButtonText = P.mContext.getText(textId);
            P.mNegativeButtonListener = listener;
            return this;
        }

        public Builder setNeutralButton(CharSequence text,
                final OnClickListener listener) {
            P.mNeutralButtonText = text;
            P.mNeutralButtonListener = listener;
            return this;
        }

        public Builder setNeutralButton(int textId,
                final OnClickListener listener) {
            P.mNeutralButtonText = P.mContext.getText(textId);
            P.mNeutralButtonListener = listener;
            return this;
        }

        public Builder setOnCancelListener(OnCancelListener onCancelListener) {
            P.mOnCancelListener = onCancelListener;
            return this;
        }

        public Builder setOnItemSelectedListener(
                final AdapterView.OnItemSelectedListener listener) {
            P.mOnItemSelectedListener = listener;
            return this;
        }

        public Builder setOnKeyListener(OnKeyListener onKeyListener) {
            P.mOnKeyListener = onKeyListener;
            return this;
        }

        public Builder setOnPrepareListViewListener(
                OnPrepareListViewListener listener) {
            P.mOnPrepareListViewListener = listener;
            return this;
        }

        public Builder setPositiveButton(CharSequence text,
                final OnClickListener listener) {
            P.mPositiveButtonText = text;
            P.mPositiveButtonListener = listener;
            return this;
        }

        public Builder setPositiveButton(int textId,
                final OnClickListener listener) {
            P.mPositiveButtonText = P.mContext.getText(textId);
            P.mPositiveButtonListener = listener;
            return this;
        }

        public Builder setRecycleOnMeasureEnabled(boolean enabled) {
            P.mRecycleOnMeasure = enabled;
            return this;
        }

        public Builder setSingleChoiceItems(CharSequence[] items,
                int checkedItem, final OnClickListener listener) {
            P.mItems = items;
            P.mOnClickListener = listener;
            P.mCheckedItem = checkedItem;
            P.mIsSingleChoice = true;
            return this;
        }

        public Builder setSingleChoiceItems(Cursor cursor, int checkedItem,
                String labelColumn, final OnClickListener listener) {
            P.mCursor = cursor;
            P.mOnClickListener = listener;
            P.mCheckedItem = checkedItem;
            P.mLabelColumn = labelColumn;
            P.mIsSingleChoice = true;
            return this;
        }

        public Builder setSingleChoiceItems(int itemsId, int checkedItem,
                final OnClickListener listener) {
            P.mItems = P.mContext.getResources().getTextArray(itemsId);
            P.mOnClickListener = listener;
            P.mCheckedItem = checkedItem;
            P.mIsSingleChoice = true;
            return this;
        }

        public Builder setSingleChoiceItems(ListAdapter adapter,
                int checkedItem, final OnClickListener listener) {
            P.mAdapter = adapter;
            P.mOnClickListener = listener;
            P.mCheckedItem = checkedItem;
            P.mIsSingleChoice = true;
            return this;
        }

        public Builder setTitle(CharSequence title) {
            P.mTitle = title;
            return this;
        }

        public Builder setTitle(int titleId) {
            P.mTitle = P.mContext.getText(titleId);
            return this;
        }

        public Builder setView(View view) {
            P.mView = view;
            P.mViewSpacingSpecified = false;
            return this;
        }

        public Builder setView(View view, int viewSpacingLeft,
                int viewSpacingTop, int viewSpacingRight, int viewSpacingBottom) {
            P.mView = view;
            P.mViewSpacingSpecified = true;
            P.mViewSpacingLeft = viewSpacingLeft;
            P.mViewSpacingTop = viewSpacingTop;
            P.mViewSpacingRight = viewSpacingRight;
            P.mViewSpacingBottom = viewSpacingBottom;
            return this;
        }

        public AlertDialog show() {
            AlertDialog dialog = create();
            dialog.show();
            return dialog;
        }
    }

    public static final int THEME_HOLO_DARK = 1;
    public static final int THEME_HOLO_LIGHT = 2;

    static int resolveDialogTheme(Context context, int resid) {
        if (resid == THEME_HOLO_DARK) {
            return R.style.Holo_Theme_Dialog_Alert;
        } else if (resid == THEME_HOLO_LIGHT) {
            return R.style.Holo_Theme_Dialog_Alert_Light;
        } else if (resid >= 0x01000000) {
            return resid;
        } else {
            TypedValue outValue = new TypedValue();
            context.getTheme().resolveAttribute(R.attr.alertDialogTheme,
                    outValue, true);
            return outValue.resourceId;
        }
    }

    private final AlertController mAlert;

    protected AlertDialog(Context context) {
        this(context, false, null, resolveDialogTheme(context, 0));
    }

    protected AlertDialog(Context context, boolean cancelable,
            OnCancelListener cancelListener) {
        this(context, cancelable, cancelListener,
                resolveDialogTheme(context, 0));
    }

    protected AlertDialog(Context context, boolean cancelable,
            OnCancelListener cancelListener, int theme) {
        super(context, resolveDialogTheme(context, theme));
        setCancelable(cancelable);
        setOnCancelListener(cancelListener);
        mAlert = new AlertController(context, this, getWindow());
    }

    protected AlertDialog(Context context, int theme) {
        this(context, false, null, theme);
    }

    public Button getButton(int whichButton) {
        return mAlert.getButton(whichButton);
    }

    public ListView getListView() {
        return mAlert.getListView();
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mAlert.installContent();
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (mAlert.onKeyDown(keyCode, event)) {
            return true;
        }
        return super.onKeyDown(keyCode, event);
    }

    @Override
    public boolean onKeyUp(int keyCode, KeyEvent event) {
        if (mAlert.onKeyUp(keyCode, event)) {
            return true;
        }
        return super.onKeyUp(keyCode, event);
    }

    @Deprecated
    public void setButton(CharSequence text, Message msg) {
        setButton(BUTTON_POSITIVE, text, msg);
    }

    @Deprecated
    public void setButton(CharSequence text, final OnClickListener listener) {
        setButton(BUTTON_POSITIVE, text, listener);
    }

    public void setButton(int whichButton, CharSequence text, Message msg) {
        mAlert.setButton(whichButton, text, null, msg);
    }

    public void setButton(int whichButton, CharSequence text,
            OnClickListener listener) {
        mAlert.setButton(whichButton, text, listener, null);
    }

    @Deprecated
    public void setButton2(CharSequence text, Message msg) {
        setButton(BUTTON_NEGATIVE, text, msg);
    }

    @Deprecated
    public void setButton2(CharSequence text, final OnClickListener listener) {
        setButton(BUTTON_NEGATIVE, text, listener);
    }

    @Deprecated
    public void setButton3(CharSequence text, Message msg) {
        setButton(BUTTON_NEUTRAL, text, msg);
    }

    @Deprecated
    public void setButton3(CharSequence text, final OnClickListener listener) {
        setButton(BUTTON_NEUTRAL, text, listener);
    }

    public void setCustomTitle(View customTitleView) {
        mAlert.setCustomTitle(customTitleView);
    }

    public void setIcon(Drawable icon) {
        mAlert.setIcon(icon);
    }

    public void setIcon(int resId) {
        mAlert.setIcon(resId);
    }

    public void setIconAttribute(int attrId) {
        TypedValue out = new TypedValue();
        getContext().getTheme().resolveAttribute(attrId, out, true);
        mAlert.setIcon(out.resourceId);
    }

    public void setInverseBackgroundForced(boolean forceInverseBackground) {
        mAlert.setInverseBackgroundForced(forceInverseBackground);
    }

    public void setMessage(CharSequence message) {
        mAlert.setMessage(message);
    }

    @Override
    public void setTitle(CharSequence title) {
        super.setTitle(title);
        mAlert.setTitle(title);
    }

    public void setView(View view) {
        mAlert.setView(view);
    }

    public void setView(View view, int viewSpacingLeft, int viewSpacingTop,
            int viewSpacingRight, int viewSpacingBottom) {
        mAlert.setView(view, viewSpacingLeft, viewSpacingTop, viewSpacingRight,
                viewSpacingBottom);
    }
}