Android 菜单动态变化【添加或去除】

最新推荐文章于 2024-07-31 19:51:57 发布

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最新推荐文章于 2024-07-31 19:51:57 发布

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CC 4.0 BY-SA版权

文章标签：移动开发

原文链接：http://www.cnblogs.com/onelikeone/p/7582676.html

本文介绍了Android应用中菜单项的显示逻辑，包括如何根据不同设备方向和当前选中的标签来动态更新菜单项的可见性。此外，还展示了如何处理菜单项点击事件。

<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <group android:id="@+id/menu_items">
        <item android:id="@+id/menu_item_night_mode"
            android:title="@string/menu_item_night_mode"
            android:icon="@android:drawable/ic_menu_preferences"/>
        <item android:id="@+id/menu_item_settings"
            android:title="@string/menu_item_settings"
            android:icon="@android:drawable/ic_menu_preferences"/>
        <item android:id="@+id/menu_item_help"
            android:title="@string/menu_item_help"
            android:icon="@android:drawable/ic_menu_preferences"/>
    </group>
</menu>

@Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // We only want to show it as a menu in landscape, and only for clock/alarm fragment.
        mMenu = menu;
        //方向水平
        if (getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE) {
            if (mActionBar.getSelectedNavigationIndex() == ALARM_TAB_INDEX ||
                    mActionBar.getSelectedNavigationIndex() == CLOCK_TAB_INDEX) {
                // Clear the menu so that it doesn't get duplicate items in case onCreateOptionsMenu
                // was called multiple times.
                menu.clear();
                getMenuInflater().inflate(R.menu.desk_clock_menu, menu);


                MenuItem nightMode = menu.findItem(R.id.menu_item_night_mode);
                MenuItem help = menu.findItem(R.id.menu_item_help);
                if (mActionBar.getSelectedNavigationIndex() == ALARM_TAB_INDEX) {
                    nightMode.setVisible(false);
                    help.setVisible(false);
                } else if (mActionBar.getSelectedNavigationIndex() == CLOCK_TAB_INDEX) {
                    nightMode.setVisible(true);
                    help.setVisible(false);
                }

            }
            // Always return true for landscape, regardless of whether we've inflated the menu, so
            // that when we switch tabs this method will get called and we can inflate the menu.
            return true;
        }
        return false;
    }

    @Override
    public boolean onPrepareOptionsMenu(Menu menu) {
        updateMenu(menu);
        return true;
    }

    private void updateMenu(Menu menu) {
        // Hide "help" if we don't have a URI for it.
        MenuItem help = menu.findItem(R.id.menu_item_help);
        if (help != null) {
            Utils.prepareHelpMenuItem(this, help);
        }

        // Hide "lights out" for timer.
        MenuItem nightMode = menu.findItem(R.id.menu_item_night_mode);
        if (mActionBar.getSelectedNavigationIndex() == ALARM_TAB_INDEX) {
            nightMode.setVisible(false);
        } else if (mActionBar.getSelectedNavigationIndex() == CLOCK_TAB_INDEX) {
            nightMode.setVisible(true);
        }
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if (processMenuClick(item)) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    private boolean processMenuClick(MenuItem item) {
        switch (item.getItemId()) {
            case R.id.menu_item_settings:
                startActivity(new Intent(DeskClock.this, SettingsActivity.class));
                return true;
            case R.id.menu_item_help:
                Intent i = item.getIntent();
                if (i != null) {
                    try {
                        startActivity(i);
                    } catch (ActivityNotFoundException e) {
                        // No activity found to match the intent - ignore
                    }
                }
                return true;
            case R.id.menu_item_night_mode:
                startActivity(new Intent(DeskClock.this, ScreensaverActivity.class));
            default:
                break;
        }
        return true;
    }