选项菜单与内容联动

最新推荐文章于 2023-01-07 08:08:34 发布

原创最新推荐文章于 2023-01-07 08:08:34 发布 · 555 阅读

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选项菜单

main.xml

<menu xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:tools="http://schemas.android.com/tools"
      tools:ignore="AppCompatResource">
    <item android:id="@+id/menu_toggle_log"
          android:showAsAction="always"
          android:title="@string/sample_show_log" />
</menu>

activity_main.xml

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/sample_main_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <ViewAnimator
        android:id="@+id/sample_output"
        android:layout_width="match_parent"
        android:layout_height="0px"
        android:layout_weight="1">

        <ScrollView
            style="@style/Widget.SampleMessageTile"
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                style="@style/Widget.SampleMessage"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:paddingBottom="@dimen/vertical_page_margin"
                android:paddingLeft="@dimen/horizontal_page_margin"
                android:paddingRight="@dimen/horizontal_page_margin"
                android:paddingTop="@dimen/vertical_page_margin"
                android:text="@string/intro_message"/>
        </ScrollView>

        <fragment
            android:id="@+id/log_fragment"
            android:name="com.example.android.common.logger.LogFragment"
            android:layout_width="match_parent"
            android:layout_height="match_parent"/>

    </ViewAnimator>

MainActivity.java

    ...
    private boolean mLogShown;
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
    @Override
    public boolean onPrepareOptionsMenu(Menu menu) {
        MenuItem logToggle = menu.findItem(R.id.menu_toggle_log);
        //根据当前显示的内容是否为ViewAnimator而决定是否显示logToogle菜单
        logToggle.setVisible(findViewById(R.id.sample_output) instanceof ViewAnimator);
        //根据ViewAnimator显示子控件而决定logToggle显示的标题内容
        logToggle.setTitle(mLogShown ? R.string.sample_hide_log : R.string.sample_show_log);
        return super.onPrepareOptionsMenu(menu);
    }
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case R.id.menu_toggle_log:
                mLogShown = !mLogShown;
                ViewAnimator output = (ViewAnimator) findViewById(R.id.sample_output);
                if (mLogShown) {
                    output.setDisplayedChild(1);
                } else {
                    output.setDisplayedChild(0);
                }
                //更新菜单，调用onCreateOptionsMenu与onPrepareOptionsMenu
                supportInvalidateOptionsMenu();
                return true;
        }
        return super.onOptionsItemSelected(item);
    }