《Android内核剖析》第8章笔记

1. 分析

1.1 主要类

1.2 主要流程

1.3 关键代码

    private void openPanel(PanelFeatureState st, KeyEvent event) {        // System.out.println("Open panel: isOpen=" + st.isOpen);        // Already open, return        if (st.isOpen) {            return;        }        Callback cb = getCallback();        if ((cb != null) && (!cb.onMenuOpened(st.featureId, st.menu))) {            // Callback doesn't want the menu to open, reset any state            closePanel(st, true);            return;        }        final WindowManager wm = getWindowManager();        if (wm == null) {            return;        }        // Prepare panel (should have been done before, but just in case)        if (!preparePanel(st, event)) {            return;        }        ....

    public final boolean preparePanel(PanelFeatureState st, KeyEvent event) {        // Already prepared (isPrepared will be reset to false later)        if (st.isPrepared)            return true;        if ((mPreparedPanel != null) && (mPreparedPanel != st)) {            // Another Panel is prepared and possibly open, so close it            closePanel(mPreparedPanel, false);        }        final Callback cb = getCallback();        if (cb != null) {            st.createdPanelView = cb.onCreatePanelView(st.featureId);        }        if (st.createdPanelView == null) {            // Init the panel state's menu--return false if init failed            if (st.menu == null) {                if (!initializePanelMenu(st) || (st.menu == null)) {                    return false;                }                // Call callback, and return if it doesn't want to display menu                if ((cb == null) || !cb.onCreatePanelMenu(st.featureId, st.menu)) {                    // Ditch the menu created above                    st.menu = null;                    return false;                }            }            // Callback and return if the callback does not want to show the menu            if (!cb.onPreparePanel(st.featureId, st.createdPanelView, st.menu)) {                return false;            }            // Set the proper keymap            KeyCharacterMap kmap = KeyCharacterMap.load(event != null ? event.getDeviceId() : 0);            st.qwertyMode = kmap.getKeyboardType() != KeyCharacterMap.NUMERIC;            st.menu.setQwertyMode(st.qwertyMode);        }        // Set other state        st.isPrepared = true;        st.isHandled = false;        mPreparedPanel = st;        return true;    }

根据Callback 也即Activity的onCreatePanelView()方法的返回结果，导致preparePanel返回不同的布尔值，最终影响openPanel()方法的执行路径。若返回false，表示使用完全自定义的OptionMenu视图，openPanel()直接退出；否则使用系统的OptionMenu视图。

所以，可以重写Activity的onCreatePanelView()方法提供一个完全自定义的OptionMenu视图

2. 示例

1. Java代码。重写Activity的onCreatePanelView()方法。

public class CustomOptionMenuActivity extends Activity {@Overridepublic View onCreatePanelView(int featureId) {// return super.onCreatePanelView(featureId);View v = getLayoutInflater().inflate(R.layout.activity_custom_option_menu, null);v.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {MyLog.i("");Toast.makeText(CustomOptionMenuActivity.this, "text",Toast.LENGTH_SHORT).show();CustomOptionMenuActivity.this.finish();}});return v;}}

2. 布局文件

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:orientation="vertical" android:layout_width="fill_parent"android:layout_height="fill_parent"><TextView android:text="TextView" android:id="@+id/textView1"android:layout_width="wrap_content" android:layout_height="wrap_content"android:paddingBottom="10dip"></TextView></LinearLayout>

3. 截图

如上图，点击Menu键后，出现一个自定义OptionMenu。

Android(安卓)简单定制OptionMenu外观

1. 分析

1.1 主要类

1.2 主要流程

1.3 关键代码

2. 示例

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