状态栏增加返回按键

Init.rc中增加按键显示开关
setprop ro.statusbar.key.support 1

StatusBarServic.java
makeStatusBarView函数会调用创建一个Myticker
mTicker = new MyTicker(context, sb);
MyTicker是继承了Ticker类，并且把Ticker的3个抽样类实例化，增加按键要在里面添加内容
private class MyTicker extends Ticker {
        MyTicker(Context context, StatusBarView sb) {
            super(context, sb);
        }

        @Override
        void tickerStarting() {
            if (SPEW) Slog.d(TAG, "tickerStarting");
            mTicking = true;
            mIcons.setVisibility(View.GONE);
            mHomeBtn.setVisibility(View.GONE);
            mBackBtn.setVisibility(View.GONE);
            mMenuBtn.setVisibility(View.GONE);
            mTickerView.setVisibility(View.VISIBLE);
            mTickerView.startAnimation(loadAnim(com.android.internal.R.anim.push_up_in, null));
            mIcons.startAnimation(loadAnim(com.android.internal.R.anim.push_up_out, null));
            if (mExpandedVisible) {
                setDateViewVisibility(false, com.android.internal.R.anim.push_up_out);
            }
        }

        @Override
        void tickerDone() {
            if (SPEW) Slog.d(TAG, "tickerDone");
            mTicking = false;
            mIcons.setVisibility(View.VISIBLE);
//wbn

        if (SystemProperties.getInt("ro.statusbar.key.support", 0) != 0) {
            mHomeBtn.setVisibility(View.VISIBLE);
            mBackBtn.setVisibility(View.VISIBLE);
            mMenuBtn.setVisibility(View.VISIBLE);
        }
            mTickerView.setVisibility(View.GONE);
            mIcons.startAnimation(loadAnim(com.android.internal.R.anim.push_down_in, null));
            mTickerView.startAnimation(loadAnim(com.android.internal.R.anim.push_down_out, null));
            if (mExpandedVisible) {
                setDateViewVisibility(true, com.android.internal.R.anim.push_down_in);
            }
        }

        void tickerHalting() {
            if (SPEW) Slog.d(TAG, "tickerHalting");
            mTicking = false;
            mIcons.setVisibility(View.VISIBLE);
//wbn

        if (SystemProperties.getInt("ro.statusbar.key.support", 0) != 0) {
            mHomeBtn.setVisibility(View.VISIBLE);
            mBackBtn.setVisibility(View.VISIBLE);
            mMenuBtn.setVisibility(View.VISIBLE);
        }
            mTickerView.setVisibility(View.GONE);
            mIcons.startAnimation(loadAnim(com.android.internal.R.anim.fade_in, null));
            mTickerView.startAnimation(loadAnim(com.android.internal.R.anim.fade_out, null));
            if (mExpandedVisible) {
                setDateViewVisibility(true, com.android.internal.R.anim.fade_in);
            }
        }
    }

    private Animation loadAnim(int id, Animation.AnimationListener listener) {
        Animation anim = AnimationUtils.loadAnimation(StatusBarService.this, id);
        if (listener != null) {
            anim.setAnimationListener(listener);
        }
        return anim;
    }


    StatusBarPolicy.java
    private BroadcastReceiver mIntentReceiver = new BroadcastReceiver()中增加获得按键控件消息
    else if (action.equals("android.intent.action.ICONKEY_CHANGED")) {
     Log.d(TAG, "Received ACTION_ICONKEY_CHANGED");
     updateIconKeyAction(intent);
                }
    并且下面增加按键消息增加更新按键的函数
     private void updateIconKeyAction(Intent intent) {
         final int keycode = intent.getIntExtra("keycode", -1);
     Thread sendKeyDelay = new Thread(){
     public void run(){
     IWindowManager wm = IWindowManager.Stub.asInterface(ServiceManager.getService("window"));
     try{
     Thread.sleep(100);
     if (keycode != -1) {
     long now = SystemClock.uptimeMillis();
     KeyEvent down = new KeyEvent(now, now, KeyEvent.ACTION_DOWN, keycode, 0);
     KeyEvent up = new KeyEvent(now, now, KeyEvent.ACTION_UP, keycode, 0);

     try {
     wm.injectKeyEvent(down, false);
     }
     catch (RemoteException e) {
     e.printStackTrace();
     Log.i("Input", "DeadObjectException1");
     }

     try {
     wm.injectKeyEvent(up, false);
     }
     catch (RemoteException e) {
     e.printStackTrace();
     Log.i("Input", "DeadObjectException2");
     }
     }
     }
            catch (InterruptedException e) {
     e.printStackTrace();
     Log.i("Input", "DeadObjectException3");
     }
         }
         };
         sendKeyDelay.start();
     };

    还需要StatusBarPolicy函数中需要添加接收key的Intent消息，这样才能获得消息实例
    filter.addAction("android.intent.action.ICONKEY_CHANGED");



    StatusBarView.java中定义发送这按键消息的函数与显示隐藏函数
     private void sendKeyIntent(int keycode) {
     Intent intent = new Intent("android.intent.action.ICONKEY_CHANGED");
     intent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY);
     intent.putExtra("keycode", keycode);
     sendIntent(intent);
     }

     private OnTouchListener homeOnTouch = new OnTouchListener() {

     @Override
     public boolean onTouch(View v, MotionEvent event) {
     // TODO Auto-generated method stub

     switch (event.getAction()) {
     case MotionEvent.ACTION_UP:
     {
     sendKeyIntent(KeyEvent.KEYCODE_HOME);
     }
     break;
     }
     return false;
     }
     };

     private OnTouchListener backOnTouch = new OnTouchListener() {

     @Override
     public boolean onTouch(View v, MotionEvent event) {
     // TODO Auto-generated method stub

     switch (event.getAction()) {
     case MotionEvent.ACTION_UP:
     {
     sendKeyIntent(KeyEvent.KEYCODE_BACK);
     }
     break;
     }
     return false;
     }
     };

     private OnTouchListener menuOnTouch = new OnTouchListener() {

     @Override
     public boolean onTouch(View v, MotionEvent event) {
     // TODO Auto-generated method stub

     switch (event.getAction()) {
     case MotionEvent.ACTION_UP:
     {
     sendKeyIntent(KeyEvent.KEYCODE_MENU);
     }
     break;
     }
     return false;
     }
     };

    public void hiddenHotIcons() {
    //wbn

     if (SystemProperties.getInt("ro.statusbar.key.support", 0) != 0) {
     mHomeBtn.setVisibility(View.INVISIBLE);
     mBackBtn.setVisibility(View.INVISIBLE);
     mMenuBtn.setVisibility(View.INVISIBLE);
     }
     }

     public void showHotIcons() {
    //wbn

     if (SystemProperties.getInt("ro.statusbar.key.support", 0) != 0) {
     mHomeBtn.setVisibility(View.VISIBLE);
     mBackBtn.setVisibility(View.VISIBLE);
     mMenuBtn.setVisibility(View.VISIBLE);
     }
     }
    }



    Status_bar.xml布局中增加按键
    <ImageButton android:id="@+id/go_home"
                android:layout_width="45dip"
                android:layout_height="wrap_content"
                android:layout_alignParentRight="true"
                android:layout_gravity="center_vertical"
                android:paddingTop="8dip"
                android:layout_alignParentBottom="true"
                android:clickable="true"
                android:background="@drawable/stat_home"
                />

            <ImageButton android:id="@+id/pop_menu"
                android:layout_width="45dip"
                android:layout_height="wrap_content"
                android:layout_alignParentLeft="true"
                android:layout_gravity="center_vertical"
                android:paddingTop="8dip"
                android:layout_alignParentBottom="true"
                android:clickable="true"
                android:background="@drawable/stat_menu"
                />

            <ImageButton android:id="@+id/go_back"
                android:layout_width="45dip"
                android:layout_height="wrap_content"
                android:layout_alignParentLeft="true"
                android:layout_gravity="center_vertical"
                android:paddingTop="8dip"
                android:layout_alignParentBottom="true"
                android:clickable="true"
                android:background="@drawable/stat_back"
                />

    按键按下与未按下图片显示不一致，所以需要2个图片与图片显示控制文件stat_home.xml，放在drawable目录下，代码如下
    <?xml version="1.0" encoding="utf-8"?>
    <selector
        xmlns:android="">
        <item
            android:state_focused="true"
            android:state_pressed="false"
            android:drawable="@drawable/stat_home_normal" />

        <item
            android:state_focused="true"
            android:state_pressed="true"
            android:drawable="@drawable/stat_home_pressed" />

        <item
            android:state_focused="false"
            android:state_pressed="true"
            android:drawable="@drawable/stat_home_pressed" />

        <item
            android:drawable="@drawable/stat_home_normal" />
    </selector>