android5.1为锁屏设置一张固定加载的背景图片

可按如下步骤实现：

1，在alps/frameworks/base/packages/SystemUI/res/drawable添加图片资源keyguard_wallpaper.png

2，PhoneStatusBar.java中：

        //begin 添加下面一行

       PanelHolder   mHolder;//成员变量

        //end

...

protected PhoneStatusBarView makeStatusBarView() {

           ...

            //begin 将下面第一行替换为第二行

            PanelHolder   holder = (PanelHolder) mStatusBarWindow.findViewById(R.id.panel_holder);           

          mHolder = (PanelHolder) mStatusBarWindow.findViewById(R.id.panel_holder);

          //end

           ...

  private void updateKeyguardState(boolean goingToFullShade, boolean fromShadeLocked) {

          ...

             if (mState == StatusBarState.KEYGUARD || mState == StatusBarState.SHADE_LOCKED) {

                       //begin 添加下面一段
                      mHolder.post(new Runnable(){

                              public void run(){

                                  mholder.setBackgroundResource(R.drawable.keyguard_wallpaper);

                              }

                      });

                       //end
                      mScrimController.setKeyguardShowing(true);
        } else {

                       //begin 添加下面一行
                      mHolder.setBackgroundResource(0);

                       //end  

                      mScrimController.setKeyguardShowing(false);
        }

          ...

}