android4.0屏蔽home键

public void onAttachedToWindow()
{
this.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD);
super.onAttachedToWindow();
}

但是这个方法到了4.0的系统上就失效了，按home照样会返回桌面。apktool了几个锁屏的软件之后发现其实现方法，即用WindowManager的addview方法将view加到窗口上，加上的时候将view的layoutparamas的type设为LayoutParams.TYPE_SYSTEM_ERROR，这个值sdk的解释为

Java代码

public static final int TYPE_SYSTEM_ERROR
Since: API Level 1
Window type: internal system error windows, appear on top of everything they can.

如果直接这样用会报错，还要在AndroidManifest.xml里面加上权限，ok上完整代码，封装了一个类，其中Lock和hide方法实现锁屏和解锁。
Java代码

public class LockLayer {
private Activity mActivty;
private WindowManager mWindowManager;
private View mLockView;
private LayoutParams mLockViewLayoutParams;

public LockLayer(Activity act) {
mActivty = act;
init();
}

private void init(){
mWindowManager = mActivty.getWindowManager();
mLockViewLayoutParams = new LayoutParams();
mLockViewLayoutParams.width = LayoutParams.MATCH_PARENT;
mLockViewLayoutParams.height = LayoutParams.MATCH_PARENT;
//实现关键
mLockViewLayoutParams.type = LayoutParams.TYPE_SYSTEM_ERROR;
//apktool value，这个值具体是哪个变量还请网友帮忙
mLockViewLayoutParams.flags = 1280;
}
public void lock() {
if(mLockView!=null){
mWindowManager.addView(mLockView, mLockViewLayoutParams);
}
}
public void unlock() {
if(mWindowManager!=null){
mWindowManager.removeView(mLockView);
}
}
public void setLockView(View v){
mLockView = v;
}
}

使用方法如下
Java代码

public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
View lock = View.inflate(this, R.layout.main, null);
LockLayer lockLayer = new LockLayer(this);
lockLayer.setLockView(lock);
lockLayer.lock();
}

ok,这时可以实现按home键不返回桌面的效果，其他的键需要用另外的代码实现，网上都有。这段代码只调用一次的时候没有问题，但是如果遇到多线程或者多次lock和hide就会有问题，修改如下，一是将LockLayer改为单例模式，二是在hide和lock的时候先判断状态。修改后代码如下
Java代码

public class LockLayer {
private Activity mActivty;
private WindowManager mWindowManager;
private View mLockView;
private LayoutParams mLockViewLayoutParams;
private static LockLayer mLockLayer;
private boolean isLocked;

public static synchronized LockLayer getInstance(Activity act){
if(mLockLayer == null){
mLockLayer = new LockLayer(act);
}
return mLockLayer;
}

private LockLayer(Activity act) {
mActivty = act;
init();
}

private void init(){
isLocked = false;
mWindowManager = mActivty.getWindowManager();
mLockViewLayoutParams = new LayoutParams();
mLockViewLayoutParams.width = LayoutParams.MATCH_PARENT;
mLockViewLayoutParams.height = LayoutParams.MATCH_PARENT;
//实现关键
mLockViewLayoutParams.type = LayoutParams.TYPE_SYSTEM_ERROR;
//apktool value，这个值具体是哪个变量还请网友帮忙
mLockViewLayoutParams.flags = 1280;
}
public synchronized void lock() {
if(mLockView!=null&&!isLocked){
mWindowManager.addView(mLockView, mLockViewLayoutParams);
}
isLocked = true;
}
public synchronized void unlock() {
if(mWindowManager!=null&&isLocked){
mWindowManager.removeView(mLockView);
}
isLocked = false;
}
public synchronized void setLockView(View v){
mLockView = v;
}
}

还有个问题是mLockViewLayoutParams.flags = 1280;1280这个值具体是哪个变量还不知道，有知道的留个言。