android 4.0 障蔽home键实现

android 4.0 屏蔽home键实现

最近研究锁屏，按照常规的方法，常规方法如下

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

 

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<uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"/>，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。

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

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

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。