dialog,activity 屏蔽Home键详解（转）

相信在Android应用上，很多时候逻辑是需要屏蔽Home键的，但这个用户体验是否需要，就看各位的需求了。?
??? 一般的方法屏蔽Home键，大家一定看过不少文章了。我总结一下，先说一下一般情况下Activity的屏蔽按键和Home键吧。?
屏蔽其他键，重写onKeyDown?

Java代码??

1. @Override??
2. public?boolean?onKeyDown(int?keyCode,?KeyEvent?event)?{??
3. ????Log.i(TAG,"keycode="+keyCode?+?"???isBan="+isBan);??
4. ????switch?(keyCode)?{??
5. ????????case?KeyEvent.KEYCODE_BACK:??
6. ????????Log.i(TAG,"KEYCODE_BACK");??
7. ????????return?true;??
8. ????}??
9. ????return?super.onKeyDown(keyCode,?event);??
10. }??

大家会发现，这里屏蔽Home键是捕捉不到的，因为大家的权限一般是User所以是无效的。?
而其实android处理Home键等系统级按键是有一定的处理的。?
引用看看源码是怎样处理的 \frameworks\policies\base\phone\com\android\internal\policy\impl\PhoneWindowManager.java #1092Java代码??

1. //?First?we?always?handle?the?home?key?here,?so?applications??
2. //?can?never?break?it,?although?if?keyguard?is?on,?we?do?let??
3. //?it?handle?it,?because?that?gives?us?the?correct?5?second??
4. //?timeout.??
5. if?(code?==?KeyEvent.KEYCODE_HOME)?{??
6. ??
7. ????//?If?a?system?window?has?focus,?then?it?doesn't?make?sense??
8. ????//?right?now?to?interact?with?applications.??
9. ????WindowManager.LayoutParams?attrs?=?win?!=?null???win.getAttrs()?:?null;??
10. ????if?(attrs?!=?null)?{??
11. ????????final?int?type?=?attrs.type;??
12. ????????if?(type?==?WindowManager.LayoutParams.TYPE_KEYGUARD??
13. ???????????||?type?==?WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG)?{??
14. ????????????//?the?"app"?is?keyguard,?so?give?it?the?key??
15. ????????????return?false;??
16. ????????}??
17. ????????final?int?typeCount?=?WINDOW_TYPES_WHERE_HOME_DOESNT_WORK.length;??
18. ????????for?(int?i=0;?i<typeCount;?i++)?{??
19. ????????????if?(type?==?WINDOW_TYPES_WHERE_HOME_DOESNT_WORK[i])?{??
20. ????????????????//?don't?do?anything,?but?also?don't?pass?it?to?the?app??
21. ????????????????return?true;??
22. ????????????}??
23. ????????}??
24. ????}??

通过源码，我们不难发现两个的参数 WindowManager.LayoutParams.TYPE_KEYGUARD和?
WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG?
借鉴于此，重写onAttachedToWindow，以实现屏蔽Home键Java代码??

1. public?void?onAttachedToWindow()?{??
2. ????this.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD);??
3. ????super.onAttachedToWindow();??
4. }??

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轮到dialog了，如果在Activity弹出dialog，在Activity设置以上2个方法是没办法屏蔽的。?
其实，原理是一样的，只是地方不一样而已。?
Java代码??

1. final?Dialog?dialog?=?new?Dialog(this);??
2. dialog.setContentView(R.layout.mydailog);??
3. dialog.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD);??
4. dialog.show();??
5. ??
6. dialog.setOnKeyListener(new?android.content.DialogInterface.OnKeyListener(){??
7. ????@Override??
8. ????public?boolean?onKey(DialogInterface?dialog,?int?keyCode,KeyEvent?event)?{??
9. ????????switch?(keyCode)?{??
10. ????????????case?KeyEvent.KEYCODE_BACK:??
11. ????????????Log.i(TAG,"KEYCODE_BACK");??
12. ????????????return?true;??
13. ????????}??
14. ????????return?false;??
15. ????}??
16. });???

这样运行后，出错如下：?
Error代码??

1. 10-18?13:27:06.380:?ERROR/AndroidRuntime(4684):?Caused?by:?android.view.WindowManager$BadTokenException:?Unable?to?add?window?android.view.ViewRoot$W@2b046d68?--?permission?denied?for?this?window?type??

其实，只需要把dialog.getWindow().setType的位置放在show后面就可以了?
正确代码??

1. dialog.show();??
2. dialog.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD);??

这么，就完成了Back键的屏蔽 和Home键盘的屏蔽了！?

总结：?
1:)在以上用WindowManager.LayoutParams.TYPE_KEYGUARD的地方改用?
WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG 效果一样。至于两者的具体差别，得以后再研究研究。?

2:)其实，在源码里是这样调用的。Java代码??

1. final?AlertDialog?dialog?=?new?AlertDialog.Builder(mContext)??
2. ????.setTitle(null)??
3. ????.setMessage(message)??
4. ????.setNeutralButton(R.string.ok,?null)??
5. ????.create();??
6. dialog.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG);??
7. dialog.show();??

??? 但我们如果这样调用就会出现之前的那个error：permission denied for this window type 这就显而易见了吧~~?

3:)ProgressDialog 默认屏蔽 Back键，Dialog，AlertDialog则需setOnKeyListener?

4:)其实屏蔽Home键，在页面的某个地方，例如一个Button的onClick里，去设置setType就可以了,如：?
Java代码??

1. button.setOnClickListener(new?View.OnClickListener()?{??
2. ????@Override??
3. ????public?void?onClick(View?v)?{??
4. ????????getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD);??
5. ????}??
6. });??

但前提是重载Activity的onAttachedToWindow()，哪怕只是一个空实现，然后返回父类方法。?
Java代码??

1. @Override????
2. public?void?onAttachedToWindow()?{??
3. ????super.onAttachedToWindow();??
4. }??

5:)其实它们，都是常用的~Java代码??

1. switch?(keyCode)?{??
2. ????case?KeyEvent.KEYCODE_HOME:??
3. ????????Log.i(TAG,"KEYCODE_HOME");??
4. ????????return?true;??
5. ????case?KeyEvent.KEYCODE_BACK:??
6. ????????Log.i(TAG,"KEYCODE_BACK");??
7. ????????return?true;??
8. ????case?KeyEvent.KEYCODE_CALL:??
9. ????????Log.i(TAG,"KEYCODE_CALL");??
10. ????????return?true;??
11. ????case?KeyEvent.KEYCODE_SYM:??
12. ????????Log.i(TAG,"KEYCODE_SYM");??
13. ????????return?true;??
14. ????case?KeyEvent.KEYCODE_VOLUME_DOWN:??
15. ????????Log.i(TAG,"KEYCODE_VOLUME_DOWN");??
16. ????????return?true;??
17. ????case?KeyEvent.KEYCODE_VOLUME_UP:??
18. ????????Log.i(TAG,"KEYCODE_VOLUME_UP");??
19. ????????return?true;??
20. ????case?KeyEvent.KEYCODE_STAR:??
21. ????????Log.i(TAG,"KEYCODE_STAR");??
22. ????????return?true;??
23. }??

希望大家看到这个文章能觉得有用，谢谢已阅者！?

- - - - - - - - - - - - -? - - - - - - - - - - - - - - - - 华丽的分界线，以下内容更精彩- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -?

2011-10-20 更新如下：?
总结1:)的问题，有答案了,时间问题我就简单写写吧：?
??? 从功能上来说，是一样的，区别在样式。?
??? 如果你喜欢用Theme.Dialog去把一个Activity装饰成一个Dialog去显示，你会发现。?
在Androidmanifest.xml代码??

1. android:theme="@android:style/Theme.Dialog"??

背景是透明的。?
如果在Android代码??

1. setTheme(android.R.style.Theme_Dialog);??

背景则是黑色的。?
这是为什么呢？。。。我不知道。?
治标不治本的方法来了！若你在Activity重写onAttachedToWindow?
Java代码??

1. public?void?onAttachedToWindow()?{??
2. ????this.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG);??
3. ????super.onAttachedToWindow();??
4. }??

那么出来的效果，就是透明背景的dialog了，当然前提是你需要实现屏蔽Home键。至于其中到底哪一代码导致样式改变呢，那就以后再去看源代码了~?

希望大家看到这个文章能觉得有用，再次谢谢已阅者

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