dispatchKeyEvent和onKeyDown
来源:互联网 发布:汤不热视频下载软件 编辑:程序博客网 时间:2024/05/18 02:38
1)当我们重写了onKeyDown方法后,如果return false,则会继续调用系统的onKeyDown方法。
如果只想让程序调用自己写的onKeyDown,则需要return true。
利用该特性可以拦截耳机耳机按键,防止启动音乐。
下面转载一下拦截屏幕按键的方法:
在Android系统中用来显示界面的组件(Component)为Activity,也就是说只有重写Activity的onKeyDown方法来监控/拦截/屏蔽系统的返回键(back)、菜单键(Menu)及Home键。
1、拦截/屏蔽返回键、菜单键实现代码
1
2
3
4
5
6
7
8
9
10
11
12
2
3
4
5
6
7
8
9
10
11
12
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if(keyCode == KeyEvent.KEYCODE_BACK) { //监控/拦截/屏蔽返回键
processExit();
return true;
} else if(keyCode == KeyEvent.KEYCODE_MENU) {
//监控/拦截菜单键
} else if(keyCode == KeyEvent.KEYCODE_HOME) {
//由于Home键为系统键,此处不能捕获,需要重写onAttachedToWindow()
}
return super.onKeyDown(keyCode, event);
}
public boolean onKeyDown(int keyCode, KeyEvent event) {
if(keyCode == KeyEvent.KEYCODE_BACK) { //监控/拦截/屏蔽返回键
processExit();
return true;
} else if(keyCode == KeyEvent.KEYCODE_MENU) {
//监控/拦截菜单键
} else if(keyCode == KeyEvent.KEYCODE_HOME) {
//由于Home键为系统键,此处不能捕获,需要重写onAttachedToWindow()
}
return super.onKeyDown(keyCode, event);
}
2、拦截/屏蔽系统Home键
1
2
3
4
2
3
4
public void onAttachedToWindow() {
this.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD);
super.onAttachedToWindow();
}
this.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD);
super.onAttachedToWindow();
}
为什么必须重写onAttachedToWindow(),看看下面的代码就知道了
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
/frameworks/policies/base/phone/com/android/internal/policy/impl/PhoneWindowManager.java 1000行附近
if (code == KeyEvent.KEYCODE_HOME) {
// If a system window has focus, then it doesn't make sense
// right now to interact with applications.
WindowManager.LayoutParams attrs = win != null ? win.getAttrs() : null;
if (attrs != null) {
final int type = attrs.type;
if (type == WindowManager.LayoutParams.TYPE_KEYGUARD
|| type == WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG) {
// the "app" is keyguard, so give it the key
return false;
}
final int typeCount = WINDOW_TYPES_WHERE_HOME_DOESNT_WORK.length;
for (int i=0; i<typeCount; i++) {
if (type == WINDOW_TYPES_WHERE_HOME_DOESNT_WORK[i]) {
// don't do anything, but also don't pass it to the app
return true;
}
}
}
}
if (code == KeyEvent.KEYCODE_HOME) {
// If a system window has focus, then it doesn't make sense
// right now to interact with applications.
WindowManager.LayoutParams attrs = win != null ? win.getAttrs() : null;
if (attrs != null) {
final int type = attrs.type;
if (type == WindowManager.LayoutParams.TYPE_KEYGUARD
|| type == WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG) {
// the "app" is keyguard, so give it the key
return false;
}
final int typeCount = WINDOW_TYPES_WHERE_HOME_DOESNT_WORK.length;
for (int i=0; i<typeCount; i++) {
if (type == WINDOW_TYPES_WHERE_HOME_DOESNT_WORK[i]) {
// don't do anything, but also don't pass it to the app
return true;
}
}
}
}
当然,重写View的onKeyDown也可以实现,但View如果没有获得焦点,那就不能监控/拦截返回键、菜单键和Home键,所有还是重写Activity的onKeyDown方法比较好。
dispatchKeyEvent和onKeyDown
return true
- dispatchKeyEvent和onKeyDown
- dispatchKeyEvent和onKeyDown
- dispatchKeyEvent和onKeyDown
- dispatchKeyEvent和onKeyDown
- 关于dispatchKeyEvent和onKeyDown关系
- dispatchKeyEvent onKeyDown
- Android dispatchKeyEvent和onKeyDown事件的处理
- Android提供的onKey(),OnKeyDown()和dispatchKeyEvent()方法之间的区别
- onkeyup,onkeydown和onkeypress
- onkeyup,onkeydown和onkeypress
- onkeyup,onkeydown和onkeypress
- onKeyDown和onBackPressed
- onkeyup,onkeydown和onkeypress
- onKeyDown()
- onKeyDown
- onKeyDown
- onkeydown
- 转 : onkeyup,onkeydown和onkeypress
- InfoWorks.Technology.History.Sweeper.v3.34-BRD
- 如何删除表
- AspxGridView 相关问题总结
- svn冲突——/trunk/.settings/org.eclipse.core.resources.prefs
- 又见一帘幽梦
- dispatchKeyEvent和onKeyDown
- Excel表格实用技巧大全
- Java运行机制
- 用U盘装操作系统
- 新版MacBook Pro拆机详解【高清大图】
- 修改服务器远程端口号
- JAVA字符串处理函数
- nginx中使用https时,证书的生成方式及配置
- 唠唠叨叨又七夕