一般AP中的back键是怎么被监听到的？

纠结的木棉花 2011-04-15 01:45:44

如题？程序片段是怎样の？

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Mourinho 2011-04-26

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void onBackPressed() //Called when the activity has detected the user's press of the back key.
在Activity里重写此方法即可

yxmsw2007 2011-04-16

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activity中onKeyDown源码是这样写的
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
if (getApplicationInfo().targetSdkVersion
>= Build.VERSION_CODES.ECLAIR) {
event.startTracking();
} else {
onBackPressed();
}
return true;
}
if (mDefaultKeyMode == DEFAULT_KEYS_DISABLE) {
return false;
} else if (mDefaultKeyMode == DEFAULT_KEYS_SHORTCUT) {
if (getWindow().performPanelShortcut(Window.FEATURE_OPTIONS_PANEL,
keyCode, event, Menu.FLAG_ALWAYS_PERFORM_CLOSE)) {
return true;
}
return false;
} else {
// Common code for DEFAULT_KEYS_DIALER & DEFAULT_KEYS_SEARCH_*
boolean clearSpannable = false;
boolean handled;
if ((event.getRepeatCount() != 0) || event.isSystem()) {
clearSpannable = true;
handled = false;
} else {
handled = TextKeyListener.getInstance().onKeyDown(
null, mDefaultKeySsb, keyCode, event);
if (handled && mDefaultKeySsb.length() > 0) {
// something useable has been typed - dispatch it now.

final String str = mDefaultKeySsb.toString();
clearSpannable = true;

switch (mDefaultKeyMode) {
case DEFAULT_KEYS_DIALER:
Intent intent = new Intent(Intent.ACTION_DIAL, Uri.parse("tel:" + str));
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
break;
case DEFAULT_KEYS_SEARCH_LOCAL:
startSearch(str, false, null, false);
break;
case DEFAULT_KEYS_SEARCH_GLOBAL:
startSearch(str, false, null, true);
break;
}
}
}
if (clearSpannable) {
mDefaultKeySsb.clear();
mDefaultKeySsb.clearSpans();
Selection.setSelection(mDefaultKeySsb,0);
}
return handled;
}
}

CyberLogix 2011-04-15

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[Quote=引用 3 楼 javasoldiers 的回复:]

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
//监听到back键了，做你想要的处理就可以了，呵呵
} ……
[/Quote]

楼上正解，帮顶

javasoldiers 2011-04-15

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@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
//监听到back键了，做你想要的处理就可以了，呵呵
}
return super.onKeyDown(keyCode, event);
}

dinjay 2011-04-15

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一般的都会在down里拦截，但是不排除一些在上层屏蔽的设备，那就需要在dispatch里处理了。

XiangZhiLiu 2011-04-15

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@Override  

        public boolean onKeyDown(int keyCode, KeyEvent event)  {  

            if (keyCode == KeyEvent.KEYCODE_BACK && event.getRepeatCount() == 0) {   

            //按下的如果是BACK，同时没有重复  

              //DO SOMETHING      

            }  

  

            return super.onKeyDown(keyCode, event);  

        }

希望对lz有用
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