Android在web view下点击返回键直接退出程序完美解决

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/q"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:fadingEdgeLength="0sp"
android:orientation="vertical" >
//下方代码
<WebView
android:id="@+id/webView"
android:layout_width="match_parent"
android:layout_height="match_parent" />

</LinearLayout>

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//下方代码
webView = (WebView) findViewById(R.id.webView);
}

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
if(webView.canGoBack()){
webView.goBack();
return true;
}
}
return super.onKeyDown(keyCode, event);
}