本文介绍了获取savedInstanceState值,NullPointerException异常的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main2);
savedInstanceState.putString("foo", "bar");
}
@Override
public void onRestoreInstanceState(Bundle savedInstanceState) {
super.onRestoreInstanceState(savedInstanceState);
String myString = savedInstanceState.getString("foo");
Log.i("debug", "saved data: " + myString);
}
我试着去preserve一些值一个活动,但我收到以下错误: 23 06-23:09:44.038:E / AndroidRuntime(17584):了java.lang.RuntimeException :无法启动活动ComponentInfo {se.johanberntsson.activitytest / se.johanberntsson.activitytest.TestActivity}:显示java.lang.NullPointerException
我错过了什么吗?谢谢
推荐答案
覆盖的onSaveInstanceState
在savedInstanceState捆绑储蓄值:
Override onSaveInstanceState
for saving values in savedInstanceState Bundle as:
public String strfoo="";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main2);
//comment this line you only fatch values from savedInstanceState
String myString = savedInstanceState.getString("foo");
Log.i("debug", "saved data: " + myString);
// savedInstanceState.putString("foo", "bar");
strfoo="bar"; set value here
}
@Override
public void onRestoreInstanceState(Bundle savedInstanceState) {
super.onRestoreInstanceState(savedInstanceState);
String myString = savedInstanceState.getString("foo");
Log.i("debug", "saved data: " + myString);
}
@Override
public void onSaveInstanceState(Bundle savedInstanceState) {
savedInstanceState.putString("foo", strfoo);
super.onSaveInstanceState(savedInstanceState);
}
这篇关于获取savedInstanceState值,NullPointerException异常的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!