Android：返回上一个活动时，文本字段显示为空

Question

I have a problem with back button functionality in an Activity of Android. The first Activity having the Spinner to select one item from the Spinner's list and second one is the text field. I implemented search functionality using the Spinner and text field. The results are displaying fine as a ListView .

Here my Problem is:

While returning to the first Activity , the Spinner and text field are showing empty in the Activity . It should show the previous searched results.

Help me with the sample code/ links.

Answer 1

Its normal. When your first Activity goes to back ground its finished by System itself. So make sure to save your data in some place and in Activitie's onCreate() and onRestart() method reload the data to TextView and spinner..

Edits: Create a Data class and Store your search results in String[] array or a String or how ever you like it. and make the class a singlton class. and when you come back to this screen fetch those data's and set Text of TextView and adapter for Spinner..

Shafi yes, i am calling the back function using Intent as Intent i=new Intent (presentClass.this, previousClass.class);

Don't do this. Because the Activity stack will become like loop with same Activities started again n again. Instead just finish presentClass .. it will come back to previousClass

Answer 2

除了@ntc帖子外，还可以查看Activity中的onSaveInstanceState(Bundle outState)和onRestoreInstanceState(Bundle state)方法。

Answer 3

Dont create a new intent. You just need to call finish() from your second Activity to handle back event and move back to your first activity.