如何在Android中使用保存的实例状态和恢复带有微调的实例状态?
我的活动中有一个带有选项列表的微调工具
当用户选择一个选项时,我使用OnItemSelected适配器来获取所选选项的位置值,并在其中添加了一些If Else语句。If语句实际上从预定义的数据库生成一个随机字符串并显示在TextView上。
现在我将切换回另一个练习,并再次返回到此练习。现在的问题是,默认情况下,微调控件的第一个选项仅处于选中状态,我需要使用用户最后选择的选项进行更新,当活动再次启动时,必须运行该选项的功能。
我也做了一些搜索,发现可以使用onSaveInstanceState
和onRestoreInstanceState
NOW:
- 如何使用这两个?应该将它们放在哪里:onItemSelected(适配器)内部还是外部?
- 如何将用户选择的新位置值更新(或存储)为随机生成的代码?
为清楚起见,请检查我的代码:
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.layout_scheduledactivity);
/**displayed when the activity is launched (this should be
updated with the user selected option)**/
Resources res = getResources();
myString = res.getStringArray(R.array.normal);
String q = myString[rgenerator.nextInt(myString.length)];
TextView tv = (TextView) findViewById(R.id.text1);
tv.setText(q);
//initiating the spinner
Spinner s = (Spinner) findViewById( R.id.spinner);
s.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener(){
@Override
public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) {
if (pos == 1){
//displayed on the time when user selects the option
Resources res = getResources();
myString = res.getStringArray(R.array.hardships);
String q = myString[rgenerator.nextInt(myString.length)];
TextView tv = (TextView) findViewById(R.id.text1);
tv.setText(q);
}
else {
//do nothing
}
编辑后的问题:
为了更清楚起见,我对问题进行了编辑。基本上我想做的是,我想保存他们的用户选择的位置,与微调。当用户点击"Thankyou"Button
时,活动将结束,并在几分钟后由来自不同班级的广播接收器呼叫开始。当活动再次开始时,用户的最后一个选定选项(上一个活动)必须作为此活动中的默认选项。
我认为如果您查看代码,问题出在保存和还原实例状态。
请看我的代码:
import java.util.Random;
import android.app.Activity;
import android.content.res.Resources;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;
public class MyScheduledActivity extends Activity {
private String[] myString;
private static final Random rgenerator = new Random();
protected int mPos;
protected String mSelection;
String situation[] = {"Normal","Hardship","Sadness","Exam"};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.layout_scheduledactivity);
if (mPos == 0) {
Resources res = getResources();
myString = res.getStringArray(R.array.normal);
String q = myString[rgenerator.nextInt(myString.length)];
TextView tv = (TextView) findViewById(R.id.text1);
tv.setText(q);
}
//selection of the spinner
Spinner s = (Spinner) findViewById( R.id.spinner);
// Application of the Array to the Spinner
ArrayAdapter<String> spinnerArrayAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, situation);
spinnerArrayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
s.setAdapter(spinnerArrayAdapter);
s.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener(){
@Override
public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) {
MyScheduledActivity.this.mPos = pos;
MyScheduledActivity.this.mSelection = parent.getItemAtPosition(pos).toString();
//display toast
Toast.makeText(parent.getContext(), "The Situation is " +
parent.getItemAtPosition(pos).toString(), Toast.LENGTH_LONG).show();
if (mPos == 0){
Resources res = getResources();
myString = res.getStringArray(R.array.hardships);
String q = myString[rgenerator.nextInt(myString.length)];
TextView tv = (TextView) findViewById(R.id.text1);
tv.setText(q);
}
if (mPos == 1){
Resources res = getResources();
myString = res.getStringArray(R.array.hardships);
String q = myString[rgenerator.nextInt(myString.length)];
TextView tv = (TextView) findViewById(R.id.text1);
tv.setText(q);
}
else {
//do nothing
}
}
@Override
public void onNothingSelected(AdapterView<?> parentView) {
//do something else
return;
}
});
//dismiss button - Thank You
Button buttonDismiss = (Button)findViewById(R.id.dismiss);
buttonDismiss.setOnClickListener(new Button.OnClickListener(){
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
finish();
}});
}
@Override
protected void onSaveInstanceState(Bundle outState) {
outState.putStringArray(mSelection, situation);
super.onSaveInstanceState(outState);
}
@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
situation = savedInstanceState.getStringArray("mSelection");
super.onRestoreInstanceState(savedInstanceState);
}
}
This is how the activity looks
解决方案
在当前活动中,重写名为onSaveInstanceState()
的方法,并将数据放入包中。
并覆盖另一个方法onRestoreInstanceState()
并从包中获取这些值...
相关文章