嗨朋友们我很长时间都在尝试在shardepreferences中保存动态添加的Viewpager视图。因此，当用户下次打开应用程序时，他添加的页面或视图应该在那里。但我没有成功。我试图在sharedpreferences中保存ArrayList的大小，然后尝试调用下次用户打开应用程序时重新生成ArrayList的大小。我正在做的是我在寻呼机中添加的页数与for循环等于ArrayList的大小。我不知道这是正确的方式还是我完全错了。请通过这个指导我。提前致谢。我正在上传我的用户界面的图片enter image description here。我在这里粘贴我的代码。首先是我的适配器的代码。
import android.content.Context;
import android.content.SharedPreferences;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.FrameLayout;
import android.widget.LinearLayout;
import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;
import java.lang.reflect.Type;
import java.util.ArrayList;
public class MainPagerAdapter extends PagerAdapter
{
private ArrayList<View> views = new ArrayList<View>();
SharedPreferences preferences;
Context context;
LayoutInflater inflater;
final static String PREF_COUNT="com.savesampledata";
final static String PREF_KEY="com.savesampledata.key";
final static String PREF_LIST="com.savesampledata.list";
final static String PREF_LIST_KEY="com.savesampledata.listkey";
int numberofview;
public MainPagerAdapter(Context c){
context=c;
}
@Override
public int getItemPosition (Object object)
{
int index = views.indexOf (object);
if (index == -1)
return POSITION_NONE;
else
return index;
}
@Override
public Object instantiateItem (ViewGroup container, int position)
{
Log.v("instantiate is called","now");
View v;
v = views.get(position);
if(v.getParent()!=null)
((ViewGroup)v.getParent()).removeView(v);
container.addView(v);
return v;
}
@Override
public void destroyItem (ViewGroup container, int position, Object object)
{
container.removeView (views.get (position));
}
@Override
public int getCount ()
{
Log.d("view list size",views.size()+"");
Log.d("numofViews before save",numberofview+"");
return views.size();
}
@Override
public boolean isViewFromObject (View view, Object object)
{
return view == object;
}
public int addView (View v)
{
return addView (v, views.size());
}
public int addView (View v, int position)
{
views.add (position, v);
return position;
}
public int removeView (ViewPager pager, View v)
{
return removeView (pager, views.indexOf (v));
}
public int removeView (ViewPager pager, int position)
{
if (numberofview > 1)
position = numberofview - 1;
if(position>0) {
pager.setAdapter(null);
views.remove(position);
pager.setAdapter(this);
}
return position;
}
public View getView (int position)
{
return views.get (position);
}
public void setCount(){
//storing size of views list
SharedPreferences preferences=context.getSharedPreferences(PREF_COUNT,Context.MODE_PRIVATE);
SharedPreferences.Editor editor=preferences.edit();
editor.putInt(PREF_KEY,views.size());
Log.d("shared stored val :",views.size()+"");
editor.apply();
}
public int getNumberOfView(){
//getting size of views list
SharedPreferences preferences=context.getSharedPreferences(PREF_COUNT, Context.MODE_PRIVATE);
numberofview=preferences.getInt(PREF_KEY,0);
return numberofview;
}
}
我的活动代码：
import android.content.Context;
import android.content.SharedPreferences;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.Button;
import android.widget.FrameLayout;
import android.widget.LinearLayout;
public class ViewPagerActivity extends AppCompatActivity implements View.OnClickListener {
private ViewPager pager =null;
private MainPagerAdapter pageradapter=null;
Button addpagebtn,removebtn;
final static String PREF_COUNT="com.savesampledata";
final static String PREF_KEY="com.savesampledata.key";
int numberofview;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.view_pager_activity);
addpagebtn=(Button)findViewById(R.id.addbtn) ;
removebtn=(Button)findViewById(R.id.removeButton);
removebtn.setOnClickListener(this);
addpagebtn.setOnClickListener(this);
pageradapter= new MainPagerAdapter(this);
pager=(ViewPager)findViewById(R.id.view_pager);
pager.setAdapter(pageradapter);
pager.setOffscreenPageLimit(3);
numberofview=pageradapter.getNumberOfView();//here i am getting the value
Log.d("value after saving",pageradapter.getNumberOfView()+"");
LayoutInflater inflater=getLayoutInflater();
FrameLayout v0=(FrameLayout)inflater.inflate(R.layout.sample_layout_page,null);
pageradapter.addView(v0,0);
pageradapter.notifyDataSetChanged();
if(numberofview>1) {
Log.d("ManyView","added");
for (int i = 1; i <= numberofview; i++) {
pageradapter.addView(v0,i);
pageradapter.notifyDataSetChanged();
}
}
}
public void addView(View newpage){
int pageIndex=pageradapter.addView(newpage);
Log.d("page added at",pageIndex+"");
pageradapter.notifyDataSetChanged();
pageradapter.setCount();
pager.setCurrentItem(pageIndex,true);
}
public void removeView(View defunctPage){
int pageindex=pageradapter.removeView(pager,defunctPage);
Log.d("page removed at",pageindex+"");
pageradapter.notifyDataSetChanged();
pageradapter.setCount();
if(pageindex==pageradapter.getCount())
pageindex--;
pager.setCurrentItem(pageindex);
}
public View getCurrentPage(){
return pageradapter.getView(pager.getCurrentItem());
}
public void setCurrentPage(View pageToShow){
pager.setCurrentItem(pageradapter.getItemPosition(pageToShow),true);
}
@Override
public void onClick(View v) {
if(v.getId()==R.id.addbtn) {
LayoutInflater inflater=getLayoutInflater();
FrameLayout v0=(FrameLayout)inflater.inflate(R.layout.sample_layout_page,null);
addView(v0);
pageradapter.setCount();
}
if(v.getId()==R.id.removeButton){
View v1=getCurrentPage();
removeView(v1);
pageradapter.setCount();
}
}
@Override
protected void onStop() {
//here I am storing value
super.onStop();
pageradapter.setCount();
}
}