我正在使用Viewpager在页面之间切换.我在ViewPager中有五个页面,它从我的自定义游标适配器获取数据.问题是切换页面不顺畅,这是不稳定的.我究竟做错了什么 ？任何帮助都非常感谢.
// MYPAGER
private class MyPagerAdapter extends PagerAdapter{
public int getCount()
{
return 5;
}
public Object instantiateItem(View collection,int position)
{
LayoutInflater inflater = (LayoutInflater) collection.getContext()
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View view;
SharedPreferences myoptions = getSharedPreferences("options",Context.MODE_PRIVATE);
SharedPreferences.Editor prefEditor = myoptions.edit();
view = inflater.inflate(R.layout.all_tasks,null);
((ViewPager) collection).addView(view,0);
//getting list view
lv= (ListView)findViewById(R.id.list);
MyAdapter adapter1;
switch (position) {
case 0:
prefEditor.putInt("filter",5);
prefEditor.commit();
if(selectedList!=null)
{
cursor1= managedQuery(uri,PROJECTION,where +" AND "+ taskColumns.LIST+ "= ?"
+" AND "+ taskColumns.DONE+ "= ?",new String[] {selectedList,"0"},sortingOrder);
}
else
cursor1= managedQuery(uri,where+" AND "+ taskColumns.DONE+ "= ?",new String[] {"0"},sortingOrder);
if (cursor1 != null)
{
cursor1.movetoFirst();
}
adapter1 = new MyAdapter(tasks.this,cursor1);
lv.setAdapter(adapter1);
break;
case 1:
prefEditor.putInt("filter",4);
prefEditor.commit();
if(selectedList!=null)
{
cursor1= managedQuery(uri,taskColumns.LIST+ "= ?",new String[] {selectedList},sortingOrder);
}
else
cursor1= managedQuery(uri,where,null,sortingOrder);
if (cursor1 != null)
{
cursor1.movetoFirst();
}
adapter1 = new MyAdapter(tasks.this,cursor1);
lv.setAdapter(adapter1);
break;
case 2:
prefEditor.putInt("filter",1);
prefEditor.commit();
if(selectedList!=null)
{
cursor1= managedQuery(uri,where +" AND "+ taskColumns.LIST+ "= ?",sortingOrder);
if (cursor1 != null)
{
cursor1.movetoFirst();
}
adapter1 = new MyAdapter(tasks.this,cursor1);
lv.setAdapter(adapter1);
break;
case 3:
prefEditor.putInt("filter",2);
prefEditor.commit();
if(selectedList!=null)
{
cursor1= managedQuery(uri,cursor1);
lv.setAdapter(adapter1);
break;
case 4:
prefEditor.putInt("filter",3);
prefEditor.commit();
if(selectedList!=null)
{
cursor1= managedQuery(uri,sortingOrder);
if (cursor1 != null)
{
cursor1.movetoFirst();
}
adapter1 = new MyAdapter(tasks.this,cursor1);
lv.setAdapter(adapter1);
break;
}
return view;
}
@Override
public void destroyItem(View arg0,int arg1,Object arg2) {
((ViewPager) arg0).removeView((View) arg2);
}
@Override
public boolean isViewFromObject(View arg0,Object arg1) {
return arg0 == ((View) arg1);
}
@Override
public Parcelable saveState()
{
return null;
}
}
//自定义适配器
static class ViewHolder {
public TextView task;
public TextView note;
public ImageView note_img;
public TextView priority;
public CheckBox done;
public TextView showingByList;
public TextView space;
public LinearLayout b;
}
public class MyAdapter extends CursorAdapter {
private final int taskIndex;
private final LayoutInflater Inflater;
private final int doneIndex;
private final int priorIndex;
private final int rowIndex;
private final int taskListIndex;
private final int NoteIndex;
boolean innewView;
public MyAdapter(Context context,Cursor c)
{
super(context,c);
this.taskIndex = c.getColumnIndex(taskColumns.TASK);
this.priorIndex = c.getColumnIndex(taskColumns.PRIORITY);
this.doneIndex = c.getColumnIndex(taskColumns.DONE);
this.rowIndex = c.getColumnIndex(taskColumns._ID);
this.taskListIndex = c.getColumnIndex(taskColumns.LIST);
this.NoteIndex = c.getColumnIndex(taskColumns.NOTE);
this.Inflater = LayoutInflater.from(context);
}
@Override
public View newView(Context context,Cursor cursor,ViewGroup parent)
{
View v = Inflater.inflate(R.layout.tasks_row,parent,false);
innewView=true;
return v;
}
@Override
public void bindView(View view,Context context,final Cursor cursor) {
final ViewHolder viewHolder;
if(innewView)
{
viewHolder = new ViewHolder();
viewHolder.task = (TextView) view.findViewById(R.id.task);
viewHolder.note = (TextView) view.findViewById(R.id.note);
viewHolder.note_img = (ImageView) view.findViewById(R.id.note_img);
viewHolder.priority = (TextView) view.findViewById(R.id.priority);
viewHolder.done = (CheckBox) view.findViewById(R.id.check);
viewHolder.b=(LinearLayout)view.findViewById(R.id.task_layout);
viewHolder.showingByList = (TextView) view.findViewById(R.id.tasklist);
view.setTag(viewHolder);
}
else
viewHolder = (ViewHolder)view.getTag();
innewView=false;
final String task = cursor.getString(taskIndex);
String TaskNote = cursor.getString(NoteIndex);
int prior= cursor.getInt(priorIndex);
int taskDone= cursor.getInt(doneIndex);
final long id=cursor.getLong(rowIndex);
int uniqueyindex = cursor.getColumnIndex(taskColumns.UNIQUEY);
if(TaskNote==null)
{
viewHolder.note.setVisibility(View.GONE);
viewHolder.note_img.setVisibility(View.GONE);
}
else
{
if(TaskNote.length()<1)
{
viewHolder.note.setVisibility(View.GONE);
viewHolder.note_img.setVisibility(View.GONE);
}
else{
viewHolder.note.setVisibility(View.VISIBLE);
viewHolder.note_img.setVisibility(View.VISIBLE);
}
}
if(showbyList){
String taskList = cursor.getString(taskListIndex);
if(taskList==null)
{
ContentValues valuey=new ContentValues();
valuey.put(taskColumns.LIST_ID,"0");
valuey.put(taskColumns.LIST,"personal");
Uri mUry = ContentUris.withAppendedId(uri,id);
getContentResolver().update(mUry,valuey,null);
taskList="personal";
}
// viewHolder.showingByList.setTypeface(tf);
viewHolder.b.setVisibility(View.VISIBLE);
viewHolder.space=(TextView)view.findViewById(R.id.space);
viewHolder.space.setVisibility(View.VISIBLE);
if(cursor.movetoPrevIoUs()){
int comparedResult= taskList.compareto(cursor.getString(taskListIndex));
if(comparedResult==0)
{
viewHolder.showingByList.setVisibility(View.GONE);
}
else{
viewHolder.showingByList.setVisibility(View.VISIBLE);
viewHolder.showingByList.setText(taskList.toupperCase());
}
}
else{
viewHolder.showingByList.setVisibility(View.VISIBLE);
viewHolder.showingByList.setText(taskList.toupperCase());
}
cursor.movetoNext();
viewHolder.showingByList.setonClickListener(new OnClickListener()
{
public void onClick(View arg0) {
}
});
}
viewHolder.b.setBackgroundResource(R.drawable.my_drawable1);
if(toModify.contains((int)id))
viewHolder.b.setBackgroundResource(R.color.light_blue);
viewHolder.task.setText(task);
if(TaskNote!=null)
viewHolder.note.setText(TaskNote);
if(taskDone==1){
viewHolder.done.setChecked(true);
viewHolder.task.setTextColor(getResources().getColor(R.color.smooth));
viewHolder.note.setTextColor(getResources().getColor(R.color.smooth));
viewHolder.note_img.setimageResource(R.drawable.note_done2);
viewHolder.priority.setBackgroundResource(R.drawable.priornone);
}
else{
viewHolder.done.setChecked(false);
viewHolder.task.setTextColor(getResources().getColor(R.color.darkthemed_text));
viewHolder.note.setTextColor(getResources().getColor(R.color.darkthemed_note));
viewHolder.note_img.setimageResource(R.drawable.note2);
if(prior==1){
viewHolder.priority.setBackgroundResource(R.drawable.priornone);
}
else{
viewHolder.priority.setBackgroundResource(R.color.priority_2);
}
}
}
}
解决方法
将来,请尝试发布少量代码.如同,请尝试隔离您可能认为发生问题的特定区域.我知道您可能不知道,在这种情况下,转储两个适配器都没问题.只要知道,当有更少的代码可供阅读时,任何人都可以帮助您.
至于你可以做什么,你应该尝试使用ViewPager中的setoffScreenPageLimit.
Set the number of pages that should be retained to either side of the
current page in the view hierarchy in an idle state. Pages beyond this
limit will be recreated from the adapter when needed.
Here are the docs for it.
例
YOURPAGER.setoffscreenPageLimit(LIMIT);