如何在Android中實現View Pager適配器？
[英]How to implement view pager adapter in android?
問題描述
我正在構建一個類似於TechCrunch的android應用程序，用戶可以在其中滑動文章。
我曾經使用過View pager適配器來做到這一點，但是我的應用程序有時崩潰了。 我在logcat中收到的錯誤是：
java.lang.IllegalStateException：應用程序的PagerAdapter更改了適配器的內容，而沒有調用PagerAdapter＃notifyDataSetChanged！ 預期的適配器項數：40，找到的：50尋呼機ID：com.yslabs.yourstory：id / myviewpager尋呼機類：類android.support.v4.view.ViewPager有問題的適配器：類android.support.v4上的singlearticle.SingleArticle $ MyPagerAdapter .view.ViewPager.populate（ViewPager.java:962）在android.support.v4.view.ViewPager.populate（ViewPager.java:914）在android.support.v4.view.ViewPager $ 3.run（ViewPager.java： 244）在android.view.Choreographer $ CallbackRecord.run（Choreographer.java:747）在android.view.Choreographer.doCallbacks（Choreographer.java:567）在android.view.Choreographer.doFrame（Choreographer.java:535）在android.os.Handler.dispatchMessage（Handler.java:92）處的android.os.Handler.handleCallback（Handler.java:615）處的android.view.Choreographer $ FrameDisplayEventReceiver.run（Choreographer.java:733） .Looper.loop（Looper.java:153）在android.app.ActivityThread.main（ActivityThread.java:5034）在java.lang.reflect.Method.invokeNative（本機方法）在java.lang.reflect.Method.invoke （遇見 com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:821）處的com.android.internal.os.ZygoteInit.main（ZygoteInit.java:584）處的od.java:511） .NativeStart.main（本機方法）
這是我使用視圖頁面適配器的類
public class SingleArticleAfrica extends Activity {
ConnectionDetector checkConnection;
Boolean isInternetPresent = false;
ViewPager viewPage;
MyPagerAdapter mypageAdapter;
@SuppressWarnings("deprecation")
@SuppressLint({ "InflateParams", "SetJavaScriptEnabled", "HandlerLeak",
"NewApi" })
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.check);
viewPage = (ViewPager) findViewById(R.id.myviewpager);
mypageAdapter = new MyPagerAdapter(this, ArticleDataHolder.getData());
viewPage.setAdapter(mypageAdapter);
viewPage.setCurrentItem(ArticleDataHolder.getPosition());
viewPage.setOnPageChangeListener(new OnPageChangeListener() {
@Override
public void onPageSelected(int position) {
// TODO Auto-generated method stub
ArticleDataHolder.setPosition(position);
viewPage.setCurrentItem(position);
}
@Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
// TODO Auto-generated method stub
}
@Override
public void onPageScrollStateChanged(int arg0) {
// TODO Auto-generated method stub
}
});
getActionBar().setBackgroundDrawable(
new ColorDrawable(Color.parseColor("#f8f8f8")));
ActionBar actionBar = getActionBar();
actionBar.setDisplayHomeAsUpEnabled(true);
ActionBar mActionBar = getActionBar();
mActionBar.setDisplayShowHomeEnabled(true);
mActionBar.setDisplayShowTitleEnabled(false);
LayoutInflater mInflater = LayoutInflater.from(this);
View mCustomView = mInflater.inflate(R.layout.customactionbar, null);
TextView mTitleTextView = (TextView) mCustomView
.findViewById(R.id.title_text);
Typeface fontt = Typeface.createFromAsset(getAssets(),
"helvetica.ttf");
mTitleTextView.setTypeface(fontt);
mActionBar.setCustomView(mCustomView);
mActionBar.setDisplayShowCustomEnabled(true);
mActionBar.setLogo(R.drawable.africaicon);
// String htmldata =
// "<html><style = text/css> img{width:100%!important;height:auto!important;}iframe{max-
width:100%;max-height:100%;}a { color:#3366CC; text-decoration: none; }</style><body
style = line-
height:25px; >"
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu items for use in the action bar
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.main2, menu);
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle presses on the action bar items
switch (item.getItemId()) {
case R.id.action_refresh:
Intent sendIntent = new Intent();
sendIntent.setAction(Intent.ACTION_SEND);
sendIntent.putExtra(
Intent.EXTRA_TEXT,
ArticleDataHolder.getData()
.get(ArticleDataHolder.getPosition()).getTitle()
+ "\n"
+ ArticleDataHolder.getData()
.get(ArticleDataHolder.getPosition())
.getPermalink());
sendIntent.setType("text/plain");
startActivity(sendIntent);
return true;
case android.R.id.home:
onBackPressed();
/*web1.loadUrl("");
web1.stopLoading();*/
return true;
default:
return super.onOptionsItemSelected(item);
}
}
public class myWebClient extends WebViewClient
{
@Override
public void onPageStarted(WebView view, String url, Bitmap favicon) {
// TODO Auto-generated method stub
super.onPageStarted(view, url, favicon);
}
@Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
// TODO Auto-generated method stub
view.loadUrl(url);
return true;
}
@Override
public void onPageFinished(WebView view, String url) {
// TODO Auto-generated method stub
super.onPageFinished(view, url);
// progressBar.setVisibility(View.GONE);
}
}
// To handle "Back" key press event for WebView to go back to previous
// screen.
@SuppressWarnings("static-access")
@Override
public boolean onKeyDown(int keyCode, KeyEvent event)
{
if (keyCode == event.KEYCODE_BACK) {
/*web1.loadUrl("");
web1.stopLoading();*/
finish();
}
return super.onKeyDown(keyCode, event);
}
private class MyPagerAdapter extends PagerAdapter {
Context context;
List<Movie> list;
public MyPagerAdapter(Context context, List<Movie> list) {
this.context = context;
this.list = list;
}
@Override
public int getCount() {
return list.size();
}
@Override
public boolean isViewFromObject(View arg0, Object arg1) {
return arg0 == arg1;
}
public Object instantiateItem(ViewGroup container, int position) {
/* *Title* */
float titleSize = 25;
TextView titleView = new TextView(SingleArticleAfrica.this);
Typeface fontType = Typeface.createFromAsset(getAssets(),
"helvetica-neue-regular-1361522098.ttf");
titleView.setTypeface(fontType);
titleView.setTextSize(titleSize);
titleView.setBackgroundResource(R.color.list_background);
titleView.setTypeface(Typeface.DEFAULT_BOLD);
titleView.setText(list.get(position).getTitle());
/* * Date * */
TextView dateView = new TextView(SingleArticleAfrica.this);
dateView.setTextColor(Color.GRAY);
dateView.setBackgroundResource(R.color.list_background);
dateView.setTextSize(14);
dateView.setPadding(10, 0, 0, 0);
dateView.setTypeface(Typeface.DEFAULT_BOLD);
dateView.setText(list.get(position).getAuthor()
+ " "
+ list.get(position)
.getDate()
.substring(0,
list.get(position).getDate().length() - 3));
/* *Article Content* */
WebView web1 = new WebView(SingleArticleAfrica.this);
web1.setWebViewClient(new myWebClient());
web1.getSettings().setJavaScriptCanOpenWindowsAutomatically(true);
web1.getSettings().setJavaScriptEnabled(true);
web1.getSettings().setDefaultFontSize(18);
web1.setWebChromeClient(new WebChromeClient());
web1.getSettings().setPluginState(PluginState.ON_DEMAND);
String c = single.content;
c = c.replace("src=\"//", "src=\"https://");
final String ALLOWED_URI_CHARS = "@#&=*+-_.,:!?()/~'%";
String htmldata = "<!DOCTYPE html><html><style = text/css>
img{width:100%!important;height:auto!important;} iframe{width:100sp;max-height:100sp;}a {
color:#3366CC; text-decoration: none; } </style> <body style = 'line-height:25px;'>"
+ list.get(position).getContent() + "</body></html>";
web1.loadData(htmldata, "text/html; charset=utf-8", null);
/* *Facebook Comment* */
WebView fbCommentview = new WebView(SingleArticleAfrica.this);
fbCommentview.setWebViewClient(new myWebClient());
fbCommentview.getSettings()
.setJavaScriptCanOpenWindowsAutomatically(true);
fbCommentview.getSettings().setJavaScriptEnabled(true);
fbCommentview.getSettings().setDefaultFontSize(18);
fbCommentview.setWebChromeClient(new WebChromeClient());
fbCommentview.getSettings().setPluginState(PluginState.ON_DEMAND);
checkConnection = new ConnectionDetector(getApplicationContext());
isInternetPresent = checkConnection.isConnectingToInternet();
if (isInternetPresent) {
// Toast.makeText(getApplicationContext(),"Internet Working",
// Toast.LENGTH_SHORT).show();
fbCommentview.setVisibility(View.VISIBLE);
} else {
// Toast.makeText(getApplicationContext(),"Internet Not Working",
// Toast.LENGTH_SHORT).show();
fbCommentview.setVisibility(View.GONE);
}
ScrollView scrollView = new ScrollView(SingleArticleAfrica.this);
LinearLayout layout = new LinearLayout(SingleArticleAfrica.this);
layout.setOrientation(LinearLayout.VERTICAL);
layout.addView(titleView);
layout.addView(dateView);
layout.addView(web1);
layout.addView(fbCommentview);
scrollView.addView(layout);
container.addView(scrollView);
return scrollView;
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
//container.removeView((ScrollView) object);
}
}
}
這是getPosition類代碼：
public class ArticleDataHolder {
static List<Movie> data = new ArrayList<Movie>();
static int position;
public static void setData(Movie movie){
data.add(movie);
}
public static List<Movie> getData(){
return data;
}
public static void setPosition(int pos){
position = pos;
}
public static int getPosition(){
return position;
}
}
請幫我！！ 為了讓我更了解這個問題並提出了解決方案。
1 個解決方案
解決方案1
0 2014-12-21 11:17:51
此錯誤表明您的data(list)大小已更改，但未pagerAdapter.notifyDataChanged() 。 當setData和list在代碼中更改時，此更改后應調用notifyDataChanged() 。 在哪里調用ArticleDataHolder.setData() ？
Android - 無法在 View Pager Adapter 中更新 textview
[英]Android - Can't update textview within View Pager Adapter
Android：如何在TabLayout中的部分尋呼機適配器內替換/刪除片段
[英]Android: how to replace/delete a fragment inside section pager adapter in TabLayout
聲明:本站的技術帖子網頁，遵循CC BY-SA 4.0協議，如果您需要轉載，請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.