嗨，我正在制作一个可以从链接下载视频的应用程序。
但是我得到了NullPointerException (在kr.co.lenonstudio.kakaovideo.webviewActivity.onCreate(webviewActivity.java:43)
webviewactivity.java:43是 link = intent.getExtras()。getString(“link”);
我已经重点介绍了出现问题的地方。谢谢。
webviewactivity.java
package kr.co.lenonstudio.kakaovideo;
import java.util.ArrayList;
import kr.co.lenonstudio.kakaovideo.R;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.View;
import android.webkit.JavascriptInterface;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Button;
import android.widget.Toast;
import com.gc.materialdesign.views.ButtonRectangle;
public class webviewActivity extends Activity{
WebView webview;
int listcount=0;
String link;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_webview);
//getExtra
Intent intent=this.getIntent();
**link=intent.getExtras().getString("link");**
///
webview=(WebView)this.findViewById(R.id.webView);
webview.setWebViewClient(new WebClient());
ButtonRectangle btn=(ButtonRectangle)this.findViewById(R.id.webView_btn);
btn.setOnClickListener(btnClickListener);
WebSettings set=webview.getSettings();
set.setJavaScriptEnabled(true);
webview.addJavascriptInterface(new myJavaInterface(this),"HtmlViewer");
webview.loadUrl(""+link+"");
webview.loadUrl("javascript:alert(InjectedObject.showHTML())");
// Bus.getInstance().adapter=new Adapter_movie(Bus.getInstance().context,R.layout.item_movie,Bus.getInstance().arrayList);
}
View.OnClickListener btnClickListener=new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
webview.loadUrl("javascript:window.HtmlViewer.setCount"+"(document.getElementsByClassName('_videoThumbnailImg').length);");
try {
Thread.sleep(1000l);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
if(listcount>0)
{
webview.loadUrl("javascript:var t=document.getElementsByClassName('_videoThumbnailImg').length; for(var i=0;i<t;i++){window.HtmlViewer.setMovie"+"(document.getElementsByClassName('bn_play _btnViewVideo')[i].getAttribute('data-url'));}");
webview.loadUrl("javascript:var t=document.getElementsByClassName('_videoThumbnailImg').length; for(var i=0;i<t;i++){window.HtmlViewer.setImg"+"(document.getElementsByClassName('_videoThumbnailImg')[i].getAttribute('src'));}");
webview.loadUrl("javascript:window.HtmlViewer.inputlist"+"();");
//
try {
Thread.sleep(2000l);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Toast.makeText(webviewActivity.this,"Video Extracted",Toast.LENGTH_SHORT).show();
}
else
{
Toast.makeText(webviewActivity.this,"Video not Extracted.",Toast.LENGTH_SHORT).show();
}
}
};
public class myJavaInterface
{
Context ctx;
ArrayList<String> movie_src=new ArrayList<String>();
ArrayList<String> img_src=new ArrayList<String>();
LoadImage li;
int i;
myJavaInterface(Context ctx)
{
this.ctx=ctx;
}
@JavascriptInterface
public void showHTML(String html)
{
new AlertDialog.Builder(ctx).setTitle("HTML").setMessage(html).setPositiveButton(android.R.string.ok,null).setCancelable(false).create().show();
}
@JavascriptInterface
public void setCount(String inputcount)
{
listcount= Integer.parseInt(inputcount);
Log.d(""+listcount,"setCount");
}
@JavascriptInterface
public void setImg(String src)
{
img_src.add(src);
//async
Log.d(""+src,"img_src");
}
Handler handler=new Handler()
{
public void handleMessage(Message message)
{
if(i<img_src.size())
Bus.getInstance().adapter.add(new Item_movie(li.bitmapImage,movie_src.get(i)));
}
};
@JavascriptInterface
public void inputlist()
{
Log.d(""+img_src.size(),"inputlist");
//
for(i=0;i<img_src.size();i++)
{
li=new LoadImage();
li.ShowImageExecute(img_src.get(i));
while(li.bitmapImage==null)
{
if(li.bitmapImage!=null)
{
break;
}
}
if(Bus.getInstance().ImageList.size()!=0)
{
Log.d(i+"ImageListSize!=0","inputlist");
boolean isequal=false;
for(LoadImage tmp:Bus.getInstance().ImageList)
{
if(tmp.src.equals(li.src))
{
Log.d("Has same list on LoadImage","inputlist");
isequal=true;
break;
}
}
if(!isequal)
{
Bus.getInstance().ImageList.add(li);
Bus.getInstance().arrayList.add(new Item_movie(li.bitmapImage,movie_src.get(i)));
Bus.getInstance().adapter.add(new Item_movie(li.bitmapImage,movie_src.get(i)));
//handler.sendEmptyMessage(0);
Bus.getInstance().adapter.notifyDataSetChanged();
}
}else
{
Log.d(i+"ImageListSize:0","inputlist");
Bus.getInstance().ImageList.add(li);
Bus.getInstance().arrayList.add(new Item_movie(li.bitmapImage,movie_src.get(i)));
Log.d("before"+Bus.getInstance().adapter.toString(),"inputlist");
handler.sendEmptyMessage(0);
Log.d("after","inputlist");
}
}//for
}
@JavascriptInterface
public void setMovie(String src)
{
movie_src.add(src);
Log.d(""+src,"movie_src");
}
}
class WebClient extends WebViewClient
{
public boolean shouldoverrideUrlLoading(WebView view,String url)
{
view.loadUrl(url);
return true;
}
}
}<br><br>
MainActivity.java
package kr.co.lenonstudio.kakaovideo;
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import com.gc.materialdesign.views.ButtonFlat;
import java.util.ArrayList;
public class MainActivity
extends Fragment
{
public void onCreate(Bundle paramBundle)
{
super.onCreate(paramBundle);
}
public View onCreateView(LayoutInflater paramLayoutInflater, ViewGroup paramViewGroup, Bundle paramBundle)
{
View localView = paramLayoutInflater.inflate(R.layout.activity_main, paramViewGroup, false);
this.linkedit = ((EditText)localView.findViewById(R.id.main_search_edit));
this.linksearch = ((ButtonFlat)localView.findViewById(R.id.main_search_btn));
this.list = ((ListView)localView.findViewById(R.id.main_list));
this.comment = ((TextView)localView.findViewById(R.id.search_comment));
this.linkedit.setText(Bus.getInstance().link);
Bus.getInstance().context = getActivity();
this.adapter = new Adapter_movie(getActivity().getApplicationContext(), 2130903076, this.arrayList);
this.list.setAdapter(this.adapter);
this.list.setOnItemClickListener(this.listItemClickListener);
Bus.getInstance().ImageList = new ArrayList();
Bus.getInstance().arrayList = this.arrayList;
Bus.getInstance().adapter = this.adapter;
this.idsearch.setOnClickListener(this.idsearchClickListener);
return localView;
}
Adapter_movie adapter;
ArrayList<Item_movie> arrayList = new ArrayList();
TextView comment;
String link = null;
EditText idedit;
ButtonFlat linksearch;
View.OnClickListener linksearchClickListener = new View.OnClickListener()
{
public void onClick(View paramAnonymousView)
{
TextView localTextView = MainActivity.this.comment;
localTextView.setVisibility(View.VISIBLE);
MainActivity.this.link = MainActivity.this.idedit.getText().toString();
if (MainActivity.this.link.length() != 0)
{
LoadMovieAsync localLoadMovieAsync = new LoadMovieAsync();
String[] arrayOfString = new String[1];
arrayOfString[0] = MainActivity.this.link;
Intent localIntent = new Intent(MainActivity.this.getActivity().getApplicationContext(), webviewActivity.class);
localIntent.putExtra("link", MainActivity.this.link);
MainActivity.this.startActivity(localIntent);
return;
}
Toast.makeText(MainActivity.this.getActivity().getApplicationContext(), "Please Input ID.", Toast.LENGTH_SHORT).show();
}
};
ListView list;
AdapterView.OnItemClickListener listItemClickListener = new AdapterView.OnItemClickListener()
{
public void onItemClick(AdapterView<?> paramAnonymousAdapterView, View paramAnonymousView, int paramAnonymousInt, long paramAnonymousLong)
{
Bus.getInstance().sel_position = paramAnonymousInt;
Log.d("aaaaa" + paramAnonymousInt, "pos");
}
};
public void fileSave(android.content.Context paramContext)
{
}
}
Logcat
02-27 01:42:06.414 907-907/kr.co.lenonstudio.kakaovideo E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: kr.co.lenonstudio.kakaovideo, PID: 907
java.lang.RuntimeException: Unable to start activity ComponentInfo{kr.co.lenonstudio.kakaovideo/kr.co.lenonstudio.kakaovideo.webviewActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.os.Bundle.getString(java.lang.String)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
at android.app.ActivityThread.access$800(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.os.Bundle.getString(java.lang.String)' on a null object reference
***at kr.co.lenonstudio.kakaovideo.webviewActivity.onCreate(webviewActivity.java:43)***
at android.app.Activity.performCreate(Activity.java:5933)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2251)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
at android.app.ActivityThread.access$800(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
最佳答案
因为使用link而不是Intent发送Bundle值。因此，使用Intent从getStringExtra获取价值:
Intent intent=this.getIntent();
if(intent !=null)
link = intent.getStringExtra("link");