Android：連接兩個活動並相應地更改清單

Question

我正在嘗試學習android/java編程的基礎知識。我從教程中創建了一個基本的RSS android應用程序。我添加了另一個活動來創建一個新的開始屏幕，我試圖鏈接到教程中的主要RSS活動，但是當我運行該應用程序時，當我點擊新開始屏幕上的按鈕時，它總是崩潰。我在這裏做了明顯錯誤的事嗎？

這裏的XML「firstscreen」爲我創造

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
android:layout_width="match_parent" 
android:layout_height="match_parent" 
android:orientation="vertical" > 

<Button 
    android:id="@+id/button1" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_gravity="center_horizontal" 
    android:onClick="gotorssfunction" 
    android:text="@string/rssfeed" /> 

</LinearLayout> 

在這裏，新的開始屏幕是我創建的是新的開始屏幕

package com.testproject.newsapp2; 

import android.app.Activity; 
import android.content.Intent; 
import android.os.Bundle; 
import android.view.View; 

public class MainScreen extends Activity{ 

@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.firstscreen); 
} 

public void gotorssfuction(View v){ 

    Intent i = new Intent(this, NewsApp2Activity.class); 
    startActivity(i); 

    } 

} 

在這裏，新的活動是一個從主要的RSS活動教程（它曾經是開始屏幕）

package com.testproject.newsapp2; 

import java.util.List; 

import com.testproject.newsapp2.data.RssItem; 
import com.testproject.newsapp2.listeners.ListListener; 
import com.testproject.newsapp2.util.RssReader; 

import android.app.Activity; 
import android.os.AsyncTask; 
import android.os.Bundle; 
import android.util.Log; 
import android.widget.ArrayAdapter; 
import android.widget.ListView; 



/** 
* Main application activity. 
* 
* Update: Downloading RSS data in an async task 
*/ 
public class NewsApp2Activity extends Activity { 

// A reference to the local object 
private NewsApp2Activity local; 

/** 
* This method creates main application view 
*/ 
@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    // Set view 
    setContentView(R.layout.main); 

    // Set reference to this activity 
    local = this; 

    GetRSSDataTask task = new GetRSSDataTask(); 

    // Start download RSS task 
    task.execute("http://rss.nytimes.com/services/xml/rss/nyt/Arts.xml"); 

    // Debug the thread name 
    Log.d("ITCRssReader", Thread.currentThread().getName()); 
} 

private class GetRSSDataTask extends AsyncTask<String, Void, List<RssItem> > { 
    @Override 
    protected List<RssItem> doInBackground(String... urls) { 

     // Debug the task thread name 
     Log.d("ITCRssReader", Thread.currentThread().getName()); 

     try { 
      // Create RSS reader 
      RssReader rssReader = new RssReader(urls[0]); 

      // Parse RSS, get items 
      return rssReader.getItems(); 

     } catch (Exception e) { 
      Log.e("ITCRssReader", e.getMessage()); 
     } 

     return null; 
    } 

    @Override 
    protected void onPostExecute(List<RssItem> result) { 

     // Get a ListView from main view 
     ListView itcItems = (ListView) findViewById(R.id.listMainView); 

     // Create a list adapter 
     ArrayAdapter<RssItem> adapter = new ArrayAdapter<RssItem> (local,android.R.layout.simple_list_item_1, result); 
     // Set list adapter for the ListView 
     itcItems.setAdapter(adapter); 

     // Set list view item click listener 
     itcItems.setOnItemClickListener(new ListListener(result, local)); 
    } 
} 
} 

而這裏是清單

<uses-sdk 
    android:minSdkVersion="7" 
    android:targetSdkVersion="17" /> 
<uses-permission android:name="android.permission.INTERNET"/> 

<application 
    android:allowBackup="true" 
    android:icon="@drawable/ic_launcher" 
    android:label="@string/app_name" 
    android:theme="@style/AppTheme" > 
    <activity 
     android:name="com.testproject.newsapp2.MainScreen" 
     android:label="@string/app_name" > 
     <intent-filter> 
      <action android:name="android.intent.action.MAIN" /> 

      <category android:name="android.intent.category.LAUNCHER" /> 
     </intent-filter> 
    </activity> 
      <activity 
     android:name=".NewsApp2Activity" 
     android:label="@string/app_name" > 
    </activity> 
</application> 

</manifest> 

這裏的logcat的

02-18 16:37:09.638: E/Trace(8930): error opening trace file: No such file or directory (2) 
02-18 16:37:09.638: D/ActivityThread(8930): setTargetHeapUtilization:0.25 
02-18 16:37:09.638: D/ActivityThread(8930): setTargetHeapIdealFree:8388608 
02-18 16:37:09.638: D/ActivityThread(8930): setTargetHeapConcurrentStart:2097152 
02-18 16:37:09.778: D/libEGL(8930): loaded /system/lib/egl/libEGL_adreno200.so 
02-18 16:37:09.778: D/libEGL(8930): loaded /system/lib/egl/libGLESv1_CM_adreno200.so 
02-18 16:37:09.788: D/libEGL(8930): loaded /system/lib/egl/libGLESv2_adreno200.so 
02-18 16:37:09.818: I/Adreno200-EGLSUB(8930): <ConfigWindowMatch:2087>: Format RGBA_8888. 
02-18 16:37:09.828: E/(8930): <s3dReadConfigFile:75>: Can't open file for reading 
02-18 16:37:09.838: E/(8930): <s3dReadConfigFile:75>: Can't open file for reading 
02-18 16:37:09.838: D/OpenGLRenderer(8930): Enabling debug mode 0 
02-18 16:37:16.916: D/AndroidRuntime(8930): Shutting down VM 
02-18 16:37:16.916: W/dalvikvm(8930): threadid=1: thread exiting with uncaught exception (group=0x41c2a438) 
02-18 16:37:16.926: E/AndroidRuntime(8930): FATAL EXCEPTION: main 
02-18 16:37:16.926: E/AndroidRuntime(8930): java.lang.IllegalStateException: Could not find a method gotorssfunction(View) in the activity class com.testproject.newsapp2.MainScreen for onClick handler on view class android.widget.Button with id 'button1' 
02-18 16:37:16.926: E/AndroidRuntime(8930):  at android.view.View$1.onClick(View.java:3661) 
2-18 16:37:16.926: E/AndroidRuntime(8930): at android.view.View.performClick(View.java:4198) 
02-18 16:37:16.926: E/AndroidRuntime(8930):  at android.view.View$PerformClick.run(View.java:17158) 
02-18 16:37:16.926: E/AndroidRuntime(8930):  at android.os.Handler.handleCallback(Handler.java:615) 
02-18 16:37:16.926: E/AndroidRuntime(8930):  at android.os.Handler.dispatchMessage(Handler.java:92) 
02-18 16:37:16.926: E/AndroidRuntime(8930):  at android.os.Looper.loop(Looper.java:137) 
02-18 16:37:16.926: E/AndroidRuntime(8930):  at android.app.ActivityThread.main(ActivityThread.java:4918) 
02-18 16:37:16.926: E/AndroidRuntime(8930):  at java.lang.reflect.Method.invokeNative(Native Method) 
02-18 16:37:16.926: E/AndroidRuntime(8930):  at java.lang.reflect.Method.invoke(Method.java:511) 
02-18 16:37:16.926: E/AndroidRuntime(8930):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1004) 
02-18 16:37:16.926: E/AndroidRuntime(8930):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:771) 
02-18 16:37:16.926: E/AndroidRuntime(8930):  at dalvik.system.NativeStart.main(Native Method) 
2-18 16:37:16.926: E/AndroidRuntime(8930): Caused by: java.lang.NoSuchMethodException: gotorssfunction [class android.view.View] 
02-18 16:37:16.926: E/AndroidRuntime(8930):  at java.lang.Class.getConstructorOrMethod(Class.java:460) 
02-18 16:37:16.926: E/AndroidRuntime(8930):  at java.lang.Class.getMethod(Class.java:915) 
02-18 16:37:16.926: E/AndroidRuntime(8930): at android.view.View$1.onClick(View.java:3654) 
2-18 16:37:16.926: E/AndroidRuntime(8930): ... 11 more 
02-18 16:37:25.517: I/Process(8930): Sending signal. PID: 8930 SIG: 9 

Answer 1

錯字。方法簽名應該是public void gotorssfunction(View v)而不是public void gotorssfuction(View v)。