的Android GridView的

Question

可以任意說，我怎樣才能在另一個活動查看圖像時，點擊特定的圖片與說明

這裏是java文件

package course.examples.UI.GridLayout; 

import java.util.ArrayList; 
import java.util.Arrays; 

import android.app.Activity; 
import android.content.Intent; 
import android.content.res.Resources; 
import android.os.Bundle; 
import android.view.View; 
import android.widget.AdapterView; 
import android.widget.AdapterView.OnItemClickListener; 
import android.widget.GridView; 

public class GridLayoutActivity extends Activity { 

protected static final String EXTRA_RES_ID = "POS"; 

private int[] mThumbIdsFlowers = {R.drawable.image1, R.drawable.image2, 
       R.drawable.image3, R.drawable.image4,    

     R.drawable.image5, 
       R.drawable.image6, R.drawable.image7, 

     R.drawable.image8, 
       R.drawable.image9, R.drawable.image10, 

    R.drawable.image11, 
       R.drawable.image12}; 


@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main); 
    String[] description=getResources().getStringArray(R.array.description); 
    GridView gridview=(GridView) findViewById(R.id.gridview); 

    gridview.setAdapter(new ImageAdapter(this, mThumbIdsFlowers,description)); 


} 
    } 

定義適配器

package course.examples.UI.GridLayout; 

    import java.util.ArrayList; 
    import java.util.List; 
    import java.util.zip.Inflater; 

    import android.annotation.SuppressLint; 
    import android.content.Context; 
    import android.view.LayoutInflater; 
    import android.view.View; 
    import android.view.ViewGroup; 
    import android.widget.BaseAdapter; 
    import android.widget.GridView; 
    import android.widget.ImageView; 
    import android.widget.TextView; 

    public class ImageAdapter extends BaseAdapter { 
    private static final int PADDING = 8; 
    private static final int WIDTH = 50; 
    private static final int HEIGHT = 50; 
    private Context mContext; 
    private int[] mThumbIds; 
    private String[] description; 
    ArrayList<row_item> arraylist; 
    class row_item{ 
    int img; 
    String description; 
    row_item(int img,String description){ 
     this.img=img; 
     this.description=description; 

    } 

    } 
    public ImageAdapter(Context c, int[] img,String[] description) { 
     mContext = c; 
     this.mThumbIds =img; 
     this.description=description; 
     this.arraylist=new ArrayList<row_item>(); 
     for(int i=0;i<12;i++) 
     { 
      arraylist.add(new row_item(img[i], description[i])); 
     } 
    } 

    @Override 
    public int getCount() { 
     return arraylist.size(); 
    } 

    @Override 
    public Object getItem(int position) { 
     return null; 
    } 

    // Will get called to provide the ID that 
    // is passed to OnItemClickListener.onItemClick() 


    // create a new ImageView for each item referenced by the Adapter 
    @Override 
    public View getView(int position, View convertView, ViewGroup parent) { 
     LayoutInflater inflater = (LayoutInflater)mContext.getSystemService 
        (Context.LAYOUT_INFLATER_SERVICE); 
     View view=inflater.inflate(R.layout.row_style,null); 
     ImageView img=(ImageView) view.findViewById(R.id.img); 
     TextView text=(TextView) view.findViewById(R.id.text); 
     img.setImageResource(arraylist.get(position).img); 
     text.setText(arraylist.get(position).description); 
     return view; 
    } 

    @Override 
    public long getItemId(int arg0) { 
     // TODO Auto-generated method stub 
     return 0; 
    } 
     } 

我想設置使用baseadapter類的佈局。我將說明和圖像ID存儲在arraylist然後我設置ImageView a nd來自ArrayList的TextView，它給運行時錯誤。

這裏是logcat的味精

06-08 02:22:29.516: E/AndroidRuntime(1322): FATAL EXCEPTION: main 
06-08 02:22:29.516: E/AndroidRuntime(1322): Process: course.examples.UI.GridLayout, PID: 1322 
06-08 02:22:29.516: E/AndroidRuntime(1322): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{course.examples.UI.GridLayout/course.examples.UI.GridLayout.GridLayoutActivity}: java.lang.NullPointerException 
06-08 02:22:29.516: E/AndroidRuntime(1322):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2102) 
06-08 02:22:29.516: E/AndroidRuntime(1322):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2226) 
06-08 02:22:29.516: E/AndroidRuntime(1322):  at android.app.ActivityThread.access$700(ActivityThread.java:135) 
06-08 02:22:29.516: E/AndroidRuntime(1322):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1397) 
06-08 02:22:29.516: E/AndroidRuntime(1322):  at android.os.Handler.dispatchMessage(Handler.java:102) 
06-08 02:22:29.516: E/AndroidRuntime(1322):  at android.os.Looper.loop(Looper.java:137) 
06-08 02:22:29.516: E/AndroidRuntime(1322):  at android.app.ActivityThread.main(ActivityThread.java:4998) 
06-08 02:22:29.516: E/AndroidRuntime(1322):  at java.lang.reflect.Method.invokeNative(Native Method) 
06-08 02:22:29.516: E/AndroidRuntime(1322):  at java.lang.reflect.Method.invoke(Method.java:515) 
06-08 02:22:29.516: E/AndroidRuntime(1322):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:777) 
06-08 02:22:29.516: E/AndroidRuntime(1322):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:593) 
06-08 02:22:29.516: E/AndroidRuntime(1322):  at dalvik.system.NativeStart.main(Native Method) 
06-08 02:22:29.516: E/AndroidRuntime(1322): Caused by: java.lang.NullPointerException 
06-08 02:22:29.516: E/AndroidRuntime(1322):  at android.content.ContextWrapper.getResources(ContextWrapper.java:89) 
06-08 02:22:29.516: E/AndroidRuntime(1322):  at android.view.ContextThemeWrapper.getResources(ContextThemeWrapper.java:78) 
06-08 02:22:29.516: E/AndroidRuntime(1322):  at course.examples.UI.GridLayout.GridLayoutActivity.<init>(GridLayoutActivity.java:24) 
06-08 02:22:29.516: E/AndroidRuntime(1322):  at java.lang.Class.newInstanceImpl(Native Method) 
06-08 02:22:29.516: E/AndroidRuntime(1322):  at java.lang.Class.newInstance(Class.java:1208) 
06-08 02:22:29.516: E/AndroidRuntime(1322):  at android.app.Instrumentation.newActivity(Instrumentation.java:1061) 
06-08 02:22:29.516: E/AndroidRuntime(1322):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2093) 
06-08 02:22:29.516: E/AndroidRuntime(1322):  ... 11 more 
06-08 02:22:34.556: I/Process(1322): Sending signal. PID: 1322 SIG: 9 

這裏佈局的xml文件 row_style

<?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="horizontal" > 
<ImageView 
    android:id="@+id/img" 
    android:layout_height="wrap_content" 
    /> 
<TextView 
    android:id="@+id/text" 
    android:layout_width="0dp" 
    android:layout_height="wrap_content" 
    android:layout_weight="1"/> 
</LinearLayout> 

這裏的main.xml佈局

<?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="horizontal" > 
<GridView 
    android:id="@+id/gridview" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    ></GridView> 
</LinearLayout> 

這裏是mainfest.xml文件

<?xml version="1.0" encoding="utf-8"?> 
<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
package="course.examples.UI.GridLayout" 
android:versionCode="1" 
android:versionName="1.0" > 

<uses-sdk 
    android:minSdkVersion="10" 
    android:targetSdkVersion="17" /> 

<application 
    android:allowBackup="false" 
    android:icon="@drawable/icon" 
    android:label="@string/app_name" > 
    <activity 
     android:name=".GridLayoutActivity" 
     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=".ImageViewActivity" > 
     <intent-filter> 
      <action android:name="android.intent.action.VIEW" > 
      </action> 

      <data 
       android:mimeType="image/*" 
       android:scheme="android.resource" > 
      </data> 

      <category android:name="android.intent.category.DEFAULT" > 
      </category> 
      </intent-filter> 
    </activity> 
    </application> 
    </manifest> 

Answer 1

堆棧跟蹤指向該線作爲異常的來源：

private String[] description=getResources().getStringArray(R.array.description); 

繼承getResources()方法拋出異常。這是因爲在構建和初始化活動之後，您不能直接調用getResources()。將這些成員變量初始化移動到onCreate()，你應該很好。

簡單地改變

private String[] description=getResources().getStringArray(R.array.description); 

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

到

@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main); 
String[] description=getResources().getStringArray(R.array.description);