不幸的是，（應用程序名稱）已停止

Question

我能夠成功編譯，構建和安裝項目。當我點擊一個按鈕時，該應用說：不幸的是已經停止。你能幫我解決這個問題嗎？

01-23 20:51:58.672: W/dalvikvm(1946): threadid=1: thread exiting with uncaught exception (group=0x409c01f8) 
01-23 20:51:58.722: E/AndroidRuntime(1946): FATAL EXCEPTION: main 
01-23 20:51:58.722: E/AndroidRuntime(1946): java.lang.NullPointerException 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at com.Divani.Marzieh.CustomlistActivity.getView(CustomlistActivity.java:32) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at android.widget.AbsListView.obtainView(AbsListView.java:2033) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at android.widget.ListView.measureHeightOfChildren(ListView.java:1244) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at android.widget.ListView.onMeasure(ListView.java:1155) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at android.view.View.measure(View.java:12723) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1369) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at android.widget.LinearLayout.measureVertical(LinearLayout.java:660) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at android.widget.LinearLayout.onMeasure(LinearLayout.java:553) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at android.view.View.measure(View.java:12723) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at android.widget.FrameLayout.onMeasure(FrameLayout.java:293) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at android.view.View.measure(View.java:12723) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at android.widget.FrameLayout.onMeasure(FrameLayout.java:293) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at android.view.View.measure(View.java:12723) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at android.widget.FrameLayout.onMeasure(FrameLayout.java:293) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at android.view.View.measure(View.java:12723) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at android.widget.LinearLayout.measureVertical(LinearLayout.java:812) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at android.widget.LinearLayout.onMeasure(LinearLayout.java:553) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at android.view.View.measure(View.java:12723) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at android.widget.FrameLayout.onMeasure(FrameLayout.java:293) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2092) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at android.view.View.measure(View.java:12723) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1064) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2442) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at android.os.Handler.dispatchMessage(Handler.java:99) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at android.os.Looper.loop(Looper.java:137) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at android.app.ActivityThread.main(ActivityThread.java:4424) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at java.lang.reflect.Method.invokeNative(Native Method) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at java.lang.reflect.Method.invoke(Method.java:511) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 
01-23 20:51:58.722: E/AndroidRuntime(1946):  at dalvik.system.NativeStart.main(Native Method) 

這是CustomListActivity代碼：

class CustomlistActivity extends ArrayAdapter<Item>{ 
    ArrayList<Item> strings; 
    public CustomlistActivity(Context context, int resource, int textViewResourceId, ArrayList<Item> string) { 
     super(context, resource, textViewResourceId, string); 
      strings = string; 
    } 
    @Override 
    public View getView(int position,View convertView,ViewGroup parent){ 
     LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
     View row = inflater.inflate(R.layout.list_item, parent ,false); 
     ImageView iv = (ImageView) row.findViewById(R.id.imageView1); 
     TextView tv = (TextView) row.findViewById(R.id.textView1); 
     Item item = strings.get(position); 
     iv.setImageResource(item.image); 
     tv.setText(item.name); 
     return row; 
    } 
    private LayoutInflater getSystemService(String layoutInflaterService) { 
     return null; 
    } 
} 

Answer 1

http://developer.android.com/reference/android/content/Context.html#getSystemService(java.lang.String)

getSystemService需要的上下文。

因此改變你的代碼如下

Context context; 
public CustomlistActivity(Context context, int resource, int textViewResourceId, 
      ArrayList<Item> string) { 
     super(context, resource, textViewResourceId, string); 
     // TODO Auto-generated constructor stub 
     strings = string; 
     this.context = context; 
    } 

然後

LayoutInflater inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 

，並刪除

private LayoutInflater getSystemService(String layoutInflaterService) { 
    // TODO Auto-generated method stub 
    return null; 
    } 

還要考慮使用ViewHolder模式

http://developer.android.com/training/improving-layouts/smooth-scrolling.html