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我使用意圖捕獲圖像並在活動結果中調用本地相機，試圖爲捕獲的圖像提供標題並將其添加到列表中，但我沒有成功做所以當我將項目添加到列表中時出現錯誤。應用程序從設備關閉，無法找出錯誤。有人可以向我建議將元素添加到列表的正確方法。它是否應該添加到適配器或底層ArrayList中？請幫助我。將條目動態添加到列表中
我的代碼如下：
public class AttachmentsActivity extends ListActivity {
private AttachmentListAdapter m_adapter;
private ArrayList<MediaData> m_orders = null;
StringBuffer nameBuffer;
private String captureDateTime;
private Uri uri;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
m_orders = new ArrayList<MediaData>();
Enumeration<MediaData> enumeration = DashboardManager.getInstance()
.getAttachmentList().elements();
while (enumeration.hasMoreElements()) {
m_orders.add((MediaData) enumeration.nextElement());
}
this.m_adapter = new AttachmentListAdapter(this,
android.R.layout.simple_list_item_1, m_orders);
setListAdapter(this.m_adapter);
this.m_adapter.notifyDataSetChanged();
}
@Override
public boolean onPrepareOptionsMenu(Menu menu) {
// TODO Auto-generated method stub
menu.removeGroup(1);
if (DashboardManager.getInstance().isEnableCamera()) {
menu.add(1, 1, Menu.NONE, "Camera");
}
if (DashboardManager.getInstance().isEnableAudio()) {
menu.add(1, 2, Menu.NONE, "Audio");
}
return true;
}
private class AttachmentListAdapter extends ArrayAdapter<MediaData> {
private ArrayList<MediaData> items;
private LayoutInflater mInflater;
private Bitmap high;
private Bitmap medium;
private Bitmap low;
private LinearLayout linearLayout;
private TextView[] textViews;
private Context context;
private Vector tableHeaders;
private int width;
private StringBuffer firstLine;
public AttachmentListAdapter(Context context, int textViewResourceId,
ArrayList<MediaData> items) {
super(context, textViewResourceId, items);
this.context = context;
System.out.println("Inside NotificationListAdapter");
System.out.println(items);
this.items = items;
firstLine = new StringBuffer();
mInflater = LayoutInflater.from(context);
Display display = getWindowManager().getDefaultDisplay();
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
MediaData mediaData = items.get(position);
ViewHolder holder = null;
if (mediaData != null) {
if (convertView == null) {
holder = new ViewHolder();
// holder.content = (TextView) mInflater.inflate(
// R.layout.column, null);
holder.content = new TextView(context);
holder.content.setGravity(Gravity.CENTER_VERTICAL);
holder.content.setHeight(25);
convertView = mInflater.inflate(R.layout.table_row, null);
linearLayout = (LinearLayout) convertView
.findViewById(R.id.linearLayout);
linearLayout.addView(holder.content);
}
firstLine.delete(0, firstLine.length());
firstLine.append(mediaData.getType()).append(" ")
.append(mediaData.toString());
holder.content.setText(firstLine.toString());
}
return linearLayout;
}
}
static class ViewHolder {
TextView content;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// TODO Auto-generated method stub
switch (item.getItemId()) {
case 1:
nameBuffer = new StringBuffer();
if (DashboardManager.getInstance().getWaterMarkingText().length() > 0) {
nameBuffer.append(
DashboardManager.getInstance().getWaterMarkingText())
.append("_");
}
captureDateTime = Calander.getSubmitDateTime(new Date());
nameBuffer
.append(captureDateTime)
.append("_")
.append(MobileBaseService.getInstance()
.getApplicationUser().getUserId()).append(".jpg");
String dirString = "/sdcard/pravaa/";
File dir = new File(dirString);
if(!dir.exists()) dir.mkdir();
File attachment=new File(dirString+nameBuffer.toString());
uri=Uri.fromFile(attachment);
System.out.println("URI:" + attachment.toURI());
int resultCode = 1337;
startActivityForResult(AttachmentUtility.getCameraIntent(uri),
resultCode);
}
return true;
}
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == Activity.RESULT_OK) {
switch (requestCode) {
case 1337:
// TODO Auto-generated method stub String
String dirString="/sdcard/pravaa/"; //Toast
File attachment=new File(dirString+nameBuffer.toString());
if(attachment.exists()){
try {
FileInputStream fis;
fis = new FileInputStream(attachment);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
Bitmap bi = BitmapFactory.decodeStream(fis);
bi.compress(CompressFormat.JPEG, 100, baos);
byte[]attData = baos.toByteArray();
fis.close();
if (attData.length>0) {
MediaData mediaData = new MediaData();
mediaData.setAttachmentUri(uri);
mediaData.setType(ApplicationStore.MEDIA_TYPE_IMAGE);
mediaData.setData(attData);
mediaData.setNewAttachment(true);
mediaData.setNote("");
mediaData.setTransactionId(MobileBaseService.getInstance().getNextTransactionId());
mediaData.setCaptureDataTime(captureDateTime);
mediaData.setCaption(mediaData.getCaptureDataTime() + "_" + MobileBaseService.getInstance().getApplicationUser().getUserId());
mediaData.setNumber(nameBuffer.toString());
if (DashboardManager.getInstance().isEnableGps() && ApplicationManager.getInstance().isGpsEnabled()) {
mediaData.setGpsEnabled(true);
Location location= ApplicationManager.getInstance().getLocation();
if (location != null) {
mediaData.getGpsData().setLattitude(location.getLatitude());
mediaData.getGpsData().setLongitude(location.getLongitude());
mediaData.getGpsData().setAltidude(location.getAltitude());
mediaData.getGpsData().setAccuracy("Y");
mediaData.getGpsData().setDateTime(Calander.getSubmitDateTime(new Date()));
} else {
// ApplicationManager.getInstance().Log(Level.TRACE, "Could not obtain GPS for Attachment " + mediaData.getNumber());
mediaData.getGpsData().setLattitude(0);
mediaData.getGpsData().setLongitude(0);
mediaData.getGpsData().setAltidude(0);
mediaData.getGpsData().setAccuracy("N");
mediaData.getGpsData().setDateTime("");
}
} else {
mediaData.getGpsData().setLattitude(0);
mediaData.getGpsData().setLongitude(0);
mediaData.getGpsData().setAltidude(0);
mediaData.getGpsData().setAccuracy("N");
mediaData.getGpsData().setDateTime(Calander.getSubmitDateTime(new Date()));
}
**//Commenting this line of code does not cause the crash**
m_adapter.add(mediaData);
}
} catch (FileNotFoundException e) {
//e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
// e.printStackTrace();
}catch (Exception e) {
}
}
break;
}
}
}
}
我得到的時候下面被調用的錯誤： m_adapter.add（mediaData）; （無線149）和我的堆棧跟蹤是如下：
E/AndroidRuntime(1367): java.lang.NullPointerException
E/AndroidRuntime(1367): at com.pravaa.dashboard.ui.components.Attachment
sActivity$AttachmentListAdapter.getView(AttachmentsActivity.java:149)
E/AndroidRuntime(1367): at android.widget.AbsListView.obtainView(AbsList
View.java:1427)
E/AndroidRuntime(1367): at android.widget.ListView.makeAndAddView(ListVi
ew.java:1802)
E/AndroidRuntime(1367): at android.widget.ListView.fillSpecific(ListView
.java:1347)
E/AndroidRuntime(1367): at android.widget.ListView.layoutChildren(ListVi
ew.java:1633)
E/AndroidRuntime(1367): at android.widget.AbsListView.onLayout(AbsListVi
ew.java:1280)
E/AndroidRuntime(1367): at android.view.View.layout(View.java:7035)
E/AndroidRuntime(1367): at android.widget.FrameLayout.onLayout(FrameLayo
ut.java:333)
E/AndroidRuntime(1367): at android.view.View.layout(View.java:7035)
E/AndroidRuntime(1367): at android.widget.LinearLayout.setChildFrame(Lin
earLayout.java:1249)
E/AndroidRuntime(1367): at android.widget.LinearLayout.layoutVertical(Li
nearLayout.java:1125)
E/AndroidRuntime(1367): at android.widget.LinearLayout.onLayout(LinearLa
yout.java:1042)
E/AndroidRuntime(1367): at android.view.View.layout(View.java:7035)
E/AndroidRuntime(1367): at android.widget.FrameLayout.onLayout(FrameLayo
ut.java:333)
E/AndroidRuntime(1367): at android.view.View.layout(View.java:7035)
E/AndroidRuntime(1367): at android.view.ViewRoot.performTraversals(ViewR
oot.java:1045)
E/AndroidRuntime(1367): at android.view.ViewRoot.handleMessage(ViewRoot.
java:1727)
E/AndroidRuntime(1367): at android.os.Handler.dispatchMessage(Handler.ja
va:99)
E/AndroidRuntime(1367): at android.os.Looper.loop(Looper.java:123)
E/AndroidRuntime(1367): at android.app.ActivityThread.main(ActivityThrea
d.java:4633)
E/AndroidRuntime(1367): at java.lang.reflect.Method.invokeNative(Native
Method)
E/AndroidRuntime(1367): at java.lang.reflect.Method.invoke(Method.java:5
21)
E/AndroidRuntime(1367): at com.android.internal.os.ZygoteInit$MethodAndA
rgsCaller.run(ZygoteInit.java:858)
E/AndroidRuntime(1367): at com.android.internal.os.ZygoteInit.main(Zygot
eInit.java:616)
E/AndroidRuntime(1367): at dalvik.system.NativeStart.main(Native Method)
在下面的行會出現錯誤holder.content.setText（firstLine.toString（））;在getView（）方法AttachmentListAdapter。 請幫助我。提前致謝。
你必須在這裏提供更多的細節。代碼和堆棧跟蹤將有所幫助。 – Haphazard 2011-06-05 13:20:51
您好，我將發佈代碼，但從設備運行時無法獲取整個堆棧跟蹤。在模擬器上，當我調用相機並捕獲圖像時，我得到一個強制關閉錯誤。 – 2011-06-05 19:16:14
命令提示符中的'adb logcat'會給你完整的路徑。 – Haphazard 2011-06-05 21:26:44