我在电影上制作了一个Android应用程序。我有数据库电影。在应用程序中，我在ListView中显示电影，然后添加一部新电影。
当我尝试在我的dataBase中插入一部新电影时，我遇到了问题。实际上，我在doInBackground中的AsyncTask中有n个错误，但我不知道为什么。当我使用调试器时，我拒绝在行的doInBackground的开头：
String title = eTitle.getText().toString();
所以我给你我的java代码：
public class AddMovie extends Activity implements OnClickListener{
// Edit and Button that the user fill
private EditText eTitle, eActors, eDirector, eKind, eDate, eImage, eSummary ;
private Button bAdd;
// Progress Dialog
private ProgressDialog pDialog;
//JSON parser class
//JSONParser jsonParser = new JSONParser();
private static final String TAG_SUCCESS = "success";
private static final String TAG_MESSAGE = "message";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add_movie);
eTitle = (EditText)findViewById(R.id.title);
eActors = (EditText)findViewById(R.id.actors);
eDirector = (EditText)findViewById(R.id.director);
eKind = (EditText)findViewById(R.id.kind);
eDate = (EditText)findViewById(R.id.date);
eImage = (EditText)findViewById(R.id.image);
eSummary = (EditText)findViewById(R.id.summary);
bAdd = (Button)findViewById(R.id.addMovies);
bAdd.setOnClickListener(this);
}
public void onClick(View v) {
// TODO Auto-generated method stub
switch (v.getId()) {
case R.id.addMovies:
new AttempMovie().execute();
// here we have used, switch case, because on login activity you may //also want to show registration button, so if the user is new ! we can go the //registration activity , other than this we could also do this without switch //case.
default:
break;
}
}
class AttempMovie extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
boolean failure = false;
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(AddMovie.this);
pDialog.setMessage("Attempting for add new movie...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
@Override
protected String doInBackground(String... args) {
// TODO Auto-generated method stub
// here Check for success tag
int success;
String title = eTitle.getText().toString();
String actors = eActors.getText().toString();
String director = eDirector.getText().toString();
String kind = eKind.getText().toString();
String date = eDate.getText().toString();
String image = eImage.getText().toString();
String summary = eSummary.getText().toString();
try {
// Building parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("title", title));
params.add(new BasicNameValuePair("actors", actors));
params.add(new BasicNameValuePair("director", director));
params.add(new BasicNameValuePair("kind", kind));
params.add(new BasicNameValuePair("date", date));
params.add(new BasicNameValuePair("image", image));
params.add(new BasicNameValuePair("summary", summary));
Log.d("request!", "starting");
JSONObject json = JSONfunctions.getJSONfromURL("http://10.0.0.35/BD_Enterprise_Mobility_Movies/add_movie.php");
// checking log for json response
Log.d("Register attempt", json.toString());
// success tag for json
success = json.getInt(TAG_SUCCESS);
if (success == 1)
{
Log.d("Successfully Register!", json.toString());
return json.getString(TAG_MESSAGE);
}
else
{
Log.d("Login Failure!", json.getString(TAG_MESSAGE));
return json.getString(TAG_MESSAGE);
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
/**
* Once the background process is done we need to Dismiss the progress dialog asap
* **/
protected void onPostExecute(String message) {
pDialog.dismiss();
if (message != null){
Intent i = new Intent(AddMovie.this,MainActivity.class);
finish();
// this finish() method is used to tell android os that we are done with current //activity now! Moving to other activity
startActivity(i);
Toast.makeText(AddMovie.this, message, Toast.LENGTH_LONG).show();
}
}
}
}
我还给你JSONfunctions.java
public class JSONfunctions {
public static JSONObject getJSONfromURL(String url) {
InputStream is = null;
String result = "";
JSONObject json = null;
// Download JSON data from URL
try {
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost(url);
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = entity.getContent();
} catch (Exception e) {
Log.e("log_tag", "Error in http connection " + e.toString());
}
// Convert response to string
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
result = sb.toString();
} catch (Exception e) {
Log.e("log_tag", "Error converting result " + e.toString());
}
try {
json = new JSONObject(result);
} catch (JSONException e) {
Log.e("log_tag", "Error parsing data " + e.toString());
}
return json;
}
}
我在logcat中的错误：
03-20 18:28:19.753: E/AndroidRuntime(14656): FATAL EXCEPTION: AsyncTask #3
03-20 18:28:19.753: E/AndroidRuntime(14656): Process: com.mickKoza.jsonkoza, PID: 14656
03-20 18:28:19.753: E/AndroidRuntime(14656): java.lang.RuntimeException: An error occured while executing doInBackground()
03-20 18:28:19.753: E/AndroidRuntime(14656): at android.os.AsyncTask$3.done(AsyncTask.java:300)
03-20 18:28:19.753: E/AndroidRuntime(14656): at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
03-20 18:28:19.753: E/AndroidRuntime(14656): at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
03-20 18:28:19.753: E/AndroidRuntime(14656): at java.util.concurrent.FutureTask.run(FutureTask.java:242)
03-20 18:28:19.753: E/AndroidRuntime(14656): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
03-20 18:28:19.753: E/AndroidRuntime(14656): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
03-20 18:28:19.753: E/AndroidRuntime(14656): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
03-20 18:28:19.753: E/AndroidRuntime(14656): at java.lang.Thread.run(Thread.java:818)
03-20 18:28:19.753: E/AndroidRuntime(14656): Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.text.Editable android.widget.EditText.getText()' on a null object reference
03-20 18:28:19.753: E/AndroidRuntime(14656): at com.mickKoza.jsonkoza.AddMovie$AttempMovie.doInBackground(AddMovie.java:81)
03-20 18:28:19.753: E/AndroidRuntime(14656): at com.mickKoza.jsonkoza.AddMovie$AttempMovie.doInBackground(AddMovie.java:1)
03-20 18:28:19.753: E/AndroidRuntime(14656): at android.os.AsyncTask$2.call(AsyncTask.java:288)
03-20 18:28:19.753: E/AndroidRuntime(14656): at java.util.concurrent.FutureTask.run(FutureTask.java:237)
03-20 18:28:19.753: E/AndroidRuntime(14656): ... 4 more
03-20 18:28:20.184: E/WindowManager(14656): android.view.WindowLeaked: Activity com.mickKoza.jsonkoza.AddMovie has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView{3e1b7378 V.E..... R......D 0,0-1026,288} that was originally added here
03-20 18:28:20.184: E/WindowManager(14656): at android.view.ViewRootImpl.<init>(ViewRootImpl.java:363)
03-20 18:28:20.184: E/WindowManager(14656): at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:261)
03-20 18:28:20.184: E/WindowManager(14656): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:69)
03-20 18:28:20.184: E/WindowManager(14656): at android.app.Dialog.show(Dialog.java:298)
03-20 18:28:20.184: E/WindowManager(14656): at com.mickKoza.jsonkoza.AddMovie$AttempMovie.onPreExecute(AddMovie.java:74)
03-20 18:28:20.184: E/WindowManager(14656): at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:587)
03-20 18:28:20.184: E/WindowManager(14656): at android.os.AsyncTask.execute(AsyncTask.java:535)
03-20 18:28:20.184: E/WindowManager(14656): at com.mickKoza.jsonkoza.AddMovie.onClick(AddMovie.java:54)
03-20 18:28:20.184: E/WindowManager(14656): at android.view.View.performClick(View.java:4756)
03-20 18:28:20.184: E/WindowManager(14656): at android.view.View$PerformClick.run(View.java:19749)
03-20 18:28:20.184: E/WindowManager(14656): at android.os.Handler.handleCallback(Handler.java:739)
03-20 18:28:20.184: E/WindowManager(14656): at android.os.Handler.dispatchMessage(Handler.java:95)
03-20 18:28:20.184: E/WindowManager(14656): at android.os.Looper.loop(Looper.java:135)
03-20 18:28:20.184: E/WindowManager(14656): at android.app.ActivityThread.main(ActivityThread.java:5221)
03-20 18:28:20.184: E/WindowManager(14656): at java.lang.reflect.Method.invoke(Native Method)
03-20 18:28:20.184: E/WindowManager(14656): at java.lang.reflect.Method.invoke(Method.java:372)
03-20 18:28:20.184: E/WindowManager(14656): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
03-20 18:28:20.184: E/WindowManager(14656): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
感谢您的帮助
迈克尔
答案 0 :(得分：0)
这些视图中的一个（或可能是全部）为空：
String title = eTitle.getText().toString();
String actors = eActors.getText().toString();
String director = eDirector.getText().toString();
String kind = eKind.getText().toString();
String date = eDate.getText().toString();
String image = eImage.getText().toString();
String summary = eSummary.getText().toString();
您在onCreate期间引用查看这些视图的视图ID可能不正确吗？