我有一个listview，长按将显示contextmenu更新，删除和发送处方。现在，当我点击更新时，它将转到EditPatientActivity。将MySql数据库中的所有数据填充到表单中。我的问题是，当我点击更新菜单时，它崩溃了应用程序。我不知道为什么。请帮我。我不知道问题是在传递uid还是遗漏了EditPatientActivity。
edit_patient.xml
<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="@drawable/white_bg" >
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:padding="10dip" >
<!-- Error message -->
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Patient Update"
android:textAppearance="?android:attr/textAppearanceLarge" />
<TextView
android:id="@+id/register_error"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:padding="10dip"
android:textColor="#e30000"
android:textStyle="bold" />
<EditText
android:id="@+id/fname"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:ems="10"
android:hint="First Name" />
<EditText
android:id="@+id/lname"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:ems="10"
android:hint="Last Name" />
<EditText
android:id="@+id/username"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="36dp"
android:ems="10"
android:hint="Username" />
<EditText
android:id="@+id/password"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="26dp"
android:ems="10"
android:hint="Password"
android:inputType="textPassword" />
<EditText
android:id="@+id/contacts"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/regPassword"
android:layout_alignRight="@+id/regPassword"
android:layout_below="@+id/regPassword"
android:ems="10"
android:hint="Contacts" >
<requestFocus android:layout_width="wrap_content" />
</EditText>
<EditText
android:id="@+id/address"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/editText1"
android:layout_alignRight="@+id/editText1"
android:layout_below="@+id/editText1"
android:ems="10"
android:hint="Address" />
<Spinner
android:id="@+id/gender"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<TextView
android:id="@+id/datetext"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Date"
android:textAppearance="?android:attr/textAppearanceMedium" />
<Button
android:id="@+id/pickdate"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Birthday" />
<RelativeLayout
android:layout_width="295dp"
android:layout_height="wrap_content"
android:layout_weight="0.06" >
<Button
android:id="@+id/add"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:layout_marginLeft="84dp"
android:text="+" />
<Button
android:id="@+id/sub"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_marginRight="14dp"
android:layout_toLeftOf="@+id/number"
android:text="-" />
<TextView
android:id="@+id/number"
android:layout_width="40dp"
android:layout_height="38dp"
android:layout_alignParentTop="true"
android:layout_alignRight="@+id/add"
android:layout_marginRight="18dp"
android:ems="10"
android:hint="age"
android:textAppearance="?android:attr/textAppearanceMedium" />
</RelativeLayout>
<ImageView
android:id="@+id/imgUpdate"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="20dp"
android:layout_marginRight="28dp"
android:layout_weight="0.16"
android:src="@drawable/update" />
</LinearLayout>
</ScrollView>
EditPatientActivity
package com.example.healthhelpv2;
//import android.widget.DatePicker;
import java.text.DateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.List;
import library.JSONParser2;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
//import com.mkyong.android.R;
import android.app.Activity;
import android.app.DatePickerDialog;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.Spinner;
import android.widget.TextView;
//import android.widget.RadioButton;
//import android.widget.Spinner;
//import android.widget.NumberPicker;
public class EditPatientActivity extends Activity implements View.OnClickListener{
EditText inputfname, inputlname, inputbirthday, inputcontact, inputaddress;
EditText txtCreatedAt, inputusername, inputpassword;
TextView inputdate, inputage;
Spinner inputgender;
ImageView imgUpdate;
Button sub, add, pickdate;
int counter = 0;
DateFormat formate = DateFormat.getDateInstance();
Calendar calendar = Calendar.getInstance();
String uid;
// Progress Dialog
private ProgressDialog pDialog;
// JSON parser class
JSONParser2 jsonParser = new JSONParser2();
// single product url
private static final String url_patient_detials = "http://10.0.2.2/android_connect/get_patient_details.php";
// url to update product
private static final String url_update_patient = "http://10.0.2.2/android_connect/updatepatient.php";
// url to delete product
//private static final String url_delete_patient = "http://10.0.2.2/android_connect/delete_patient.php";
// JSON Node names
private static final String TAG_SUCCESS = "success";
private static final String TAG_PATIENT = "patient";
private static final String TAG_UID = "uid";
private static final String TAG_FNAME = "fname";
private static final String TAG_USERNAME = "username";
private static final String TAG_PASSWORD = "password";
private static final String TAG_LNAME = "lname";
private static final String TAG_ADDRESS = "address";
private static final String TAG_GENDER = "gender";
//private static final String TAG_GENDER2 = "female";
private static final String TAG_CONTACT = "contact";
private static final String TAG_AGE = "age";
private static final String TAG_BIRTHDAY = "birthday";
public void onBackPressed() {
super.onBackPressed();
//userFunctions.logoutUser(getApplicationContext());
Intent intent = new Intent(this, EditMenuActivity.class);
startActivity(intent);
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.edit_patient);
// save button
//btnsave = (Button) findViewById(R.id.btnsave);
//btndelete = (Button) findViewById(R.id.btndelete);
// getting product details from intent
Intent i = getIntent();
// getting product id (pid) from intent
uid = i.getStringExtra(TAG_UID);
// Getting complete product details in background thread
new GetProductDetails().execute();
imgUpdate = (ImageView) findViewById(R.id.imgUpdate);
// save button click event
imgUpdate.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// starting background task to update product
new SaveProductDetails().execute();
}
});
//gender
pickdate = (Button) findViewById(R.id.pickdate);
pickdate.setOnClickListener(this);
updateDate();
//inputdate = (TextView) findViewById(R.id.datetext);
ArrayAdapter adapter = ArrayAdapter.createFromResource(
this, R.array.gender_array, android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
inputgender.setAdapter(adapter);
//age form
add = (Button) findViewById(R.id.add);
sub = (Button) findViewById(R.id.sub);
add.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
counter++;
inputage.setText( "" + counter);
}
});
sub.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
counter--;
inputage.setText( "" + counter);
}
});
/* // Delete button click event
btndelete.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// deleting product in background thread
new DeleteProduct().execute();
}
});
*/
}
/**
* Background Async Task to Get complete product details
* */
class GetProductDetails extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(EditPatientActivity.this);
pDialog.setMessage("Loading patient details. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
/**
* Getting product details in background thread
* */
protected String doInBackground(String... params) {
// updating UI from Background Thread
runOnUiThread(new Runnable() {
public void run() {
// Check for success tag
int success;
try {
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("uid", uid));
// getting product details by making HTTP request
// Note that product details url will use GET request
JSONObject json = jsonParser.makeHttpRequest(
url_patient_detials, "GET", params);
// check your log for json response
Log.d("Single Patient Details", json.toString());
// json success tag
success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// successfully received product details
JSONArray productObj = json
.getJSONArray(TAG_PATIENT); // JSON Array
// get first product object from JSON Array
JSONObject product = productObj.getJSONObject(0);
// product with this pid found
// Edit Text
inputusername= (EditText) findViewById(R.id.username);
inputpassword = (EditText) findViewById(R.id.password);
inputfname= (EditText) findViewById(R.id.fname);
inputlname = (EditText) findViewById(R.id.lname);
inputcontact = (EditText) findViewById(R.id.contacts);
inputaddress = (EditText) findViewById(R.id.address);
inputdate = (TextView) findViewById(R.id.datetext);//bday
inputgender = (Spinner) findViewById(R.id.gender);
inputage = (TextView) findViewById(R.id.number);
//rdmale = (RadioButton) findViewById(R.id.rdmale);
//rdfemale = (RadioButton) findViewById(R.id.rdfemale);
// display product data in EditText
inputusername.setText(product.getString(TAG_USERNAME));
inputpassword.setText(product.getString(TAG_PASSWORD));
inputfname.setText(product.getString(TAG_FNAME));
inputlname.setText(product.getString(TAG_LNAME));
inputcontact.setText(product.getString(TAG_CONTACT));
inputaddress.setText(product.getString(TAG_ADDRESS));
if(product.getString(TAG_GENDER).equals("male"))
inputgender.setSelection(0);//if male is at 0 position
else
inputgender.setSelection(1);//if female is at 1 position
inputage.setText(product.getString(TAG_AGE));
inputdate.setText(product.getString(TAG_BIRTHDAY));
}else{
// product with pid not found
}
} catch (JSONException e) {
e.printStackTrace();
}
}
});
return null;
}
/**
* After completing background task Dismiss the progress dialog
* **/
protected void onPostExecute(String file_url) {
// dismiss the dialog once got all details
pDialog.dismiss();
}
}
/**
* Background Async Task to Save product Details
* */
class SaveProductDetails extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(EditPatientActivity.this);
pDialog.setMessage("Saving patient ...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
/**
* Saving product
* */
protected String doInBackground(String... args) {
// getting updated data from EditTexts
String username = inputusername.getText().toString();
String password = inputpassword.getText().toString();
String fname = inputfname.getText().toString();
String lname = inputlname.getText().toString();
String contact = inputcontact.getText().toString();
String age = inputage.getText().toString();
String address = inputaddress.getText().toString();
//String birthday = inputbirthday.getText().toString();
String gender = inputgender.getSelectedItem().toString();
String bday = inputdate.getText().toString();
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
//params.add(new BasicNameValuePair(TAG_PID, pid));
params.add(new BasicNameValuePair(TAG_USERNAME, username));
params.add(new BasicNameValuePair(TAG_PASSWORD, password));
params.add(new BasicNameValuePair(TAG_FNAME, fname));
params.add(new BasicNameValuePair(TAG_LNAME, lname));
params.add(new BasicNameValuePair(TAG_ADDRESS, address));
params.add(new BasicNameValuePair(TAG_BIRTHDAY, bday));
params.add(new BasicNameValuePair(TAG_AGE, age));
params.add(new BasicNameValuePair(TAG_GENDER, gender));
params.add(new BasicNameValuePair(TAG_CONTACT, contact));
// sending modified data through http request
// Notice that update product url accepts POST method
JSONObject json = jsonParser.makeHttpRequest(url_update_patient,
"POST", params);
// check json success tag
try {
int success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// successfully updated
Intent i = getIntent();
// send result code 100 to notify about product update
setResult(100, i);
finish();
} else {
// failed to update product
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
/**
* After completing background task Dismiss the progress dialog
* **/
protected void onPostExecute(String file_url) {
// dismiss the dialog once product uupdated
pDialog.dismiss();
}
}
/*****************************************************************
* Background Async Task to Delete Product
* */
/*class DeleteProduct extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
/*
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(EditPatientActivity.this);
pDialog.setMessage("Deleting Patient...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
/**
* Deleting product
* */
/* protected String doInBackground(String... args) {
// Check for success tag
int success;
try {
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("uid", uid));
// getting product details by making HTTP request
JSONObject json = jsonParser.makeHttpRequest(
url_delete_patient, "POST", params);
// check your log for json response
Log.d("Delete Patient", json.toString());
// json success tag
success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// product successfully deleted
// notify previous activity by sending code 100
Intent i = getIntent();
// send result code 100 to notify about product deletion
setResult(100, i);
finish();
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
/**
* After completing background task Dismiss the progress dialog
* **/
protected void onPostExecute(String file_url) {
// dismiss the dialog once product deleted
pDialog.dismiss();
}
public void updateDate(){
inputdate.setText(formate.format(calendar.getTime()));
}
//setdate
public void setDate(){
new DatePickerDialog(EditPatientActivity.this,d,calendar.get(Calendar.YEAR),calendar.get(Calendar.MONTH),calendar.get(Calendar.DAY_OF_MONTH)).show();
}
//date form
DatePickerDialog.OnDateSetListener d=new DatePickerDialog.OnDateSetListener(){
@Override
public void onDateSet(DatePicker View, int year, int monthOfYear, int dayOfMonth){
calendar.set(Calendar.YEAR,year);
calendar.set(Calendar.MONTH,monthOfYear);
calendar.set(Calendar.DAY_OF_MONTH,dayOfMonth);
updateDate();
}
};
@Override
public void onClick(View v){
setDate();
}
}
logcat的
02-08 15:33:06.042: E/AndroidRuntime(276): FATAL EXCEPTION: main
02-08 15:33:06.042: E/AndroidRuntime(276): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.healthhelpv2/com.example.healthhelpv2.EditPatientActivity}: java.lang.NullPointerException
02-08 15:33:06.042: E/AndroidRuntime(276): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
02-08 15:33:06.042: E/AndroidRuntime(276): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
02-08 15:33:06.042: E/AndroidRuntime(276): at android.app.ActivityThread.access$2300(ActivityThread.java:125)
02-08 15:33:06.042: E/AndroidRuntime(276): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
02-08 15:33:06.042: E/AndroidRuntime(276): at android.os.Handler.dispatchMessage(Handler.java:99)
02-08 15:33:06.042: E/AndroidRuntime(276): at android.os.Looper.loop(Looper.java:123)
02-08 15:33:06.042: E/AndroidRuntime(276): at android.app.ActivityThread.main(ActivityThread.java:4627)
02-08 15:33:06.042: E/AndroidRuntime(276): at java.lang.reflect.Method.invokeNative(Native Method)
02-08 15:33:06.042: E/AndroidRuntime(276): at java.lang.reflect.Method.invoke(Method.java:521)
02-08 15:33:06.042: E/AndroidRuntime(276): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
02-08 15:33:06.042: E/AndroidRuntime(276): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
02-08 15:33:06.042: E/AndroidRuntime(276): at dalvik.system.NativeStart.main(Native Method)
02-08 15:33:06.042: E/AndroidRuntime(276): Caused by: java.lang.NullPointerException
02-08 15:33:06.042: E/AndroidRuntime(276): at com.example.healthhelpv2.EditPatientActivity.onCreate(EditPatientActivity.java:125)
02-08 15:33:06.042: E/AndroidRuntime(276): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
02-08 15:33:06.042: E/AndroidRuntime(276): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
02-08 15:33:06.042: E/AndroidRuntime(276): ... 11 more
答案 0 :(得分：1)
在评论专栏105中，imgUpdate.setOnClickListener(new View.OnClickListener() {表示imgUpdate为空。
所以改变这个
imgUpdate = (ImageView) findViewById(R.id.imgReg);
到
imgUpdate = (ImageView) findViewById(R.id.imgUpdate);
因为你有
<ImageView
android:id="@+id/imgUpdate" // id is imgUpdate