通过 android 模拟器成功登录后应用程序崩溃
Application was crashing after successful Login through android emulator
我正在使用我的 Web 应用程序端点创建本机登录 android 应用程序。但是在尝试登录时，我可以在控制台 log.But 上看到登录成功的结果，我希望 activity 重定向到另一个 activity。下面我发布我的
androidmanifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest
xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.reception.farbinder_test">
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission
android:name="android.permission.READ_EXTERNAL_STORAGE" />
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category
android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
<activity android:name=".ResponseActivity"></activity>
<activity android:name=".SettingsActivity"></activity>
</application>
</manifest>
mainactivity.java
public class MainActivity extends AppCompatActivity
implements
View.OnClickListener {
private List<String> stringList;
private ListView list;
private LoginPOJO jsonResponse;
EditText etUserName;
EditText etPassword;
ImageView btnLogin;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
jsonResponse = new LoginPOJO();
// UserLogin Field
etUserName = (EditText) findViewById(R.id.etUserName);
// UserLogin Password
etPassword = (EditText) findViewById(R.id.etPassword);
// Login Button Image
btnLogin = (ImageView) findViewById(R.id.btnLogin);
btnLogin.setOnClickListener(this);
// User SignUp Button Image
ImageView btnSignUp = (ImageView)
findViewById(R.id.btnSignUp);
btnSignUp.setOnClickListener(this);
// Forget Password Textbutton
TextView frgtPassword = (TextView)
findViewById(R.id.forgetpassword);
frgtPassword.setOnClickListener(this);
// Skip for now button
final TextView skipfornow = (TextView)
findViewById(R.id.skipnow);
skipfornow.setOnClickListener(this);
}
private void
logIn(final String username, final String password)
{
final ProgressDialog progressDialog = new
ProgressDialog(MainActivity.this);
progressDialog.
setProgressStyle(ProgressDialog.STYLE_SPINNER);
progressDialog.setMessage("Logging you in...");
progressDialog.setIndeterminate(true);
progressDialog.setCancelable(false);
progressDialog.show();
String UPLOAD_URL = "http://xxxxx-
dev.elasticbeanstalk.com/api/v1/login";
final StringRequest stringRequest = new
StringRequest(Request.Method.POST, UPLOAD_URL,
new Response.Listener<String>() {
@Override
public void onResponse(String s) {
//Dismissing the progress dialog
progressDialog.dismiss();
// Getting the final Json Object
JSONObject parentObject;
try {
parentObject = new JSONObject(s);
// Getting the data from Data Json Object
JSONObject dataObject =
parentObject.getJSONObject("data");
// Getting data from Geo object
JSONObject geoObject =
dataObject.getJSONObject("geo");
// Getting data from businesses Array
JSONArray businessesArray =
dataObject.getJSONArray("businesses");
// Getting data from Meta Object
JSONObject metaObject =
parentObject.getJSONObject("meta");
startActivity(new Intent(MainActivity.this,
ResponseActivity.class));
} catch (JSONException e) {
e.printStackTrace();
}
//Showing toast message of the response
Log.i("TAG", "onResponse: " + s);
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError volleyError)
{
//Dismissing the progress dialog
progressDialog.dismiss();
//Showing snackbar
Toast.makeText(MainActivity.this, "Connection
Problem", Toast.LENGTH_SHORT).show();
}
}) {
@Override
protected Map<String, String> getParams() throws
AuthFailureError {
//Converting Bitmap to String
//Creating parameters
Map<String, String> params = new Hashtable<>();
params.put("apikey", Utilities.API_KEY);
params.put("secret", Utilities.SECRET_KEY);
params.put("email", username);
params.put("password",password);
//Adding parameters
//returning parameters
return params;
}
};
//Creating a Request Queue
RequestQueue requestQueue =Volley.newRequestQueue(this);
//Adding request to the queue
requestQueue.add(stringRequest);
}
private void forgetPassword(final String userName) {
final ProgressDialog progressDialog = new
ProgressDialog(MainActivity.this);
progressDialog.setProgressStyle
(ProgressDialog.STYLE_SPINNER);
progressDialog.setMessage("Logging you in...");
progressDialog.setIndeterminate(true);
progressDialog.setCancelable(false);
progressDialog.show();
String UPLOAD_URL = "http://xxxxxx-
dev.elasticbeanstalk.com/api/v1/request_password_reset";
final StringRequest stringRequest = new
StringRequest(Request.Method.POST, UPLOAD_URL,
new Response.Listener<String>() {
@Override
public void onResponse(String s) {
//Dismissing the progress dialog
progressDialog.dismiss();
// Getting the final Json Object
JSONObject parentObject;
try {
parentObject = new JSONObject(s);
// Getting the data from Data Json Object
JSONObject dataObject =
parentObject.getJSONObject("data");
// Getting data from Geo object
JSONObject geoObject =
dataObject.getJSONObject("geo");
// Getting data from businesses Array
JSONArray businessesArray =
dataObject.getJSONArray("businesses");
// Getting data from Meta Object
JSONObject metaObject =
parentObject.getJSONObject("meta");
startActivity(new Intent(MainActivity.this,
ResponseActivity.class));
} catch (JSONException e) {
e.printStackTrace();
}
//Showing toast message of the response
Log.i("TAG", "onResponse: " + s);
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError volleyError)
{
//Dismissing the progress dialog
progressDialog.dismiss();
//Showing snackbar
Toast.makeText(MainActivity.this, "Connection
Problem", Toast.LENGTH_SHORT).show();
}
}) {
@Override
protected Map<String, String> getParams() throws
AuthFailureError {
//Converting Bitmap to String
//Creating parameters
Map<String, String> params = new Hashtable<>();
params.put("apikey", Utilities.API_KEY);
params.put("secret", Utilities.SECRET_KEY);
params.put("email", userName);
//Adding parameters
//returning parameters
return params;
}
};
//Creating a Request Queue
RequestQueue requestQueue = Volley.newRequestQueue(this);
//Adding request to the queue
requestQueue.add(stringRequest);
}
private void signUp() {
Intent singUppage = new
Intent(MainActivity.this,ResponseActivity.class);
startActivity(singUppage);
}
private void skipForNow(){
Intent skipForNowPage = new
Intent(MainActivity.this,ResponseActivity.class);
startActivity(skipForNowPage);
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.btnLogin: {
String username = etUserName.getText().toString().trim();
String password = etPassword.getText().toString().trim();
logIn(username, password);
break;
}
case R.id.forgetpassword: {
String username = etUserName.getText().toString().trim();
forgetPassword(username);
break;
}
case R.id.btnSignUp:{
signUp();
break;
}
case R.id.skipnow:{
skipForNow();
break;
}
}
}
activitymain.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="com.example.reception.xxx.MainActivity">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:background="@drawable/signin_bg"
android:orientation="vertical"
android:paddingEnd="20dp"
android:paddingLeft="20dp"
android:paddingRight="20dp"
android:paddingStart="20dp"
android:weightSum="1">
<ImageView
android:id="@+id/imageView"
android:layout_width="wrap_content"
android:layout_height="40dp"
android:contentDescription="@string/farbinder_text"
android:src="@drawable/vdsss"/>
<ImageView
android:id="@+id/facebookSigninButton"
android:layout_width="343dp"
android:layout_height="76dp"
android:contentDescription="@string/connect_with_facebook"
android:src="@drawable/signin_fb"/>
<ImageView
android:layout_width="match_parent"
android:layout_height="92dp"
android:contentDescription="@string/connect_with_twitter"
android:src="@drawable/signin_twitter"/>
<ImageView
android:id="@+id/btnSignUp"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:contentDescription="@string/signup_with_email"
android:src="@drawable/signup_button"/>
<TextView
android:id="@+id/skipnow"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:text="@string/skip_login_for_now"
android:textColor="#FFF"
android:textSize="16sp"/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="187dp"
android:orientation="vertical"
android:paddingLeft="20dp"
android:paddingStart="20dp"
android:paddingEnd="20dp"
android:paddingRight="20dp"
android:paddingBottom="5dp">
<EditText
android:id="@+id/etUserName"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:autoLink="email"
android:hint="@string/enter_email"
android:inputType="text"/>
<EditText
android:id="@+id/etPassword"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="textPassword"
android:hint="@string/enter_password"/>
<ImageView
android:id="@+id/btnLogin"
android:layout_width="match_parent"
android:layout_height="63dp"
android:contentDescription="@string/sign_in"
android:src="@drawable/signin_button"/>
<TextView
android:id="@+id/forgetpassword"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/forgot_password"
android:textSize="16sp"
android:layout_gravity="center_horizontal"/>
</LinearLayout>
</LinearLayout>
activityresponse.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:padding="16dp"
tools:context=
"com.example.reception.xxxx.MainActivity">
<TextView
android:id="@+id/tvStatus"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="20sp"
android:layout_gravity="center_horizontal"/>
<ImageView
android:id="@+id/backArrow"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:scaleType="center"
android:src="@drawable/backarrow"
android:contentDescription="@string/backarrow"
/>
<ImageView
android:id="@+id/image"
android:layout_width="match_parent"
android:layout_height="240dp"
android:scaleType="centerCrop"/>
<Button
android:id="@+id/btnSelectImage"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/select_image"
android:textAllCaps="false"
android:layout_gravity="center_horizontal"/>
</LinearLayout>
responseactivity.java
public class ResponseActivity extends AppCompatActivity
implements
View.OnClickListener {
private final int IMAGE_REQUEST_CODE = 5;
private ImageView ivImage;
private Bitmap selectedImage;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_response);
TextView tvResponse = (TextView)
findViewById(R.id.tvStatus);
ivImage = (ImageView) findViewById(R.id.image);
ImageView etSignUp = (ImageView)
findViewById(R.id.btnSignUp);
etSignUp.setOnClickListener(this);
ImageView backArrow =
(ImageView)findViewById(R.id.backArrow);
backArrow.setOnClickListener(this);
}
private void backArrow(){
Intent bckArrow = new
Intent(ResponseActivity.this,MainActivity.class);
startActivity(bckArrow);
}
private void signUp(){
Intent signUp = new
Intent(ResponseActivity.this,SettingsActivity.class);
startActivity(signUp);
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.backArrow:{
backArrow();
break;
}
case R.id.btnSignUp:{
signUp();
break;
}
}
}
问题在这里：
ImageView etSignUp = (ImageView)findViewById(R.id.btnSignUp);
etSignUp.setOnClickListener(this);
您的 ResponseActivity 布局中没有 ID 为 btnSignUp 的图像视图。
这就是为什么它给出了 imageview
的 nullpointerException
androidmanifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest
xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.reception.farbinder_test">
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission
android:name="android.permission.READ_EXTERNAL_STORAGE" />
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category
android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
<activity android:name=".ResponseActivity"></activity>
<activity android:name=".SettingsActivity"></activity>
</application>
</manifest>
mainactivity.java
public class MainActivity extends AppCompatActivity
implements
View.OnClickListener {
private List<String> stringList;
private ListView list;
private LoginPOJO jsonResponse;
EditText etUserName;
EditText etPassword;
ImageView btnLogin;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
jsonResponse = new LoginPOJO();
// UserLogin Field
etUserName = (EditText) findViewById(R.id.etUserName);
// UserLogin Password
etPassword = (EditText) findViewById(R.id.etPassword);
// Login Button Image
btnLogin = (ImageView) findViewById(R.id.btnLogin);
btnLogin.setOnClickListener(this);
// User SignUp Button Image
ImageView btnSignUp = (ImageView)
findViewById(R.id.btnSignUp);
btnSignUp.setOnClickListener(this);
// Forget Password Textbutton
TextView frgtPassword = (TextView)
findViewById(R.id.forgetpassword);
frgtPassword.setOnClickListener(this);
// Skip for now button
final TextView skipfornow = (TextView)
findViewById(R.id.skipnow);
skipfornow.setOnClickListener(this);
}
private void
logIn(final String username, final String password)
{
final ProgressDialog progressDialog = new
ProgressDialog(MainActivity.this);
progressDialog.
setProgressStyle(ProgressDialog.STYLE_SPINNER);
progressDialog.setMessage("Logging you in...");
progressDialog.setIndeterminate(true);
progressDialog.setCancelable(false);
progressDialog.show();
String UPLOAD_URL = "http://xxxxx-
dev.elasticbeanstalk.com/api/v1/login";
final StringRequest stringRequest = new
StringRequest(Request.Method.POST, UPLOAD_URL,
new Response.Listener<String>() {
@Override
public void onResponse(String s) {
//Dismissing the progress dialog
progressDialog.dismiss();
// Getting the final Json Object
JSONObject parentObject;
try {
parentObject = new JSONObject(s);
// Getting the data from Data Json Object
JSONObject dataObject =
parentObject.getJSONObject("data");
// Getting data from Geo object
JSONObject geoObject =
dataObject.getJSONObject("geo");
// Getting data from businesses Array
JSONArray businessesArray =
dataObject.getJSONArray("businesses");
// Getting data from Meta Object
JSONObject metaObject =
parentObject.getJSONObject("meta");
startActivity(new Intent(MainActivity.this,
ResponseActivity.class));
} catch (JSONException e) {
e.printStackTrace();
}
//Showing toast message of the response
Log.i("TAG", "onResponse: " + s);
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError volleyError)
{
//Dismissing the progress dialog
progressDialog.dismiss();
//Showing snackbar
Toast.makeText(MainActivity.this, "Connection
Problem", Toast.LENGTH_SHORT).show();
}
}) {
@Override
protected Map<String, String> getParams() throws
AuthFailureError {
//Converting Bitmap to String
//Creating parameters
Map<String, String> params = new Hashtable<>();
params.put("apikey", Utilities.API_KEY);
params.put("secret", Utilities.SECRET_KEY);
params.put("email", username);
params.put("password",password);
//Adding parameters
//returning parameters
return params;
}
};
//Creating a Request Queue
RequestQueue requestQueue =Volley.newRequestQueue(this);
//Adding request to the queue
requestQueue.add(stringRequest);
}
private void forgetPassword(final String userName) {
final ProgressDialog progressDialog = new
ProgressDialog(MainActivity.this);
progressDialog.setProgressStyle
(ProgressDialog.STYLE_SPINNER);
progressDialog.setMessage("Logging you in...");
progressDialog.setIndeterminate(true);
progressDialog.setCancelable(false);
progressDialog.show();
String UPLOAD_URL = "http://xxxxxx-
dev.elasticbeanstalk.com/api/v1/request_password_reset";
final StringRequest stringRequest = new
StringRequest(Request.Method.POST, UPLOAD_URL,
new Response.Listener<String>() {
@Override
public void onResponse(String s) {
//Dismissing the progress dialog
progressDialog.dismiss();
// Getting the final Json Object
JSONObject parentObject;
try {
parentObject = new JSONObject(s);
// Getting the data from Data Json Object
JSONObject dataObject =
parentObject.getJSONObject("data");
// Getting data from Geo object
JSONObject geoObject =
dataObject.getJSONObject("geo");
// Getting data from businesses Array
JSONArray businessesArray =
dataObject.getJSONArray("businesses");
// Getting data from Meta Object
JSONObject metaObject =
parentObject.getJSONObject("meta");
startActivity(new Intent(MainActivity.this,
ResponseActivity.class));
} catch (JSONException e) {
e.printStackTrace();
}
//Showing toast message of the response
Log.i("TAG", "onResponse: " + s);
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError volleyError)
{
//Dismissing the progress dialog
progressDialog.dismiss();
//Showing snackbar
Toast.makeText(MainActivity.this, "Connection
Problem", Toast.LENGTH_SHORT).show();
}
}) {
@Override
protected Map<String, String> getParams() throws
AuthFailureError {
//Converting Bitmap to String
//Creating parameters
Map<String, String> params = new Hashtable<>();
params.put("apikey", Utilities.API_KEY);
params.put("secret", Utilities.SECRET_KEY);
params.put("email", userName);
//Adding parameters
//returning parameters
return params;
}
};
//Creating a Request Queue
RequestQueue requestQueue = Volley.newRequestQueue(this);
//Adding request to the queue
requestQueue.add(stringRequest);
}
private void signUp() {
Intent singUppage = new
Intent(MainActivity.this,ResponseActivity.class);
startActivity(singUppage);
}
private void skipForNow(){
Intent skipForNowPage = new
Intent(MainActivity.this,ResponseActivity.class);
startActivity(skipForNowPage);
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.btnLogin: {
String username = etUserName.getText().toString().trim();
String password = etPassword.getText().toString().trim();
logIn(username, password);
break;
}
case R.id.forgetpassword: {
String username = etUserName.getText().toString().trim();
forgetPassword(username);
break;
}
case R.id.btnSignUp:{
signUp();
break;
}
case R.id.skipnow:{
skipForNow();
break;
}
}
}
activitymain.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="com.example.reception.xxx.MainActivity">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:background="@drawable/signin_bg"
android:orientation="vertical"
android:paddingEnd="20dp"
android:paddingLeft="20dp"
android:paddingRight="20dp"
android:paddingStart="20dp"
android:weightSum="1">
<ImageView
android:id="@+id/imageView"
android:layout_width="wrap_content"
android:layout_height="40dp"
android:contentDescription="@string/farbinder_text"
android:src="@drawable/vdsss"/>
<ImageView
android:id="@+id/facebookSigninButton"
android:layout_width="343dp"
android:layout_height="76dp"
android:contentDescription="@string/connect_with_facebook"
android:src="@drawable/signin_fb"/>
<ImageView
android:layout_width="match_parent"
android:layout_height="92dp"
android:contentDescription="@string/connect_with_twitter"
android:src="@drawable/signin_twitter"/>
<ImageView
android:id="@+id/btnSignUp"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:contentDescription="@string/signup_with_email"
android:src="@drawable/signup_button"/>
<TextView
android:id="@+id/skipnow"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:text="@string/skip_login_for_now"
android:textColor="#FFF"
android:textSize="16sp"/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="187dp"
android:orientation="vertical"
android:paddingLeft="20dp"
android:paddingStart="20dp"
android:paddingEnd="20dp"
android:paddingRight="20dp"
android:paddingBottom="5dp">
<EditText
android:id="@+id/etUserName"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:autoLink="email"
android:hint="@string/enter_email"
android:inputType="text"/>
<EditText
android:id="@+id/etPassword"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="textPassword"
android:hint="@string/enter_password"/>
<ImageView
android:id="@+id/btnLogin"
android:layout_width="match_parent"
android:layout_height="63dp"
android:contentDescription="@string/sign_in"
android:src="@drawable/signin_button"/>
<TextView
android:id="@+id/forgetpassword"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/forgot_password"
android:textSize="16sp"
android:layout_gravity="center_horizontal"/>
</LinearLayout>
</LinearLayout>
activityresponse.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:padding="16dp"
tools:context=
"com.example.reception.xxxx.MainActivity">
<TextView
android:id="@+id/tvStatus"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="20sp"
android:layout_gravity="center_horizontal"/>
<ImageView
android:id="@+id/backArrow"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:scaleType="center"
android:src="@drawable/backarrow"
android:contentDescription="@string/backarrow"
/>
<ImageView
android:id="@+id/image"
android:layout_width="match_parent"
android:layout_height="240dp"
android:scaleType="centerCrop"/>
<Button
android:id="@+id/btnSelectImage"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/select_image"
android:textAllCaps="false"
android:layout_gravity="center_horizontal"/>
</LinearLayout>
responseactivity.java
public class ResponseActivity extends AppCompatActivity
implements
View.OnClickListener {
private final int IMAGE_REQUEST_CODE = 5;
private ImageView ivImage;
private Bitmap selectedImage;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_response);
TextView tvResponse = (TextView)
findViewById(R.id.tvStatus);
ivImage = (ImageView) findViewById(R.id.image);
ImageView etSignUp = (ImageView)
findViewById(R.id.btnSignUp);
etSignUp.setOnClickListener(this);
ImageView backArrow =
(ImageView)findViewById(R.id.backArrow);
backArrow.setOnClickListener(this);
}
private void backArrow(){
Intent bckArrow = new
Intent(ResponseActivity.this,MainActivity.class);
startActivity(bckArrow);
}
private void signUp(){
Intent signUp = new
Intent(ResponseActivity.this,SettingsActivity.class);
startActivity(signUp);
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.backArrow:{
backArrow();
break;
}
case R.id.btnSignUp:{
signUp();
break;
}
}
}
问题在这里：
ImageView etSignUp = (ImageView)findViewById(R.id.btnSignUp);
etSignUp.setOnClickListener(this);
您的 ResponseActivity 布局中没有 ID 为 btnSignUp 的图像视图。
这就是为什么它给出了 imageview
nullpointerException