问题
I'm building a amazon like app. after coding the loginactivity I can't access it from mainactivity because it always crashes
this is my loginactivity.java
public class loginActivity extends AppCompatActivity
{
private EditText InputPhoneNumber, InputPassword;
private Button LoginButtonPage;
private ProgressDialog loadingBar;
private String parentDbname = "Users";
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
LoginButtonPage = findViewById(R.id.page_login_btn);
InputPhoneNumber = findViewById(R.id.login_phone_number_input);
InputPassword = findViewById(R.id.login_password_input);
loadingBar = new ProgressDialog(this);
LoginButtonPage.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view)
{
LoginUser();
}
});
}
private void LoginUser()
{
String phone =InputPhoneNumber.getText().toString();
String password =InputPassword.getText().toString();
if (TextUtils.isEmpty(phone))
{
Toast.makeText(this,"Please Write Your Phone Number...", Toast.LENGTH_SHORT).show();
}
else if (TextUtils.isEmpty(password))
{
Toast.makeText(this,"Please Write Your Password...", Toast.LENGTH_SHORT).show();
}
else
{
loadingBar.setTitle("Login Account");
loadingBar.setMessage("Please Wait, while we are checking the credentials.");
loadingBar.setCanceledOnTouchOutside(false);
loadingBar.show();
AllowAccessToAccount(phone, password);
}
}
private void AllowAccessToAccount(final String phone, final String password)
{
final DatabaseReference RootRef;
RootRef = FirebaseDatabase.getInstance().getReference();
RootRef.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot)
{
if (dataSnapshot.child(parentDbname).child(phone).exists())
{
Users usersData = dataSnapshot.child(parentDbname).child(phone).getValue(Users.class);
assert usersData != null;
if (usersData.getPhone().equals(phone))
{
if (usersData.getPassword().equals(password))
{
Toast.makeText(loginActivity.this, "logged in successfully...", Toast.LENGTH_SHORT).show();
loadingBar.dismiss();
Intent intent = new Intent(loginActivity.this, HomeActivity.class);
Prevalent.currentOnlineUser = usersData;
startActivity(intent);
}
else
{
loadingBar.dismiss();
Toast.makeText(loginActivity.this, "Password is incorrect", Toast.LENGTH_SHORT).show();
}
}
}
else
{
Toast.makeText(loginActivity.this, "Account with this" + phone + "number do not exists", Toast.LENGTH_SHORT).show();
loadingBar.dismiss();
Toast.makeText(loginActivity.this, "you need to create a new account", Toast.LENGTH_SHORT).show();
}
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError)
{
}
});
}
}
and this is my loginactivity layout
<RelativeLayout 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:background="@color/orange"
tools:context=".loginActivity">
<ImageView
android:id="@+id/login_applogo"
android:layout_width="300dp"
android:layout_height="100dp"
android:src="@drawable/applogo"
android:layout_centerHorizontal="true"
android:layout_marginTop="170dp"
/>
<EditText
android:id="@+id/login_phone_number_input"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@+id/login_applogo"
android:background="@drawable/input_design"
android:padding="20dp"
android:layout_marginLeft="15dp"
android:layout_marginRight="15dp"
android:hint="Phone Number"
android:inputType="number"
android:textColor="@color/black"
android:textColorHint="@color/black"
android:textSize="17sp"
android:textStyle="bold"
/>
<EditText
android:id="@+id/login_password_input"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@+id/login_phone_number_input"
android:background="@drawable/input_design"
android:padding="20dp"
android:layout_marginLeft="15dp"
android:layout_marginRight="15dp"
android:layout_marginTop="6dp"
android:hint="Password"
android:inputType="textPassword"
android:textColor="@color/black"
android:textColorHint="@color/black"
android:textSize="17sp"
android:textStyle="bold"
/>
<LinearLayout
android:id="@+id/linear_layout_1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_below="@id/login_password_input"
android:layout_marginTop="5dp"
>
<CheckBox
android:id="@+id/remember_me_checkBox"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
style="@style/Material.Drawable.CheckBox"
android:text="Remember Me"
android:textColor="@color/black"
app:cbd_strokeColor="@color/black"
android:gravity="center_vertical"
android:textSize="16sp"
android:textStyle="bold"
android:layout_marginLeft="17dp"
/>
<TextView
android:id="@+id/forget_password_link"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Forgot Password?"
android:textColor="@color/black"
android:textSize="17sp"
android:textStyle="bold"
android:layout_marginLeft="80dp"
/>
</LinearLayout>
<Button
android:id="@+id/page_login_btn"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@+id/linear_layout_1"
android:layout_marginTop="5dp"
android:layout_marginLeft="15dp"
android:layout_marginRight="15dp"
android:background="@drawable/loginbutton"
android:padding="17dp"
android:textAllCaps="false"
android:textSize="18sp"
android:text="Login"
android:textColor="@color/black"
/>
<TextView
android:id="@+id/admin_panel_link"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="I'm an Admin"
android:layout_alignParentEnd="true"
android:layout_below="@+id/page_login_btn"
android:textColor="@color/black"
android:textSize="20sp"
android:textStyle="bold"
android:layout_marginLeft="80dp"
android:layout_marginEnd="23dp"
/>
<TextView
android:id="@+id/not_admin_panel_link"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="I'm an not Admin"
android:layout_alignParentStart="true"
android:layout_below="@+id/page_login_btn"
android:textColor="@color/black"
android:textSize="20sp"
android:textStyle="bold"
android:layout_marginLeft="80dp"
android:layout_marginStart="25dp"
android:visibility="invisible"
/>
</RelativeLayout>
then I get this error
E/AndroidRuntime: FATAL EXCEPTION: main Process: com.infinite.fastfood, PID: 12305 java.lang.RuntimeException: Unable to start activity ComponentInfo{com.infinite.fastfood/com.infinite.fastfood.loginActivity}: java.lang.ClassCastException: androidx.appcompat.widget.AppCompatButton cannot be cast to com.rey.material.widget.Button at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2646) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707) at android.app.ActivityThread.-wrap12(ActivityThread.java) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:154) at android.app.ActivityThread.main(ActivityThread.java:6077) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756) Caused by: java.lang.ClassCastException: androidx.appcompat.widget.AppCompatButton cannot be cast to com.rey.material.widget.Button at com.infinite.fastfood.loginActivity.onCreate(loginActivity.java:36) at android.app.Activity.performCreate(Activity.java:6662) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2599) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707) at android.app.ActivityThread.-wrap12(ActivityThread.java) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:154) at android.app.ActivityThread.main(ActivityThread.java:6077) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)
回答1:
Try changing com.rey.material.widget.Button import to androidx.appcompat.widget.AppCompatButton
回答2:
Try using "Users" instead of parentDbName. if (dataSnapshot.child("Users").child(phone).exists())
回答3:
In firebase, you are creating account for admin, change in firebase from phone: 9999999999 to phone: "9999999999". means add double quote(") in name,phone and password.
if you are not puting double quote in firebase the data is in long datatype. But the java file want all data in string value.
来源：https://stackoverflow.com/questions/57264088/how-to-fix-androidx-appcompat-widget-appcompatbutton-cannot-be-cast-to-com-rey-m