Chris Chris - 3 months ago 25
Android Question

New to Android - Exception - cannot be cast to android.widget.EditText

I'm new to android and am running into an error on a basic app. I am getting the following error,


Caused by: java.lang.ClassCastException: android.widget.RelativeLayout
cannot be cast to android.widget.EditText at
com.example.chris.mytestv1.MainActivity.onCreate(MainActivity.java:39)


Below is the line causing it

numberTxt = (EditText) findViewById(R.id.numberTxt);


In my MainActivity.java i have

package com.example.chris.mytestv1;

import android.net.Uri;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

import com.google.android.gms.appindexing.Action;
import com.google.android.gms.appindexing.AppIndex;
import com.google.android.gms.common.api.GoogleApiClient;

public class MainActivity extends AppCompatActivity {

TextView totalTextView = null;
EditText percentageTxt = null;
EditText numberTxt = null;
/**
* ATTENTION: This was auto-generated to implement the App Indexing API.
* See https://g.co/AppIndexing/AndroidStudio for more information.
*/
private GoogleApiClient client;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);


totalTextView = (TextView) findViewById(R.id.TotalTextView);
percentageTxt = (EditText) findViewById(R.id.percentageTxt);
numberTxt = (EditText) findViewById(R.id.numberTxt);


Button calcBtn = (Button) findViewById(R.id.calcBtn);
calcBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
float percentage = Float.parseFloat(percentageTxt.getText().toString());
float dec = percentage / 100;
float total = dec * Float.parseFloat(numberTxt.getText().toString());
totalTextView.setText(Float.toString(total));
}
});

// ATTENTION: This was auto-generated to implement the App Indexing API.
// See https://g.co/AppIndexing/AndroidStudio for more information.
client = new GoogleApiClient.Builder(this).addApi(AppIndex.API).build();
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();

//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}

return super.onOptionsItemSelected(item);
}

@Override
public void onStart() {
super.onStart();

// ATTENTION: This was auto-generated to implement the App Indexing API.
// See https://g.co/AppIndexing/AndroidStudio for more information.
client.connect();
Action viewAction = Action.newAction(
Action.TYPE_VIEW, // TODO: choose an action type.
"Main Page", // TODO: Define a title for the content shown.
// TODO: If you have web page content that matches this app activity's content,
// make sure this auto-generated web page URL is correct.
// Otherwise, set the URL to null.
Uri.parse("http://host/path"),
// TODO: Make sure this auto-generated app URL is correct.
Uri.parse("android-app://com.example.chris.mytestv1/http/host/path")
);
AppIndex.AppIndexApi.start(client, viewAction);
}

@Override
public void onStop() {
super.onStop();

// ATTENTION: This was auto-generated to implement the App Indexing API.
// See https://g.co/AppIndexing/AndroidStudio for more information.
Action viewAction = Action.newAction(
Action.TYPE_VIEW, // TODO: choose an action type.
"Main Page", // TODO: Define a title for the content shown.
// TODO: If you have web page content that matches this app activity's content,
// make sure this auto-generated web page URL is correct.
// Otherwise, set the URL to null.
Uri.parse("http://host/path"),
// TODO: Make sure this auto-generated app URL is correct.
Uri.parse("android-app://com.example.chris.mytestv1/http/host/path")
);
AppIndex.AppIndexApi.end(client, viewAction);
client.disconnect();
}
}


In my content_main.xml i have -

<?xml version="1.0" encoding="utf-8"?>
<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:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:context="com.example.chris.mytestv1.MainActivity"
tools:showIn="@layout/activity_main"
android:id="@+id/numberTxt">

<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="0"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="41dp"
android:textAlignment="center"
android:textSize="50dp"
android:id="@+id/TotalTextView" />

<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="What is"
android:id="@+id/textView"
android:layout_below="@+id/TotalTextView"
android:layout_centerHorizontal="true"
android:layout_marginTop="41dp"
android:layout_marginBottom="10dp" />

<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:inputType="numberDecimal"
android:ems="10"
android:id="@+id/percentageTxt"
android:layout_below="@+id/textView"
android:layout_centerHorizontal="true"
android:hint="Enter Percentage"
android:textAlignment="center" />

<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:inputType="numberDecimal"
android:ems="10"
android:id="@+id/numberTxt"
android:hint="Enter Number"
android:textAlignment="center"
android:layout_marginTop="48dp"
android:layout_below="@+id/textView3"
android:layout_alignStart="@+id/percentageTxt" />

<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="%"
android:id="@+id/textView2"
android:layout_marginRight="50dp"
android:layout_alignTop="@+id/percentageTxt"
android:layout_toEndOf="@+id/calcBtn"
android:paddingTop="10dp" />

<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Of"
android:id="@+id/textView3"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true" />

<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="CALCULATE"
android:id="@+id/calcBtn"
android:layout_marginTop="70dp"
android:textSize="30dp"
android:background="#b91313"
android:textColor="#ffffff"
android:layout_below="@+id/numberTxt"
android:layout_centerHorizontal="true" />

</RelativeLayout>


I've searched for why this error could be occurring however i was unable to find out why.

Answer

You have duplication in ids, your RelativeLayout and EditText use the same id:

<RelativeLayout 
    android:id="@+id/numberTxt">

<EditText
    android:id="@+id/numberTxt">

so when android try to findViewById he try to use first which is RelativeLayout not EditText.