[androidbrasil-dev] Re: Exemplo de tratamento de evento gerando erro " Unable to start activity ComponentInfo"

Para identificar o problema você deve verificar o tipo da exceção. Nesse caso lendo essa linha:

ClassCastException: android.support.v7.widget.AppCompatTextView cannot be cast to android.widget.EditText

Isso me diz que o problema foi causado por um ClassCastException, específicamente você tentou fazer type casting de um TextView para um EditText. Essas duas classes não estão relacionadas na hierarquia de classes.

E de fato, você colocou em código a view com id "resultado" como sendo do tipo EditText, quando no layout ela realmente é um TextView.

Nelson

On Thursday, January 21, 2016 at 6:58:44 AM UTC-5, ricardo barbosa wrote:

Pessoal bom dia,

Estou iniciando no dev do android adquiri o livro do Ricardo Lecheta e estou testando os codigos da pagina 109 mas esta me gerando os seguintes erros abaixo. Estou enviando o codigo java o layout e manifest se alguem ja passou por isso e puder me ajudar, muito Obrigado

01-21 11:51:06.411 5902-5902/corp.capsula.tratamentoeventos W/System: ClassLoader referenced unknown path: /data/app/corp.capsula.tratamentoeventos-2/lib/x86
01-21 11:51:06.595 5902-5902/corp.capsula.tratamentoeventos D/AndroidRuntime: Shutting down VM
01-21 11:51:06.602 5902-5902/corp.capsula.tratamentoeventos E/AndroidRuntime: FATAL EXCEPTION: main
                                                                              Process: corp.capsula.tratamentoeventos, PID: 5902
                                                                              java.lang.RuntimeException: Unable to start activity ComponentInfo{corp.capsula.tratamentoeventos/corp.capsula.tratamentoeventos.MainActivity}: java.lang.ClassCastException: android.support.v7.widget.AppCompatTextView cannot be cast to android.widget.EditText
                                                                                  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
                                                                                  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
                                                                                  at android.app.ActivityThread.-wrap11(ActivityThread.java)
                                                                                  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
                                                                                  at android.os.Handler.dispatchMessage(Handler.java:102)
                                                                                  at android.os.Looper.loop(Looper.java:148)
                                                                                  at android.app.ActivityThread.main(ActivityThread.java:5417)
                                                                                  at java.lang.reflect.Method.invoke(Native Method)
                                                                                  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
                                                                                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
                                                                               Caused by: java.lang.ClassCastException: android.support.v7.widget.AppCompatTextView cannot be cast to android.widget.EditText
                                                                                  at corp.capsula.tratamentoeventos.MainActivity.onCreate(MainActivity.java:17)
                                                                                  at android.app.Activity.performCreate(Activity.java:6237)
                                                                                  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
                                                                                  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)
                                                                                  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
                                                                                  at android.app.ActivityThread.-wrap11(ActivityThread.java)
                                                                                  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
                                                                                  at android.os.Handler.dispatchMessage(Handler.java:102)
                                                                                  at android.os.Looper.loop(Looper.java:148)
                                                                                  at android.app.ActivityThread.main(ActivityThread.java:5417)
                                                                                  at java.lang.reflect.Method.invoke(Native Method)
                                                                                  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
                                                                                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
01-21 11:51:08.662 5902-5902/? I/Process: Sending signal. PID: 5902 SIG: 9


MainActivity.java

package corp.capsula.tratamentoeventos;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        final EditText textNome = (EditText) findViewById(R.id.nome);
        final EditText textResultado = (EditText) findViewById(R.id.resultado);

        Button botao = (Button) findViewById(R.id.enviar);

        botao.setOnClickListener(new Button.OnClickListener() {
            public void onClick(View v) {
                String nome = textNome.getText().toString();
                textResultado.setText("Obrigado " + nome);
            }
        });

    }
}


activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    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"
    tools:context="corp.capsula.tratamentoeventos.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        android:id="@+id/textView" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="New Button"
        android:id="@+id/enviar"
        android:layout_below="@+id/textView"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="24dp" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/nome"
        android:layout_below="@+id/textView"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:inputType="none" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="New Text"
        android:id="@+id/resultado"
        android:layout_below="@+id/enviar"
        android:layout_toRightOf="@+id/nome"
        android:layout_toEndOf="@+id/nome" />
</RelativeLayout>


AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="corp.capsula.tratamentoeventos">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        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>
    </application>

</manifest>


Desde já agradeço

Atenciosamente