How I handle this error [closed]

Question

How I handle this error [closed]

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#1 by (1 votes)

-3

I'm new to programming for android, I know java and c #, I want to push the button and change the text of the label I just managed to make it appear on toast

    package gabriel.meaperte;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;

import static android.widget.TextView.*;

public class MainActivity extends AppCompatActivity;

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

    public void exibirmensagem(View view){

        Toast.makeText(MainActivity.this, "Você apertou o botão", Toast.LENGTH_LONG).show();

    }

}

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Aperte o botão"
    android:textSize="30sp"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintVertical_bias="0.174"
    app:layout_constraintHorizontal_bias="0.502"
    android:id="@+id/textView" />

<Button
    android:id="@+id/button"
    android:layout_width="159dp"
    android:layout_height="85dp"
    android:text="Botão"
    android:onClick="exibirmensagem"
    android:textSize="24sp"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/textView"
    app:layout_constraintVertical_bias="0.55"
    app:layout_constraintHorizontal_bias="0.502" />

android

asked by anonymous 31.08.2017 / 05:31

1 answer

Code working only on localhost [closed] Corporate Cloud Services [closed]

score 1 · Accepted Answer

You need to find the view by its ID within your layout, after you have set the text you need. Check google documentation

Follow your code as an example:

package gabriel.meaperte;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;

import static android.widget.TextView.*;

public class MainActivity extends AppCompatActivity;

    private TextView textView;

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

        // Localiza a View através do seu id
        textView = (TextView) findViewById(R.id.textView);
    }

    public void exibirmensagem(View view){
        // Altera o valor da View      
        textView.setText("Seu novo valor no label");
        Toast.makeText(MainActivity.this, "Você apertou o botão", Toast.LENGTH_LONG).show();

    }

}