PRÁTICA 4 – LINEAR LAYOUT

Objetivo:

Utilizar Linear Layout para organizar componentes no Layout.

Introdução

Existem 4 tipos básicos de layout de componentes em um Activity Android:

Linear Horizontal: Os componentes ficam dispostos na horizontal dividindo o espaço.
Linear Vertical: Os componentes ficam dispostos na vertical dividindo o espaço.
Table: Os componentes ficam dispostos em uma tabela.
Relative: Os componentes ficam dispostos de forma relativa a outros.

Tarefa:

Criar tipos diferentes de layout com buttons, editText e textView:

Programa 1 – Três editTexts em um linear layout horizontal com weigh=1:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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="empty.ammsoft.empty.MainActivity"
    android:id="@+id/layout"
    android:orientation="horizontal">

   <TextView
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:textAppearance="?android:attr/textAppearanceMedium"
     android:text="a"
     android:id="@+id/textView" />

   <EditText
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:id="@+id/editText"
     android:layout_weight="1" />

   <TextView
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:textAppearance="?android:attr/textAppearanceMedium"
     android:text="c"
     android:id="@+id/textView3" />

   <EditText
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:id="@+id/editText2"
     android:layout_weight="1" />

   <TextView
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:textAppearance="?android:attr/textAppearanceMedium"
     android:text="b"
     android:id="@+id/textView2" />

   <EditText
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:id="@+id/editText3"
     android:layout_weight="1" />
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout 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="empty.ammsoft.empty.MainActivity"

android:id="@+id/layout"

android:orientation="horizontal">

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:textAppearance="?android:attr/textAppearanceMedium"

android:text="a"

android:id="@+id/textView" />

<EditText

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:id="@+id/editText"

android:layout_weight="1" />

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:textAppearance="?android:attr/textAppearanceMedium"

android:text="c"

android:id="@+id/textView3" />

<EditText

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:id="@+id/editText2"

android:layout_weight="1" />

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:textAppearance="?android:attr/textAppearanceMedium"

android:text="b"

android:id="@+id/textView2" />

<EditText

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:id="@+id/editText3"

android:layout_weight="1" />

</LinearLayout>

Programa 2 – Três componentes em um linear layout vertical:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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="empty.ammsoft.empty.MainActivity"
    android:id="@+id/layout"
    android:orientation="vertical">

    <TextClock
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/textClock"
        android:layout_gravity="center_horizontal"
        android:text="z" />

    <AnalogClock
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/analogClock"
        android:layout_gravity="center_horizontal" />

    <DatePicker
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/datePicker"
        android:layout_gravity="center_horizontal" />
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout 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="empty.ammsoft.empty.MainActivity"

android:id="@+id/layout"

android:orientation="vertical">

<TextClock

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:id="@+id/textClock"

android:layout_gravity="center_horizontal"

android:text="z" />

<AnalogClock

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:id="@+id/analogClock"

android:layout_gravity="center_horizontal" />

<DatePicker

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:id="@+id/datePicker"

android:layout_gravity="center_horizontal" />

</LinearLayout>

Programa 3 – Vários linear layout diferentes dentro de um linear layout pai:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:id="@+id/layout"
    android:orientation="vertical">

   <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="Equação de Segundo Grau"
        android:id="@+id/textView4"
        android:layout_gravity="center_horizontal" />

    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_alignParentBottom="true">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceMedium"
            android:text="a"
            android:id="@+id/textView" />

        <EditText
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/a"
            android:layout_weight="1"
            android:inputType="numberDecimal" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceMedium"
            android:text="b"
            android:id="@+id/textView3" />

        <EditText
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/b"
            android:layout_weight="1"
            android:inputType="numberSigned|numberDecimal" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceMedium"
            android:text="c"
            android:id="@+id/textView2" />

        <EditText
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/c"
            android:layout_weight="1"
            android:inputType="numberSigned|numberDecimal" />

    </LinearLayout>

    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceLarge"
            android:text="X1="
            android:id="@+id/x1"
            android:layout_weight="1" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceLarge"
            android:text="X2="
            android:id="@+id/x2"
            android:layout_weight="1" />

    </LinearLayout>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Resolver"
        android:id="@+id/button2"
        android:layout_weight="1"
        android:layout_gravity="right"
        android:clickable="true"
        android:onClick="calculaSegundoGrau" />

</LinearLayout>

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<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:paddingBottom="@dimen/activity_vertical_margin"

android:paddingLeft="@dimen/activity_horizontal_margin"

android:paddingRight="@dimen/activity_horizontal_margin"

android:paddingTop="@dimen/activity_vertical_margin"

android:id="@+id/layout"

android:orientation="vertical">

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:textAppearance="?android:attr/textAppearanceLarge"

android:text="Equação de Segundo Grau"

android:id="@+id/textView4"

android:layout_gravity="center_horizontal" />

<LinearLayout

android:orientation="horizontal"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_alignParentTop="true"

android:layout_alignParentLeft="true"

android:layout_alignParentStart="true"

android:layout_alignParentBottom="true">

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:textAppearance="?android:attr/textAppearanceMedium"

android:text="a"

android:id="@+id/textView" />

<EditText

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:id="@+id/a"

android:layout_weight="1"

android:inputType="numberDecimal" />

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:textAppearance="?android:attr/textAppearanceMedium"

android:text="b"

android:id="@+id/textView3" />

<EditText

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:id="@+id/b"

android:layout_weight="1"

android:inputType="numberSigned|numberDecimal" />

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:textAppearance="?android:attr/textAppearanceMedium"

android:text="c"

android:id="@+id/textView2" />

<EditText

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:id="@+id/c"

android:layout_weight="1"

android:inputType="numberSigned|numberDecimal" />

</LinearLayout>

<LinearLayout

android:orientation="horizontal"

android:layout_width="match_parent"

android:layout_height="wrap_content">

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:textAppearance="?android:attr/textAppearanceLarge"

android:text="X1="

android:id="@+id/x1"

android:layout_weight="1" />

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:textAppearance="?android:attr/textAppearanceLarge"

android:text="X2="

android:id="@+id/x2"

android:layout_weight="1" />

</LinearLayout>

<Button

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="Resolver"

android:id="@+id/button2"

android:layout_weight="1"

android:layout_gravity="right"

android:clickable="true"

android:onClick="calculaSegundoGrau" />

</LinearLayout>

Programa 4 – Inserindo código para resolver a equação do segundo grau:

package nome do seu pacote! // Esta linha deve ser mantida com o nome do pacote!

import android.content.Intent;
import android.renderscript.Double2;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.MotionEvent;
import android.view.View;
import android.widget.EditText;
import android.widget.RelativeLayout;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    public void calculaSegundoGrau(View v) {
        EditText a_edit = (EditText) findViewById(R.id.a);
        EditText b_edit = (EditText) findViewById(R.id.b);
        EditText c_edit = (EditText) findViewById(R.id.c);
        TextView x1_text = (TextView) findViewById(R.id.x1);
        TextView x2_text = (TextView) findViewById(R.id.x2);

        double a = Double.parseDouble(a_edit.getText().toString());
        double b = Double.parseDouble(b_edit.getText().toString());
        double c = Double.parseDouble(c_edit.getText().toString());

        double delta = b * b - 4*a*c;

        double x1 = -b + Math.sqrt(delta);
        double x2 = -b - Math.sqrt(delta);

        x1_text.setText("X1 = " + String.valueOf(x1));
        x2_text.setText("X2 = " + String.valueOf(x2));

        Toast.makeText(this, "Resolvido!",Toast.LENGTH_SHORT).show();
    }
}

package nome do seu pacote! // Esta linha deve ser mantida com o nome do pacote!

import android.content.Intent;

import android.renderscript.Double2;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.view.Menu;

import android.view.MenuInflater;

import android.view.MenuItem;

import android.view.MotionEvent;

import android.view.View;

import android.widget.EditText;

import android.widget.RelativeLayout;

import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

}

public void calculaSegundoGrau(View v) {

EditText a_edit = (EditText) findViewById(R.id.a);

EditText b_edit = (EditText) findViewById(R.id.b);

EditText c_edit = (EditText) findViewById(R.id.c);

TextView x1_text = (TextView) findViewById(R.id.x1);

TextView x2_text = (TextView) findViewById(R.id.x2);

double a = Double.parseDouble(a_edit.getText().toString());

double b = Double.parseDouble(b_edit.getText().toString());

double c = Double.parseDouble(c_edit.getText().toString());

double delta = b * b - 4*a*c;

double x1 = -b + Math.sqrt(delta);

double x2 = -b - Math.sqrt(delta);

x1_text.setText("X1 = " + String.valueOf(x1));

x2_text.setText("X2 = " + String.valueOf(x2));

Toast.makeText(this, "Resolvido!",Toast.LENGTH_SHORT).show();

}

Desafio: Melhore o programa de forma que não dê erros se o formulário estiver vazio e avise se delta for menor que zero:

package nome do seu pacote! // Esta linha deve ser mantida com o nome do pacote!

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

public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    public void calculaSegundoGrau(View v) {
        EditText a_edit = (EditText) findViewById(R.id.a);
        EditText b_edit = (EditText) findViewById(R.id.b);
        EditText c_edit = (EditText) findViewById(R.id.c);
        TextView x1_text = (TextView) findViewById(R.id.x1);
        TextView x2_text = (TextView) findViewById(R.id.x2);

        x1_text.setText("X1 = ");
        x2_text.setText("X2 = ");

        if (a_edit.getText().length() == 0) {
            Toast.makeText(this, "Esqueceu o valor de a!",Toast.LENGTH_SHORT).show();
            return;
        }

        if (b_edit.getText().length() == 0) {
            Toast.makeText(this, "Esqueceu o valor de b!",Toast.LENGTH_SHORT).show();
            return;
        }

        if (c_edit.getText().length() == 0) {
            Toast.makeText(this, "Esqueceu o valor de c!",Toast.LENGTH_SHORT).show();
            return;
        }

        double a = Double.parseDouble(a_edit.getText().toString());
        double b = Double.parseDouble(b_edit.getText().toString());
        double c = Double.parseDouble(c_edit.getText().toString());

        double delta = b * b - 4*a*c;

        if (delta < 0) {
            Toast.makeText(this, "Delta menor que ZERO!",Toast.LENGTH_SHORT).show();
            return;
        }

        double x1 = -b + Math.sqrt(delta);
        double x2 = -b - Math.sqrt(delta);

        x1_text.setText("X1 = " + String.format("%.2f",x1));
        x2_text.setText("X2 = " + String.format("%.2f",x2));
    }
}

package nome do seu pacote! // Esta linha deve ser mantida com o nome do pacote!

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.view.View;

import android.widget.EditText;

import android.widget.TextView;

import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

}

public void calculaSegundoGrau(View v) {

EditText a_edit = (EditText) findViewById(R.id.a);

EditText b_edit = (EditText) findViewById(R.id.b);

EditText c_edit = (EditText) findViewById(R.id.c);

TextView x1_text = (TextView) findViewById(R.id.x1);

TextView x2_text = (TextView) findViewById(R.id.x2);

x1_text.setText("X1 = ");

x2_text.setText("X2 = ");

if (a_edit.getText().length() == 0) {

Toast.makeText(this, "Esqueceu o valor de a!",Toast.LENGTH_SHORT).show();

return;

}

if (b_edit.getText().length() == 0) {

Toast.makeText(this, "Esqueceu o valor de b!",Toast.LENGTH_SHORT).show();

return;

}

if (c_edit.getText().length() == 0) {

Toast.makeText(this, "Esqueceu o valor de c!",Toast.LENGTH_SHORT).show();

return;

}

double a = Double.parseDouble(a_edit.getText().toString());

double b = Double.parseDouble(b_edit.getText().toString());

double c = Double.parseDouble(c_edit.getText().toString());

double delta = b * b - 4*a*c;

if (delta < 0) {

Toast.makeText(this, "Delta menor que ZERO!",Toast.LENGTH_SHORT).show();

return;

}

double x1 = -b + Math.sqrt(delta);

double x2 = -b - Math.sqrt(delta);

x1_text.setText("X1 = " + String.format("%.2f",x1));

x2_text.setText("X2 = " + String.format("%.2f",x2));

}