Question

如果您在以下情况下无需登录，就可以看到我的链接。我遇到的问题与描述的人一样。蓝色操作栏在我创建的每个项目中阻止了我的应用程序的名称。除了发表讨论的人之外，我还没有看到任何有这个问题的人。如果可以，请帮帮我，我很感激。

-Timmy

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    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:orientation="vertical"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context=".MainActivity"
    tools:showIn="@layout/activity_main">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="16dp"
        android:layout_marginLeft="8dp"
        android:layout_marginTop="16dp"
        android:paddingBottom="16dp"
        android:text="Quantity"
        android:textAllCaps="true"/>

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

        <Button
            android:layout_width="48dp"
            android:layout_height="48dp"
            android:layout_marginBottom="16dp"
            android:onClick="minusIncrement"
            android:text="-"/>

        <TextView
            android:id="@+id/quantity_text_view"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginBottom="16dp"
            android:layout_marginLeft="8dp"
            android:layout_marginRight="8dp"
            android:text="2"
            android:textColor="@android:color/black"
            android:textSize="16sp"/>

        <Button
            android:layout_width="48dp"
            android:layout_height="48dp"
            android:layout_marginBottom="16dp"
            android:onClick="plusIncrement"
            android:text="+"/>

    </LinearLayout>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="16dp"
        android:layout_marginLeft="8dp"
        android:layout_marginTop="16dp"
        android:text="Price"
        android:textAllCaps="true"/>

    <TextView
        android:id="@+id/price_text_view"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="16dp"
        android:layout_marginLeft="8dp"
        android:layout_marginTop="16dp"
        android:text="$10"/>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:onClick="submitOrder"
        android:text="Order"/>
</LinearLayout>

package com.example.android.justjava;

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

import java.text.NumberFormat;

/**
 * This app displays an order form to order coffee.
 */
public class MainActivity extends AppCompatActivity {

    int quantity = 2;

    /**
     * This method displays the given text on the screen.
     */

    private void displayMessage(String message) {
        TextView priceTextView = (TextView) findViewById(R.id.price_text_view);
        priceTextView.setText(message);
    }

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

    /**
     * This method is called when the order button is clicked.
     */
    public void submitOrder(View view) {
     String priceMessage = "Total: $" + (quantity * 5);
        priceMessage = priceMessage + "\nThank you!";
        displayMessage(priceMessage);
    }

    /**
     * This method is called when the plus button is clicked.
     */
    public void plusIncrement(View view) {
        quantity = quantity + 1;
        display(quantity);
    }

    /**
     * This method is called when the minus button is clicked.
     */
    public void minusIncrement(View view) {
        quantity = quantity - 1;
        display(quantity);
    }

    /**
     * This method displays the given quantity value on the screen.
     */
    private void display(int number) {
        TextView quantityTextView = (TextView) findViewById(
                R.id.quantity_text_view);
        quantityTextView.setText("" + number);
    }

    /**
     * This method displays the given price on the screen.
     */
    private void displayPrice(int number) {
        TextView priceTextView = (TextView) findViewById(R.id.price_text_view);
        priceTextView.setText(NumberFormat.getCurrencyInstance().format(number));
    }
}

https://discussions.udacity.com/t/title-on-the-app-is-not-showing/37056

Answer 1

使用工具栏时，您必须做一些不同的事情。你可以这样做：

<强> MainActivity.java

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

    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    if(toolbar != null) {
        setSupportActionBar(toolbar);
        getSupportActionBar().setTitle("My custom toolbar!");
        getSupportActionBar().setHomeButtonEnabled(true);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    }
 }

}

<强> activity_main.xml中

<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"
tools:context=".MainActivity">

<android.support.v7.widget.Toolbar 
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/toolbar"
    android:layout_width="match_parent"
    android:layout_height="100dp"
    android:background="@android:color/holo_red_light"
    android:minHeight="100dp">

</android.support.v7.widget.Toolbar>

</RelativeLayout>

因此，最大的问题是ToolBar永远不会添加到当前内容视图中，因此在您将ToolBar实际添加到当前内容视图之前永远不会显示。

答案取自这里： Title, etc. not showing in Android Toolbar

Android Studio未显示应用程序名称

1 个答案: