Question

感谢您提供有用的建议，我已经编辑了最初的问题，因为我想要显示项目的图像以及我得到的空白屏幕，这与教程指示应该显示的内容不同。我能够解决第一个问题（它只是有点消失）然而，我在创建第一个意图后遇到了问题，如本文第二部分所述：developer.android.com/training/基础/ firstapp /起始-activity.html＃receivetheintent

项目构建但我为项目设置的运行配置不显示下面代码中列出的任何输入元素。我不确定如何进一步解决问题，并真的很感激任何额外的帮助。再次感谢您的帮助。

仿真器： http://s1278.beta.photobucket.com/user/cetmrw791346/media/1_zps116f17a9.png.html

包资源管理器： http://s1278.beta.photobucket.com/user/cetmrw791346/media/2_zps0f2b94a2.png.html

以下是相关文件：

**AndroidManifest.xml**


<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.firstapp"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="17" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.firstapp.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name="com.example.firstapp.DisplayMessageActivity"
            android:label="@string/title_activity_display_message"
            android:parentActivityName="com.example.firstapp.MainActivity" >
            <meta-data
                android:name="android.support.PARENT_ACTIVITY"
                android:value="com.example.firstapp.MainActivity" />
        </activity>
    </application>

</manifest>


**MainActivity.java**


package com.example.firstapp;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;

public class MainActivity extends Activity {

    public final static String EXTRA_MESSAGE = "com.example.myfirstapp.MESSAGE";

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

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


    /** Called when the user clicks the Send button */
    public void sendMessage(View view) {
        Intent intent = new Intent(this, DisplayMessageActivity.class);
        EditText editText = (EditText) findViewById(R.id.edit_message);
        String message = editText.getText().toString();
        intent.putExtra(EXTRA_MESSAGE, message);
        startActivity(intent);
    }
}
activity_main.xml
<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:orientation="horizontal"
    tools:context=".MainActivity" >
  <EditText android:id="@+id/edit_message"
        android:layout_weight="1"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:hint="@string/edit_message" />
<Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/button_send"
         android:onClick="sendMessage" />

</LinearLayout>


**strings.xml**


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

    <string name="app_name">My First App</string>
    <string name="edit_message">Enter a message</string>
    <string name="button_send">Send</string>
    <string name="menu_settings">Settings</string>
    <string name="title_activity_main">MainActivity</string>
    <string name="title_activity_display_message">DisplayMessageActivity</string>
    <string name="action_settings">Settings</string>
    <string name="hello_world">Hello world!</string>

</resources>

activity_display_message.xml
<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=".DisplayMessageActivity" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />

</RelativeLayout>


**DisplayMessageActivity.java**


package com.example.firstapp;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.MenuItem;
import android.support.v4.app.NavUtils;
import android.annotation.TargetApi;
import android.os.Build;

public class DisplayMessageActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_display_message);
        // Show the Up button in the action bar.
        setupActionBar();
    }

    /**
    * Set up the {@link android.app.ActionBar}, if the API is available.
    */
    @TargetApi(Build.VERSION_CODES.HONEYCOMB)
    private void setupActionBar() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
            getActionBar().setDisplayHomeAsUpEnabled(true);
        }
    }


    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
        case android.R.id.home:
            // This ID represents the Home or Up button. In the case of this
            // activity, the Up button is shown. Use NavUtils to allow users
            // to navigate up one level in the application structure. For
            // more details, see the Navigation pattern on Android Design:
            //
            // http://developer.android.com/design/patterns/navigation.html#up-vs-back
            //
            NavUtils.navigateUpFromSameTask(this);
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

}

Answer 1

在控制台日志中：

错误：找不到匹配给定名称的资源（在'title'处值'@ string / action_settings'）

表示您需要在action_settings文件中定义res/values/strings.xml字符串：

<resources>
        <!-- Other String name- value -->
    <string name="action_settings">Action Settings</string>
</resources>

，第二种方式是，如果您没有将Menu用于您的应用，那么只需在android:title内对res/menu/main.xml项属性进行评论。

Answer 2

抱怨menu/main.xml，而不是layout/activity_main.xml

您的菜单项似乎没有使用android:title的完全限定名称，而不仅仅是title，或者您还没有定义它正在使用的字符串。

Android开发者第一个应用教程

2 个答案: