android - 创建新的 Android MainActivity 的问题

Question

我是 Android 编程的新手，正在尝试为我的应用创建一个新的 Main Activity(取自 Android 教程网站)。我原来的主要 Activity 叫做“MainActivity”。我想成为我的主要 Activity 的新 Activity 称为“主页”，它应该包含一个按钮，点击后会产生“MainActivity”。我不确定我应该在 list 中包含有关新页面“homepage”、homepage.xml 和按钮的信息的内容或位置。具体代码将不胜感激。

首页:

package com.myphoneapp;

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

public class HomePage extends Activity {

    private Button ScheduleBtn;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.homepage);

         ScheduleBtn = (Button) findViewById(R.id.home_btn);

        ScheduleBtn.setOnClickListener(new View.OnClickListener() {

            public void onClick(View v) {
                // TODO Auto-generated method stub


                Intent myIntent = new Intent(HomePage.this, MainActivity.class);
                HomePage.this.startActivity(myIntent);


            }
        });
    }   


}

主页.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <Button 

    android:layout_width="wrap_content" 

    android:layout_height="wrap_content" 

    android:text="Welcome to ClearLight" 

    android:id="@+id/home_btn"

    />

</LinearLayout>

主要 Activity :

package com.myphoneapp;

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


    public class MainActivity extends Activity {

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



    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // Get the message from the intent
        Intent intent = getIntent();
        String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);

        // Create the text view
        TextView textView = new TextView(this);
        textView.setTextSize(40);
        textView.setText(message);

        // Set the text view as the activity layout
        setContentView(textView);
        setContentView(R.layout.activity_main);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }

    /** Called when the user clicks the Send button */
    public void sendMessage(View view) {
        // Do something in response to button
        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);
    }

    }

list :

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

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="15" />

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

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

            <meta-data
                android:name="android.support.PARENT_ACTIVITY"
                android:value="com.example.myphoneapp.MainActivity" />
        </activity>
    </application>

</manifest>

Answer 1

要使 HomePage 成为您的第一个 Activity，请编辑您的 Manifest 文件，使其具有 action.MAIN 的 Intent 过滤器。而且您不必在 Manifest 文件中定义任何关于布局的内容。只有 Activity 声明(您已经拥有)

所以你的新 list 文件看起来像

    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.myphoneapp.MainActivity"
            android:label="@string/title_activity_main" >

        </activity>
        <activity
            android:name="com.myphoneapp.DisplayMessageActivity"
            android:label="@string/title_activity_display_message"
            android:parentActivityName="com.example.myphoneapp.MainActivity" >
            <meta-data
                android:name="android.support.PARENT_ACTIVITY"
                android:value="com.example.myphoneapp.MainActivity" />
        </activity>
        <activity
            android:name="com.myphoneapp.HomePage"
            android:label="@string/homepage" 
            android:parentActivityName="com.example.myphoneapp.MainActivity" >

            <!-- Move the intent filter to HomePage -->
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>

            <meta-data
                android:name="android.support.PARENT_ACTIVITY"
                android:value="com.example.myphoneapp.MainActivity" />
        </activity>
    </application>

</manifest>

对于启动 mainActivity 的按钮，您已经在 HomePage.java

中完成了

ScheduleBtn = (Button) findViewById(R.id.home_btn);
ScheduleBtn.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        Intent myIntent = new Intent(HomePage.this, MainActivity.class);
        HomePage.this.startActivity(myIntent);
    }
});

此代码(取自您的 HomePage.java 从 Intent 中打开 MainActivity