Application值传递。

1、layout下面的布局

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<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="com.example.app.androidvaluespass.MainActivity">


    <Button
        android:id="@+id/btnSubmit"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="值传递"/>

</RelativeLayout>

values.xml用于接收值

<?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">


  <EditText
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:id="@+id/Msg"/>

</LinearLayout>

2、类及启动项

MainActivity

package com.example.app.androidvaluespass;

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

public class MainActivity extends Activity {

    private Button btn;
    private MyApp myApp;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        btn = (Button)this.findViewById(R.id.btnSubmit);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                myApp = (MyApp)getApplication();
                myApp.setName("赵信!");//修改后的名称
                Intent intent = new Intent(MainActivity.this,ValuesActivity.class);
                startActivity(intent);
            }
        });
    }
}

定义一个Application类 MyApp

package com.example.app.androidvaluespass;

import android.app.Application;

/**
 * Created by honghong on 2016/6/18.
 */
public class MyApp extends Application {

    public String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public void onCreate() {
        super.onCreate();
        setName("张三");
    }
}

定义一个接收值的类

package com.example.app.androidvaluespass;

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;

/**
 * Created by honghong on 2016/6/18.
 */
public class ValuesActivity extends Activity {

    private MyApp myApp;
    private TextView editText;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.values);
        editText = (TextView)this.findViewById(R.id.Msg);
        myApp = (MyApp)getApplication();
        editText.setText(myApp.getName());
    }
}

最后要在AndroidManifest.xml 文件中配置一下

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

    <application
        android:name=".MyApp" // ← 继承Application类的名称，这个一定要对应。
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name=".ValuesActivity"></activity>  // 这个类调用Application类ValuesActivity
    </application>

</manifest>