第五集android使用全局变量传递数据

安下图新建出

MainActivity.java

Mapp.java

OtherActivity.java

main.xml

other.xml

MainActivity.java

package com.fxp.app;

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

public class MainActivity extends Activity {
    private Button gobutton;
    private TextView firstTextView;
    private Mapp mapp;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        gobutton = (Button) findViewById(R.id.goButton);
        firstTextView = (TextView) findViewById(R.id.firstTextView);
        mapp = (Mapp) getApplication();
        
        firstTextView.setText(mapp.getName());
        GoButtonListener goButtonListener = new GoButtonListener();
        gobutton.setOnClickListener(goButtonListener);
    }
    class GoButtonListener implements OnClickListener{
        @Override
        public void onClick(View v) {
            mapp.setName("张三");
            Intent intent=new Intent();
            intent.setClass(MainActivity.this, OtherActivity.class);
            startActivity(intent);
        }
    }

    @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;
    }

}

Mapp.java

package com.fxp.app;

import android.app.Application;

public class Mapp extends Application {
    private String name;

    public String getName() {
        return name;
    }

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

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

OtherActivity.java

package com.fxp.app;

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

public class OtherActivity extends Activity {
    private Button backButton;
    private TextView secondTextView;
    private Mapp mapp;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.other);
        backButton = (Button) findViewById(R.id.backButton);
        secondTextView = (TextView) findViewById(R.id.secondTextView);
        mapp = (Mapp) getApplication();

        secondTextView.setText(mapp.getName());
        BackButtonListener backButtonListener = new BackButtonListener();
        backButton.setOnClickListener(backButtonListener);
    }

    class BackButtonListener implements OnClickListener {
        @Override
        public void onClick(View v) {
            mapp.setName("李四回到第一页");
            Intent intent = new Intent();
            intent.setClass(OtherActivity.this, MainActivity.class);
            startActivity(intent);
        }
    }
}

main.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=".MainActivity" >

    <TextView
        android:id="@+id/firstTextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="开始" />
    <Button
        android:id="@+id/goButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/firstTextView"
        android:text="跳第二页" />
</RelativeLayout>

other.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=".MainActivity" >

    <TextView
        android:id="@+id/secondTextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="开始" />
    <Button
        android:id="@+id/backButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/secondTextView"
        android:text="跳第一页" />
</RelativeLayout>