数据存储之Network

Android中发送电子邮件是通过startActivity方法来调用要发送的邮件数据的Intent。我们可以通过putExtra方法来设置邮件的主题、内容、附件等。


发送邮件：

import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.KeyEvent;

public class Activity_01 extends Activity {
	
	private int mCount = 0;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        mCount = 1000;
    }
	@Override
	public boolean onKeyDown(int keyCode, KeyEvent event) {
		if(keyCode == KeyEvent.KEYCODE_BACK){
			//按下退出是保持邮件
			//发送邮件的地址
			Uri uri = Uri.parse("mailto:[e-mail]");
			//创建Intent
			Intent intent = new Intent(Intent.ACTION_SENDTO, uri);
			//设置邮件的主题
			intent.putExtra(android.content.Intent.EXTRA_SUBJECT, "数据备份");
			//设置邮件内容
			intent.putExtra(android.content.Intent.EXTRA_TEXT, "本次计数：" + mCount);
			//开启
			startActivity(intent);
			this.finish();
			return true;
		}
		return super.onKeyDown(keyCode, event);
	}
    
}

从网络上获取数据：

import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;

import org.apache.http.util.ByteArrayBuffer;

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

public class Activity_01 extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        
        TextView tv = new TextView(this);
        
        String myString = null;
        
        try {
			//定义我们要访问的地址
			URL uri = new URL("http://www.baidu.com");
			
			//打开这个url链接
			URLConnection ucon = uri.openConnection();
			
			//从上面的链接中取得InputStream
			InputStream is = ucon.getInputStream();
			
			BufferedInputStream bis = new BufferedInputStream(is);
			
			ByteArrayBuffer bab = new ByteArrayBuffer(100);
			
			int current = 0;
			
			// 一直读到文件结束
			while((current = bis.read()) != -1){
				bab.append((byte)current);
			}
			
			myString = new String(bab.toByteArray());
		} catch (MalformedURLException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
        
		tv.setText(myString);
		setContentView(tv);
    }
}

注意：
需要设置权限
<uses-permission android:name="android.permission.INTERNET" />