初学Android,数据存储之File存储(四十二)

Android提供了如下两个方法来打开本应用程序的数据文件夹里的文件IO流

openFileInput(String name)

openFileOutput(String name)

打开应用程序的数据文件夹下的name文件对应输入/输出流

下面是一个示例

界面代码

package WangLi.IO.FileTest;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.PrintStream;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;

public class FileTest extends Activity {
	final String FILE_NAME = "test.txt";
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        //获取两个按钮
        Button read = (Button)findViewById(R.id.read);
        Button write = (Button)findViewById(R.id.write);
        //获取两个文本框
        final EditText edit1 = (EditText)findViewById(R.id.edit1);
        final EditText edit2 = (EditText)findViewById(R.id.edit2);
        //为write按钮绑定事件监听器
        write.setOnClickListener(new OnClickListener(){
        	public void onClick(View source)
        	{
        		//将edit1中的内容写入文件中
        		write(edit1.getText().toString());
        		edit1.setText("");
        	}
        });
        
        read.setOnClickListener(new OnClickListener(){
        	public void onClick(View source)
        	{
        		//读取指定文件中的内容并显示出来
        		edit2.setText(read());
        	}
        });
    }
    
    private String read()
    {
    	try
    	{
    		//打开文件件输入流
    		FileInputStream fis = openFileInput(FILE_NAME);
    		byte[] buff = new byte[1024];
    		int hasRead = 0;
    		StringBuilder sb = new StringBuilder("");
    		while((hasRead = fis.read(buff)) > 0)
    		{
    			sb.append(new String(buff, 0 , hasRead));
    		}
    		return sb.toString();
    	}
    	catch(Exception e)
    	{
    		e.printStackTrace();
    	}
    	return null;
    }
    
    private void write(String content)
    {
    	try
    	{
    		//以追加模式打开文件输出流
    		FileOutputStream fos = openFileOutput(FILE_NAME,MODE_APPEND);
    		//将FileOutputStream包装成PrintStream
    		PrintStream ps = new PrintStream(fos);
    		//输出文件内容
    		ps.println(content);
    		ps.close();
    	}
    	catch(Exception e)
    	{
    		e.printStackTrace();
    	}
    }
}

下图为DDMS里的路径