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  • Android SD卡读取简单操作

    package com.example.sdcardtest;
    
    import java.io.BufferedReader;
    import java.io.File;
    import java.io.FileInputStream;
    import java.io.FileNotFoundException;
    import java.io.IOException;
    import java.io.InputStreamReader;
    import java.io.RandomAccessFile;
    
    import android.app.Activity;
    import android.os.Bundle;
    import android.os.Environment;
    import android.view.View;
    import android.view.View.OnClickListener;
    import android.widget.Button;
    import android.widget.EditText;
    
    public class MainActivity extends Activity {
    	
    	
    	final String FILE_NAME = "/baidu/hello.txt";
    	@Override
    	protected void onCreate(Bundle savedInstanceState) {
    		super.onCreate(savedInstanceState);
    		setContentView(R.layout.activity_main);
    		
    		Button read = (Button) findViewById(R.id.read);
    		Button write = (Button) findViewById(R.id.write);
    		
    		final EditText edit1 = (EditText) findViewById(R.id.editText1);
    		final EditText edit2 = (EditText) findViewById(R.id.editText2);
    		
    		//为write事件绑定监听器
    		write.setOnClickListener(new OnClickListener() {
    			
    			public void onClick(View v) {
    				write(edit1.getText().toString());
    				edit1.setText("");
    				
    			}
    		});
    		
    		//为read事件绑定监听器
    		read.setOnClickListener(new OnClickListener() {
    			
    			public void onClick(View v) {
    				edit2.setText(read());
    			}
    		});
    		
    		
    	}
    	
    	
    	public String read(){
    		if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
    			File sdCardDir = Environment.getExternalStorageDirectory();
    			try {
    				FileInputStream fis = new FileInputStream(sdCardDir.getCanonicalPath() + FILE_NAME);
    				BufferedReader br = new BufferedReader(new InputStreamReader(fis));
    				StringBuilder sb = new StringBuilder("");
    				
    				String line = null;
    				while( (line = br.readLine()) != null ){
    					sb.append(line);
    				}
    				br.close();
    				return sb.toString();
    			} catch (FileNotFoundException e) {
    				e.printStackTrace();
    			} catch (IOException e) {
    				e.printStackTrace();
    			}
    			
    		}
    		return null;
    	}
    	
    	public void write(String content){
    		if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
    			RandomAccessFile raf = null;
    			try {
    				//获取sd卡的目录
    				File sdCardDir = Environment.getExternalStorageDirectory();
    				File targetFile = new File(sdCardDir.getCanonicalFile() + FILE_NAME);
    				
    				raf = new RandomAccessFile(targetFile, "rw");
    				raf.seek(targetFile.length());
    				raf.write(content.getBytes());
    				
    			} catch (IOException e) {
    				e.printStackTrace();
    			}
    			
    			try {
    				raf.close();
    			} catch (IOException e) {
    				e.printStackTrace();
    			}
    			
    		}
    	}
    
    }
    =====================
    布局文件
    简单的两个按钮,没什么好说的
    
    读好书,如同与先哲们交谈。
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  • 原文地址:https://www.cnblogs.com/ft039x/p/5621479.html
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