Android存储——SD卡或者文件存储实现。

Android实现SD卡和实现内存文件存储的做法基本是一样的。只是取得文件路径的方法不一样，基本上跟java的文件操作是一致的，下面是程序的代码。配置取的位置和实现有所不同，其他是一样的，下面是代码：

main.xml:

在AndroidManifest清单文件中要对SD卡读取进行支持。代码如下：

在String.xml中添加两个内容:

读取 写入
下面是文件实现的代码：

package cn.jason.io; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; 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 FileTestActivity extends Activity { final String FILE = "jason.bin"; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); Button read = (Button) findViewById(R.id.read); Button write = (Button) findViewById(R.id.write); final EditText edit1 = (EditText) findViewById(R.id.edit1); final EditText edit2 = (EditText) findViewById(R.id.edit2); write.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { write(edit1.getText().toString()); edit1.setText(""); } }); read.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { edit2.setText(read()); } }); } private String read() { try { FileInputStream fis = openFileInput(FILE); byte[] buffer = new byte[1024]; int hasRead = 0; StringBuilder sb = new StringBuilder(""); while ((hasRead = fis.read(buffer)) > 0) { sb.append(new String(buffer, 0, hasRead)); } return sb.toString(); } catch (IOException 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, 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(); } } }

下面是sd卡存储实现的代码：

package cn.jason.io; 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 java.net.ContentHandler; 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 SDCardTestActivity extends Activity { final String FILE = "/jason.bin"; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); 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() { @Override 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() { @Override public void onClick(View v) { // 读取指定文件中的内容，并显示出来 edit2.setText(read()); } }); } private String read() { // 如果手机插入了SD卡，而且应用程序具有访问SD的权限 try { if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) { // 获取SD卡的目录 File sdDirFile = Environment.getExternalStorageDirectory(); //获取指定文件对应的输入流 FileInputStream fis = new FileInputStream(sdDirFile.getCanonicalPath()+ FILE); //将指定输入流包装成BufferedReader BufferedReader br = new BufferedReader(new InputStreamReader(fis)); StringBuilder sb = new StringBuilder(""); String line = null; while ((line =br.readLine())!=null) { sb.append(line); } return sb.toString(); } } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } return null; } private void write(String context){ try { if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){ File sdDir = Environment.getExternalStorageDirectory(); File targetFile = new File(sdDir.getCanonicalPath()+ FILE); RandomAccessFile raf = new RandomAccessFile(targetFile, "rw"); raf.seek(targetFile.length()); raf.write(context.getBytes()); raf.close(); } } catch (Exception e) { } } }