//檔案寫入SD卡操作
public class Main extends Activity {
/* Called when the activity is first created. /
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
try {
// 建立FileWriter物件，並將寫入位置設定為SD卡中的output.txt
FileWriter fw = new FileWriter(“/mnt/sdcard/output1.txt”, false);
// 建立fw的Output Buffer,緩衝寫滿後在將資料寫入硬碟 這樣做極大的提高了效能
//如果單獨使用 FileWriter也可以,但是每寫一個數據,硬碟就有一個寫動作,效能極差
BufferedWriter bw = new BufferedWriter(fw);
bw.write(“Come on baby, 今天天氣很好”);
bw.newLine();
bw.close();
} catch (IOException e) {
e.printStackTrace();
}
}

}
//讀取SD卡里面的文字內容
public class MainActivity extends Activity {

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    try {
        // 建立FileReader物件，設定讀取的檔案為SD卡中的output.txt
        FileReader fr = new FileReader("/sdcard/output1.txt");
        // 建立fr的Input Buffer
        BufferedReader br = new BufferedReader(fr);
        String readData = "";
        String temp = br.readLine();
        //迴圈一行一行的讀取文字內容
        while (temp != null) {
            readData += temp;
            temp = br.readLine();
        }
        Context context = getApplicationContext();//建立的context指向整個應用程式,this指向當前的Acticity
        Toast toast = Toast.makeText(context, readData, Toast.LENGTH_LONG);
        toast.show();
    } catch (Exception e) {
        e.printStackTrace();
    }
}
 

}