Android 学习笔记 文本文件的读写操作

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity" >

<Button
android:id="@+id/btn01"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="保存" />
<Button
android:id="@+id/btn02"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="读取" />

<TextView
android:id="@+id/msg"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
</LinearLayout>

public class MainActivity extends Activity {
private static final String FILENAME="Test01.txt";
private Button btn01=null;
private Button btn02=null;
private TextView msg=null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
super.setContentView(R.layout.activity_main);
this.btn01=(Button)super.findViewById(R.id.btn01);
this.btn02=(Button)super.findViewById(R.id.btn02);
this.btn01.setOnClickListener(new OnClickListenerImpl());
this.btn02.setOnClickListener(new OnClickListenerImpl());
this.msg=(TextView)super.findViewById(R.id.msg);
}
private class OnClickListenerImpl implements OnClickListener{

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
switch (v.getId()) {
case R.id.btn01:
FileOutputStream output=null;
try {
output=MainActivity.this.openFileOutput(FILENAME, Activity.MODE_PRIVATE);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
PrintStream out=new PrintStream(output);
out.println(sdf.format(new Date()));
out.println("文本内容aa");
out.close();
Toast.makeText(MainActivity.this, "文件已经保存", Toast.LENGTH_SHORT).show();
break;
case R.id.btn02:
FileInputStream input=null;
try {
input=MainActivity.this.openFileInput(FILENAME);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Scanner scanner=new Scanner(input);
MainActivity.this.msg.setText("");
MainActivity.this.msg.append("-------Start--------\n");
while (scanner.hasNext()) {
MainActivity.this.msg.append(scanner.next()+"\n");
}
MainActivity.this.msg.append("-------End--------\n");
Toast.makeText(MainActivity.this, "文件已经读取", Toast.LENGTH_SHORT).show();
break;
default:
break;
}
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}

}

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>