這是在本網站的一篇博文,原文題目是
Android數據訪問存儲之內存讀寫
,但是呢,在實踐的時候,運行有差別.估計是jdk版本的問題或者eclipse版本的問題.現在在我這裏是完美運行了的/package wangjun.day15;
/*** 在手機中進行文件的寫入.還對手機中的TXT文件的內容進行編輯
* 這個有助於以後判斷手機上是否寫入什麼東西/
* 但是還是有很多地方,自己還是不是很清楚.太多的專業的詞.
* 還需要加強啊
*/
import java.io.FileOutputStream;
import java.io.IOException;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.os.Environment;
import android.os.StatFs;
import android.text.format.Formatter;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends Activity implements OnClickListener {
private TextView tv_main_memerysize;
private TextView tv_main_sdcard;
private TextView tv_main_sdcardsize;
private EditText et_main_content;
private Button btn_main_writememery;
private Button btn_main_writesdcard;
private boolean sdcardMount = false;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tv_main_memerysize = (TextView) findViewById(R.id.sj_neicun_tv);
tv_main_sdcard = (TextView) findViewById(R.id.sd_cunzai_tv);
tv_main_sdcardsize = (TextView) findViewById(R.id.sd_neicun_tv);
et_main_content = (EditText) findViewById(R.id.csxieru_et);
btn_main_writememery = (Button) findViewById(R.id.xieru_btn);
btn_main_writesdcard = (Button) findViewById(R.id.xrsd_btn);
btn_main_writememery.setOnClickListener(this);
btn_main_writesdcard.setOnClickListener(this);
//判斷sdcard是否已安裝
tv_main_sdcard.setText("sdcard未安裝");
if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
sdcardMount = true;
tv_main_sdcard.setText("sdcard已安裝");
}
//得到sdcard和內存的大小及可用容量
if(sdcardMount){
tv_main_sdcardsize.setText("sdcard" + getStorgeFileSize(Environment.getExternalStorageDirectory().getPath()));
}else {
tv_main_sdcardsize.setText("sdcard總內存:0MB; 可用內存:0MB");
}
tv_main_memerysize.setText("手機" + getStorgeFileSize(Environment.getDataDirectory().getPath()));
}
/* 兩個按鈕的監聽事件，將內容寫入內存文件testmemeryio.txt */
@Override
public void onClick(View v) {
String text = et_main_content.getText().toString();
boolean success = true;
switch (v.getId()) {
case R.id.xrsd_btn: //寫入sdcard
FileOutputStream fos = null;
try {
fos = new FileOutputStream(Environment.getExternalStorageDirectory().getPath() + "/m.txt");
fos.write(text.getBytes("utf-8"));
fos.flush();
} catch (IOException e) {
success = false;
e.printStackTrace();
} finally {
if(fos != null){
try {
fos.close();
fos = null;
} catch (IOException e) {
e.printStackTrace();
}
}
}
Toast.makeText(MainActivity.this, success == true ? "寫入sdcard文件成功" : "寫入sdcard文件失敗", 0).show();
break;
case R.id.xieru_btn: //寫入內存
FileOutputStream openFileOutput = null;
try {
//使用openFileOutput()函數,直接在/data/data/包名/files/目錄下創建文件
openFileOutput = openFileOutput("testmemeryio.txt", Context.MODE_PRIVATE); //私有模式寫文件
openFileOutput.write(text.getBytes("utf-8"));
openFileOutput.flush();
} catch (IOException e) {
success = false;
e.printStackTrace();
} finally {
if(openFileOutput != null){
try {
openFileOutput.close();
openFileOutput = null;
} catch (IOException e) {
e.printStackTrace();
}
}
}
Toast.makeText(MainActivity.this, success == true ? "寫入內存文件成功" : "寫入內存文件失敗", 0).show();
break;
default:
break;
}
}
/* 取得內存文件空間大小及可用大小 */
@SuppressLint("NewApi") private String getStorgeFileSize(String path){
String fileSizeDesc = null;
StatFs statFs = new StatFs(path); //獲得磁盤狀態的對象
long blockSizeLong = statFs.getBlockSize(); //獲得磁盤一個扇區的大小
long blockCountLong = statFs.getBlockCount(); //獲得磁盤空間總的扇區數
long availableBlocksLong = statFs.getAvailableBlocks(); //獲得磁盤空間總的可用扇區數
fileSizeDesc = "總內存:" + Formatter.formatFileSize(MainActivity.this, blockSizeLong*blockCountLong)
+ "; 可用內存:" + Formatter.formatFileSize(MainActivity.this, blockSizeLong*availableBlocksLong);
return fileSizeDesc;
}
}