Android 讀寫文件方法匯總

2020-04-11 12:04:34

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來源：轉載

供稿：網友

一、從resource中的raw文件夾中獲取文件并讀取數據（資源文件只能讀不能寫）

String res = "";
try{
InputStream in = getResources().openRawResource(R.raw.bbi);
//在/Test/res/raw/bbi.txt,
int length = in.available();
byte [] buffer = new byte[length];
in.read(buffer);
//res = EncodingUtils.getString(buffer, "UTF-8");
//res = EncodingUtils.getString(buffer, "UNICODE");
res = EncodingUtils.getString(buffer, "BIG5");
//依bbi.txt的編碼類型選擇合適的編碼，如果不調整會亂碼
in.close();
}catch(Exception e){
e.printStackTrace();
}

myTextView.setText(res);//把得到的內容顯示在TextView上

二、從asset中獲取文件并讀取數據（資源文件只能讀不能寫）

復制代碼代碼如下:

String fileName = "yan.txt"; //文件名字
String res="";
try{
InputStream in = getResources().getAssets().open(fileName);
// /Test/assets/yan.txt這里有這樣的文件存在
int length = in.available();
byte [] buffer = new byte[length];
in.read(buffer);
res = EncodingUtils.getString(buffer, "UTF-8");
}catch(Exception e){
e.printStackTrace();
}

三、從sdcard中去讀文件，首先要把文件通過/android-sdk-windows/tools/adb.exe把本地計算機上的文件copy到sdcard上去，adb.exe push e:/Y.txt /sdcard/, 不可以用adb.exe push e:/Y.txt /sdcard/ 同樣：把仿真器上的文件copy到本地計算機上用： adb pull ./data/data/com.tt/files/Test.txt e:/

復制代碼代碼如下:

String fileName = "/sdcard/Y.txt";
//也可以用String fileName = "mnt/sdcard/Y.txt";
String res="";
try{
FileInputStream fin = new FileInputStream(fileName);
//FileInputStream fin = openFileInput(fileName);
//用這個就不行了，必須用FileInputStream
int length = fin.available();
byte [] buffer = new byte[length];
fin.read(buffer);
res = EncodingUtils.getString(buffer, "UTF-8");
fin.close();
}catch(Exception e){
e.printStackTrace();
}
myTextView.setText(res);

四、寫文件，一般寫在/data/data/com.test/files/里面，打開DDMS查看file explorer是可以看到仿真器文件存放目錄的結構的

復制代碼代碼如下:

String fileName = "TEST.txt";
String message = "FFFFFFF11111FFFFF" ;
writeFileData(fileName, message);
public voidwriteFileData(String fileName,String message){
try{
FileOutputStream fout =openFileOutput(fileName, MODE_PRIVATE);
byte [] bytes = message.getBytes();
fout.write(bytes);
fout.close();
}
catch(Exception e){
e.printStackTrace();
}
}

五、寫，讀data/data/目錄(相當AP工作目錄)上的文件，用openFileOutput

復制代碼代碼如下:

//寫文件在./data/data/com.tt/files/下面
public voidwriteFileData(String fileName,String message){
try{
FileOutputStream fout =openFileOutput(fileName, MODE_PRIVATE);
byte [] bytes = message.getBytes();
fout.write(bytes);
fout.close();
}
catch(Exception e){
e.printStackTrace();
}
}
//-------------------------------------------------------
//讀文件在./data/data/com.tt/files/下面
public String readFileData(String fileName){
String res="";
try{
FileInputStream fin = openFileInput(fileName);
int length = fin.available();
byte [] buffer = new byte[length];
fin.read(buffer);
res = EncodingUtils.getString(buffer, "UTF-8");
fin.close();
}
catch(Exception e){
e.printStackTrace();
}
return res;
}

六、寫，讀sdcard目錄上的文件，要用FileOutputStream，不能用openFileOutput

復制代碼代碼如下:

//寫在/mnt/sdcard/目錄下面的文件
public voidwriteFileSdcard(String fileName,String message){
try{
//FileOutputStream fout = openFileOutput(fileName, MODE_PRIVATE);
FileOutputStream fout = newFileOutputStream(fileName);
byte [] bytes = message.getBytes();
fout.write(bytes);
fout.close();
}
catch(Exception e){
e.printStackTrace();
}
}
//讀在/mnt/sdcard/目錄下面的文件
public String readFileSdcard(String fileName){
String res="";
try{
FileInputStream fin = new FileInputStream(fileName);
int length = fin.available();
byte [] buffer = new byte[length];
fin.read(buffer);
res = EncodingUtils.getString(buffer, "UTF-8");
fin.close();
}
catch(Exception e){
e.printStackTrace();
}
return res;
}