Android 如何将数据写入文件
在以下几行中,我在“Environment.getExternalStorageDirectory()中创建了一个文件Android 如何将数据写入文件,android,file,Android,File,在以下几行中,我在“Environment.getExternalStorageDirectory()中创建了一个文件 我的问题是:如何将文本数据写入此创建的文件?您可以使用写入文件来将文本输出到文件。您可以使用具有不同有用方法的类来写入数据。您还可以从以下内容查看流: 下面是一个将数据写入文件的快速片段。请注意,它被设计为在一个单独的线程中运行,因此您不会在主UI线程中执行文件IO new Thread(new Runnable() { public void run() { St
我的问题是:如何将文本数据写入此创建的文件?您可以使用写入文件来将文本输出到文件。您可以使用具有不同有用方法的类来写入数据。您还可以从以下内容查看流:
下面是一个将数据写入文件的快速片段。请注意,它被设计为在一个单独的线程中运行,因此您不会在主UI线程中执行文件IO
new Thread(new Runnable() {
public void run() {
String FILENAME = "hello_file";
String string = "hello world!";
FileOutputStream fos = openFileOutput(FILENAME, Context.MODE_PRIVATE);
fos.write(string.getBytes());
fos.close();
}
}).start();
您要创建什么类型的文件?文本?二进制文件?我试过了,但是当我检查文件是否真的被创建时,我发现没有创建任何文件
//Writing a file...
try {
// catches IOException below
final String TESTSTRING = new String("Hello Android");
/* We have to use the openFileOutput()-method
* the ActivityContext provides, to
* protect your file from others and
* This is done for security-reasons.
* We chose MODE_WORLD_READABLE, because
* we have nothing to hide in our file */
FileOutputStream fOut = openFileOutput("samplefile.txt",
MODE_WORLD_READABLE);
OutputStreamWriter osw = new OutputStreamWriter(fOut);
// Write the string to the file
osw.write(TESTSTRING);
/* ensure that everything is
* really written out and close */
osw.flush();
osw.close();
//Reading the file back...
/* We have to use the openFileInput()-method
* the ActivityContext provides.
* Again for security reasons with
* openFileInput(...) */
FileInputStream fIn = openFileInput("samplefile.txt");
InputStreamReader isr = new InputStreamReader(fIn);
/* Prepare a char-Array that will
* hold the chars we read back in. */
char[] inputBuffer = new char[TESTSTRING.length()];
// Fill the Buffer with data from the file
isr.read(inputBuffer);
// Transform the chars to a String
String readString = new String(inputBuffer);
// Check if we read back the same chars that we had written out
boolean isTheSame = TESTSTRING.equals(readString);
Log.i("File Reading stuff", "success = " + isTheSame);
} catch (IOException ioe)
{ioe.printStackTrace();}
new Thread(new Runnable() {
public void run() {
String FILENAME = "hello_file";
String string = "hello world!";
FileOutputStream fos = openFileOutput(FILENAME, Context.MODE_PRIVATE);
fos.write(string.getBytes());
fos.close();
}
}).start();