Android 从其他活动读取文件
我想读取使用OutputStreamWriter在另一个活动中编写的文本文件。 这是Sale.java中的readFromFile方法:Android 从其他活动读取文件,android,fileinputstream,Android,Fileinputstream,我想读取使用OutputStreamWriter在另一个活动中编写的文本文件。 这是Sale.java中的readFromFile方法: private int readFromFile(String request) { int res = 0; try { //InputStream inputStream = openFileInput("dalassnums.txt"); File file=new Fil
private int readFromFile(String request) {
int res = 0;
try {
//InputStream inputStream = openFileInput("dalassnums.txt");
File file=new File("dalassnums.txt");
InputStream inputStream = new FileInputStream(file);
if ( inputStream != null ) {
InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
String receiveString = "";
while ( (receiveString = bufferedReader.readLine()) != null ) {
String s=bufferedReader.readLine();
if(receiveString==request) {
res=Integer.valueOf(s);
break;
}
}
inputStream.close();
}
}
catch (FileNotFoundException e) {
Log.e("login activity", "File not found: " + e.toString());
res=0;
} catch (IOException e) {
//Log.e("login activity", "Can not read file: " + e.toString());
}
return res;
}
这是MainActivity.java中的writeToFile方法:
private void writeToFile2(String numchar) {
try {
//File file=new File("dalassnums.txt");
//OutputStream outputStream=new FileOutputStream(file);
OutputStreamWriter outputStreamWriter;
if(numchar=="1") outputStreamWriter = new OutputStreamWriter(openFileOutput("dalassnums.txt", Context.MODE_PRIVATE));
else outputStreamWriter = new OutputStreamWriter(openFileOutput("dalassnums.txt", Context.MODE_APPEND));
for(int k=0; k<imageNums.size();k+=2){
outputStreamWriter.append(imageNums.get(k));
outputStreamWriter.append("\n");
outputStreamWriter.append(imageNums.get(k+1));
outputStreamWriter.append("\n");
}
outputStreamWriter.close();
}
catch (IOException e) {
Log.e("Exception", "File write failed: " + e.toString());
}
}
private void writeToFile2(字符串numchar){
试一试{
//File File=新文件(“dalassnums.txt”);
//OutputStream OutputStream=新文件OutputStream(文件);
OutputStreamWriter OutputStreamWriter;
如果(numchar==“1”)outputStreamWriter=新的outputStreamWriter(openFileOutput(“dalassnums.txt”,Context.MODE_PRIVATE));
else outputStreamWriter=新的outputStreamWriter(openFileOutput(“dalassnums.txt”,Context.MODE_APPEND));
对于readFromFile
中的(int k=0;k使用:openFileInput
),请查看以下示例:
另一个问题是,这是无效的:
if(numchar=="1")
你应该
if(numchar.equals("1"))
否则,您将比较引用值而不是字符串的内容您的上下文有什么问题?使用活动作为上下文,即从活动内部传递此
,或者使用getApplicationContext。openFileInput/openFileOutput设置文件的正确路径,因此它们应该一起使用。我使用了getApplicationContextxt;未更改,仍然返回0:/噢,谢谢,我正在查找此错误。如果我打扰您,很抱歉……您对我无法读取该文件的原因有其他想法吗?使用FileInputStream
而不是InputStream
并将if(receiveString==request)
更改为if(receiveString.equals(request))
问题已解决。谢谢