android openFileInput openFileOutput

最新推荐文章于 2017-06-11 23:39:18 发布

原创最新推荐文章于 2017-06-11 23:39:18 发布 · 556 阅读

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#android #openFileInput #openFileOutput

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本文提供了一个Android应用中文件读写的示例代码，展示了如何使用openFileInput和openFileOutput方法来操作本地文件，包括从文件中读取字符串及向文件追加字符串。

openFileInput 打开应用程序的数据文件夹下的name文件对应的输入流

openFileOutput打开应用程序的数据文件夹下的name文件对应的输出流

下面是读写的例子

public class MainActivity extends Activity {

private EditText et1;
private EditText et2;
private Button bt1;
private Button bt2;
final String FILE_NAME = "crazyit.bin";

@Override
protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  et1 = (EditText) findViewById(R.id.editText1);
  et2 = (EditText) findViewById(R.id.editText2);
  bt1 = (Button) findViewById(R.id.button1);
  bt2 = (Button) findViewById(R.id.button2);
  bt1.setOnClickListener(new OnClickListener() {

   @Override
   public void onClick(View arg0) {
    write(et1.getText().toString());
    et1.setText("");
   }
  });
  bt2.setOnClickListener(new OnClickListener() {

   @Override
   public void onClick(View v) {
    et2.setText(read());
   }
  });

}

private String read(){

  try {
   FileInputStream fis = openFileInput(FILE_NAME);
   byte[] buff = new byte[1024];
   int hasread = 0;
   StringBuilder sb = new StringBuilder();
   while((hasread=fis.read(buff))>0){
    sb.append(new String(buff,0,hasread));
   }
   fis.close();
   return sb.toString();
  } catch (FileNotFoundException e) {
   e.printStackTrace();
  } catch (IOException e) {
   e.printStackTrace();
  }
  return null ;
}

private void write(String content){

  try {
   FileOutputStream fos = openFileOutput(FILE_NAME, MODE_APPEND);
   PrintStream ps = new PrintStream(fos);
   ps.println(content);
   ps.close();
  } catch (FileNotFoundException e) {
   e.printStackTrace();
  }
}

}