我是Android开发的新手。
我需要从SD卡中读取一个文本文件并显示该文本文件。有没有办法在Android中直接查看文本文件,或者如何读取和显示文本文件的内容?
发布于 2010-05-25 17:27:12
In your layout你需要一些东西来显示文本。TextView
是显而易见的选择。所以你会得到类似这样的东西:
<TextView
android:id="@+id/text_view"
android:layout_width="fill_parent"
android:layout_height="fill_parent"/>
您的代码将如下所示:
//Find the directory for the SD Card using the API
//*Don't* hardcode "/sdcard"
File sdcard = Environment.getExternalStorageDirectory();
//Get the text file
File file = new File(sdcard,"file.txt");
//Read text from file
StringBuilder text = new StringBuilder();
try {
BufferedReader br = new BufferedReader(new FileReader(file));
String line;
while ((line = br.readLine()) != null) {
text.append(line);
text.append('\n');
}
br.close();
}
catch (IOException e) {
//You'll need to add proper error handling here
}
//Find the view by its id
TextView tv = (TextView)findViewById(R.id.text_view);
//Set the text
tv.setText(text);
这可以放在Activity
的onCreate()
方法中,也可以放在其他地方,具体取决于你想要做什么。
发布于 2018-08-21 17:23:22
您需要有READ_EXTERNAL_STORAGE权限才能读取SD卡。在manifest.xml中添加权限
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
从android 6.0或更高版本开始,您的应用程序必须要求用户在运行时授予危险权限。请参阅此链接Permissions overview
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
if (checkSelfPermission(Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, 0);
}
}
发布于 2014-08-07 14:04:24
package com.example.readfilefromexternalresource;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import android.app.Activity;
import android.app.ActionBar;
import android.app.Fragment;
import android.os.Bundle;
import android.os.Environment;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import android.widget.Toast;
import android.os.Build;
public class MainActivity extends Activity {
private TextView textView;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
textView = (TextView)findViewById(R.id.textView);
String state = Environment.getExternalStorageState();
if (!(state.equals(Environment.MEDIA_MOUNTED))) {
Toast.makeText(this, "There is no any sd card", Toast.LENGTH_LONG).show();
} else {
BufferedReader reader = null;
try {
Toast.makeText(this, "Sd card available", Toast.LENGTH_LONG).show();
File file = Environment.getExternalStorageDirectory();
File textFile = new File(file.getAbsolutePath()+File.separator + "chapter.xml");
reader = new BufferedReader(new FileReader(textFile));
StringBuilder textBuilder = new StringBuilder();
String line;
while((line = reader.readLine()) != null) {
textBuilder.append(line);
textBuilder.append("\n");
}
textView.setText(textBuilder);
} catch (FileNotFoundException e) {
// TODO: handle exception
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
finally{
if(reader != null){
try {
reader.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
}
}
https://stackoverflow.com/questions/2902689
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