问题
i am new at android development and i need your help. I was locking at topics that are similar for my development but non of then help me. So far i create functions that gets me the files from my sdcard and shows me the list of then. That is working
this is the code for getting the paths on sdcard:
package com.seminarskirad;
import android.app.AlertDialog;
import android.app.AlertDialog.Builder;
import android.app.ListActivity;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FilenameFilter;
import java.io.IOException;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.List;
public class LoadActivity extends ListActivity{
private enum DISPLAYMODE{ ABSOLUTE, RELATIVE; }
private final DISPLAYMODE displayMode = DISPLAYMODE.ABSOLUTE;
private List<String> directoryEntries = new ArrayList<String>();
private File currentDirectory = new File("/");
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Browse(Environment.getExternalStorageDirectory());
}
private void upOneLevel(){
if(this.currentDirectory.getParent() != null)
this.Browse(this.currentDirectory.getParentFile());
}
private void Browse(final File aDirectory){
if (aDirectory.isDirectory()){
this.currentDirectory = aDirectory;
fill(aDirectory.listFiles());
}
}
private void fill(File[] files) {
this.directoryEntries.clear();
if(this.currentDirectory.getParent() != null)
this.directoryEntries.add("..");
switch(this.displayMode){
case ABSOLUTE:
for (File file : files){
this.directoryEntries.add(file.getPath());
}
break;
case RELATIVE: // On relative Mode, we have to add the current-path to the beginning
int currentPathStringLenght = this.currentDirectory.getAbsolutePath().length();
for (File file : files){
this.directoryEntries.add(file.getAbsolutePath().substring(currentPathStringLenght));
}
break;
}
ArrayAdapter<String> directoryList = new ArrayAdapter<String>(this, R.layout.load, this.directoryEntries);
this.setListAdapter(directoryList);
}
protected void onListItemClick(ListView l, View v, int position, long id) {
int selectionRowID = position;
String selectedFileString = this.directoryEntries.get(selectionRowID);
if(selectedFileString.equals("..")){
this.upOneLevel();
}else if(selectedFileString.equals()){ /// what to write here ???
this.readFile(); ///what to write here???
} else {
File clickedFile = null;
switch(this.displayMode){
case RELATIVE:
clickedFile = new File(this.currentDirectory.getAbsolutePath()
+ this.directoryEntries.get(selectionRowID));
break;
case ABSOLUTE:
clickedFile = new File(this.directoryEntries.get(selectionRowID));
break;
}
if(clickedFile.isFile())
this.Browse(clickedFile);
}
}
private void readFile() {
// what to write here???
}
Sorry i cant put the image because i dont have reputation, but when i run it on my emulator a get something like this:
/mnt/sdcard/kuzmanic.c
/mnt/sdcard/text.txt
/mnt/sdcard/DCIM
/mnt/sdcard/LOST.DIR
So what I want to do is when i click on the text.txt or kuzmanic.c file I want to open then in the same layout file, that is my load.xml file:
This is the code for the xml file:
<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:textSize="18sp">
</TextView>
What i need to write in my code and do I have to write anything in the manifest???
回答1:
Try this code:
package com.javasamples;
import java.io.*;
import android.app.Activity;
import android.os.Bundle;
import android.view.*;
import android.view.View.OnClickListener;
import android.widget.*;
public class FileDemo2 extends Activity {
// GUI controls
EditText txtData;
Button btnWriteSDFile;
Button btnReadSDFile;
Button btnClearScreen;
Button btnClose;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// bind GUI elements with local controls
txtData = (EditText) findViewById(R.id.txtData);
txtData.setHint("Enter some lines of data here...");
btnWriteSDFile = (Button) findViewById(R.id.btnWriteSDFile);
btnWriteSDFile.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
// write on SD card file data in the text box
try {
File myFile = new File("/sdcard/mysdfile.txt");
myFile.createNewFile();
FileOutputStream fOut = new FileOutputStream(myFile);
OutputStreamWriter myOutWriter =
new OutputStreamWriter(fOut);
myOutWriter.append(txtData.getText());
myOutWriter.close();
fOut.close();
Toast.makeText(getBaseContext(),
"Done writing SD 'mysdfile.txt'",
Toast.LENGTH_SHORT).show();
} catch (Exception e) {
Toast.makeText(getBaseContext(), e.getMessage(),
Toast.LENGTH_SHORT).show();
}
}// onClick
}); // btnWriteSDFile
btnReadSDFile = (Button) findViewById(R.id.btnReadSDFile);
btnReadSDFile.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
// write on SD card file data in the text box
try {
File myFile = new File("/sdcard/mysdfile.txt");
FileInputStream fIn = new FileInputStream(myFile);
BufferedReader myReader = new BufferedReader(
new InputStreamReader(fIn));
String aDataRow = "";
String aBuffer = "";
while ((aDataRow = myReader.readLine()) != null) {
aBuffer += aDataRow + "\n";
}
txtData.setText(aBuffer);
myReader.close();
Toast.makeText(getBaseContext(),
"Done reading SD 'mysdfile.txt'",
Toast.LENGTH_SHORT).show();
} catch (Exception e) {
Toast.makeText(getBaseContext(), e.getMessage(),
Toast.LENGTH_SHORT).show();
}
}// onClick
}); // btnReadSDFile
btnClearScreen = (Button) findViewById(R.id.btnClearScreen);
btnClearScreen.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
// clear text box
txtData.setText("");
}
}); // btnClearScreen
btnClose = (Button) findViewById(R.id.btnClose);
btnClose.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
// clear text box
finish();
}
}); // btnClose
}// onCreate
}// AndSDcard
the layout file is
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
android:id="@+id/widget28"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#ff0000ff"
android:orientation="vertical"
xmlns:android="http://schemas.android.com/apk/res/android"
>
<EditText
android:id="@+id/txtData"
android:layout_width="fill_parent"
android:layout_height="180px"
android:textSize="18sp" />
<Button
android:id="@+id/btnWriteSDFile"
android:layout_width="143px"
android:layout_height="44px"
android:text="1. Write SD File" />
<Button
android:id="@+id/btnClearScreen"
android:layout_width="141px"
android:layout_height="42px"
android:text="2. Clear Screen" />
<Button
android:id="@+id/btnReadSDFile"
android:layout_width="140px"
android:layout_height="42px"
android:text="3. Read SD File" />
<Button
android:id="@+id/btnClose"
android:layout_width="141px"
android:layout_height="43px"
android:text="4. Close" />
</LinearLayout>
回答2:
I used this code to read a text file in SD card,
public class ReadFileSDCardActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
//Find the view by its id
TextView tv = (TextView)findViewById(R.id.fileContent);
File dir = Environment.getExternalStorageDirectory();
//File yourFile = new File(dir, "path/to/the/file/inside/the/sdcard.ext");
//Get the text file
File file = new File(dir,"text.txt");
// i have kept text.txt in the sd-card
if(file.exists()) // check if file exist
{
//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');
}
}
catch (IOException e) {
//You'll need to add proper error handling here
}
//Set the text
tv.setText(text);
}
else
{
tv.setText("Sorry file doesn't exist!!");
}
}
}
回答3:
first you have to give an id to your textview into the load.xml file and define the textview inside a linear layout. like this
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent" android:layout_height="match_parent"
<TextView android:id="@+id/tv1
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:textSize="18sp"/>
now you have to set the layout of your activity.you can do this in the onCreate() method only.
setContentView(R.layout.load);
now make a TextVew object like this.
TextView tview = (TextView) findViewById(R.id.tv1);
now you have to read the text file using FileInputStream and keep it into a string variable.
after that you can assign the string to the text view.
tview.setText(string variable name);
来源：https://stackoverflow.com/questions/10549741/how-to-read-a-selected-text-file-from-sdcard-on-android