android文件访问实例

古城微笑少年丶 2022-01-13 23:55 210阅读 0赞

[2019独角兽企业重金招聘Python工程师标准>>> ][2019_Python_] ![hot3.png][]

主布局文件ch9\_filemain.xml:

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical" >
    	<TextView android:layout_width="fill_parent"
    	    android:layout_height="wrap_content"
    	    android:text="这是一个文件操作的示例"/>
    	<Button android:layout_width="fill_parent"
    	    android:layout_height="wrap_content"
    	    android:id="@+id/bt_createFile"
    	    android:text="创建文件"/>
    	<Button android:layout_width="fill_parent"
    	    android:layout_height="wrap_content"
    	    android:id="@+id/bt_readFile"
    	    android:text="读取文件"/>
    	<Button android:layout_width="fill_parent"
    	    android:layout_height="wrap_content"
    	    android:id="@+id/bt_readRawFile"
    	    android:text="读取资源文件"/>
    	<Button android:layout_width="fill_parent"
    	    android:layout_height="wrap_content"
    	    android:id="@+id/bt_readXMLFile"
    	    android:text="读取XML文件"/>
    	<Button android:layout_width="fill_parent"
    	    android:layout_height="wrap_content"
    	    android:id="@+id/bt_createXMLFile"
    	    android:text="创建XML文件"/>
    	
    
    </LinearLayout>

主活动类FileMainActivity.java：

package com.example.ch9;
    
    import com.example.baseexample.R;
    
    import android.app.Activity;
    import android.content.Intent;
    import android.os.Bundle;
    import android.view.View;
    import android.widget.Button;
    
    public class FileMainActivity extends Activity {
    	private Button bt_createFile;
    	private Button bt_readFile;
    	private Button bt_readRawFile;
    	private Button bt_readXMLFile;
    	private Button bt_createXMLFile;
    	
    	public void onCreate(Bundle savedInstanceState){
    		super.onCreate(savedInstanceState);
    		setContentView(R.layout.ch9_fliemain);
    		
    		bt_createFile = (Button)findViewById(R.id.bt_createFile);
    		bt_readFile = (Button)findViewById(R.id.bt_readFile);
    		bt_readRawFile = (Button)findViewById(R.id.bt_readRawFile);
    		bt_readXMLFile = (Button)findViewById(R.id.bt_readXMLFile);
    		bt_createXMLFile = (Button)findViewById(R.id.bt_createXMLFile);
    		
    		bt_createFile.setOnClickListener(new btClickListener());
    		bt_readFile.setOnClickListener(new btClickListener());
    		bt_readRawFile.setOnClickListener(new btClickListener());
    		bt_readXMLFile.setOnClickListener(new btClickListener());
    		bt_createXMLFile.setOnClickListener(new btClickListener());
    		
    	}
    	
    	class btClickListener implements View.OnClickListener{
    		
    		Intent intent = new Intent();
    
    		@Override
    		public void onClick(View v) {
    			
    			switch(v.getId()){
    			case R.id.bt_createFile:
    				intent.setClass(FileMainActivity.this, CreateFileActivity.class);
    				startActivity(intent);
    				break;
    			case R.id.bt_readFile:
    				intent.setClass(FileMainActivity.this, ReadFileActivity.class);
    				startActivity(intent);
    				break;
    			case R.id.bt_readRawFile:
    				intent.setClass(FileMainActivity.this, ReadRawFileActivity.class);
    				startActivity(intent);
    				break;
    			case R.id.bt_readXMLFile:
    				intent.setClass(FileMainActivity.this, ReadXmlFileActivity.class);
    				startActivity(intent);
    				break;
    			case R.id.bt_createXMLFile:
    				intent.setClass(FileMainActivity.this, CreateXmlFileActivity.class);
    				startActivity(intent);
    				break;
    			}
    		}
    		
    	}
    	
    }

创建ch9\_createfile.xml:

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical" >
        <LinearLayout android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal">
            <TextView android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="用户名:"/>
            <EditText android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:id="@+id/edt_username"/>
            
            
        </LinearLayout>
        <LinearLayout android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal">
            <TextView android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="密码:"/>
            <EditText android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:id="@+id/edt_userpwd"/>
            
        </LinearLayout>
        <Button android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:id="@+id/bt_save"
                android:text="保存"/>
    
    </LinearLayout>

创建CreateFileActivity.java:

package com.example.ch9;
    
    import java.io.FileOutputStream;
    import java.io.IOException;
    
    import com.example.baseexample.R;
    
    import android.app.Activity;
    import android.content.Context;
    import android.os.Bundle;
    import android.view.View;
    import android.widget.Button;
    import android.widget.EditText;
    import android.widget.Toast;
    
    public class CreateFileActivity extends Activity {
    	private EditText edt_file;
    	private EditText edt_filename;
    	private Button bt_saveFile;
    	
    	protected void onCreate(Bundle savedInstanceState){
    		super.onCreate(savedInstanceState);
    		setContentView(R.layout.ch9_createfile);
    		edt_file = (EditText)findViewById(R.id.edt_file);
    		edt_filename =(EditText)findViewById(R.id.edt_filename);
    		bt_saveFile =(Button)findViewById(R.id.bt_saveFile);
    		
    		
    		bt_saveFile.setOnClickListener(new Button.OnClickListener(){
    			public void onClick(View v){
    				FileOutputStream fos = null;
    				String filename = edt_filename.getText().toString();
    				try{
    					fos = openFileOutput(filename,Context.MODE_PRIVATE);
    					fos.write(edt_file.getText().toString().getBytes());
    				}catch(Exception e){
    					Toast.makeText(CreateFileActivity.this, "文件保存失败", Toast.LENGTH_LONG).show();
    				}finally{
    					if(fos!=null){
    						try{
    							fos.flush();
    							fos.close();
    						}catch(IOException e){
    							e.printStackTrace();
    						}
    					}
    				}
    			}
    		});
    	}
    }

创建ch9\_readfile.xml:

创建ReadFileActivity.java:

package com.example.ch9;
    
    import java.io.FileInputStream;
    import java.io.IOException;
    
    import com.example.baseexample.R;
    
    import android.app.Activity;
    import android.os.Bundle;
    import android.view.View;
    import android.widget.Button;
    import android.widget.EditText;
    import android.widget.TextView;
    import android.widget.Toast;
    
    public class ReadFileActivity extends Activity {
    	private EditText edt_fname;
    	private TextView tv_fileContent;
    	private Button bt_readoutfile;
    	protected void onCreate(Bundle savedInstanceState){
    		super.onCreate(savedInstanceState);
    		setContentView(R.layout.ch9_readfile);
    		
    		edt_fname = (EditText)findViewById(R.id.edt_fname);
    		tv_fileContent = (TextView)findViewById(R.id.tv_filecontent);
    		bt_readoutfile = (Button)findViewById(R.id.bt_readOutFile);
    		
    		bt_readoutfile.setOnClickListener(new Button.OnClickListener(){
    			public void onClick(View v){
    				FileInputStream fis = null;
    				String filename = edt_fname.getText().toString();
    				try{
    					fis = openFileInput(filename);
    					byte[] reader = new byte[fis.available()];
    					while(fis.read(reader)!=-1){}
    					tv_fileContent.setText(new String(reader));
    				}catch(Exception e){
    					Toast.makeText(ReadFileActivity.this, "文件读取失败", Toast.LENGTH_LONG).show();
    				}finally{
    					if(fis!=null){
    						try{
    							fis.close();
    						}catch(IOException e){
    							e.printStackTrace();
    						}
    					}
    				}
    			}
    		});
    	}
    }

创建ch9\_readrawfile.xml：

创建ReadRawFileActivity.java:

package com.example.ch9;
    
    import java.io.IOException;
    import java.io.InputStream;
    
    import com.example.baseexample.R;
    
    import android.app.Activity;
    import android.content.res.Resources;
    import android.os.Bundle;
    import android.widget.TextView;
    import android.widget.Toast;
    
    public class ReadRawFileActivity extends Activity {
    	private TextView tv_filerawContent;
    	protected void onCreate(Bundle savedInstanceState){
    		super.onCreate(savedInstanceState);
    		setContentView(R.layout.ch9_readrawfile);
    		
    		tv_filerawContent = (TextView)findViewById(R.id.tv_rawfilecontent);
    		
    		Resources rs = this.getResources();
    		InputStream is = null;
    		try{
    			is = rs.openRawResource(R.raw.wang);
    			byte[] reader = new byte[is.available()];
    			while(is.read(reader)!=-1){}
    			tv_filerawContent.setText(new String(reader));
    		}catch(Exception e){
    			Toast.makeText(ReadRawFileActivity.this, "文件读取失败", Toast.LENGTH_LONG).show();
    		}finally{
    			if(is!=null){
    				try{
    					is.close();
    				}catch(IOException e){
    					e.printStackTrace();
    				}
    			}
    		}
    	}
    }

创建ch9\_readxmlfile.xml:

在res/xml/目录 下创建book.xml:

<?xml version="1.0" encoding="UTF-8"?>
    <BookList>
        <Book Category="Android类">
            <bookitem name="Google Android揭秘" author="W.Franl Ableson"/>
            <bookitem name="Android 应用开发揭秘" author="杨丰盛"/>
            <bookitem name="精通Android3" author="Satya Komatineni"/>
        </Book>
        <Book Category="程序设计类">
            <bookitem name="java 编程思想" author="埃史尔"/>
            <bookitem name="java语言程序设计" author="Y.Danial Liang"/>
            <bookitem name="java 核心技术(卷1)" author="Horstmann Gay S"/>
        </Book>
        
    </BookList>

创建ReadXmlFileActivity.java:

package com.example.ch9;
    
    import org.xmlpull.v1.XmlPullParser;
    
    import com.example.baseexample.R;
    
    import android.app.Activity;
    import android.os.Bundle;
    import android.widget.TextView;
    import android.widget.Toast;
    
    public class ReadXmlFileActivity extends Activity {
    
    	private TextView tv_xmlfilecontent;
    	protected void onCreate(Bundle savedInstanceState){
    		super.onCreate(savedInstanceState);
    		setContentView(R.layout.ch9_readxmlfile);
    		
    		tv_xmlfilecontent = (TextView)findViewById(R.id.tv_xmlfilecontent);
    		XmlPullParser xp = this.getResources().getXml(R.xml.book);
    		String content="";
    		try{
    			while(xp.next()!=XmlPullParser.END_DOCUMENT){
    				String nodeName = xp.getName();
    				String bookCategory = null;
    				String bookName = null;
    				String bookAuthor= null;
    				if(nodeName!=null && nodeName.equals("Book")){
    					if(nodeName.equals("Book")&&xp.getAttributeCount()!=-1){
    						bookCategory = xp.getAttributeValue(0);
    					}
    					if(bookCategory!=null){
    						content+="图书类别:"+bookCategory+"\n";
    					}
    				}
    				if(nodeName!=null && nodeName.equals("bookitem")){
    					for(int i=0;i<xp.getAttributeCount();i++){
    						String attrName = xp.getAttributeName(i);
    						String attrValue = xp.getAttributeValue(i);
    						if(attrName.equals("name")){
    							bookName = attrValue;
    						}
    						if(attrName.equals("author")){
    							bookAuthor = attrValue;
    						}
    					}
    					
    				}
    				if(bookName!=null && bookAuthor!=null){
    					content+="书名："+bookName+",作者："+bookAuthor+"\n";
    				}
    			}
    			this.tv_xmlfilecontent.setText(content);
    		}catch(Exception e){
    			Toast.makeText(ReadXmlFileActivity.this, "文件读取失败", Toast.LENGTH_LONG).show();
    		}
    	}
    }

创建ch9\_createxmlfile.xml：

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical" >
        <LinearLayout android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal">
            <TextView android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="用户名:"/>
            <EditText android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:id="@+id/edt_username"/>
            
            
        </LinearLayout>
        <LinearLayout android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal">
            <TextView android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="密码:"/>
            <EditText android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:id="@+id/edt_userpwd"/>
            
        </LinearLayout>
        <Button android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:id="@+id/bt_save"
                android:text="保存"/>
    
    </LinearLayout>

创建CreateXmlFileActivity.java：

package com.example.ch9;
    
    import java.io.OutputStream;
    import java.io.OutputStreamWriter;
    import java.io.StringWriter;
    
    import org.xmlpull.v1.XmlSerializer;
    
    import com.example.baseexample.R;
    
    import android.app.Activity;
    import android.os.Bundle;
    import android.util.Xml;
    import android.view.View;
    import android.widget.Button;
    import android.widget.EditText;
    import android.widget.Toast;
    
    public class CreateXmlFileActivity extends Activity {
    
    	private EditText edt_username;
    	private EditText edt_userpwd;
    	private Button bt_save;
    	
    	protected void onCreate(Bundle savedInstanceState){
    		super.onCreate(savedInstanceState);
    		setContentView(R.layout.ch9_createxmlfile);
    		
    		edt_username = (EditText)findViewById(R.id.edt_username);
    		edt_userpwd = (EditText)findViewById(R.id.edt_userpwd);
    		bt_save = (Button)findViewById(R.id.bt_save);
    		
    		bt_save.setOnClickListener(new Button.OnClickListener(){
    			public void onClick(View v){
    				String username = edt_username.getText().toString();
    				String userpwd = edt_userpwd.getText().toString();
    				XmlSerializer serialer = Xml.newSerializer();
    				StringWriter writer = new StringWriter();
    				try{
    					serialer.setOutput(writer);
    					serialer.startDocument("utf-8", true);
    					serialer.startTag("", "UserList");
    					serialer.startTag("", "user");
    					serialer.attribute("", "username", username);
    					serialer.attribute("", "userpwd", userpwd);
    					serialer.endTag("", "user");
    					serialer.endTag("", "UserList");
    					serialer.endDocument();
    					OutputStream os = openFileOutput("user.xml",MODE_PRIVATE);
    					OutputStreamWriter oswriter = new OutputStreamWriter(os,"GB2312");
    					oswriter.write(writer.toString());
    					oswriter.close();
    					os.close();
    				}catch(Exception e){
    					Toast.makeText(CreateXmlFileActivity.this, "用户信息保存不成功", Toast.LENGTH_LONG).show();
    				}
    			}
    		});
    	}
    }

转载于:https://my.oschina.net/u/2552902/blog/543872

[2019_Python_]: https://my.oschina.net/u/2663968/blog/3061697
[hot3.png]: /images/20220113/93b5e7c5241c412e9f811e8752ba8cb2.png