Android 文件的保存和读取

Android 给我们提供了两个方法返回输入、输出流,分别为：openFileInput(String fileName)
、openFileOutput(String fileName,int mode);
下面看一自己写了一个简单的例子:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >
    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/hello" />

    <EditText 
        	android:id="@+id/fileName"
        	android:layout_width="match_parent"
        	android:layout_height="wrap_content"
        	android:hint="请输入文件名称"
        >
       <requestFocus />
    </EditText>

    <EditText
        android:id="@+id/fileContent"
        android:layout_width="match_parent"
        android:layout_height="200dp"
        />
    
    <LinearLayout 
        	 android:orientation="horizontal"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
        >
        <Button 
             android:id="@+id/saveData"
             android:text="保存"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
            />
        <Button 
             android:id="@+id/readData"
             android:text="读取"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
            />
    </LinearLayout>
</LinearLayout>

public class FileActivity extends Activity {

    EditText fileName;
    EditText fileContent;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        fileName = (EditText)findViewById(R.id.fileName);
        fileContent = (EditText)findViewById(R.id.fileContent);
        
        Button saveData = (Button)findViewById(R.id.saveData);
        saveData.setOnClickListener(new OnClickListener() {
			@Override
			public void onClick(View v) {
				OutputStream output;
				try {
			      output =
                               FileActivity.this.openFileOutput(fileName.getText().toString(),   
                                                                            Context.MODE_APPEND);
				FileService.save(output, fileContent.getText().toString());
				Toast.makeText(getApplicationContext(), "保存成功", 
                                                       Toast.LENGTH_LONG).show();
				} catch (FileNotFoundException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		});
        
        Button readData  = (Button)findViewById(R.id.readData);
        readData.setOnClickListener(new OnClickListener() {
			@Override
			public void onClick(View v) {
				try {
			InputStream intput = 
                              FileActivity.this.openFileInput(fileName.getText().toString());
			      String content = FileService.read(intput);
			Toast.makeText(getApplicationContext(), content, 
                                                     Toast.LENGTH_LONG).show();
				} catch (FileNotFoundException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		});
    }
}

FileService.java

public class FileService {

	/**
	 * 保存文件
	 * @param output
	 * @param content
	 * @throws IOException
	 */
	public static void save(OutputStream output,String content) throws 
IOException{
		output.write(content.getBytes());
		output.close();
	}
	
	/**
	 * 读取文件
	 * @param input
	 * @throws IOException 
	 */
	public static String read(InputStream intput) throws IOException{
		ByteArrayOutputStream output = new ByteArrayOutputStream();
		byte[] bt = new byte[1024];
		int length = intput.read(bt);
		while(length != -1){
			output.write(bt, 0, bt.length);
			length = intput.read(bt);
		}
		byte[] data = output.toByteArray();
		intput.close();
		output.close();
		return new String(data);
	}
}