Android 原始資源

Android允許除了任意XML文件之外的原始文件。這些資源放在 /res/raw 文件夾中。

原始文件可能是音頻，視頻或文本文件，需要通過資源ID進行本地化或引用。

這些文件不會編譯，而是按原樣移動到應(yīng)用程序包。

每個文件都有一個在R.java中生成的標識符。

例子

如果你要在 /res/raw/test.txt 中放置一個文本文件，你將能夠使用以下代碼讀取該文件。

String getStringFromRawFile(Activity activity)
throws IOException{
   Resources r = activity.getResources();
   InputStream is = r.openRawResource(R.raw.test);
   String myText = workOnInputStream(is);
   is.close();
   return myText;
}

具有重復(fù)基本名稱的文件名會生成構(gòu)建錯誤。

加載和解析原始xml文件

下面的代碼顯示了如何加載和解析原始xml文件。

布局文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="fill_parent" 
  android:layout_height="fill_parent" >
  <TextView
    android:id="@+id/selection"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
  />
  <ListView
    android:id="@android:id/list"
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent"
    android:drawSelectorOnTop="false"
  />
</LinearLayout>

res/raw/words.xml

<words>
  <word value="lorem" />
  <word value="ipsum" />
  <word value="dolor" />
  <word value="sit" />
  <word value="amet" />
  <word value="consectetuer" />
  <word value="adipiscing" />
  <word value="elit" />
  <word value="morbi" />
  <word value="vel" />
  <word value="ligula" />
  <word value="vitae" />
  <word value="arcu" />
  <word value="aliquet" />
  <word value="mollis" />
  <word value="etiam" />
  <word value="vel" />
  <word value="erat" />
  <word value="placerat" />
  <word value="ante" />
  <word value="porttitor" />
  <word value="sodales" />
  <word value="pellentesque" />
  <word value="augue" />
  <word value="purus" />
</words>

Java代碼

import android.app.Activity;
import android.os.Bundle;
import android.app.ListActivity;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import java.io.InputStream;
import java.util.ArrayList;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;
/*from  www.o2fo.com*/
public class MainActivity extends ListActivity {
  TextView selection;
  ArrayList<String> items=new ArrayList<String>();
  
  @Override
  public void onCreate(Bundle icicle) {
    super.onCreate(icicle);
    setContentView(R.layout.main);
    selection=(TextView)findViewById(R.id.selection);
    
    try {
      InputStream in=getResources().openRawResource(R.raw.words);
      DocumentBuilder builder=DocumentBuilderFactory
                                .newInstance()
                                .newDocumentBuilder();
      Document doc=builder.parse(in, null);
      NodeList words=doc.getElementsByTagName("word");
      
      for (int i=0;i<words.getLength();i++) {
        items.add(((Element)words.item(i)).getAttribute("value"));
      }
      
      in.close();
    }
    catch (Throwable t) {
      Toast
        .makeText(this, "Exception: "+t.toString(), 2000)
        .show();
    }
    
    setListAdapter(new ArrayAdapter<String>(this,
                                  android.R.layout.simple_list_item_1,
                                  items));
  }
  
  public void onListItemClick(ListView parent, View v, int position,
                  long id) {
    selection.setText(items.get(position).toString());
  }
}
/***
  Copyright (c) 2008-2009 CommonsWare, LLC
  
  Licensed under the Apache License, Version 2.0 (the "License"); you may
  not use this file except in compliance with the License. You may obtain
  a copy of the License at
    http://www.apache.org/licenses/LICENSE-2.0
  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
*/

靜態(tài)資源

這里是使用靜態(tài)資源的三個步驟:

• 將文件放入你的包的res/raw文件夾
• 使用Activity類中的getResources()方法返回一個Resources對象
• 使用其openRawResource()方法打開res/raw文件夾中包含的文件

package cn.w3cschool.myapplication3.app;
//from  www.o2fo.com
import android.app.Activity;
import android.os.Bundle;
import android.widget.EditText;
import android.widget.Toast;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

public class MainActivity extends Activity {
    EditText textBox;
    static final int READ_BLOCK_SIZE = 100;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        textBox = (EditText) findViewById(R.id.txtText1);

        InputStream is = this.getResources().openRawResource(R.raw.textfile);
        BufferedReader br = new BufferedReader(new InputStreamReader(is));
        String str = null;
        try {
            while ((str = br.readLine()) != null) {
                Toast.makeText(getBaseContext(),
                        str, Toast.LENGTH_SHORT).show();
            }
            is.close();
            br.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

存儲在 res/raw 文件夾中資源的ID以其沒有擴展名的文件名命名。例如，如果文本文件是textfile.txt，則其資源ID為R.raw.textfile。