3.3 文件I/O

错误的解决方法请参考:http://liangruijun.blog.51cto.com/3061169/673776

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3.3.2 访问手机中的存储文件夹

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3.3.3 读取assets中的文件

package com.example.sample3_5;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;

import android.os.Bundle;
import android.app.Activity;
import android.content.res.AssetManager;
import android.content.res.Resources;
//import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MyActivity extends Activity {
    private Button but;             //打开按钮
    private EditText etContent;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        but = (Button) findViewById(R.id.Button01);
        but.setOnClickListener(new View.OnClickListener() {

            //private EditText etContent;
            //private String contentResult;

            @Override
            public void onClick(View v) {
                etContent = (EditText) findViewById(R.id.EditText01);
                loadFromAssert("AndroidSummary.txt");
            }
        });
    }
/*
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }*/
    //public String loadFromAssert(String fileName){
    public void loadFromAssert(String fileName){
        //String content = null;                                   //结果字符串
        //final String content = null;                                   //结果字符串
        try {

            //InputStream is = this.getResources().getAssets().open(fileName);
            Resources resources = this.getResources();
            AssetManager assets = resources.getAssets();
            InputStream is = assets.open(fileName);
            int ch = 0;
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            byte[] buff = null;
            while((ch=is.read())!=-1){
                baos.write(ch);
            }
            buff = baos.toByteArray();
            baos.close();
            is.close();
            //content = new String(buff,"UTF-8");
            final String content = new  String(buff,"UTF-8");                                   //结果字符串
            runOnUiThread(new Runnable(){

                @Override
                public void run() {
                    // TODO Auto-generated method stub
                    etContent.setText(content);
                }

            });
        } catch (IOException e) {
            // TODO Auto-generated catch block
            Toast.makeText(this, "对不起,没有找到指定文件!!!", Toast.LENGTH_SHORT).show();
            e.printStackTrace();

        }

        //return content;

    }

}

package com.example.sample3_5;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;

import android.os.Bundle;
import android.app.Activity;
import android.content.res.AssetManager;
import android.content.res.Resources;
//import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MyActivity extends Activity {
    private Button but;             //打开按钮
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        but = (Button) findViewById(R.id.Button01);
        but.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                EditText etContent = (EditText) findViewById(R.id.EditText01);
                String contentResult = loadFromAssert("AndroidSummary.txt");
                etContent.setText(contentResult);
            }
        });
    }
/*
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }*/
    public String loadFromAssert(String fileName){
        String content = null;                                   //结果字符串
        try {

            InputStream is = this.getResources().getAssets().open(fileName);
            int ch = 0;
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            byte[] buff = null;
            while((ch=is.read())!=-1){
                baos.write(ch);
            }
            buff = baos.toByteArray();
            baos.close();
            is.close();
            content = new String(buff,"UTF-8");
        } catch (IOException e) {
            // TODO Auto-generated catch block
            Toast.makeText(this, "对不起,没有找到指定文件!!!", Toast.LENGTH_SHORT).show();
            e.printStackTrace();

        }
        return content;
    }

}

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.sample3_5"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="17" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/icon"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.sample3_5.MyActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

<?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" >
    <Button
        android:text="打开"
        android:id="@+id/Button01"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        >
        </Button>                              <!-- 添加Button按钮 -->
       <ScrollView
           android:id="@+id/ScrollView01"
           android:layout_height="wrap_content"
           android:layout_width="fill_parent">
           <EditText
             android:editable="false"
               android:id="@+id/EditText01"
               android:layout_width="fill_parent"
               android:layout_height="wrap_content"
               >
               </EditText>                         <!-- 添加EditText -->
           </ScrollView>                           <!-- 添加ScrollView -->

</LinearLayout>