狂刷Android范例之一：ReadAsset

说明

狂刷Android范例系列文章开张了。每篇学习一个Android范例，将一个范例单独生成一个可运行的app，并对重点源代码进行简要分析。然后提供打包好的源代码下载。

功能

功能很简单，读取app自带的资源，例如一个文本。
代码包在此，无需下载分：
http://download.csdn.net/detail/logicteamleader/8780131

来源

ReadAsset例子来自于Android-20的com.example.android.apis.content.ReadAsset。

环境

代码运行环境：
1.ADT2014版本；
2.android:minSdkVersion=”8”；android:targetSdkVersion=”20”
3.workspace中已经生成了appcompatv7，它的版本是android-22；

代码

/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * 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.
 */

package com.dumaisoft.readasset;

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

import android.app.Activity;
import android.content.res.AssetManager;
import android.os.Bundle;
import android.widget.TextView;


/**
 * Demonstration of styled text resources.
 */
public class ReadAsset extends Activity
{
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);

        // See assets/res/any/layout/styled_text.xml for this
        // view layout definition.
        setContentView(R.layout.read_asset);

        // Programmatically load text from an asset and place it into the
        // text view.  Note that the text we are loading is ASCII, so we
        // need to convert it to UTF-16.
        try {
            AssetManager assetManager = this.getAssets();
            InputStream is = assetManager.open("read_asset.txt");

            // We guarantee that the available method returns the total
            // size of the asset...  of course, this does mean that a single
            // asset can‘t be more than 2 gigs.
            int size = is.available();

            // Read the entire asset into a local byte buffer.
            byte[] buffer = new byte[size];
            is.read(buffer);
            is.close();

            // Convert the buffer into a string.
            String text = new String(buffer);

            // Finally stick the string into the text view.
            TextView tv = (TextView)findViewById(R.id.text);
            tv.setText(text);
        } catch (IOException e) {
            // Should never happen!
            throw new RuntimeException(e);
        }
    }
}