package com.itheima.netimageviewer;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import android.app.Activity;
import android.content.res.Resources.Theme;
import android.graphics.Bitmap;
import android.graphics.Bitmap.CompressFormat;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.widget.ImageView;
import android.widget.Toast;
public class MainActivity extends Activity {
protected static final int LOAD_IMAGE = 1;
protected static final int LOAD_ERROR = 2;
// 服务器所有图片的路径
private List<String> paths;
private ImageView iv;
/**
* 当前的位置
*/
private int currentPosition = 0;
//1.创建一个消息处理器
private Handler handler = new Handler(){
//3.处理消息
public void handleMessage(Message msg) {
switch (msg.what) {
case LOAD_IMAGE:
Bitmap bitmap = (Bitmap) msg.obj;
iv.setImageBitmap(bitmap);
break;
case LOAD_ERROR:
Toast.makeText(getApplicationContext(), (String)msg.obj, 0).show();
break;
}
};
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
iv = (ImageView) findViewById(R.id.iv);
// 1.连接服务器 获取所有的图片的目录信息
loadAllImagePath();
}
/**
* 开始加载图标,在从服务器获取完毕资源路径之后执行
*/
private void beginLoadImage() {
// TODO:把每个图片的路径获取出来, 通过路径加载图片.
try {
paths = new ArrayList<String>();
File file = new File(getCacheDir(), "info.txt");
FileInputStream fis = new FileInputStream(file);
BufferedReader br = new BufferedReader(new InputStreamReader(fis));
String line;
while ((line = br.readLine()) != null) {
paths.add(line);
}
fis.close();
// 2.加载图片资源
loadImageByPath(paths.get(currentPosition));
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
/**
* 通过路径获取图片资源
*
* @param path
* 图片的路径
* @return
*/
private void loadImageByPath(final String path) {
new Thread() {
public void run() {
try {
Thread.sleep(2000);
// 判断缓存是否存在,如果存在就那缓存图片,如果不存在才去获取服务器的资源
File file = new File(getCacheDir(), path.replace("/", "")
+ ".jpg");
if (file.exists() && file.length() > 0) {
System.out.println("通过缓存把图片资源获取出来....");
// 缓存存在
//iv.setImageBitmap( BitmapFactory.decodeFile(file.getAbsolutePath()));
//2.子线程想去更新ui,发送消息
Message msg = Message.obtain();
msg.what = LOAD_IMAGE;
msg.obj = BitmapFactory.decodeFile(file.getAbsolutePath());
handler.sendMessage(msg);
} else {
System.out.println("通过访问网络把图片资源获取出来....");
URL url = new URL(path);
HttpURLConnection conn = (HttpURLConnection) url
.openConnection();
conn.setRequestMethod("GET");
int code = conn.getResponseCode();
if (code == 200) {
InputStream is = conn.getInputStream();
// 内存中的图片
Bitmap bitmap = BitmapFactory.decodeStream(is);
// 如果图片被下载完毕了,应该把图片缓存起来.
// CompressFormat.JPEG 压缩的方式 png jpg
// 100 压缩比例 100 无损压缩
// stream 把图片写入到哪个缓存流里面
FileOutputStream stream = new FileOutputStream(file);
bitmap.compress(CompressFormat.JPEG, 100, stream);
stream.close();
is.close();
Message msg = Message.obtain();
msg.obj = bitmap;
msg.what = LOAD_IMAGE;
handler.sendMessage(msg);
//iv.setImageBitmap(bitmap);
} else {
//Toast.makeText(MainActivity.this, "获取失败", 0).show();
Message msg = Message.obtain();
msg.what = LOAD_ERROR;
msg.obj = "获取失败";
handler.sendMessage(msg);
}
}
} catch (Exception e) {
e.printStackTrace();
Toast.makeText(MainActivity.this, "获取失败", 0).show();
Message msg = Message.obtain();
msg.what = LOAD_ERROR;
msg.obj = "获取失败";
handler.sendMessage(msg);
}
};
}.start();
}
/**
* 获取全部图片资源的路径
*/
private void loadAllImagePath() {
new Thread() {
public void run() {
// 浏览器发送一个get请求就可以把服务器的数据获取出来.
// 用代码模拟一个http的get请求
try {
// 1.得到服务器资源的路径
URL url = new URL("http://192.168.1.109:8080/img/gaga.html");
// 2.通过这个路径打开浏览器的连接.
HttpURLConnection conn = (HttpURLConnection) url
.openConnection();// ftp
// http
// https
// rtsp
// 3.设置请求方式为get请求
conn.setRequestMethod("GET");// 注意get只能用大写 不支持小写
// 为了有一个更好的用户ui提醒,获取服务器的返回状态码
int code = conn.getResponseCode();// 200 ok 404资源没有找到 503
// 服务器内部错误
if (code == 200) {
// 4.获取服务器的返回的流
InputStream is = conn.getInputStream();
File file = new File(getCacheDir(), "info.txt");
FileOutputStream fos = new FileOutputStream(file);
byte[] buffer = new byte[1024];
int len = 0;
while ((len = is.read(buffer)) != -1) {
fos.write(buffer, 0, len);
}
is.close();
fos.close();
beginLoadImage();
} else if (code == 404) {
Message msg = Message.obtain();
msg.what = LOAD_ERROR;
msg.obj = "获取失败,资源没有找到";
handler.sendMessage(msg);
//Toast.makeText(MainActivity.this, "获取失败,资源没有找到", 0).show();
} else {
//Toast.makeText(MainActivity.this, "服务器异常", 0).show();
Message msg = Message.obtain();
msg.what = LOAD_ERROR;
msg.obj = "服务器异常";
handler.sendMessage(msg);
}
} catch (Exception e) {
e.printStackTrace();
//Toast.makeText(MainActivity.this, "获取失败", 0).show();
Message msg = Message.obtain();
msg.what = LOAD_ERROR;
msg.obj = "获取失败";
handler.sendMessage(msg);
}
};
}.start();
}
/**
* 上一张
*
* @param view
*/
public void pre(View view) {
currentPosition--;
if (currentPosition < 0) {
currentPosition = paths.size() - 1;
}
loadImageByPath(paths.get(currentPosition));
}
/**
* 下一张
*
* @param view
*/
public void next(View view) {
currentPosition++;
if (currentPosition == paths.size()) {
currentPosition = 0;
}
loadImageByPath(paths.get(currentPosition));
}
}
添加权限
<uses-permission android:name="android.permission.INTERNET"/>
时间： 2024-07-28 17:13:49