Android进阶之动态加载图片(runOnUiThread/handler)

1、权限

<!-- 访问服务器权限 -->
<uses-permission android:name="android.permission.INTERNET" />

2、activity_image_view.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.guan.http.activity.ImageViewActivity" >

<ImageView
android:id="@+id/iv_image"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/handler"
android:contentDescription="@string/abc_action_bar_home_description"/>

</RelativeLayout>

3、UserService.java

package com.guan.http.service;

import java.io.InputStream;
import java.util.List;
import java.util.Map;
import android.graphics.Bitmap;
import com.guan.http.model.Student;

public interface UserService {

public Bitmap getImage() throws Exception;
}

4、UserServiceImpl.java

package com.guan.http.service;

public class UserServiceImpl implements UserService {

/**
* 获取图片业务
*/
@Override
public Bitmap getImage() throws Exception {
Bitmap bitmap = null;
InputStream in = null;
URL url = null;
HttpURLConnection urlConnection = null;
OutputStream out = null;
byte[] data = null;

try {
/**
* Post方法
*/
Map<String, String> params = new HashMap<String, String>();
params.put("id", "1");
// 封装参数
data = setPostPassParams(params).toString().getBytes();

url = new URL(Constant.uri + "GetImageServlet");
// 打开连接
urlConnection = (HttpURLConnection) url.openConnection();
// 设置连接超时时间
urlConnection.setConnectTimeout(3000);
// 设置响应超时时间
urlConnection.setReadTimeout(3000);
// 设置可以读取数据
urlConnection.setDoInput(true);
// 设置可以写数据
urlConnection.setDoOutput(true);
// 设置请求方法时POST请求
urlConnection.setRequestMethod("POST");
// 设置缓冲
urlConnection.setUseCaches(false);

/**
* HTTP协议
*/
// urlConnection.setRequestProperty("Content-Type", newValue);
// urlConnection.setRequestProperty("Content-Length", newValue);

// 连接
urlConnection.connect();
// 输出流、客户端向服务器发送数据
out = urlConnection.getOutputStream();
// 向服务器写数据的关键代码
out.write(data);
// 刷新
out.flush();

// 响应状态
int response = urlConnection.getResponseCode();
if (response != HttpURLConnection.HTTP_OK) {
throw new ServiceRulesException("请求服务器出错");
}
// 服务器传给客户端
in = new BufferedInputStream(urlConnection.getInputStream());
if (in != null) {
// 转化类型 InputStream --> Bitmap 操作图片流的工厂方法
// 其他的转化： InputStream Bitmap Drawable byte[]
bitmap = BitmapFactory.decodeStream(in);
}

/**
* Get方法
*/
// url = new URL(Constant.uri + "GetImageServlet?id=1");
// // 打开连接
// urlConnection = (HttpURLConnection) url.openConnection();
// // 设置可以读取
// urlConnection.setDoInput(true);
// // 设置请求类型
// urlConnection.setRequestMethod("GET");
// // 连接
// urlConnection.connect();
// // 响应状态
// int response = urlConnection.getResponseCode();
// if (response != HttpStatus.SC_OK) {
// throw new ServiceRulesException("请求服务器出错");
// }
//
// in = urlConnection.getInputStream();
// if(in != null) {
// // 转化类型 InputStream --> Bitmap 操作图片流的工厂方法
// // 其他的转化： InputStream Bitmap Drawable byte[]
// bitmap = BitmapFactory.decodeStream(in);
// }
} finally {
if (in != null) {
in.close();
}
if (urlConnection != null) {
urlConnection.disconnect();
}
}

return bitmap;
}

// 静态方法，重复使用
/**
* @description 构造Post参数传递
* @param params
* @return
* @throws UnsupportedEncodingException
*/
private static StringBuffer setPostPassParams(Map<String, String> params)
throws UnsupportedEncodingException {

StringBuffer stringBuffer = new StringBuffer();

for (Map.Entry<String, String> entry : params.entrySet()) {
stringBuffer.append(entry.getKey()).append("=")
.append(URLEncoder.encode(entry.getValue(), "UTF-8"))
.append("&");
}

// 把最后&去掉
stringBuffer.deleteCharAt(stringBuffer.length() - 1);

return stringBuffer;
}
}

5、ImageViewActivity.java

package com.guan.http.activity;

import android.graphics.Bitmap;
import android.os.Bundle;
import android.widget.ImageView;

import com.guan.http.R;
import com.guan.http.exception.ServiceRulesException;
import com.guan.http.service.UserService;
import com.guan.http.service.UserServiceImpl;

public class ImageViewActivity extends BaseActivity {

private ImageView mImage;
private UserService userService;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_image_view);

/**
* 初始化变量
*/
initVariable();
/**
* 线程
*/
thread();
}

/**
* 初始化变量
*/
private void initVariable() {
mImage = (ImageView) findViewById(R.id.iv_image);
userService = new UserServiceImpl();
}

/**
* 线程
*/
private void thread() {
new Thread(new Runnable() {

@Override
public void run() {
try {
// 获取图片bitmap对象
final Bitmap bitmap = userService.getImage();

// runOnUiThread类似于Handler的方法
runOnUiThread(new Runnable() {

@Override
public void run() {
if (bitmap != null) {
mImage.setImageBitmap(bitmap);
} else {
// 代码指定控件加载图片两方法
mImage.setImageResource(R.drawable.ic_launcher);
mImage.setImageDrawable(getResources()
.getDrawable(R.drawable.ic_launcher));
}
}
});

} catch (final ServiceRulesException e) {
e.printStackTrace();

runOnUiThread(new Runnable() {
@Override
public void run() {
showMsg(e.getMessage());
}
});
} catch (Exception e) {
e.printStackTrace();

runOnUiThread(new Runnable() {
@Override
public void run() {
showMsg("获取服务器出错");
}
});
}
}
}).start();
}
}

6、BaseActivity.java

package com.guan.http.activity;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.provider.MediaStore.Images.Media;
import android.view.Window;
import android.widget.Toast;

/**
* @author Guan
* @file com.example.guan.activity
* @date 2015/8/14
* @Version 1.0
*/
public class BaseActivity extends Activity {

public final static int FIAL_LOAD_IMAGE = 1;
public final static int FLAG_STUDENT_SUCCCESS = 1;
public final static int FLAG_LOGIN_SUCCCESS = 1;
public final static int FLAG_REGISTER_SUCCCESS = 1;
public final static String MSG_LOGIN_ERROR = "登录出错";
public final static String MSG_LOGIN_SUCCESS = "登录成功";
public final static String MSG_LOGIN_FAILED = "登录名|登录密码错误";
public final static String MSG_SERVER_ERROR = "请求服务器错误";
public final static String MSG_REQUEST_TIMEOUT = "请求服务器超时";
public final static String MSG_REPONSE_TIMEOUT = "服务器响应超时";
public final static String MSG_STUDENT_ERROR = "加载数据出错";
public final static String MSG_REGISTER_ERROR = "注册出错";
public final static String MSG_REGISTER_SUCCESS = "注册成功";
public final static String MSG_REGISTER_FAILED = "注册名|注册密码错误";

/**
* 把与业务相关的系统框架、界面初始化、设置等操作封装
*
* @param savedInstanceState
*/
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
}

/**
* Toast公共方法
* @param pMsg
*/
public void showMsg(String pMsg) {
Toast.makeText(BaseActivity.this, pMsg, Toast.LENGTH_SHORT).show();
}

/**
* intent 跳转Activity公共方法
*/
public void openActivity(Class<?> pClass) {

Intent _intent = new Intent(this,pClass);
startActivity(_intent);
}

/**
* intent startActivityForResult 打开系统加载图片
*/
public void startActivityForResult() {
Intent intent = new Intent(Intent.ACTION_PICK, Media.EXTERNAL_CONTENT_URI);
startActivityForResult(intent,FIAL_LOAD_IMAGE);
}

/**
* dialog 对话框公共方法
*/
public void showAlterDialog() {

}

}

7、效果图