android 多线程

功能：下载网络图片，保存到本地

下载图片，显示图片

Handler Message 消息测试

参考：

API
http://www.cnblogs.com/shirley-1019/p/3557800.html
书籍：android 开发范例实践宝典

1. A Handler allows you to send and process

Message

and Runnable objects associated with a thread's

MessageQueue.

package com.test.network;

import android.graphics.Bitmap;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

private EditText eUrlPath;

private ImageView imageView;

private Button btnNullMsg;

private Button btndelayMessage;

private Button btnRunnableMsg;

private EditText editText;

private Handler mHandler = new Handler() {
@Override
public void handleMessage(Message msg) {

if (msg.what == 1) {
imageView.setImageBitmap((Bitmap) msg.obj);
} else if (msg.what == 2) {
Toast.makeText(MainActivity.this, "下载成功", Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(MainActivity.this, (String) msg.obj, Toast.LENGTH_SHORT).show();
}
}
};

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
eUrlPath = (EditText) findViewById(R.id.eUrlPath);

imageView = (ImageView) findViewById(R.id.imageView);

btnNullMsg = (Button) findViewById(R.id.sendNullMessage);

btndelayMessage = (Button) findViewById(R.id.btndelayMessage);

btnRunnableMsg = (Button) findViewById(R.id.btnRunnableMsg);

editText = (EditText) findViewById(R.id.editText);

btnRunnableMsg.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
new Thread(new Runnable() {
@Override
public void run() {
mHandler.post(new Runnable() {
@Override
public void run() {
editText.setText("RunnaleMessage");
Toast.makeText(MainActivity.this, "RunnalbeMessage", Toast.LENGTH_SHORT);
}
});
}
}).start();
}
});
btndelayMessage.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
new Thread(new Runnable() {
@Override
public void run() {

Message msg = Message.obtain();
msg.obj = "sendMessageDelayed";
mHandler.sendMessageDelayed(msg, 3000);
}
}).start();
}
});
btnNullMsg.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
new Thread(new Runnable() {
@Override
public void run() {
Message msg = Message.obtain(mHandler);
msg.what = 3;
msg.obj = "sendToTarget";
msg.sendToTarget();
}
}).start();
}
});
}

public void btnGetHttp(View view) {
new Thread(new DownLoadImageThread()).start();

}

public void showImage(View view) {
new Thread(new DownLoadImageBitMapThread()).start();
}

class DownLoadImageBitMapThread implements Runnable {

@Override
public void run() {
//定义一个Message对象
//Message msg = Message.obtain();
Message message = mHandler.obtainMessage();
HttpDownloader httpDownloader = new HttpDownloader();
//String urlPath =eUrlPath.getText().toString();
String urlPath = "http://img4.imgtn.bdimg.com/it/u=3340865222,3464212128&fm=21&gp=0.jpg";
Bitmap bitmap = httpDownloader.getBitMapFromInput(urlPath);
message.what = 1;
message.obj = bitmap;

mHandler.sendMessage(message);

}
}

class DownLoadImageThread implements Runnable {

@Override
public void run() {
//定义一个Message对象
//Message msg = Message.obtain();
Message message = mHandler.obtainMessage();
HttpDownloader httpDownloader = new HttpDownloader();
//String urlPath =eUrlPath.getText().toString();
String urlPath = "http://img4.imgtn.bdimg.com/it/u=3340865222,3464212128&fm=21&gp=0.jpg";
httpDownloader.downFile(urlPath, FileUtils.PATH, "test.jpg");
message.what = 2;
message.obj = "success";

mHandler.sendMessage(message);

}
}

}

2. 使用 HttpDownloader 下载图片，处理流。

package com.test.network;

import android.os.Environment;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;

/**
* Created by 1 on 2016/4/12.
*/
public class FileUtils {

public static String PATH = Environment.getExternalStorageDirectory() + "/00DownLoad/";

public static boolean isFileExist(String fileName) {
File file = new File(fileName);
return file.exists();
}

public static void createDir(String path) {

File file = new File(path);
if (!file.exists()) {
file.mkdirs();
}

}

public static void createFile(String path, String fileName) {
File file = new File(path + fileName);
if (!file.exists()) {
try {
file.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}
}
}

public static void write2SDFromInput(InputStream inputStream, String path, String fileName) {

//创建目录
createDir(path);
//创建文件
createFile(path, fileName);

File file = new File(path + fileName);
OutputStream outputStream = null;
try {
outputStream = new FileOutputStream(file);
byte[] buffer = new byte[4 * 1024];
while ((inputStream.read(buffer)) != -1) {
outputStream.write(buffer);
}
outputStream.flush();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (outputStream != null) {
outputStream.close();
}
} catch (Exception e) {

}
}

}
}

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